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Journal articles on the topic 'Intake flow process'
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1
Khalighi, Bahram. "Multidimensional In-Cylinder Flow Calculations and Flow Visualization in a Motored Engine." Journal of Fluids Engineering 117, no. 2 (June 1, 1995): 282–88. http://dx.doi.org/10.1115/1.2817142.
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Multidimensional simulations of coupled intake port/valve and in-cylinder flow structures in a pancake-shape combustion chamber engine are reported. The engine calculations include moving piston, moving intake valve, and valve stem. In order to verify the calculated results, qualitative flow visualization experiments were carried out for the same intake geometry during the induction process using a transient water analog. During the intake process the results of the multidimensional simulation agreed very well with the qualitative flow visualization experiments. An important finding in this study is the generation of a well-defined tumbling flow structure at BDC in the engine. In addition, this tumbling flow is sustained and amplified by the compression process and in turn causes generation of a high turbulence level before TDC. Many interesting features of the in-cylinder flow structures such as tumble, swirl, and global turbulent kinetic energy are discussed.
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Lanson, F., and J. L. Stollery. "Some hypersonic intake studies." Aeronautical Journal 110, no. 1105 (March 2006): 145–56. http://dx.doi.org/10.1017/s0001924000001123.
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Abstract A ‘two dimensional’ air intake comprising a wedge followed by an isentropic compression has been tested in the Cranfield Gun Tunnel at Mach 8·2. These tests were performed to investigate qualitatively the intake flow starting process. The effects of cowl position, Reynolds number, boundary-layer trip and introduction of a small restriction in the intake duct were investigated. Schlieren pictures of the flow on the compression surface and around the intake entrance were taken. Results showed that the intake would operate over the Reynolds number range tested. Tests with a laminar boundary layer demonstrated the principal influence of the Reynolds number on the boundary-layer growth and consequently on the flow structure in the intake entrance. In contrast boundary layer tripping produced little variation in flow pattern over the Reynolds number range tested. The cowl lip position appeared to have a strong effect on the intake performance. The only parameter which prevented the intake from starting was the introduction of a restriction in the intake duct. The experimental data obtained were in good qualitative agreement with the CFD predictions. Finally, these experimental results indicated a good intake flow starting process over multiple changes of parameters.
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Ashhab, M. S. S., A. G. Stefanopoulou, J. A. Cook, and M. B. Levin. "Control of Camless Intake Process—Part II1." Journal of Dynamic Systems, Measurement, and Control 122, no. 1 (July 14, 1998): 131–39. http://dx.doi.org/10.1115/1.482448.
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A model-based control scheme is designed to regulate the cylinder air charge of a camless multicylinder engine for unthrottled operation. The controller consists of a feedforward and an adaptive feedback scheme based on a control-oriented model of the breathing process of an engine equipped with electro-hydraulic springless valvetrain. The nonlinear control scheme is designed to achieve cylinder-to-cylinder balancing, fast cycle-to-cycle response, and minimization of pumping losses. The algorithm uses conventional sensor measurements of intake manifold pressure and mass air flow to the intake manifold, and intake valve duration measurement. Closed-loop simulation results are shown for a four-cylinder engine. [S0022-0434(00)03001-X]
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Fan, Yu, De Xin Liu, and Li Wang. "3D Numerical Simulation on the Variable Swirl Intake Process of Diesel Engine." Applied Mechanics and Materials 273 (January 2013): 143–47. http://dx.doi.org/10.4028/www.scientific.net/amm.273.143.
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To study the flow and swirl characteristics in the variable swirl intake system of a four-valve diesel engine, a numerical simulation with using the three dimensional CFD software AVL-FIRE, was calculated on the intake flow in three types of inlet of the engine. Two swirl-control valve plans are posed and a better plan was selected through the comparative study. The result shows that with a lager valve lift the flow characteristic of spiral inlet is better than that of tangential inlet, and in the opposite case the results are also opposite. The double inlets make the swirl torque increase. When a swirl-control valve is set in the spiral inlet, the variable swirl effect is better, and it ensures better flow capacity and larger swirl ratio range.
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Gaspar, Stefan, and Ján Pasko. "Metal Flow Velocity in an Intake Port in the Process of Die Casting." Advanced Materials Research 705 (June 2013): 177–80. http://dx.doi.org/10.4028/www.scientific.net/amr.705.177.
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The paper deals with metal flow velocity in an intake port in the process of die casting. In the theoretical part the author defines theoretical knowledge from the field of the mold cavity filling regime and the velocity of pressing the melt into the mold cavity. The practical part focuses on the impact of metal flow velocity in an intake port and the filling regime of the pressure foundry mold cavity, related to the former, on the homogeneity of the casting.
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Dong, Zhi Feng, Yin Song, Yong Zheng Gu, and Wei Fu. "Flow Field Numerical Simulation of Diesel Engine Working Process." Advanced Materials Research 468-471 (February 2012): 1781–84. http://dx.doi.org/10.4028/www.scientific.net/amr.468-471.1781.
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The spatial fluid model in diesel engine was built, and multiphase flow transient numerical simulation of working process of diesel engine was done based on computational fluid dynamics. The visualized result of simulation shows the distribution of flow field, press and particle trajectory which can hardly tested direct under the actual working condition. Swirl formed during the intake process and accompanied the whole working process of diesel engine. Keywords: Diesel engine; Numerical simulation; Flow field; Particle trajectory
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Khalighi, B. "Intake Swirl Process Generated by an Engine Head: a Flow Visualization Study." Journal of Engineering for Gas Turbines and Power 113, no. 3 (July 1, 1991): 433–39. http://dx.doi.org/10.1115/1.2906249.
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In-cylinder charge swirl is used in many internal combustion engines to promote combustion. The purpose of this work is to investigate the in-cylinder swirl characteristics generated by an engine head during the induction process by means of flow visualization and Particle Tracking Velocimetry (PTV). The study was carried out for an engine head with a shrouded intake valve in a special single-cylinder transient water analog. The results revealed that the in-cylinder swirl generated by the shroud is characterized by a strong single vortex with its center of rotation eccentric to the cylinder axis. The location of the center rotation differs from plane to plane along the cylinder axis. Furthermore, velocity data obtained for this study suggest that the in-cylinder swirl is not solid body rotation. Finally, the velocity fields were integrated and an equivalent swirl was calculated for the engine under transient conditions.
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Hussain, Ahmad, Mahrukh Mahrukh, and Iqbal Ahmed. "Review The Importance of Seawater Intake and its Treatment Techniques for RO Desalination Plant." Pakistan Journal of Scientific & Industrial Research Series A: Physical Sciences 62, no. 3 (November 28, 2019): 215–22. http://dx.doi.org/10.52763/pjsir.phys.sci.62.3.2019.215.222.
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Seawater intake and its treatments are one of the main upstream processes of every seawater desalination plant (RO, ED, MSF, MED). However, the process has turned out to be of utmost importance for reverse osmosis (RO) desalination plant. It is to be sure that sufficient and steady flow and quality of water is available to the RO desalination plant. Prior to RO feed water, the seawater intake pre-treatment process has to be tailored and the quality of seawater intake to be treated either subsurface intake or open surface intakes, particularly when treating open surface intakes seawater (OSIS) with exceedingly unpredictable quality. According to the well-established membrane manufacturer and supplier, the RO membrane warranty and guarantee are depended on seawater intake quality and its pre-treatment. Thus, the current state-of-the-art RO membranes life and performance success for desalination processing depend upon OSIS pre-treatment processing techniques. This article is emphasizing an overview on recent OSIS and its pre-treatment techniques for RO desalination plant.
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Michael, Sean S., Daniel Bickley, Kelly Bookman, Richard Zane, and Jennifer L. Wiler. "Emergency department front-end split-flow experience: ‘physician in intake’." BMJ Open Quality 8, no. 4 (November 2019): e000817. http://dx.doi.org/10.1136/bmjoq-2019-000817.
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BackgroundEmergency department (ED) crowding is a critical problem in the delivery of acute unscheduled care. Many causes are external to the ED, but antiquated operational traditions like triage also contribute. A physician intake model has been shown to be beneficial in a single-centre study, but whether this solution is generalisable is not clear. We aimed to characterise the current state of front-end intake models in a national sample of EDs and quantify their effects on throughput measures.MethodsWe performed a descriptive mixed-method analysis of ED process changes implemented by a cross section of self-selecting institutions who reported 2 years of demographic/operational data and structured process descriptions of any ‘new front-end processes to replace traditional nurse-based triage’.ResultsAmong 25 participating institutions, 19 (76%) provided data. While geographically diverse, most were urban, academic adult level 1 trauma centres. Thirteen (68%) reported implementing a new intake process. All were run by attending emergency physicians, and six (46%) also included advanced practice providers. Daily operating hours ranged from 8 to 16 (median 12, IQR 10.25–15.85), and the majority performed labs, imaging and medication administration and directly discharged patients. Considering each site’s before-and-after data as matched pairs, physician-driven intake was associated with mean decreases in arrival-to-provider time of 25 min (95% CI 13 to 37), ED length of stay 36 min (95% CI 12 to 59), and left before being seen rate 1.2% (95% CI 0.6% to 1.8%).ConclusionsIn this cross section of primarily academic EDs, implementing a physician-driven front-end intake process was feasible and associated with improvement in operational metrics.
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Шмырев, Владимир Федорович. "ОСОБЛИВОСТІ ПРОЕКТУВАННЯ НОСКА ПОВІТРОЗАБІРНИКА ТУРБОВЕНТИЛЯТОРНОГО ДВИГУНА." Open Information and Computer Integrated Technologies, no. 86 (February 14, 2020): 25–36. http://dx.doi.org/10.32620/oikit.2019.86.02.
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Optimization of turbofan engine air intake as well as geometry of intake lip, in-let cross-sectional area and its length is a relevant task in optimizing aerodynamic configuration of an aircraft. It is necessary to ensure a smooth entry of air flow into the engine at all modes of its operation and at various aircraft evolutions while minimizing impact on the overall aerodynamic efficiency of the aircraft. Development of engine air intake was once a very long, routine process that could last for months be-fore design completion, followed by expensive tests on determination of air intake performances on the engine test bench and in flight. Today, we can evaluate performances for a large number of air intake options using design software. The use of computational methods does not exclude tests of air intakes but dramatically reduces their quantity, testing costs and allows designers to focus mainly on the best candidates for air intakes avoiding potential surprises such as shock waves or flow separation caused by a shock wave. Optimal design of the air intake includes determining the right balance between the air intake characteristics, structural load and weight. An over-designed air intake will ultimately be overweight and thus more expensive in terms of flight cost. In a well-designed air intake the Mach number should not exceed 1, in order to avoid a sudden change in static pressure, temperature and density, which can lead to potential shock waves and flow separation caused by a shock wave in all areas throughout the flight. The use of computational fluid dynamics al-lows a better understanding of the conditions under which such adverse events occur. Adjacent to this task is the provision of necessary area on the inside of air intake to ensure sufficient noise absorption generated by the engine fan. The article considers evolution of research on the example of air intake of the D-436 engine of the An-148 aircraft.
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Zhang, Shi Qiang, Hui Gang Wang, Xiao Wen Liu, and Hai Sheng Liu. "Study on Packing Process of the Plastic Air Intake Manifold of Engines." Advanced Materials Research 482-484 (February 2012): 663–66. http://dx.doi.org/10.4028/www.scientific.net/amr.482-484.663.
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Packing pressure directly influences quality of the plastic part. It is an important stage of plastic injection molding. This paper introduces the packing process.CAE software Moldflow provided the possibility to simulate the flow process of the plastic air intake manifold at different pressure and to predict the position of air traps. Packing pressure is determined by comparing analysis results and avoided mold adjustment and mold repairing. Analytic result shows that packing pressure at 70MPa can make the maximum injection pressure, melt flow rate, the required maximum clamp force smaller. And at that time, The air traps situation is also better. Practice proves that it is perfect of the finished sample of the plastic air intake manifold on basis of simulation.
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Gazaryan, Alexander, and Oleg Glovatskii. "Flow calculations in intake structures of hydropower plants." E3S Web of Conferences 264 (2021): 03021. http://dx.doi.org/10.1051/e3sconf/202126403021.
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Research is carried out for design institutes in which the structures of pumping stations are designed. In the regional conditions of the Republic of Uzbekistan, when operating pumping stations, the problem of protecting equipment from pumps and fin is of particular importance, as well as the stability of water supply structures and the creation of favorable hydraulic conditions for supplying flow to the pumps. The main factors in the flow conditions are the calculations associated with suspended particles. The purpose of the research was to study the kinematics of the flow of intake structures in the problem of protecting equipment from pumps and fin. The research subject was to identify the regularities of the operation of intake structures depending on the structure of the flow supply. Experimental methods of hydraulic research of intake structures of pumping stations are used in the work. The analysis of the current state of water supply to the intake structures of pumping stations is carried out based on calculation schemes, which make it possible to establish the nature of the influence of flow parameters and soil particles on this process.
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Li, Hong Meng, Guo Xiu Li, Yuan Jing Hou, and Yu Song Yu. "Three-Dimensional Simulation of the Intake Port Combination Effect on Intake Flow Characteristic in a Highly Intensified Diesel Engine." Advanced Materials Research 744 (August 2013): 211–14. http://dx.doi.org/10.4028/www.scientific.net/amr.744.211.
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In this paper, the three-dimensional CFD method is used in numerical simulation of the highly intensified diesel engine intake process. The effect of different intake flow compound modes on the highly intensified diesel engine is studied (Including compounded port with helical and tangential intake port, compounded port with two helical intake ports and compounded port with two tangential intake ports). By contrasting the instantaneous flow field, flow characteristic and inlet ability of the three compound modes, the pattern of influence on the inlet flow characteristics by compound modes is analyzed. The results indicate that the combinations of the intake port greatly affect the swirl rate and the inlet ability. The interference of the two helical intake ports is serious, causing more inlet loss. The two helical intake ports have the weakest inlet ability among the three types of intake ports. However, two helical intake ports can cause higher swirl rate. Two tangential intake ports inlet ability is the most excellent, but its swirl rate is the lowest.
14
Qin, Zhang, Man Lai Zhang, and Zhi Hong Zhou. "Hydrodynamic Simulation for Intake Valve of Reciprocating Compressor." Applied Mechanics and Materials 318 (May 2013): 216–19. http://dx.doi.org/10.4028/www.scientific.net/amm.318.216.
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The aim of the present paper is to simulate the work process of intake valve in reciprocating compressor.To understand the flow, temperature characters and valve plate movement, the Computational Fluid Dynamics (CFD) is used to simulate the process of expansion and suction. In each time step, the fluid motion equation is iteratively solved to obtain the pressure distribution on the valve plate, and the valve plate moving can been determined by solving the valve plate motion equation at the end of time step. The simulation result shows the pressure and temperature field is uniform in cylinder during compressor expansion, but very different in suction process. The valve plate opens from 53.2° to 219.5°, which is well consistent with the theoretical calculation results (56°, 220°). This study identifies that CFD is a valid tool for exactly investigating the flow and valve plate movement.
15
Ashhab, M. S. S., A. G. Stefanopoulou, J. A. Cook, and M. B. Levin. "Control-Oriented Model for Camless Intake Process—Part I1." Journal of Dynamic Systems, Measurement, and Control 122, no. 1 (July 14, 1998): 122–30. http://dx.doi.org/10.1115/1.482447.
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The improvement of internal combustion engine is largely accomplished though the introduction of innovative actuators that allow optimization and control of the flow, mixing, and combustion processes. The realization of such a novel system depends on the existence of an operational controller that will stabilize the engine and allow experimental testing which, consequently, leads to further development of the actuator and the engine controller. This iterative process requires a starting point which is the development of a control-oriented model. Although not fully validated, the control-oriented model reveals issues associated with uncertainties, nonlinearities, and limitation of different subsystems. Moreover, it aides in defining the controller structure and the necessary parameters for the calibration of the closed loop system. In this paper (Part I) we describe the development process of a control-oriented model for a camless intake process. We first model the multicylinder crankangle-based breathing dynamics and validate it against experimental data of a conventional engine with cam-driven valve profile during unthrottled operation. We then employ the assumption of uniform air pulses during the intake duration and derive a simple input-output representation of the cylinder air charge, pumping losses and associated uncertainties that can be used for designing an electronic valvetrain controller (Part II). [S0022-0434(00)02901-4]
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Montaseri, H., K. Tavakoli, S. Evangelista, and P. Omidvar. "Sediment transport and bed evolution in a 180∘ curved channel with lateral intake: Numerical simulations using Eulerian and Discrete Phase models." International Journal of Modern Physics C 31, no. 08 (August 2020): 2050113. http://dx.doi.org/10.1142/s0129183120501132.
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Lateral intakes are hydraulic structures used for domestic, agricultural and industrial water conveyance, characterized by a very complex three-dimensional morphodynamic behavior: since streamlines near the lateral intake are deflected, some vortices form, pressure gradient, shear and centrifugal forces at the intake generate flow separation and a secondary movement, responsible for local scour and sediment deposition. On the other side, the modeling of flows, besides the sediment transport, in curved channels implies some more complications in comparison with straight channels. In this research, this complex process has been investigated experimentally and numerically, with the mechanism of sediment transport, bed topography evolution, flow pattern and their interactions. Experiments were performed in the Laboratory of Tarbiat Modares University, Iran, where a U-shaped channel with a lateral intake was installed and dry sediment was injected at constant rate into a steady flow. Due to the spiral flow, the bed topography changes significantly and the bed forms in turn affect the sediment entering the intake. Different from the previous works on this topic which were mainly based on laboratory experiments, here, Computational Fluid Dynamics (CFD) numerical simulations with FLUENT software were also performed, specifically with the two-phase Eulerian Model (EM) and Discrete Phase Model (DPM), at the aim of evaluating their performance in reproducing the observed physical processes. This software is used for a large variety of CFD problems, but not much for simulating sediment transport phenomena and bed topography evolution. The comparison of the results obtained through the two models against the laboratory experimental data proved a good performance of both the models in reproducing the main features of the flow, for example, the longitudinal and vertical streamlines and the mechanism of particles movement. However, the EM reveals a better performance than DPM in the prediction of the secondary flows and, consequently, of the bed topography evolution, whereas the DPM well depicts the particles pattern, predicts the location of trapped particles and determines the percentage of sediment entering the intake. The numerical models so calibrated and validated were applied to other cases with different positions of the intake in the bend. The results show that mechanism of sediment entrance into the intake varies in different position. If the intake is installed in the second half of the bend, the sediment accumulates along the inner bank of the bend and enters the intake from downstream edge of intake; on the other side, if it is placed in the first half of the bend, the sediment accumulates along both the inner and the outer bends and, therefore, more sediment enters the intake. Also the results of the simulations performed with the DPM model for different positions of the lateral intake show that for all discharge ratios, the position of 120∘ is the one which guarantees the minimum ratio of sediment diverted to the intake (Gr).
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Suhaimi, Shafiq, Rizalman Mamat, Abdul Adam Abdullah, Amir Aziz, and Nik Rosli Abdullah. "Investigation of Intake Flow Rate and Swirl Motion of Sl Engine." Applied Mechanics and Materials 465-466 (December 2013): 409–17. http://dx.doi.org/10.4028/www.scientific.net/amm.465-466.409.
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In the process of producing an optimized air intake system design, detailed understanding of the airflow motion is required. To reach such understanding, this paper aims to investigate the flow rate and swirl motion of an engines inlet system at different pressures and different conditions. Using a commercial steady flow bench and a swirl meter, the different parameters, the flow rate and swirl coefficient, is obtained at different valve lifts. The inlet system will then be tested in different pressures and at different engine configurations. Since the tested inlet system has two valves in its intake port, both valves are tested separately as well as tested together. It is found that the flow rate pattern mirrors the swirl pattern where the value increases as the valve lift increases but decreases and levels after a certain valve lift. Increase in pressure from 5kPa to 10kPa exhibits a 43% increase in flow rate and 90% increase in swirl coefficient and by removing the manifold, the flow rate only increase by 4% but the swirl coefficient changes by 30%. Theses findings show the main factors that affects the intake process and the results will be used as a baseline to improve the intake system.
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Yoshizawa, K., K. Mori, Y. Matayoshi, and S. Kimura. "Development of an Exhaust Gas Recirculation Distribution Prediction Method Using Three-Dimensional Flow Analysis and Its Application." Journal of Engineering for Gas Turbines and Power 125, no. 4 (October 1, 2003): 1066–74. http://dx.doi.org/10.1115/1.1581896.
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A multidimensional computational fluid dynamics (CFD) method has been used to improve the exhaust gas recirculation (EGR) distribution in the intake manifold. Since gas flow in the intake system is affected by intake pulsation caused by the gas exchange process, a pulsation flow simulation is used. A one-dimensional gas exchange calculation is combined with three-dimensional intake gas flow calculation to simulate pulsation flow. This pulsation flow simulation makes it possible to predict the EGR distribution. The gas flow in the intake system was analyzed in detail. It was found that a reverse flow region formed downstream of the throttle valve. The size and shape of the reverse flow region greatly depend on the engine operating conditions. With a conventional EGR system, it is difficult to distribute EGR uniformly under various engine operating conditions. A new EGR system that uses a spiral flow to mix the fresh air and EGR gas has been developed to obtain a uniform EGR distribution. As a result of adopting this system, a uniform EGR distribution is obtained regardless of the engine operating conditions. This spiral flow EGR system was applied to a low-emission vehicle (LEV) put on the Japanese market.
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Yao, Yu Feng. "Scramjet Flow and Intake SBLI: Technical Challenges and Case Study." Applied Mechanics and Materials 315 (April 2013): 344–48. http://dx.doi.org/10.4028/www.scientific.net/amm.315.344.
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This paper reviews some basic research areas associated with Scramjet-powered hypersonic flying vehicle, particularly the forebody boundary-layer transition and intake shock-wave boundary-layer interactions (SBLI). Some technical and physical challenges in aerodynamics, aero-thermodynamics, aero-design are visited with focuses being placed on hypersonic boundary-layer transition process and its underlying physical mechanics, feasible physics-based engineering transition prediction methods, and physics-based modelling of shock-shock, shock-wave/boundary-layer interactions of Scramjet flows. Experimental, analytical and numerical studies of previously relevant studies have also been summarized with a total of twelve transition/intake configurations that can be used as benchmarks for validating physical model development and numerical simulation tools. A case study of Scramjet intake SBLI has been carried out by using computational fluid dynamics approach to understand shock induced flow separation and its consequent influences on combustion performance, along with research perspectives discussed accordingly.
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Kołaska, Sylwia, Joanna Jeż-Walkowiak, and Zbysław Dymaczewski. "Experiment in infiltration studies as a water treatment process." E3S Web of Conferences 59 (2018): 00015. http://dx.doi.org/10.1051/e3sconf/20185900015.
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This article contains the concept of research methodology of the water infiltration process. The described research was conducted at Dębina intake in Poznan, Poland. Based on the temperature variation curves, it was possible to determine the water retention time in the ground during the flow of water from the infiltration pond through piezometers to the collecting well
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Stivanin, Sheila Cristina Bosco, Marta Gomes da Rocha, Luciana Pötter, Viviane Da Silva Hampel, Marcos Bernardino Alves, Paulo Roberto Salvador, Érica Dambrós de Moura, and Lidiane Raquel Eloy. "Biomass flows and defoliation pattern of ryegrass grazed by supplemented heifers." Semina: Ciências Agrárias 38, no. 5 (October 3, 2017): 3193. http://dx.doi.org/10.5433/1679-0359.2017v38n5p3193.
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To strategically define the best stocking rate management strategy for ryegrass, it is important to know the growth process of forage plants in detail. The study was conducted to analyze the leaf biomass flows and the defoliation intensity and frequency of Italian ryegrass (Lolium multiflorum Lam) grazed by heifers fed exclusively on pasture or on pasture and supplemented with corn or white oat grain. The experimental design was completely randomized following a repeated measures arrangement with three feeding systems and three area replications. Biomass flows (kg DM leaf blades ha1 day1) for leaf growth (40.6), leaf senescence (40.7), and leaf intake (29.7) were similar in the different feeding systems. Leaf blade intake adjusted to body weight was lower in supplemented heifers regardless of grain type. Actual and potential utilization efficiencies and ryegrass biomass net balance were not affected by feeding system. The leaf intake flow was 1.4 times lower than the growth flow, resulting in an actual utilization efficiency less than one (0.7), whereas the senescence flow was higher than the growth flow, resulting in a negative potential utilization efficiency (0.2). Leaf defoliation intensity was similar (54.4%) across feeding systems and defoliation frequency was higher in supplemented heifers. The 29.2% increase in stocking rate of heifers fed corn or oat grain as supplement did not affect the dynamics of ryegrass biomass flows, but reduced leaf blade intake adjusted to heifer body weight leading to alterations in the defoliation frequency of ryegrass pasture.
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Honus, Stanislav, Przemyslaw Bukowski, and Dagmar Juchelková. "Properties of Process Gas Combustion Products." Applied Mechanics and Materials 397-400 (September 2013): 73–78. http://dx.doi.org/10.4028/www.scientific.net/amm.397-400.73.
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The study deals with the issue of combustion of process gas that resulted from the pyrolyticly processed varied organic materials. The study describes combustion properties of the gas and the properties of the combustion product considering kinds of the entry materials. The selected materials (coal, rubber, or biomass) were pyrolysed at the temperature of 650°C in the experimental system having the maximal heat output of 200 kW. It was the system with the continual intake of entry materials the flow of which could reach the maximum of about 150 kg.h-1.
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PIĄTKOWSKI, Piotr. "The impact of kinematics of the airflow on the efficiency of combustion process in piston engines." Combustion Engines 145, no. 2 (May 1, 2011): 82–88. http://dx.doi.org/10.19206/ce-117105.
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The technical possibility of decreasing engine emissions and fuel consumption in relation to the increase in the usable engine parameters has been presented in the paper. The above problem relates to the dynamic and kinematic properties of airflow into the combustion chamber. The effect of swirl in the intake manifold that refers to the achieved engine operating parameters and emission level was presented in the paper. The included results of the experimental research of airflow swirl in the air intake model allowed getting answers related to the issues of flow resistance. The analysis of literature and the analysis of the modeling results led to conclusions about the theoretical and practical possibilities of flexible intake duct implementation.
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Li, Chang Yuan, Dong Tang, and Nan Li. "Simulation of Scavenging Process in a Two-Stroke Gasoline Engine." Advanced Materials Research 614-615 (December 2012): 376–80. http://dx.doi.org/10.4028/www.scientific.net/amr.614-615.376.
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Three-dimension transient numerical simulation of flow field in the transfer ports , exhaust port, intake port, crankcase and cylinder system of two-stroke gasoline engine was studied by using CFD software Fire, and the situations of airflow movement and exhaust gas distribution were presented dynamically in the scavenging process. The results show that flow field structure of the upper cylinder is mainly comprised of a pair of toroidal vortex and tumble vortex, while flow field structure of the lower cylinder is mainly comprised of four radial swirls and "short-circuiting" fuel losses. Along with the progress of scavenging process, the area of fresh charge and mixture increase while the exhaust gas area decreases accordingly. When the piston reaches to the BDC (bottom dead center), the exhaust gas area almost disappears.
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John, A., J. Bower, N. Qin, S. Shahpar, and A. Smith. "Using shock control bumps to improve engine intake performance and operability." Aeronautical Journal 124, no. 1282 (November 23, 2020): 1913–44. http://dx.doi.org/10.1017/aer.2020.87.
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AbstractShock control bumps can be used to control and weaken the shock waves that form on engine intakes at high angles of attack. In this paper, it is demonstrated how shock control bumps applied to an engine intake can reduce or eliminate shock-induced separation at high incidence, and also increase the incidence at which critical separation occurs. Three-dimensional Reynolds-average Navier–Stokes (RANS) simulations are used to model the flow through a large civil aircraft engine intake at high incidence. The variation in shock strength and separation with incidence is first studied, along with the flow distribution around the nacelle. An optimisation process is then employed to design shock control bumps that reduce shock strength and separation at a fixed high incidence condition. The bump geometry is allowed to vary in shape, size, streamwise position and circumferential direction around the nacelle. This is shown to be key to the success of the shock control geometry. A further step is then taken, using the optimisation methodology to design bumps that can increase the incidence at which critical separation occurs. It is shown that, by using this approach, the operating range of the engine intake can be increased by at least three degrees.
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Cheema, Izzat Iqbal, and Ulrike Krewer. "Optimisation of the Autothermal NH3 Production Process for Power-to-Ammonia." Processes 8, no. 1 (December 30, 2019): 38. http://dx.doi.org/10.3390/pr8010038.
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The power-to-ammonia process requires flexible operation due to intermittent renewable energy supply. In this work, we analyse three-bed autothermal reactor systems for design and off-design performance for power-to-ammonia application. The five reactor systems differ in terms of inter-stage cooling methods, i.e., direct cooling by quenching (2Q), combination of indirect and direct cooling (HQ and QH) and indirect cooling (2H) with variations. At optimum nominal operation conditions, the inter-stage indirect cooling (2H) reactor systems result in the highest NH3 production. For off-design performance analysis, NH3 production is minimised or maximised by varying one of the following process variables at a time: inert gas, feed flow rate or H2-to-N2 ratio. For each variation, the effect on H2 intake, recycle stream load and recycle-to-feed ratio is also analysed. Among the three process variables, the H2-to-N2 ratio provided ca. 70% lower NH3 production and 70% lower H2 intake than at nominal operation for all five reactor systems. Operation of autothermal reactor systems at significantly lower H2 intake makes them reliable for power-to-ammonia application; as during energy outage period, shutdown can be delayed.
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Young, J. B. "Condensation in Jet Engine Intake Ducts During Stationary Operation." Journal of Engineering for Gas Turbines and Power 117, no. 2 (April 1, 1995): 227–36. http://dx.doi.org/10.1115/1.2814085.
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The paper describes an analysis of the condensation of moist air in very long intake ducts of jet engines during stationary operation. Problems arising from such condensation include fan overspeed and increased stagnation pressure loss in the intake duct. The analysis demonstrates that, for moderate values of relative humidity, homogeneous condensation will occur in an outer annulus adjacent to the intake cowling if the local flow Mach number attains values of about 1.0. In the central region of the intake duct, where design Mach numbers of 0.8 may be attained, homogeneous condensation is unlikely to occur except, possibly, when the relative humidity is close to 100 percent and the ambient temperature very high. However, if the intake duct is very long, significant heterogeneous condensation on foreign particles present in the atmosphere is possible. The concentration of foreign nuclei required for this type of condensation is comparable to the likely levels of contamination at many industrial test sites. The effects of condensation on engine test results are twofold. First, condensation is a thermodynamically irreversible process and results in an increase of entropy and hence loss of total pressure in the intake duct. Uncorrected measurements using Pitot probes may not record this loss correctly. Second, the mass and energy transfer between the phases during the condensation process has a tendency to accelerate the flow approaching the engine, an effect that may be counteracted by a reduction in mass flow rate in order to maintain the static pressure constant. These conclusions are in agreement with experimental results obtained on-site during the testing of a jet engine fitted with a very long intake duct.
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Algieri, Angelo. "Comparative analysis of the fluid dynamic efficiency of standard and alternative intake strategies for multivalve spark-ignition engines." International Journal of Engineering & Technology 2, no. 2 (May 20, 2013): 140. http://dx.doi.org/10.14419/ijet.v2i2.892.
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The work aims at investigating the fluid dynamic performances of a multivalve spark-ignition engine and at evaluating the influence of the throttling process on the engine permeability. To this purpose, a production four-stroke internal combustion engine is analysed during the intake phase. The experimental characterisation is carried out at the steady flow rig in terms of dimensionless discharge and flow coefficients. The global investigation illustrates the noticeable effect of the valve lift on the engine head breathability. Furthermore, the experimental analysis demonstrates that the throttling process has a significant influence on the volumetric efficiency of the intake system and this effect increases with the valve lift. Finally, alternative strategies are studied in order to improve the engine fluid dynamic efficiency at partial loads. Specifically, the research shows that inlet valve deactivation and the adoption of asymmetric intake valve lifts assure an increase in head permeability.
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Kong, Kyeong-Ju. "1D–3D Coupling Algorithm of Gas Flow for the Valve System in a Compression Ignition Engine." Journal of Marine Science and Engineering 9, no. 10 (September 27, 2021): 1061. http://dx.doi.org/10.3390/jmse9101061.
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Emission control devices such as selective catalytic reduction (SCR), exhaust gas recirculation (EGR), and scrubbers were installed in the compression ignition (CI) engine, and flow analysis of intake air and exhaust gas was required to predict the performance of the CI engine and emission control devices. In order to analyze such gas flow, it was inefficient to comprehensively analyze the engine’s cylinder and intake/exhaust systems because it takes a lot of computation time. Therefore, there is a need for a method that can quickly calculate the gas flow of the CI engine in order to shorten the development process of emission control devices. It can be efficient and quickly calculated if only the parts that require detailed observation among the intake/exhaust gas flow of the CI engine are analyzed in a 3D approach and the rest are analyzed in a 1D approach. In this study, an algorithm for gas flow analysis was developed by coupling 1D and 3D in the valve systems and comparing with experimental results for validation. Analyzing the intake/exhaust gas flow of the CI engine in a 3D approach took about 7 days for computation, but using the developed 1D–3D coupling algorithm, it could be computed within 30 min. Compared with the experimental results, the exhaust pipe pressure occurred an error within 1.80%, confirming the accuracy and it was possible to observe the detailed flow by showing the contour results for the part analyzed in the 3D zone. As a result, it was possible to accurately and quickly calculate the gas flow of the CI engine using the 1D–3D coupling algorithm applied to the valve system, and it was expected that it can be used to shorten the process for analyzing emission control devices, including predicting the performance of the CI engine.
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Langston, Lee S. "Out Through the Intake." Mechanical Engineering 139, no. 04 (April 1, 2017): 36–41. http://dx.doi.org/10.1115/1.2017-apr-2.
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This article elaborates various challenges presented by stall and surge to the gas turbine research community and jet engine designers. The article also presents several examples of stall and surge faced by the pilots. Stall and surge emerge from basic physics: the behavior of the boundary layer on the compressor blades and stators; however, current technology has no means to completely eliminate it. Engine control systems, such as the Full Authority Digital Electric Control (FADEC), are programmed to keep the operating point of the compressor well away from the surge line. Researchers have been studying stall and surge for decades, looking for ways to predict and combat the phenomena. Meanwhile, there has been some success in using FADEC to either prevent a stall and surge or to limit the number of repetitions. FADEC can also step in during flights in heavy rain or hailstorms. In those conditions, extra fuel is needed to process and evaporate the water being swallowed by the engine. The electronic control system can sense the mismatch between the power setting and the fuel flow and take action to prevent possible engine instability.
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Czyż, Zbigniew, Ksenia Siadkowska, and Rafał Sochaczewski. "CFD Analysis of Charge Exchange in an Aircraft Opposed-Piston Diesel Engine." MATEC Web of Conferences 252 (2019): 04002. http://dx.doi.org/10.1051/matecconf/201925204002.
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The paper presents a description of geometric models, computational algorithms, and results of numerical analysis of charge exchange in an opposed-piston two-stroke engine. The research engine is a newly designed internal diesel engine. This unit is composed of three cylinders in which operate three pairs of opposed-pistons. The engine generates a power output equal to 100 kW at a crankshaft rotation speed of 3800-4000 rpm. The numerical investigations were carried out using ANSYS FLUENT solver. The geometrical model includes an intake manifold, a cylinder and an outlet manifold. The study was conducted for a series of modifications of manifolds and intake and exhaust ports to optimise the charge exchange process in the engine. In addition, we attempted to verify the effect of the combustion chamber shape on the charge exchange process in the engine. The calculations specified a swirl coefficient obtained under steady conditions for fully open intake and exhaust ports as well as the CA value of 280° for all cylinders. In addition, mass flow rates were identified separately in all of the intake and exhaust ports to achieve the best possible uniformity of flow in particular cylinders. The paper includes comparative analyses of all of the intake and exhaust manifolds of the designed engine.
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Naumova, Tatyana V., Anatoliy M. Kusher, and Irina F. Рikalova. "Improving the efficiency of operational measures on reducing the sediment capture in the irrigation system water intake." Vestnik MGSU, no. 9 (September 2019): 1167–79. http://dx.doi.org/10.22227/1997-0935.2019.9.1167-1179.
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Introduction. The article considers operational measures of channel process regulation in the headwater of low-pressure front water intake located on rivers with abundant sediment loads. In addition to deep hydraulic flushing, the study proposes the method of task-oriented handling of the watergate screens. It allows reducing the amount of irrigation system channel siltation and significantly reducing the expenses for mechanical cleaning. An analysis of the problems of practical implementation of hydraulic methods to reduce the sediment capture in water intakes and the necessity of moving to the advanced technological level of irrigation system management is given. The international experience of irrigation system management modernization based on the principle of integration and activation of interested parties in the decision-making process is considered.
Materials and methods. The studies of hydraulic methods of impact on channel processes during the water intake operation were carried out on physical eroded models (large-scale one and fragmented one). When conducting field research, the article analyzed the economic situations in addition to the hydraulic studies.
Results. The research has developed a schematic diagram for the creation of artificial circulation zones, Based on the results of the research on a large-scale field eroded model of the frontal water intake. This makes it possible to redirect a part of the sediment flow from the water intake to the spillway dam open gates and reduce the channel siltation intensity. The dependences were obtained for the amount of sediment captured in the water intake on the ratio of water flow taken into the main channel and discharged through the bottom flushing galleries, which allow interactive schedule adjustment of water supply to agricultural producers depending on hydrological and climatic conditions.
Conclusions. The hydraulic methods usage scale and their efficiency depend on applying modern analytical methods and digital technologies in the development of operational patterns as well as on the improvement of the regulatory framework and the organizational and economic mechanism for the irrigation system management.
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Thamaraikanan, R., M. Anish, B. Kanimozhi, Thomaskutty George, and Vivek George Koshy. "Design and Analysis of an Intake Manifold in an IC Engine." Applied Mechanics and Materials 766-767 (June 2015): 1021–27. http://dx.doi.org/10.4028/www.scientific.net/amm.766-767.1021.
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The paper investigates the properly designed Intake or Inlet Manifold (IM) is vital for the optimal performance of an Internal Combustion (IC) engine. The primary function of the intake manifold is to evenly distribute the combustion mixture (or just air in a direct injection engine) to each intake performance of the engine. Even distribution is important to optimize the efficiency and performance of the engine. It is known that uneven air distribution leads to less volumetric efficiency, increased fuel consumption and also power loss. The main objective of the present work was to make a computational study of flow distribution in an intake manifold under steady state turbulence conditions in the current project work an intake manifold for 3-cylinder engine was modeled and analyzed numerically for evaluating the fluid flow. In this process, the geometric model was created with approximate dimensions (by using curves and points) in ANSA a pre-processing tool and the analysis was carried out using STAR CCM+ which is a solver and post-processing tool port in the cylinder head (s).
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NAITOH, Ken, Yasuo YOSHIKAWA, Hiroyuki FUJII, and Yasuo TAKAGI. "A higher-order accurate computation of three-dimensional flow in the intake process of a reciprocal engine." Transactions of the Japan Society of Mechanical Engineers Series B 55, no. 515 (1989): 1868–75. http://dx.doi.org/10.1299/kikaib.55.1868.
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Franchek, Matthew A., Patrick J. Buehler, and Imad Makki. "Intake Air Path Diagnostics for Internal Combustion Engines." Journal of Dynamic Systems, Measurement, and Control 129, no. 1 (May 29, 2006): 32–40. http://dx.doi.org/10.1115/1.2397150.
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Presented is the detection, isolation, and estimation of faults that occur in the intake air path of internal combustion engines during steady state operation. The proposed diagnostic approach is based on a static air path model, which is adapted online such that the model output matches the measured output during steady state conditions. The resulting changes in the model coefficients create a vector whose magnitude and direction are used for fault detection and isolation. Fault estimation is realized by analyzing the residual between the actual sensor measurement and the output of the original (i.e., healthy) model. To identify the structure of the steady state air path model a process called system probing is developed. The proposed diagnostics algorithm is experimentally validated on the intake air path of a Ford 4.6L V-8 engine. The specific faults to be identified include two of the most problematic faults that degrade the performance of transient fueling controllers: bias in the mass air flow sensor and a leak in the intake manifold. The selected model inputs include throttle position and engine speed, and the output is the mass air flow sensor measurement.
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Bazarov, Dilshod, Bekhzod Norkulov, Oybek Vokhidov, Fotima Artikbekova, Bobur Shodiev, and Ikboloy Raimova. "Regulation of the flow in the area of the damless water intake." E3S Web of Conferences 263 (2021): 02036. http://dx.doi.org/10.1051/e3sconf/202126302036.
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The article discusses the results of numerical studies of the flow of the Amudarya river above the point of the damless water intake to the head structure of the damless water intake to the Karshi Main Canal-KMC. The system of two-dimensional equations of hydrodynamics-Saint-Venant is used as the basis of the mathematical model. In this work, a series of calculations of the field of currents in the river channel during low-water periods is carried out. Below are the main research results and proposals for ensuring the stable operation of the damless water intake in low-water conditions. The applicability of a numerical model composed of the equations of shallow water -the vector equation for the conservation of momentum and the scalar equation for the conservation of mass, has been proved, when describing a flow with the presence of circulation zones, which is typical when the water flow is constrained by blind dams. In this case, the solution pulsates around a certain average value, and the average length of the circulation zone behind the sudden expansion of the open flow is in good agreement with laboratory experiments. Numerical studies have shown that the device of a jet-guiding dam 150 m above the water intake gate in the CMC is more effective than when the dam is located 250 m above. In essence, dam № 2 with a length of 65 m does not affect the conditions at the water intake in the KMC at all, and dam № 2 with a length of 120 m is almost equivalent in its impact on the flow to dam №1 with a length of 50 m. Analysis of the results shows that the placement of an additional threshold in the Amudarya river bed improves the situation by raising the water level at the water intake. The threshold is flooded even at low water levels, which reduces the speed load on its body. At the same time, the threshold is located directly at the beginning of the channel, in part to protect the intake from incoming sediment, and high enough speed water glistening over the threshold in line, ensure the transit of sediment that can reduce enters the intake. Such measures will reduce the turbidity of water entering the channel. This, in turn, reduces the intensity of the silting process.
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Shaari, Muhammad Farid, Husaini Abu Bakar, and Samad Zahurin. "Fluid Flow Characterization in IPMC Actuated Contractile Water Jet Thruster." Advanced Materials Research 622-623 (December 2012): 1226–30. http://dx.doi.org/10.4028/www.scientific.net/amr.622-623.1226.
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Contractile water jet thruster is an alternative method for Autonomous Underwater Vehicle (AUV) locomotion as well as for the AUV’s manoeuvrability control. Currently, studies on contractile water jet thruster focus more on the thrust force performance and its efficiency, such as the characterization of vortex ring formation process, the slug model L/D ratio and the influence of the thrust performance on the AUV. The aim of this paper is to discuss the fluid flow behaviour in the thruster during contraction process under different actuation frequency. This research utilized Ionic Polymer Metal Composite (IPMC) as the actuators instead of electric motor for the contractile function. The result shows that the Reynolds number of the intake flow has negative linear relation with the actuation frequency.
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Heywood, John B. "Fluid Motion Within the Cylinder of Internal Combustion Engines—The 1986 Freeman Scholar Lecture." Journal of Fluids Engineering 109, no. 1 (March 1, 1987): 3–35. http://dx.doi.org/10.1115/1.3242612.
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The flow field within the cylinder of internal combustion engines is the most important factor controlling the combustion process. Thus it has a major impact on engine operation. This paper reviews those aspects of gas motion into, within, and out of the engine cylinder that govern the combustion characteristics and breathing capabilities of spark-ignition engines and compression-ignition or diesel engines. Necessary background information on reciprocating engine operating cycles, the primary effect of piston motion and the spark-ignition and diesel engine combustion processes is first summarized. Then the characteristics of flow through inlet and exhaust valves in four-stroke cycle engines, and through ports in the cylinder liner in two-stroke cycle engines are reviewed. These flows govern the airflow through the engine, and set up the in-cylinder flow that controls the subsequent combustion process. The essential features of common in-cylinder flows—the large scale rotating flows set up by the conical intake jet, the creation and development of swirl about the cylinder axis, the flows produced during compression due to combustion chamber shape called squish, flow during the combustion process, and two-stroke scavenging flows—are then described. The turbulence characteristics of these flows are then defined and discussed. Finally, flow phenomena which occur near the walls, which are important to heat transfer and hydrocarbon emissions phenomena, are reviewed. The primary emphasis is on developing insight regarding these important flow phemomena which occur within the cylinder. To this end, results from many different research techniques—experimental and computational, established and new—have been used as resources. It is the rapidly increasing convergence of engine flow information from these many sources that make this an exciting topic with promise of significant practical contributions.
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Benajes, J., E. Reyes, and J. M. Luján. "Modelling Study of the Scavenging Process in a Turbocharged Diesel Engine with Modified Valve Operation." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 210, no. 4 (July 1996): 383–93. http://dx.doi.org/10.1243/pime_proc_1996_210_210_02.
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The instantaneous gas exchange process in a turbocharged direct injection diesel engine with an intake valve pre-lift and an exhaust valve post-lift has been studied in detail by means of a wave action model. Such a modified valve timing operation allows the internal exhaust gas recirculation and the residual burnt gas ratio in the combustion chamber to be increased and modulated. A simple scavenging model has been included in the global calculation code, in order to obtain information on the instantaneous composition of the gas flow across valves. The analysis sheds light on the intricate flow phenomena produced by the additional valve lift periods, and evaluates the potential of this technique in the control of the residual burnt gas in the cylinder.
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Chen, Yue, Lin Lv, and Jie Shen. "Effects of Intake Port Optimization on Soot Emission from Diesel Engine." Applied Mechanics and Materials 535 (February 2014): 333–39. http://dx.doi.org/10.4028/www.scientific.net/amm.535.333.
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All future engine developments must consider the primary task of achieving the required emission levels. An important step towards the development of combustion engines is the optimization of the flow in the intake ports. The charging movement in the combustion chamber, which is generated by the intake flow, considerably influences the quality of the combustion engine. In this paper, steady CFD analysis were applied to different structures of double-tangent-port. The swirl ratio can be improved while flow coefficient remains unchanged if port eccentricity is 34.4 mm. By defining three characteristic parameters, the speed non-uniformity index, standard deviation and mixture concentration standard deviation and equivalent ratio range, quantitatively describing the combustion process in cylinder, and then compared with transient CFD three-dimensional contours, we can see that characteristic parameters can be more accurate and comprehensive in analyzing the influence of inlet structure of soot formation. Effects of different intake ports on fuel-air mixing in a turbocharged diesel direct injection engine during intake and compression strokes are analyzed. It turns out that the optimized double-tangent-port has the highest uniformity of velocity, in the meanwhile, air/fuel mixing is relatively uniform. On the other hand, mixed-port and double-helix-port can cause uneven flow field which is bad for combustion, even though the swirl ratio can increase largely. Finally, the simulation results show that soot emissions of the optimized double-tangent-port have significantly lower levels, at 2200 r/min under full load.
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Ma, R.-H. "The activity airflow detection of vehicle intake system using hot-film anemometry sensors instrument." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 225, no. 12 (July 25, 2011): 2900–2906. http://dx.doi.org/10.1177/0954406211411865.
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The goal of this study is to develop an airflow meter sensor for the detection of vehicle intake system in internal combustion engines. The study uses micro-electromechanical process technology to develop a hot-film flow meter with an alumina substrate and platinum film heater; the hot-line method is used to create a micro-airflow anemometry meter sensor relying on variations in resistance of the platinum film corresponding to different wind velocities at the set temperatures. The alumina plate used in this study is produced by polishing an alumina substrate; a platinum film is then deposited on the plate to complete the micro-heater used in the sensor. Resistance on the sensor side varies as gas flows through the sensor, and the instrument determines airflow velocity on the basis of the changes in resistance caused by gas flow differences. Airflow velocities ranging from 10 to 60 m/s are used to test. Signals of change in resistance display a regular slope, indicating that the relationship between the changes in airflow velocity remains predictable throughout the sensing range. Therefore, the sensor can achieve its purpose of airflow measurement completely.
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Birkett, Stephen, and Kees de Lange. "A computational framework for a nutrient flow representation of energy utilization by growing monogastric animals." British Journal of Nutrition 86, no. 6 (December 2001): 661–74. http://dx.doi.org/10.1079/bjn2001442.
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A computational framework to represent nutrient utilization for body protein and lipid accretion by growing monogastric animals is presented. Nutrient and metabolite flows, and the biochemical and biological processes which transform these, are explicitly represented. A minimal set of calibration parameters is determined to provide five degrees of freedom in the adjustment of the marginal input–output response of this nutritional process model for a particular (monogastric) animal species. These parameters reflect the energy requirements to support the main biological processes: nutrient intake, faecal and urinary excretion, and production in terms of protein and lipid accretion. Complete computational details are developed and presented for these five nutritional processes, as well as a representation of the main biochemical transformations in the metabolic processing of nutrient intake. Absolute model response is determined as the residual nutrient requirements for basal processes. This model can be used to improve the accuracy of predicting the energetic efficiency of utilizing nutrient intake, as this is affected by independent diet and metabolic effects. Model outputs may be used to generate mechanistically predicted values for the net energy of a diet at particular defined metabolic states.
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Oh, Jungmo, Kichol Noh, and Changhee Lee. "A Theoretical Study on the Thermodynamic Cycle of Concept Engine with Miller Cycle." Processes 9, no. 6 (June 16, 2021): 1051. http://dx.doi.org/10.3390/pr9061051.
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The Atkinson cycle, where expansion ratio is higher than the compression ratio, is one of the methods used to improve thermal efficiency of engines. Miller improved the Atkinson cycle by controlling the intake- or exhaust-valve closing timing, a technique which is called the Miller cycle. The Otto–Miller cycle can improve thermal efficiency and reduce NOx emission by reducing compression work; however, it must compensate for the compression pressure and maintain the intake air mass through an effective compression ratio or turbocharge. Hence, we performed thermodynamic cycle analysis with changes in the intake-valve closing timing for the Otto–Miller cycle and evaluated the engine performance and Miller timing through the resulting problems and solutions. When only the compression ratio was compensated, the theoretical thermal efficiency of the Otto–Miller cycle improved by approximately 18.8% compared to that of the Otto cycle. In terms of thermal efficiency, it is more advantageous to compensate only the compression ratio; however, when considering the output of the engine, it is advantageous to also compensate the boost pressure to maintain the intake air mass flow rate.
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Музаев, Илларион Давидович, Константин Сергеевич Харебов, and Нугзар Илларионович Музаев. "Mathematical modelling of the method for controlling selective water intake process in a stratified reservoir." Вычислительные технологии, no. 5(25) (October 28, 2020): 4–16. http://dx.doi.org/10.25743/ict.2020.25.5.002.
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Разработана математическая модель способа управления селективным водозаборным процессом, когда вода забирается из водоема с вертикальной непрерывной температурной стратификацией. Предлагаемый способ обеспечивает снабжение холодной водой систем технического водоснабжения ТЭС, АЭС, предприятий. Составленная математическая модель представляет стационарную краевую задачу гидродинамики мало сжимаемой жидкости. Сжимаемость обусловлена вертикальной температурной стратификацией. В результате решения поставленной краевой задачи определены проекции вектора скорости, вычислена линия тока, приходящая к верхней кромке донного водозаборного окна. По мере увеличения скорости водозабора через вспомогательное окно упомянутая линия тока опускается вертикально вниз и температура забираемой через нижнее окно воды уменьшается. Составляющие вектора скорости движения воды в водоеме вычислены строгими аналитическими методами математической физики. Линии тока рассчитаны методами конечных разностей Рунге - Кутты. The purpose of this study is to develop a mathematical model of a method for controlling selective water intake process, when water is taken from a reservoir with continuous vertical temperature stratification. The methodology for solving the problem implies that water is taken from the reservoir through a window, which is adjacent to the bottom of reservoir. The water intake process is controlled by varying the rate of water intake through an auxiliary window located above the main bottom window. As the speed of water intake through the auxiliary window increases, the thickness of the active layer of water entering the opening of the bottom window decreases. The average temperature of water taken through the bottom window is shown to decrease. The stationary boundary value problem for hydrodynamics of a slightly compressible fluid is chosen as a mathematical model. In the immediate vicinity of the vertical pressure head of the reservoir, the velocity field was calculated using the theory of the boundary layer. Further, a nonlinear boundary value problem was posed that simulates the position of the streamline coming to the upper edge of the lower water intake window. The boundary value problem is solved by the Runge - Kutta finite-difference method. A set of formulas for calculating the velocity field of fluid flow was then obtained. Originality/value: 1. A new original method for controlling selective water intake in a reservoir with continuous vertical temperature stratification has been developed and theoretically justified. The method allows taking water exclusively from the deep-cold layers of the reservoir. 2. The value of the method leads to a technical solution - the installation of an additional upper water intake window above the bottom intake one. This allows controlling the temperature of water used in technical water supply systems of thermal power stations, nuclear power plants and enterprises. 3. An adequate mathematical model for the proposed method was developed and solved. Based on this model, a set of calculation formulas that allow controlling the temperature of the extracted water is obtained.
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Chie, Lee Hooi, Ahmad Khairi Abd Wahab, and Fauzan Kamal Mohd Yapandi. "Development of the Long-Term Morphodynamic Model to Determine the Seawater Intake Location." MATEC Web of Conferences 203 (2018): 01004. http://dx.doi.org/10.1051/matecconf/201820301004.
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Seawater intake structures are often used at coastal power plant to draw ambient seawater into the cooling system for operation. However, improper selection of water intake location will lead to sediments deposition at the intake structure causing lower intake flow rate, clogging of water filtration devices and reduces the efficiency of the power plant. A 2D process-based model is developed to investigate the morphodynamic behavior of the Kapar coast. The model is developed by coupling the processes of hydrodynamic, waves and sediment transport. The processes are interacted dynamically with bathymetry and lead to the morphological changes. The model is input with the schematisation of seasonal wind-wave conditions and a representative morphological tide. Morphological acceleration technique is used to simulate the long-term morphodynamic changes with acceptable computational times. Sedimentation and erosion patterns are represented by the model and suitable intake location is determined based on the long-term morphodynamic investigation.
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Algieri, Angelo. "An Experimental Analysis of the Fluid Dynamic Efficiency of a Production Spark-Ignition Engine during the Intake and Exhaust Phase." ISRN Mechanical Engineering 2011 (May 14, 2011): 1–8. http://dx.doi.org/10.5402/2011/427976.
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The present work aims at analyzing the fluid dynamic efficiency of a four-stroke spark-ignition engine. Specifically, a production four-cylinder internal combustion engine has been investigated during the intake and exhaust phase. The experimental characterization has been carried out at the steady flow rig adopting the dimensionless flow and discharge coefficients. The analysis has highlighted the great influence of the valve lift on the volumetric efficiency of the intake and exhaust system. Furthermore, the global investigation has demonstrated that the throttle angle has a significant influence on the head permeability during the induction phase. Particularly, the throttling process effect increases with the valve lift. Finally, the work has shown that all experimental data can be correlated by a single curve if an opportune dimensionless plot is adopted.
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Ge, Wen Qing, Si Qin Chang, Liang Liu, and Bin Bin Sun. "3D Numerical Simulation and Analysis of Electrically Controlled Injection Device for Gaseous Fuel Engine." Advanced Materials Research 614-615 (December 2012): 441–45. http://dx.doi.org/10.4028/www.scientific.net/amr.614-615.441.
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To study the flow characteristics of the electrically controlled injection device (abbreviate ECID), 3D static and transient numerical simulation were studied during the injection process of electrically controlled injection device using computational fluid dynamic software FLUENT. Simulation results revealed that the flow of ECID was influenced by the injection valve diameter, valve lift and the pressure difference; gaseous fuel was still left after inlet valve closed; mixing quality of gaseous fuel and air gradually improved along the intake manifold.
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McLelland, Grant, David MacManus, and Chris Sheaf. "A semi-empirical model for streamwise vortex intensification." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 233, no. 12 (April 2019): 4396–409. http://dx.doi.org/10.1177/0954410019838421.
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Vortex intensification plays an important role in a wide range of flows of engineering interest. One scenario of interest is when a streamwise vortex passes through the contracting streamtube of an aircraft intake. There is, however, limited experimental data of flows of this type to reveal the dominant flow physics and to guide the development of vortex models. To this end, the evolution of wing-tip vortices inside a range of streamtube contractions has been measured using stereoscopic particle image velocimetry. A semi-empirical model has been applied to provide new insight on the role of vorticity diffusion during the intensification process. The analysis demonstrates that for mild flow contractions, vorticity diffusion has a negligible influence due to the low rates of diffusion in the vortex flow prior to intensification and the short convective times associated with the streamtube contraction. As the contraction levels increase, there is a substantial increase in the rates of diffusion which is driven by the greater levels of vorticity in the vortex core. A new semi-empirical relationship, as a function of the local streamtube contraction levels and vortex Reynolds number, has been developed. The model comprises a simple correction to vortex filament theory and provides a significant improvement in the estimation of vortex characteristics in contracting flows. For the range of contractions investigated, errors in the estimation of vortex core radius, peak tangential velocity and vorticity are reduced by an order of magnitude. The model can be applied to estimate the change in vortex characteristics for a range of flows with intense axial strain, such as contracting intake streamtubes and swirling flows in turbomachinery.
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Wang, Zhong Yi, Shao Hai Sun, Yu Lin Deng, and Chang Long Yuan. "The Resistance Performance Study of Cyclone Separator in Gas Turbine." Applied Mechanics and Materials 271-272 (December 2012): 1173–77. http://dx.doi.org/10.4028/www.scientific.net/amm.271-272.1173.
Full textAbstract:
The configuration and aerodynamics performance of the inlet system are important aspects in the process of gas turbine installation on naval vessels. Under the requirements, using CFD method simulated four kinds of structure cyclone flow field of the marine gas turbine intake filters, found the lowest flow resistance structure, then verified by experiment. Through comparison, the numerical simulation results agree with experimental study well. The methods used in the article have some reference significance for the design of the inlet system.
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Li, Y., H. Zhao, and N. Ladommatos. "Analysis of large-scale flow characteristics in a four-valve spark ignition engine." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 216, no. 9 (September 1, 2002): 923–38. http://dx.doi.org/10.1177/095440620221600906.
Full textAbstract:
A digital particle image velocimetry (PIV) measurement has been carried out to study the large-scale flow characteristics in a single-cylinder engine with a production-type four-valve cylinder head under one intake port deactivation. The measurement plane was located 12 mm below the cylinder head parallel to the flat piston top. Two-dimensional velocity fields from 100 consecutive cycles were acquired at every 30 crank angle interval in the compression stroke to analyse ensemble-averaged mean velocity, cyclic variation of the swirl motion, low-frequency and total velocity fluctuations and their integral length scales. The analysis shows that as one intake port is deactivated, strong swirl forms at the end of the intake stroke and sustains its flow pattern up to the late stage of the compression stroke with the precessing of the swirl centre. Both swirl ratio and swirl centre show significant cyclic variations in the compression process. A low-frequency component with spatial frequency below 0.05 mm-1 (corresponding to a large-scale structure with a spatial scale over 20 mm) is absolutely predominant in the flow field and therefore the low-frequency large-scale flow behaviour determines the basic characteristics of the total in-cylinder flow. The flow field is considerably anisotopic because the integral length scale of any velocity fluctuation components along any direction is different. However, the velocity fluctuation field in the horizontal plane will gradually become homogeneous as the piston moves up in the compression stroke. The integral length scale is in the range of 4-10 mm at an engine speed of 600 r/min. When the engine speed is doubled, flow velocity in the cylinder nearly doubles and velocity fluctuation kinetic energy more than triples though the flow pattern hardly changes.