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1
Pan, D., A. Whitfield et M. Wilson. « Design considerations for the volutes of centrifugal fans and compressors ». Proceedings of the Institution of Mechanical Engineers, Part C : Journal of Mechanical Engineering Science 213, no 4 (1 avril 1999) : 401–10. http://dx.doi.org/10.1243/0954406991522356.
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The initial conceptual design of centrifugal fan and compressor volutes is considered and extended to accommodate overhung volute designs often used in process and turbocharger compressors. The initial passage design is then developed through the application of a commercial computational fluid dynamics (CFD) code.’ Based on the experimental data of a turbocharger compressor volute, three-dimensional, compressible, steady flow computations were carried out for alternative volute designs. Detailed internal flow data in both a conventional and a modified volute design, at both design and off-design flow conditions, are presented. The design investigation showed that enlarging the flow passage area near the tongue region, but without changing the exit-inlet area ratio of the volute, led to an improvement in the internal flow distribution at off-design flow conditions.
2
Lee, Yu-Tai, Vineet Ahuja, Ashvin Hosangadi, Michael E. Slipper, Lawrence P. Mulvihill, Roger Birkbeck et Roderick M. Coleman. « Impeller Design of a Centrifugal Fan with Blade Optimization ». International Journal of Rotating Machinery 2011 (2011) : 1–16. http://dx.doi.org/10.1155/2011/537824.
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A method is presented for redesigning a centrifugal impeller and its inlet duct. The double-discharge volute casing is a structural constraint and is maintained for its shape. The redesign effort was geared towards meeting the design volute exit pressure while reducing the power required to operate the fan. Given the high performance of the baseline impeller, the redesign adopted a high-fidelity CFD-based computational approach capable of accounting for all aerodynamic losses. The present effort utilized a numerical optimization with experiential steering techniques to redesign the fan blades, inlet duct, and shroud of the impeller. The resulting flow path modifications not only met the pressure requirement, but also reduced the fan power by 8.8% over the baseline. A refined CFD assessment of the impeller/volute coupling and the gap between the stationary duct and the rotating shroud revealed a reduction in efficiency due to the volute and the gap. The calculations verified that the new impeller matches better with the original volute. Model-fan measured data was used to validate CFD predictions and impeller design goals. The CFD results further demonstrate a Reynolds-number effect between the model- and full-scale fans.
3
Liu, Xiang Ling, Liao Ping Hu, Jin Ke Gong et Jia Qiang E. « The CFD Analysis of Internal Flow Field in Turbocharger Compressor ». Applied Mechanics and Materials 628 (septembre 2014) : 279–82. http://dx.doi.org/10.4028/www.scientific.net/amm.628.279.
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In this paper, the 3D flow analysis model of gasoline engine turbocharger compressor was built by using the software NUMECA. The flow fields of the vaneless diffuser and volute, such as airflow velocity field, temperature field, pressure field and the entropy field were simulated. The internal flow performance of the vaneless diffuser and volute were analyzed. The simulation results show that the field changes accord with the compressor characteristics, thus the vaneless diffuser and volute of the compressor design is reasonable. The approach of numerical simulation and flow field analysis by using CFD method can accurately predict the compressor performance. The research methods and conclusions provide theoretical and practical reference for the optimization design of the compressor.
4
Liu, Xiang Ling, Meng Xiang Liu et Jin Ke Gong. « The CFD Analysis of Gasoline Engine Turbocharger Compressor Based on NUMECA ». Applied Mechanics and Materials 433-435 (octobre 2013) : 2169–73. http://dx.doi.org/10.4028/www.scientific.net/amm.433-435.2169.
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In this paper, the finite element model and mesh model of JQ40A gasoline engine turbocharger compressor was built by using Computational Fluid Dynamics(CFD) software NUMECA. The compression ratio and efficiency characteristics of compressor were simulated and verified experimentally. Based on the established models, the airflow velocity field, pressure field, temperature field and entropy field in the compressor volute passage and impeller clearance were simulated and analyzed. The simulation results show that the pressure loss is low and the flow passage design is reasonable; A rational volute export curvatureRdoes not affect the compressor efficiency; the compressor impeller rim size can be adjusted to accommodate the engine torque characteristics; the engine speed affects internal loss of the flow field; within a certain range the impeller tip clearance is smaller, the higher the efficiency of the compressor is. The research methods and conclusions provide a basis for the optimization design of the compressor.
5
Heinrich, Martin, et Rüdiger Schwarze. « Genetic Algorithm Optimization of the Volute Shape of a Centrifugal Compressor ». International Journal of Rotating Machinery 2016 (2016) : 1–13. http://dx.doi.org/10.1155/2016/4849025.
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A numerical model for the genetic optimization of the volute of a centrifugal compressor for light commercial vehicles is presented. The volute cross-sectional shape is represented by cubic B-splines and its control points are used as design variables. The goal of the global optimization is to maximize the average compressor isentropic efficiency and total pressure ratio at design speed and four operating points. The numerical model consists of a density-based solver in combination with the SSTk-ωturbulence model with rotation/curvature correction and the multiple reference frame approach. The initial validation shows a good agreement between the numerical model and test bench measurements. As a result of the optimization, the average total pressure rise and efficiency are increased by over1.0%compared to the initial designs of the optimization, while the maximum efficiency rise is nearly 2.5% atm˙corr=0.19 kg/s.
6
JI, Chunjun. « Analysis and Optimization of the Internal Flow in Centrifugal Compressor Volute ». Journal of Mechanical Engineering 45, no 05 (2009) : 311. http://dx.doi.org/10.3901/jme.2009.05.311.
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Gu, Fahua, Abraham Engeda, Mike Cave et Jean-Luc Di Liberti. « A Numerical Investigation on the Volute/Diffuser Interaction Due to the Axial Distortion at the Impeller Exit ». Journal of Fluids Engineering 123, no 3 (17 avril 2001) : 475–83. http://dx.doi.org/10.1115/1.1385515.
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A numerical simulation is performed on a single-stage centrifugal compressor using the commercially available CFD software, CFX-TASCflow. The steady flow is obtained by circumferentially averaging the exit fluxes of the impeller. Three runs are made at the design condition and off-design conditions. The predicted performance is in agreement with experimental data. The flow details inside the stationary components are investigated, resulting in a flow model describing the volute/diffuser interaction at design and off-design conditions. The recirculation and twin vortex structure are found to explain the volute loss increase at lower and higher mass flows, respectively.
8
Dickmann, Hans-Peter, Thomas Secall Wimmel, Jaroslaw Szwedowicz, Dietmar Filsinger et Christian H. Roduner. « Unsteady Flow in a Turbocharger Centrifugal Compressor : Three-Dimensional Computational Fluid Dynamics Simulation and Numerical and Experimental Analysis of Impeller Blade Vibration ». Journal of Turbomachinery 128, no 3 (1 février 2005) : 455–65. http://dx.doi.org/10.1115/1.2183317.
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Experimental investigations on a single stage centrifugal compressor showed that measured blade vibration amplitudes vary considerably along a constant speed line from choke to surge. The unsteady flow has been analyzed to obtain detailed insight into the excitation mechanism. Therefore, a turbocharger compressor stage impeller has been modeled and simulated by means of computational fluid dynamics (CFD). Two operating points at off-design conditions were analyzed. One was close to choke and the second one close to the surge line. Transient CFD was employed, since only then a meaningful prediction of the blade excitation, caused by the unsteady flow situation, can be expected. Actually, it was observed that close to surge a steady state solution could not be obtained; only transient CFD could deliver a converged solution. The CFD results show the effect of the interaction between the inducer casing bleed system and the main flow. Additionally, the effect of the nonaxisymmetric components, such as the suction elbow and the discharge volute, was analyzed. The volute geometry itself had not been modeled. It turned out to be sufficient to impose a circumferentially asymmetric pressure distribution at the exit of the vaned diffuser to simulate the volute. Volute and suction elbow impose a circumferentially asymmetric flow field, which induces blade excitation. To understand the excitation mechanism, which causes the measured vibration behavior of the impeller, the time dependent pressure distribution on the impeller blades was transformed into the frequency domain by Fourier decomposition. The complex modal pressure data were imposed on the structure that was modeled by finite element methods (FEM). Following state-of-the-art calculations to analyze the free vibration behavior of the impeller, forced response calculations were carried out. Comparisons with the experimental results demonstrate that this employed methodology is capable of predicting the impeller’s vibration behavior under real engine conditions. Integrating the procedure into the design of centrifugal compressors will enhance the quality of the design process.
9
Flathers, M. B., et G. E. Bache´. « Aerodynamically Induced Radial Forces in a Centrifugal Gas Compressor : Part 2—Computational Investigation ». Journal of Engineering for Gas Turbines and Power 121, no 4 (1 octobre 1999) : 725–34. http://dx.doi.org/10.1115/1.2818533.
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Radial loads and direction of a centrifugal gas compressor containing a high specific speed mixed flow impeller and a single tongue volute were determined both experimentally and computationally at both design and off-design conditions. The experimental methodology was developed in conjunction with a traditional ASME PTC-10 closed-loop test to determine radial load and direction. The experimental study is detailed in Part 1 of this paper (Moore and Flathers, 1998). The computational method employs a commercially available, fully three-dimensional viscous code to analyze the impeller and the volute interaction. An uncoupled scheme was initially used where the impeller and volute were analyzed as separate models using a common vaneless diffuser geometry. The two calculations were then repeated until the boundary conditions at a chosen location in the common vaneless diffuser were nearly the same. Subsequently, a coupled scheme was used where the entire stage geometry was analyzed in one calculation, thus eliminating the need for manual iteration of the two independent calculations. In addition to radial load and direction information, this computational procedure also provided aerodynamic stage performance. The effect of impeller front face and rear face cavities was also quantified. The paper will discuss computational procedures, including grid generation and boundary conditions, as well as comparisons of the various computational schemes to experiment. The results of this study will show the limitations and benefits of Computational Fluid Dynamics (CFD) for determination of radial load, direction, and aerodynamic stage performance.
10
Galerkin, Y., et A. Drozdov. « Sample of CFD optimization of a centrifugal compressor stage ». IOP Conference Series : Materials Science and Engineering 90 (10 août 2015) : 012041. http://dx.doi.org/10.1088/1757-899x/90/1/012041.
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Wakaki, Daich, Yuta Sakuka, Yuzo Inokuchi, Kosuke Ueda, Nobuhiko Yamasaki et Akihiro Yamagata. « CFD simulation of pulsation noise in a small centrifugal compressor with volute and resonance tube ». Journal of Thermal Science 24, no 1 (10 janvier 2015) : 24–29. http://dx.doi.org/10.1007/s11630-015-0751-9.
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Zhu, Wei, Xiao-Dong Ren, Xue-Song Li et Chun-Wei Gu. « Analysis and Improvement of a Two-Stage Centrifugal Compressor Used in an MW-Level Gas Turbine ». Applied Sciences 8, no 8 (10 août 2018) : 1347. http://dx.doi.org/10.3390/app8081347.
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The performance of a low/high-pressure-stage centrifugal compressor in a land-use MW-level gas turbine with a pressure ratio of approximately 11 is analyzed and optimized with a 1D aerodynamic design and modeling optimization system. 1D optimization results indicate that the diameter ratio of the low-pressure-stage centrifugal compressor with a vane-less diffuser, and the divergent angle of the high-pressure-stage centrifugal compressor with a vaned diffuser, are extremely large and result in low efficiency. Through modeling design and optimization system analysis, a tandem vaned diffuser is used in the low-pressure stage, and a tandem vaned diffuser with splitter vanes is adopted in the high-pressure stage. Computational fluid dynamics (CFD) results show that the pressure ratio and efficiency of the optimized low/high-pressure-stage centrifugal compressor are significantly improved. Coupling calculations of the low/high-pressure stage of the original and optimized designs are conducted based on the results of MW-level gas turbine cycles. CFD results show that the pressure ratio and efficiency of the optimized two-stage centrifugal compressor increase by approximately 8% and 4%, respectively, under three typical load conditions of 100%, 90%, and 60%.
13
Mostefa, Brihmat, Refassi Kaddour, Douroum Embarek et Kouadri Amar. « Analysis and Optimization of the Performances of the Centrifugal Compressor Using the CFD ». International Journal of Heat and Technology 39, no 1 (28 février 2021) : 107–20. http://dx.doi.org/10.18280/ijht.390111.
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Centrifugal compressors have been used in many areas of the machinery. The centrifugal compressor design is very complex, and a unique design system needs to be developed. A centrifugal compressor design system should be easy to use in interface and also flexible for inputs and outputs. The design tool also needs to be able to predicate the compressor performance in a fairly accurate level. In this study, we have developed a general analyses and optimization approach in the design and performance analysis of centrifugal turbomachines. This approach is based on different methods starting from a 1D approach up to the 3D study of the internal flow. It presents itself as a robust procedure for predicting and understanding the phenomena associated with the operation of turbomachines, but also for predicting performance. Current design system includes initial parameter studies, throughflow calculation, impeller design. The main improvements of the design system are adding the interface to allow users easy to use, adding the input and output capabilities and modifying few correlations. Current design system can predict the blade loading and compressor performance better compared with original design system. To check the aerodynamic appearance of the centrifugal compressor impeller blades, we must change the impeller dimensions and focus on changing axial length, but when changing the blade numbers, the model that improved efficiency and power at the same time introduced a design with a 0.274% and 10.735% improvement in each respectively in comparison to the initial impeller at the design point.
14
Cho, Soo-Yong, Kook-Young Ahn, Young-Duk Lee et Young-Cheol Kim. « Optimal Design of a Centrifugal Compressor Impeller Using Evolutionary Algorithms ». Mathematical Problems in Engineering 2012 (2012) : 1–22. http://dx.doi.org/10.1155/2012/752931.
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An optimization study was conducted on a centrifugal compressor. Eight design variables were chosen from the control points for the Bezier curves which widely influenced the geometric variation; four design variables were selected to optimize the flow passage between the hub and the shroud, and other four design variables were used to improve the performance of the impeller blade. As an optimization algorithm, an artificial neural network (ANN) was adopted. Initially, the design of experiments was applied to set up the initial data space of the ANN, which was improved during the optimization process using a genetic algorithm. If a result of the ANN reached a higher level, that result was re-calculated by computational fluid dynamics (CFD) and was applied to develop a new ANN. The prediction difference between the ANN and CFD was consequently less than 1% after the 6th generation. Using this optimization technique, the computational time for the optimization was greatly reduced and the accuracy of the optimization algorithm was increased. The efficiency was improved by 1.4% without losing the pressure ratio, and Pareto-optimal solutions of the efficiency versus the pressure ratio were obtained through the 21st generation.
15
Abed, Cheikh Brahim, Sofiane Khelladi, Michael Deligant, Abdellatif El Marjani, Moisés Solis et Farid Bakir. « Experimental Validation of the Aerodynamic Performance of an Innovative Counter-Rotating Centrifugal Compressor ». Energies 14, no 9 (30 avril 2021) : 2582. http://dx.doi.org/10.3390/en14092582.
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Turbomachinery with double counter-rotating impellers offers more degrees of freedom in the choice of design and control parameters compared to conventional machines. For these innovative machines, the literature review shows that more publications concerning axial type turbomachines are available than centrifugal ones. This work deals with a design and experimental performance analysis, applied to two counter-rotating impellers of a centrifugal compressor “CRCC”. CRCC was designed with a specifically developed tool based on mean-line approach coupled with optimization algorithms and a stream-curvature through-flow method to satisfy the design criteria. This paper presents an experimental validation of the CRCC design tool and its performances against the baseline “SR”, composed of one centrifugal impeller and a volute for which experimental data are available. CRCC numeric simulations are also validated by experimental data. For a fair comparison between CRCC and SR, the same volute is used for both configurations. The CRCC studied here includes a first conventional impeller with an axial inlet and a radial outlet, while the second impeller is parametrically designed and can be considered a rotating bladed diffuser with a radial inlet and outlet. The obtained results show that CRCC can deliver a pressure rise increase of two compared to SR, along with an increase of isentropic efficiency and also validate the design method of this novel layout. The experimental results also show that the speed ratio of CRCC has a positive effect on the surge and shock margin.
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Marenina, Lyubov, Yuri Galerkin et Alexandr Drozdov. « Stator elements optimization of centrifugal compressor intermediate type stage by CFD methods ». E3S Web of Conferences 178 (2020) : 01020. http://dx.doi.org/10.1051/e3sconf/202017801020.
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Optimal gas-dynamic design is a complex and time-consuming process. Modern CFD methods help in solving optimization problems and reliably calculating characteristics of stator elements of centrifugal compressor stages. To carry out such calculations, it is necessary to create a parametrized model, which facilitates automation of the process of changing the flow path geometry, rebuilding its dimensions and the computational grid. Using the Direct Optimization program of the ANSYS software package, we have optimized the flow path of the stator elements of a centrifugal compressor intermediate type stage consisting of a vaneless diffuser and a return channel. In this paper, the MOGA (Multi-Objective Genetic Algorithm) optimization method was used. The object of the study was stator elements of one of the model stages designed by the Problem Laboratory of Compressor Engineering, SPbPU. The goal was to achieve the minimum value of the loss coefficient of stator elements when changing 5 geometric parameters: the number of vanes, the inlet vane angle, the height of the vane at the inlet to the return channel vane cascade, the radius of curvature of the leading edge and the thickness of the vane profile. For the best variants based on the results of optimization, the characteristics of the loss coefficient depending on the flow rate coefficient were calculated, their characteristics were compared with the initial variant of the stator elements. The best variant in the design mode has a loss coefficient 4.4% lower than the reference model. With a flow rate coefficient of 1.63 times greater than the calculated one, the optimized variant’s loss coefficient is 33% less.
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Dumitrescu, O., B. Gherman et A. Alcea. « Tip clearance influence in CFD calculations and optimization of a centrifugal compressor stage through CFD methods ». IOP Conference Series : Materials Science and Engineering 400 (18 septembre 2018) : 042018. http://dx.doi.org/10.1088/1757-899x/400/4/042018.
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Galerkin, Yuri, Aleksey Rekstin, Lyubov Marenina, Aleksandr Drozdov, Olga Solovyeva et Vasiliy Semenovskiy. « Optimization of Return Channels of High Flow Rate Centrifugal Compressor Stages Using CFD Methods ». Energies 13, no 22 (16 novembre 2020) : 5968. http://dx.doi.org/10.3390/en13225968.
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Calculations performed with modern CFD programs aid in optimizing flow paths of centrifugal compressors. Characteristics of stator elements of flow paths, calculated via CFD methods, are considered quite accurate. We present optimized return channels (RCh) of three model industrial compressor stages with vaneless diffusers. A parameterized model was created for optimization. The MOGA (Multi-Objective Genetic Algorithm) optimization method was applied in the Direct Optimization program of the ANSYS (Analysis System) software package. Optimization objects were return channels of the stages with high flow rate 0.15. The stages have three different loading factors 0.45, 0.60, 0.70. The optimization goal was to achieve the minimum loss coefficient at the design point. During the optimization process, we varied the following: the number of vanes, the inlet angle of the vanes, the height of the vanes at the inlet, the outer and inner radii of curvature of the U-bend. The outlet angle of the vanes was selected to minimize outlet circumferential velocity. In comparison with preliminary design, the optimized RCh are more efficient across the entire range of flow rates. The optimization reduced the loss coefficient by 20% at the design flow rate.
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Tang, Cheng, You-Chao Yang, Peng-Zhan Liu et Youn-Jea Kim. « Prediction of Abrasive and Impact Wear Due to Multi-Shaped Particles in a Centrifugal Pump via CFD-DEM Coupling Method ». Energies 14, no 9 (23 avril 2021) : 2391. http://dx.doi.org/10.3390/en14092391.
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Since solid particles suspended in the fluid can cause wear in centrifugal pumps, intensive attention has been focused on the numerical prediction for the wear of flow parts in centrifugal pumps. However, most numerical studies have focused on only one wear model and a sphere particle model. The impact of particle shape on the wear of flow parts in centrifugal pumps is under-studied, particularly considering abrasive and impact wear simultaneously. In this work, the Computational Fluid Dynamics (CFD)-Discrete Element Method (DEM) coupling method with an abrasive and impact wear prediction model was adopted to study the wear characteristics of a centrifugal pump. Moreover, four regular polyhedron particles and a sphere particle with the same equivalent diameter but different sphericity were mainly analyzed. The results demonstrate that more particles move closer to the blade pressure side in the impeller passage, and particles tend to cluster in specific areas within the volute as sphericity increases. The volute suffers the principal wear erosion no matter what the shapes of particles and wear model are. Both the impact and abrasive wear within the impeller occur primarily on the blade leading edge. The pump’s overall impact wear rate decreases first and then increases with particle sphericity rising, while the pump’s overall abrasive wear rate grows steadily.
20
Chen, Jian Dong, et Bei Bei Sun. « Optimization of Low-Noise and Large Air Volume Blower Based on Load Characteristic ». Key Engineering Materials 656-657 (juillet 2015) : 700–705. http://dx.doi.org/10.4028/www.scientific.net/kem.656-657.700.
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The blower is a kind of garden machinery, which blows strong wind to clean up leaves by a centrifugal fan, but it causes a loud aerodynamic noise. To compromise the contradiction between large air flow rate and low fan noise, some optimizations are proposed to reduce fan noise without lowering its air volume. In this paper, a CFD numerical model to compute airflow field of blower is established, where the centrifugal fan is simulated by the MRF model, and theturbulent model is selected. By smoothing the transition section, improving the volute tongue and optimizing the shape and optimizing number of fan blade, the blower work performance is increased obviously. In order to find out the actual working point, both the fan and motor load characteristic curves are drawn out. The simulation results show that, at the actual working point, the speed of the centrifugal fan is reduced, while the flow rate of blower is raised up. The optimizations are applied to the blower, and the experiment of the improved blower shows the flow rate is increased 5%, and the noise is reduced 2dB.
21
Ratz, Johannes, Sebastian Leichtfuß, Maximilian Beck, Heinz-Peter Schiffer et Friedrich Fröhlig. « Surge Margin Optimization of Centrifugal Compressors Using a New Objective Function Based on Local Flow Parameters ». International Journal of Turbomachinery, Propulsion and Power 4, no 4 (17 décembre 2019) : 42. http://dx.doi.org/10.3390/ijtpp4040042.
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Currently, 3D-CFD design optimization of centrifugal compressors in terms of the surge margin is one major unresolved issue. On that account, this paper introduces a new kind of objective function. The objective function is based on local flow parameters present at the design point of the centrifugal compressor. A centrifugal compressor with a vaned diffuser is considered to demonstrate the performance of this approach. By means of a variation of the beta angle distribution of the impeller and diffuser blade, 73 design variations are generated, and several local flow parameters are evaluated. Finally, the most promising flow parameter is transferred into an objective function, and an optimization is carried out. It is shown that the new approach delivers similar results as a comparable optimization with a classic objective function using two operating points for surge margin estimation, but with less computational effort since no second operating point near the surge needs to be considered.
22
Cui, Michael M. « Comparative Study of Unsteady Flows in a Transonic Centrifugal Compressor with Vaneless and Vaned Diffusers ». International Journal of Rotating Machinery 2005, no 1 (2005) : 90–103. http://dx.doi.org/10.1155/ijrm.2005.90.
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To reduce vibration and noise level, the impeller and diffuser blade numbers inside an industrial compressor are typically chosen without common divisors. The shapes of volutes or collectors in these compressors are also not axis-symmetric. When impeller blades pass these asymmetric structures, the flow field in the compressor is time-dependent and three-dimensional. To obtain a fundamental physical understanding of these three-dimensional unsteady flow fields and assess their impact on the compressor performance, the flow field inside the compressors needs to be studied as a whole to include asymmetric and unsteady interaction between the compressor components. In the current study, a unified three-dimensional numerical model was built for a transonic centrifugal compressor including impeller, diffusers, and volute. HFC 134a was used as the working fluid. The thermodynamic and transport properties of the refrigerant gas were modeled by the Martin-Hou equation of state and power laws, respectively. The three-dimensional unsteady flow field was simulated with a Navier-Stokes solver using thek−εturbulent model. The overall performance parameters are obtained by integrating the field quantities. Both the unsteady flow field and the overall performance are analyzed comparatively for each component. The compressor was tested in a water chiller system instrumented to obtain both the overall performance data and local flow-field quantities. The experimental and numerical results agree well. The correlation between the overall compressor performance and local flow-field quantities is defined. The methodology developed and data obtained in these studies can be applied to the centrifugal compressor design and optimization.
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Neverov, V. V., Y. V. Kozhukhov, A. M. Yablokov et A. A. Lebedev. « Optimization of a centrifugal compressor impeller using CFD : the choice of simulation model parameters ». IOP Conference Series : Materials Science and Engineering 232 (août 2017) : 012037. http://dx.doi.org/10.1088/1757-899x/232/1/012037.
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Cho, Soo Yong, Jin Han Kim et Chae Sil Kim. « Design of Compressor Impeller Using Evolutionary Optimization Technique ». Applied Mechanics and Materials 271-272 (décembre 2012) : 833–37. http://dx.doi.org/10.4028/www.scientific.net/amm.271-272.833.
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Configuration design on an impeller using to the centrifugal compressor of turbocharger was conducted to improve its performance. Impeller shape was adjusted by changing its meridional contours and blade profile. Total nine design variables were chosen with constraints. ANN (Artificial Neural Net) was adopted as a main optimization algorithm with PSO (Particle Swarm Optimization) in order to reduce the optimization time. This ANN was learned and trained with the design variable sets which were obtained using DOE (Design of Experiment). This ANN was continuously improved its accuracy for each generation of which population was one hundred. New design variable set in each generation was selected using a non-gradient based method of PSO in order to obtain the global optimized result. After 7th generation, the difference of efficiency and pressure ratio predicted by ANN and CFD (Computational Fluid Dynamics) was less than 0.6%. From more than 1,200 design variable sets, a pareto of efficiency versus pressure ratio was obtained and an optimized result was selected based on the multi-objective function. On this optimized impeller, the efficiency and pressure ratio were improved by 1% and 9.3%, respectively.
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Li, Wei, Leilei Ji, Weidong Shi, Ling Zhou, Hao Chang et Ramesh K. Agarwal. « Expansion of High Efficiency Region of Wind Energy Centrifugal Pump Based on Factorial Experiment Design and Computational Fluid Dynamics ». Energies 13, no 2 (19 janvier 2020) : 483. http://dx.doi.org/10.3390/en13020483.
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The wind energy pump system is a new green energy technology. The wide high efficiency region of pump is of great significance for energy conservation of wind power pumping system. In this study, factorial experiment design (FED) and computational fluid dynamics (CFD) are employed to optimize the hydraulic design of wind energy centrifugal pump (WECP). The blade outlet width b2, blade outlet angle β2, and blade wrap angle ψ are chosen as factors of FED. The effect of the factors on the efficiency under the conditions of 0.6Qdes, 0.8Qdes, 1.0Qdes, and 1.4Qdes is systematically analyzed. The matching feature of various volute tongue angle with the optimized impeller is also investigated numerically and experimentally. After the optimization, the pump head changes smoothly during full range of flow condition and the high efficiency region is effectively improved. The weighted average efficiency of four conditions increases by 2.55%, which broadens the high efficiency region of WECP globally. Besides, the highest efficiency point moves towards the large flow conditions. The research results provide references for expanding the efficient operation region of WECP.
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Ismail, Mohd Azlan, Al Khalid Othman et Hushairi Zen. « Numerical Simulation on End Suction Centrifugal Pump Running in Inverse Flow for Microhydro Applications ». Applied Mechanics and Materials 773-774 (juillet 2015) : 358–62. http://dx.doi.org/10.4028/www.scientific.net/amm.773-774.358.
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The initial capital cost for most microhydro projects has always been an overriding issue for self-funded remote communities. The cost will escalate significantly in the absence of local microhydro electromechanical manufacturers. The application of end suction centrifugal pump as turbine will reduce the overall cost, which renders microhydro systems feasible for self-funded projects and are therefore suitable for rural communities. The goal of this study is to design and develop a pump as turbine (PAT) which serves as a substitute to commercial electromechanical components. Numerical analysis of an inverse flow for an end suction centrifugal pump is presented in this paper, which includes the performance curves and hydraulic characteristics of the pump. ANSYS CFX, a commercial CFD software is used to simulate the performance of the pump with specific speed, Ns of 70 units (Euroflo EU50-20). The computational flow domain inside the pump is comprises of impeller, volute and draft tube. Unstructured tetrahedral mesh is used to maintain good surface mesh due to complex flow domain geometries. The governing equations used in the simulations are three-dimensional, incompressible Navier-Stokes and k-ϵ turbulence model under steady-state condition. The simulation results are compared with pump performance curve supplied by the pump manufacturer. The verification results show good agreement for flow rates between 0.7 and 1.3 QBEP. The best efficient point (BEP) for inverse flow is attained at a higher head and flow rate compared to pump mode, whereby the value is found to be 21.55 m and 14.0 l/s, respectively. It is believed that the findings of this study will be useful to predict hydraulic characteristics and performance curves of PAT and the model may be used to identify poor flow characteristics inside the pump. It is recommended that optimization process is carried out using CFD tools in future studies.
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McClanahan, Dustin R., G. R. Liu, Mark G. Turner et Devanathan Anantharaman. « Topology Optimization of the Interior Structure of Blades with an Outer Surface Determined Through Aerodynamic Design ». International Journal of Computational Methods 16, no 06 (27 mai 2019) : 1840027. http://dx.doi.org/10.1142/s0219876218400273.
Texte intégralRésumé :
This work performs a topology optimization of the interior structure of engine blades in compressors with any given geometry of the desired outer-surface shape that may be determined by CFD and aerodynamic design software for the desired performance for thermal and fluid flows. A lofted compressor airfoil surface from the aerodynamic design was used to create a three-dimensional (3D) solid in SolidWorks. This was converted to an .IGS file that would be imported into HyperMesh® for the meshing and submitted to OptiStruct® for optimization. An optimization process is designed to produce an optimal interior structure, considering both pressure on the outer surface and centrifugal forces produced by rotational movements. The optimized blade becomes hollow in an optimal pattern with minimum materials needed for the pressure loading on outer skin and the distributed centrifugal forces. The final design was compared to the initial design using finite element method (FEM) to confirm that the mass, stress, strain, and displacement were reduced. The mass was reduced by 59.8% and the stresses reduced by a factor of 3.66! These results were validated by conducting a mesh independence study. 3D printers were used to produce the optimized blades in both plastic and metal.
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Wang, Longyan, Stephen Ntiri Asomani, Jianping Yuan et Desmond Appiah. « Geometrical Optimization of Pump-As-Turbine (PAT) Impellers for Enhancing Energy Efficiency with 1-D Theory ». Energies 13, no 16 (10 août 2020) : 4120. http://dx.doi.org/10.3390/en13164120.
Texte intégralRésumé :
This paper presents a multi-objective optimization strategy for pump-as-turbines (PAT), which relies on one-dimensional theory and analysis of geometrical parameters. In this strategy, a theoretical model, which considers all possible losses incurred (mainly by the components of pipe inlet, impeller and volute), has been put forward for performance prediction of centrifugal pumps operating as turbines (PAT). With the established mathematical relationship between the efficiency of PAT (both at pump and turbine mode) and the impeller controlling variables, the geometric optimization of the PAT impeller is performed with constant rotational speed. Specifically, the optimization data consist of 50 sets of impellers generated from Latin Hypercube Sampling method with its corresponding efficiencies calculated. Subsequently, the pareto-based genetic algorithm (PBGA) was adopted to optimize the geometic parameters of the impellers through the theoretical model. To validate the theoretical optimization results, the high-fidelity Computational Fluid Dynamics (CFD) simulation and the experimental data are employed for comparison of the PAT performance. The findings show that the efficiencies of both the pump and PAT optimized variables increased by 0.27% and 16.3% respectively under the design flow condition. Based on the one-dimensional theoretical optimization results, the geometry of the impeller is redesigned to suit both pump and PAT mode operations. It is concluded that the chosen design variables (b2, β1, β2, and z) have a significant impact on the PAT efficiency, which demonstrates that the optimization scheme proposed in this study is practicable.
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Kabalyk, Kirill, Andrzej Jaeschke, Grzegorz Liśkiewicz, Michał Kulak, Tomasz Szydłowski et Robert Pietruszewski. « Structural Response of a Single-Stage Centrifugal Compressor to Fluid-Induced Excitations at Low-Flow Operating Condition : Experimental and Numerical Study ». Energies 14, no 14 (16 juillet 2021) : 4292. http://dx.doi.org/10.3390/en14144292.
Texte intégralRésumé :
The article describes an assessment of possible changes in constant fatigue life of a medium flow-coefficient centrifugal compressor impeller subject to operation at close-to-surge point. Some aspects of duct acoustics are additionally analyzed. The experimental measurements at partial load are presented and are primarily used for validation of unidirectionally coupled fluid-structural numerical model. The model is based on unsteady finite-volume fluid-flow simulations and on finite-element transient structural analysis. The validation is followed by the model implementation to replicate the industry-scale loads with reasonably higher rotational speed and suction pressure. The approach demonstrates satisfactory accuracy in prediction of stage performance and unsteady flow field in vaneless diffuser. The latter is deduced from signal analysis relying on continuous wavelet transformations. On the other hand, it is found that the aerodynamic incidence losses at close-to-surge point are underpredicted. The structural simulation generates considerable amounts of numerical noise, which has to be separated prior to evaluation of fluid-induced dynamic strain. The main source of disturbance is defined as a stationary region of static pressure drop caused by flow contraction at volute tongue and leading to first engine-order excitation in rotating frame of reference. Eventually, it is concluded that the amplitude of excitation is too low to lead to any additional fatigue.
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Sun-Sheng, Yang, Punit Singh et Hui Zhang. « Flow investigations of reverse running volute pumps with backward vanes in comparison to forward type turbine vanes ». Proceedings of the Institution of Mechanical Engineers, Part A : Journal of Power and Energy 233, no 1 (9 avril 2018) : 111–31. http://dx.doi.org/10.1177/0957650918768354.
Texte intégralRésumé :
The use of centrifugal pumps as turbines in the recent years has come as a boon to small and micro power application given its simplicity and robustness. However, attempts are continuously being made to improve the performance by modifying the geometry, and yet to retain its simpleness. This paper proposes a new design to the impeller of an existing pump with forward-shaped vanes in an unchanged volute that is in complete contrast to the conventional backward vanes. Three methodologies are involved in the analysis starting with classical theory, experiment and simulations. The theory entails the focus on optimizing the nozzle shape of the impeller to reduce viscous and eddies. The forward vane having shorter nozzle length has proved to be more efficient compared to the longer backward vane impeller, with an efficiency increase of nearly 5%. The experimental and CFD analysis to study the internal flow saw similitude in the streamline change in Euler moment. It also showed that there were not only increased viscous effects but also enhanced flow separation in the backward vanes at overload flows. The study also found radial clearance losses to be unacceptable for both the shapes. The overall conclusion was to move ahead with the forward design and convince the industry to adopt them for there have been greater strides in cost-effective manufacturing processes. The paper also recommends more study of intermediate blade angles since there was still persistence of small degree of vorticities in the forward blade nozzle. The optimization of volute-impeller interface along with the influence of non-flow zone would be other areas for future investigation. Synergy of academia and industry is also welcome to lend improved understanding in pumps as turbines and better translation to praxis.
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Ko¨ppel, Pascal, Christian Roduner, Peter Kupferschmied et Georg Gyarmathy. « On the Development and Application of the Fast-Response Aerodynamic Probe System in Turbomachines—Part 3 : Comparison of Averaging Methods Applied to Centrifugal Compressor Measurements ». Journal of Turbomachinery 122, no 3 (1 février 1999) : 527–35. http://dx.doi.org/10.1115/1.1303820.
Texte intégralRésumé :
Typically several hundred million data points arise from a comprehensive measurement campaign carried out in a centrifugal compressor test rig with the fast-response aerodynamic probe system (see Part 1). In order to obtain a maximum of information about the unsteady flow at any position in this turbomachine, the time-resolved data processing method has to be optimized. In contrast to the standard time-averaged flow measurements with pneumatic probes, the objective of fast-response aerodynamic probe measurements and of data processing is to extract novel information about crucial unsteady phenomena like turbulence, row-to-row interaction, modal or rotating stall, leakage flow effects, etc. In such cases, the simultaneous measurement of static and total pressures and flow vectors is of particular interest. Novel information means the analysis of averaged and time-resolved (wavelet) spectra, autocorrelations or time averages properly conserving physical fluxes, etc. Different averaging methods are applied to compress the time-dependent data measured by a one-sensor-probe (see Part 2) in a centrifugal compressor. Such results could be used for comparison with pneumatic sensor measurements and CFD calculations. The comparison of averaging methods includes the averaging theories by Traupel and by Dzung, which are compared to simple arithmetic time averaging. From there the specific stage work is calculated. In analyzing the time dependency, several ensemble-averaging procedures for flow pressure and velocity are utilized for separating deterministic from stochastic fluctuations, extracting blade row finger prints or investigating low-frequency surge type fluctuations. With respect to the selection and overall optimization of data processing methods, an overview of generic tools is given and the modularity of the processing procedures is discussed. [S0889-504X(00)01203-4]
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Danilishin, A. M., Y. V. Kozhukhov et V. K. Yun. « Multi-objective optimization for impeller shroud contour, the width of vane diffuser and the number of blades of the centrifugal compressor stage based on the CFD calculation ». IOP Conference Series : Materials Science and Engineering 90 (10 août 2015) : 012046. http://dx.doi.org/10.1088/1757-899x/90/1/012046.
Texte intégral
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Xu, C., et R. S. Amano. « The Performance Influences of a Centrifugal Compressor Due to Volute Local Deformation ». Journal of Energy Resources Technology 141, no 9 (4 avril 2019). http://dx.doi.org/10.1115/1.4043134.
Texte intégralRésumé :
Centrifugal compressors have broad applications in gas compression processes, especially in automobile turbocharger. During the turbocharger installation, there are many installation limitations in the compressor stage. Due to the restriction in the size of the engine bay, it always has limitations of installation for turbochargers. The compressor package always requests to modify the compressor geometry to fit specific constraints. The volute is the largest geometry of the turbocharger package in most of the case. Very often modifications of the volute were performed to meet the space constraints. In this study, the authors investigated the compressor performance for an initially designed volute and a modified volute. The study followed by an on engine performance comparisons, compressor performance gas stand tests and computational fluid fynamics (CFD) analysis. The studies provided the performance impacts of the local volute deformation due to installation constraints, i.e., a kink in a volute. The studies showed the local volute kink has small implications on compressor performance when the maximum kink depth is less than 10% of the local volute hydraulic diameter. The numerical analysis is in favorable agreements with experiments. The results of this study can be used as a basic guideline for local deformation performance impacts for the future turbocharger compressor volute modifications.
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Zheng, Xinqian, Zhenzhong Sun, Tomoki Kawakubo et Hideaki Tamaki. « Stability Improvement of a Turbocharger Centrifugal Compressor by a Nonaxisymmetric Vaned Diffuser ». Journal of Turbomachinery 140, no 4 (13 février 2018). http://dx.doi.org/10.1115/1.4038875.
Texte intégralRésumé :
The nonuniformity of the flow field induced by a nonaxisymmetric volute significantly degrades the stability of a turbocharger centrifugal compressor. In this paper, a nonaxisymmetric vaned diffuser is investigated as a nonaxisymmetric flow control method using both three-dimensional computational fluid dynamics (CFD) and experiment. The numerical study first focuses on the relationship between the flow field and the static pressure distortion, and the steady CFD results indicate that the positive static pressure gradient in the rotating direction facilitates flow separation in the vaned diffuser and induces a nonuniform flow field. A nonaxisymmetric flow control method with variable stagger and solidity of the vaned diffuser is developed to suppress the flow separation, and the guideline of the method suggests narrowing flow passages where the flow separates or closing diffuser vanes upstream of flow separations. Steady CFD also presents the flow field of the investigated turbocharger centrifugal compressor with volute, and flow separation is found in the flow passages near the volute tongue. Under the guidance of the nonaxisymmetric flow control method, several nonaxisymmetric vaned diffusers are designed to make the flow field uniform, which are believed to be beneficial for compressor stability. Finally, an experiment is carried out to validate the positive effects of the nonaxisymmetric vaned diffuser for stability improvement. The test data show that Non-AxisVD (with a nonaxisymmetric vaned diffuser) extends the stable flow range (SFR) of the compressor by 26% compared with the AxisVD (with an axisymmetric vaned diffuser), at the cost of acceptable decreases in the maximum total pressure ratio and peak efficiency.
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Faßbender, Armin, Martin Enneking et Peter Jeschke. « Rotor-Alone Tones in the Outflow Noise of a Centrifugal Compressor ». Journal of Turbomachinery 142, no 11 (14 septembre 2020). http://dx.doi.org/10.1115/1.4047893.
Texte intégralRésumé :
Abstract This article investigates the generation of rotor-alone tones and their contribution to the outflow noise of a transonic centrifugal compressor stage with vaneless diffuser and volute by means of unsteady full-annulus computational fluid dynamics (CFD) simulations. The aerodynamic field and the generation and propagation of sound were simulated simultaneously using the unsteady Reynolds-averaged Navier–Stokes (URANS) approach of the solver trace and a numerical grid consisting of 170 M cells. To assess the accuracy of the predicted fluctuations, the investigation compares the simulated diffuser flow field to measured flow angles and pressure fluctuations obtained from experiments conducted on a large-scale test rig. The analysis explains the different sound generation mechanisms responsible for tonal components in the acoustic spectrum at the compressor outlet based on the Fourier decomposition of the pressure fluctuations in diffuser and volute. Furthermore, this article analyzes the modal structure of the simulated sound field at the volute outlet by means of a radial mode analysis and discusses the influence of changing operating conditions on the sound power emitted. The analyses reveal that supersonic flow phenomena occurring at choked operating conditions cause a significant increase in noise emissions. Furthermore, the investigation shows that the sound field at the volute outlet is dominated by few low-order modes, a fact that justifies the analysis using methods based on the compressed sensing in future experimental investigations.
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Aka, Ibrahim Basar, Caglar Ozturk et Ismail Lazoglu. « Numerical investigation of volute tongue design on hemodynamic characteristics and hemolysis of the centrifugal blood pump ». SN Applied Sciences 3, no 1 (janvier 2021). http://dx.doi.org/10.1007/s42452-021-04142-1.
Texte intégralRésumé :
AbstractIn the design of rotary blood pumps, the optimization of design parameters plays an essential role in enhancing the hydrodynamic performance and hemocompatibility. This study investigates the influence of the volute tongue angle as a volute geometric parameter on the hemodynamic characteristics of a blood pump. A numerical investigation on five different versions of volute designs is carried out by utilizing a computational fluid dynamics (CFD) software ANSYS-FLUENT. The effect of volute tongue angle is evaluated regarding the hydrodynamic performance, circumferential pressure distribution, the radial force, and the blood damage potential. A series of volute configurations are constructed with a fixed radial gap (5%), but varying tongue angles ranging from 10 to 50°. The relative hemolysis is assessed with the Eulerian based empirical power-law blood damage model. The pressure-flow rate characteristics of the volute designs at a range of rotational speeds are obtained from the experimental measurements by using the blood analog fluid. The results indicate an inverse relationship between hydraulic performance and the tongue angle; at higher tongue angles, a decrease in performance was observed. However, a higher tongue angle improves the net radial force acting on the impeller. The pump achieves the optimized performance at 20° of the tongue angle with the relatively high hydrodynamic performance and minor blood damage risk.
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Shu, Mengying, Mingyang Yang, Ricardo F. Martinez-Botas, Kangyao Deng et Lei Shi. « Unsteady Responses of the Impeller of a Centrifugal Compressor Exposed to Pulsating Backpressure ». Journal of Engineering for Gas Turbines and Power 141, no 4 (1 novembre 2018). http://dx.doi.org/10.1115/1.4041658.
Texte intégralRésumé :
The flow in intake manifold of a heavily downsized internal combustion engine has increased levels of unsteadiness due to the reduction of cylinder number and manifold arrangement. The turbocharger compressor is thus exposed to significant pulsating backpressure. This paper studies the response of a centrifugal compressor to this unsteadiness using an experimentally validated numerical method. A computational fluid dynamic (CFD) model with the volute and impeller is established and validated by experimental measurements. Following this, an unsteady three-dimensional (3D) simulation is conducted on a single passage imposed by the pulsating backpressure conditions, which are obtained by one-dimensional (1D) unsteady simulation. The performance of the rotor passage deviates from the steady performance and a hysteresis loop, which encapsulates the steady condition, is formed. Moreover, the unsteadiness of the impeller performance is enhanced as the mass flow rate reduces. The pulsating performance and flow structures near stall are more favorable than those seen at constant backpressure. The flow behavior at points with the same instantaneous mass flow rate is substantially different at different time locations on the pulse. The flow in the impeller is determined by not only the instantaneous boundary condition but also by the evolution history of flow field. This study provides insights in the influence of pulsating backpressure on compressor performance in actual engine situations, from which better turbo-engine matching might be benefited.
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Ngo Boum, Ghislaine, Rodolfo Bontempo et Isabelle Trébinjac. « Three-Dimensional/One-Dimensional Combined Simulation of Deep Surge Loop in a Turbocharger Compressor With Vaned Diffuser ». Journal of Engineering for Gas Turbines and Power 141, no 7 (5 mars 2019). http://dx.doi.org/10.1115/1.4042833.
Texte intégralRésumé :
High accuracy simulation of compressor surge origin and growth is an important challenge for designers of systems using compressors likely to develop that severe instability. Indeed, understanding its driving phenomena, which can be system dependent, is necessary to build an adequate strategy to avoid or control surge emergence. Computational fluid dynamics (CFD) simulations, commonly used to explore flow in the compressor, need then to be extended beyond the compressor as surge is a system scale instability. To get an insight on the path to surge and through surge cycles, a reliable alternative to full three-dimensional (3D) system modeling is used for a turbocharger compressor inserted in an experimental test rig. The air flow in the whole circuit, is modeled with a one-dimensional (1D) Navier Stokes approach which is coupled with a 3D unsteady RANS modeling of the 360 deg air flow in the centrifugal compressor including the volute. Starting from an initial stable flow solution in the system, the back-pressure valve is progressively closed to reduce the massflow and trigger the instability. An entire deep surge loop is simulated and compared with good agreement with the experimental data. The existence of a system-induced convective wave is revealed, and its major role on surge inception at diffuser inlet demonstrated.
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Mohammedali, Abubaker A. M., et Kiseong Kim. « Development of High-Efficient Centrifugal Pump Through Optimization of Its Volute Tongue and Expeller Vane ». Journal of Fluids Engineering 143, no 7 (9 avril 2021). http://dx.doi.org/10.1115/1.4050345.
Texte intégralRésumé :
Abstract Centrifugal pumps are often used for pumping liquids from one priority area to another, which require working effectively in terms of performance and reliability. The objective of this study is to enhance the hydraulic performance and reliability of a centrifugal pump based on computational fluid dynamics (CFD) optimization. The shapes of the expeller vane and volute tongue were optimized based on the following six design parameters; outer diameter, exit angle, front and rear heights, back sidewall gap, and tongue angle. The hydraulic efficiency and axial thrust were chosen as the optimization objectives. In this sense, a design of experiment (DOE) technique was utilized to generate 45 design samples. A response surface modeling (RSM) approach was employed to investigate the interaction between the parameters and objectives. The accuracy of the numerical simulation was verified by the experimental data and showed a good agreement. The optimization was found to improve the hydraulic efficiency by 2.92%, whereas the axial thrust was decreased by 7.51%.
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Javed, A., R. Pecnik et J. P. van Buijtenen. « Optimization of a Centrifugal Compressor Impeller for Robustness to Manufacturing Uncertainties ». Journal of Engineering for Gas Turbines and Power 138, no 11 (3 mai 2016). http://dx.doi.org/10.1115/1.4033185.
Texte intégralRésumé :
Compressor impellers for mass-market turbochargers are die-casted and machined with an aim to achieve high dimensional accuracy and acquire specific performance. However, manufacturing uncertainties result in dimensional deviations causing incompatible operational performance and assembly errors. Process capability limitations of the manufacturer can cause an increase in part rejections, resulting in high production cost. This paper presents a study on a centrifugal impeller with focus on the conceptual design phase to obtain a turbomachine that is robust to manufacturing uncertainties. The impeller has been parameterized and evaluated using a commercial computational fluid dynamics (CFDs) solver. Considering the computational cost of CFD, a surrogate model has been prepared for the impeller by response surface methodology (RSM) using space-filling Latin hypercube designs. A sensitivity analysis has been performed initially to identify the critical geometric parameters which influence the performance mainly. Sensitivity analysis is followed by the uncertainty propagation and quantification using the surrogate model based Monte Carlo simulation. Finally, a robust design optimization has been carried out using a stochastic optimization algorithm leading to a robust impeller design for which the performance is relatively insensitive to variability in geometry without reducing the sources of inherent variation, i.e., the manufacturing noise.
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Hazby, Hamid, Chris Robinson, Michael Casey, Daniel Rusch et Rene Hunziker. « Free-Form Versus Ruled Inducer Design in a Transonic Centrifugal Impeller ». Journal of Turbomachinery 140, no 1 (31 octobre 2017). http://dx.doi.org/10.1115/1.4038176.
Texte intégralRésumé :
The detailed design of the inducer of a high pressure ratio transonic radial compressor impeller with a design inlet tip relative Mach number of 1.4 is considered. Numerical analysis has been used to compare a datum impeller with ruled inducer design with a number of different free-form design concepts, generated following the same aerodynamic design philosophy. The datum stage and one with a free-form inducer, referred to as “barrelled forward swept,” with forward swept leading edge near the tip and increased chord at midspan, have been manufactured and tested. The tests were performed with the same stationary components, including the casing, vaned diffuser, and the volute. The design with a barrelled forward sweep of the inducer allows the designer more control of the strength and position of the passage shock at the inlet while meeting mechanical constraints. Interestingly, the performance is also enhanced at off-design points at lower tip-speeds. The measurements show that the stage tested with the swept impeller achieves higher efficiency of between 0.5% and 1.6% compared to the datum design, depending on the operating speed. The computational fluid dynamics (CFD) simulations are used to further study the flow at part speeds, in order to explain the causes of the observed performance differences at off design conditions.
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Hehn, Alexander, Moritz Mosdzien, Daniel Grates et Peter Jeschke. « Aerodynamic Optimization of a Transonic Centrifugal Compressor by Using Arbitrary Blade Surfaces ». Journal of Turbomachinery 140, no 5 (6 avril 2018). http://dx.doi.org/10.1115/1.4038908.
Texte intégralRésumé :
A transonic centrifugal compressor was aerodynamically optimized by means of a numerical optimization process. The objectives were to increase the isentropic efficiency and to reduce the acoustic signature by decreasing the amplitude of pre-shock pressure waves at the inlet of the compressor. The optimization was performed at three operating points on the 100% speed line in order to maintain choke mass flow and surge margin. At the design point, the specific work input was kept equal. The baseline impeller was designed by using ruled surfaces due to requirements for flank milling. To investigate the benefits of arbitrary blade surfaces, the restrictions of ruled surfaces were abolished and fully three-dimensional (3D) blade profiles allowed. In total, therefore, 45 parameters were varied during the optimization. The combined geometric and aerodynamic analysis reveals that a forward swept leading edge (LE) and a concave suction side at the tip of the LE are effective design features for reducing the shock strength. Beyond that, the blade shape of the optimized compressor creates a favorable impeller outlet flow, which is the main reason why the performance of the vaneless diffuser improves. In total, a gain of 1.4% points in isentropic total-to-static efficiency, evaluated by computational fluid dynamics (CFD) at the exit plane of the vaneless diffuser, is achieved.
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Hildebrandt, A., et T. Ceyrowsky. « One-Dimensional and Three-Dimensional Design Strategies for Pressure Slope Optimization of High-Flow Transonic Centrifugal Compressor Impellers ». Journal of Turbomachinery 141, no 5 (21 janvier 2019). http://dx.doi.org/10.1115/1.4041907.
Texte intégralRésumé :
This paper deals with the numerical and theoretical investigations of the effect of geometrical dimensions and one-dimensional (1D)-design parameters on the impeller pressure slope of a transonic centrifugal compressor stage for industrial process application. A database being generated during the multi-objective and multipoint design process of a high flow coefficient impeller, comprising 545 computational fluid dynamics (CFD) designs is investigated in off-design and design conditions by means of Reynolds-averaged Navier–Stokes (RANS) simulation of an impeller with vaneless diffuser. For high flow coefficients of 0.16 < ϕdes < 0.18, the CFD-setup has been validated against measurement data regarding stage and impeller performance taken from MAN test rig experimental data for a centrifugal compressor stage of similar flow coefficient. This paper aims at answering the question how classical design parameter, such as the impeller blade angle distribution, impeller suction diameter, and camber line length affect the local and total relative diffusion and pressure slope toward impeller stall operation. A second-order analysis of the CFD database is performed by cross-correlating the CFD data with results from impeller two-zone 1D modeling and a rapid loading calculation process by Stanitz and Prian. The statistical covariance of first-order 1D-analysis parameters such as the mixing loss of the impeller secondary flow, the slip factor, impeller flow incidence is analyzed, thereby showing strong correlation with the design and off-design point efficiency and pressure slope. Finally, guide lines are derived in order to achieve either optimized design point efficiency or maximum negative pressure slope characteristics toward impeller stall operation.
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Wang, Peng, Mehrdad Zangeneh, Bryn Richards, Kevin Gray, James Tran et Asuquo Andah. « Redesign of a Compressor Stage for a High-Performance Electric Supercharger in a Heavily Downsized Engine ». Journal of Engineering for Gas Turbines and Power 140, no 4 (7 novembre 2017). http://dx.doi.org/10.1115/1.4038021.
Texte intégralRésumé :
Engine downsizing is a modern solution for the reduction of CO2 emissions from internal combustion engines. This technology has been gaining increasing attention from industry. In order to enable a downsized engine to operate properly at low speed conditions, it is essential to have a compressor stage with very good surge margin. The ported shroud, also known as the casing treatment, is a conventional way used in turbochargers to widen the working range. However, the ported shroud works effectively only at pressure ratios higher than 3:1. At lower pressure ratio, its advantages for surge margin enhancements are very limited. The variable inlet guide vanes are also a solution to this problem. By adjusting the setting angles of variable inlet guide vanes, it is possible to shift the compressor map toward the smaller flow rates. However, this would also undermine the stage efficiency, require extra space for installing the inlet guide vanes, and add costs. The best solution is therefore to improve the design of impeller blade itself to attain high aerodynamic performances and wide operating ranges. This paper reports a recent study of using inverse design method for the redesign of a centrifugal compressor stage used in an electric supercharger, including the impeller blade and volute. The main requirements were to substantially increase the stable operating range of the compressor in order to meet the demands of the downsized engine. The three-dimensional (3D) inverse design method was used to optimize the impeller geometry and achieve higher efficiency and stable operating range. The predicted performance map shows great advantages when compared with the existing design. To validate the computational fluid dynamics (CFD) results, this new compressor stage has also been prototyped and tested. It will be shown that the CFD predictions have very good agreement with experiments and the redesigned compressor stage has improved the pressure ratio, aerodynamic efficiency, choke, and surge margins considerably.
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Zhang, Luying, Gabriel Davila et Mehrdad Zangeneh. « Multi-Objective Optimization of a High Specific Speed Centrifugal Volute Pump Using Three-Dimensional Inverse Design Coupled With Computational Fluid Dynamics Simulations ». Journal of Fluids Engineering 143, no 2 (26 octobre 2020). http://dx.doi.org/10.1115/1.4048292.
Texte intégralRésumé :
Abstract This paper presents three different multiobjective optimization strategies for a high specific speed centrifugal volute pump design. The objectives of the optimization consist of maximizing the efficiency and minimizing the cavitation while maintaining the Euler head. The first two optimization strategies use a three-dimensional (3D) inverse design method to parametrize the blade geometry. Both meridional shape and 3D blade geometry are changed during the optimization. In the first approach, design of experiment (DOE) method is used and the pump efficiency is obtained from computational fluid dynamics (CFD) simulations, while cavitation is evaluated by using minimum pressure on blade surface predicted by 3D inverse design method. The design matrix is then used to create a surrogate model where optimization is run to find the best tradeoff between cavitation and efficiency. This optimized geometry is manufactured and tested and is found to be 3.9% more efficient than the baseline with reduced cavitation at high flow. In the second approach, only the 3D inverse design method output is used to compute the efficiency and cavitation parameters and this leads to considerable reduction to the computational time. The resulting optimized geometry is found to be similar to the computationally more expensive solution based on 3D CFD results. In order to compare the inverse design based optimization to the conventional optimization, an equivalent optimization is carried out by parametrizing the blade angle and meridional shape.
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Li, Xiaojian, Zhengxian Liu et Yijia Zhao. « Redesign of casing treatment for a transonic centrifugal compressor based on a hybrid global optimization method ». Proceedings of the Institution of Mechanical Engineers, Part C : Journal of Mechanical Engineering Science, 18 août 2021, 095440622110398. http://dx.doi.org/10.1177/09544062211039878.
Texte intégralRésumé :
As a typical black-box problem, recirculating casing treatment (RCT) optimization of compressor stages is computationally intensive and time consuming, even though surrogate models are usually employed. In order to improve efficiency and robustness of the optimization, an expected-improvement (EI) based hybrid global optimization (EHGO) algorithm is developed by coupling an EI-based surrogate model with a hybrid optimization algorithm. Highly nonlinear and multiple modality mathematical tests show that the EHGO algorithm is able to create a high-fidelity surrogate model near targeted regions with less evaluated samples, and to obtain the global optimal solution simultaneously. The RCT of a compressor stage is optimized based on this algorithm. The number of CFD simulations required for obtaining an optimum solution is greatly reduced, as compared to similar studies using conventional methods. The optimization results show that the aerodynamic performance is improved over the whole speed line and the flow range is also extended. The dominant factors for the performance improvements and the enhanced stall margin are addressed by analyzing the local flow characteristics before and after optimization. It is found that those factors include: removing a larger amount of low-momentum fluid, achieving a more uniform flow of impeller passage in circumferential direction, and reducing the radial distortion of impeller inlet flow. The proposed algorithm has the potential to considerably speed up the optimization process and make the optimization much more accessible. It can be generalized to deal with other computationally intensive black-box problems, for example, turbomachinery optimization.
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Gugau, Marc, et Harald Roclawski. « On the Design and Matching of Turbocharger Single Scroll Turbines for Pass Car Gasoline Engines ». Journal of Engineering for Gas Turbines and Power 136, no 12 (27 juin 2014). http://dx.doi.org/10.1115/1.4027710.
Texte intégralRésumé :
With emission legislation becoming more stringent within the next years, almost all future internal combustion gasoline engines need to reduce specific fuel consumption, most of them by using turbochargers. Additionally, car manufactures attach high importance to a good drivability, which usually is being quantified as a target torque already available at low engine speeds—reached in transient response operation as fast as possible. These engine requirements result in a challenging turbocharger compressor and turbine design task, since for both not one single operating point needs to be aerodynamically optimized but the components have to provide for the optimum overall compromise for maximum thermodynamic performance. The component design targets are closely related and actually controlled by the matching procedure that fits turbine and compressor to the engine. Inaccuracies in matching a turbine to the engine full load are largely due to the pulsating engine flow characteristic and arise from the necessity of arbitrary turbine map extrapolation toward low turbine blade speed ratios and the deficient estimation of turbine efficiency for low engine speed operating points. This paper addresses the above described standard problems, presenting a methodology that covers almost all aspects of thermodynamic turbine design based on a comparison of radial and mixed-flow turbines. Wheel geometry definition with respect to contrary design objectives is done using computational fluid dynamics (CFD), finite element analysis (FEA), and optimization software. Parametrical turbine models, composed of wheel, volute, and standard piping allow for fast map calculation similar to steady hot gas tests but covering the complete range of engine pulsating mass flow. These extended turbine maps are then used for a particular assessment of turbine power output under unsteady flow admission resulting in an improved steady-state matching quality. Additionally, the effect of various design parameters like either volute sizing or the choice of compressor to turbine diameter ratio on turbine blade speed ratio operating range as well as well as turbine inertia effect is analyzed. Finally, this method enables the designer to comparatively evaluate the ability of a turbine design to accelerate the turbocharger speed for transient engine response while still offering a map characteristic that keeps fuel consumption low at all engine speeds.