Academic literature on the topic 'Jet spread angle'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'Jet spread angle.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Journal articles on the topic "Jet spread angle"
1
Zhao, S. M., Z. D. Yang, Q. L. Zhang, J. L. Sun, and Y. Wang. "Experimental study on temperature spread of multi-angle inclined buoyant jet." IOP Conference Series: Earth and Environmental Science 191 (November 5, 2018): 012063. http://dx.doi.org/10.1088/1755-1315/191/1/012063.
Full text
2
Li, Xin, Yurong Wang, and Jianmin Zhang. "Numerical Simulation of an Offset Jet in Bounded Pool with Deflection Wall." Mathematical Problems in Engineering 2017 (2017): 1–11. http://dx.doi.org/10.1155/2017/5943143.
Full textAbstract:
The k-ε turbulent model and VOF methods were used to simulate the three-dimensional turbulence jet. Numerical simulations were carried out for three different kinds of jets in a bounded pool with the deflection wall with angles of 0°, 3°, 6°, and 9°. The numerical simulation agrees well with the experimental data. The studies show that the length of the potential core zone increases with the increase of the deflection angle. The velocity distribution is consistent with the Gaussian distribution and almost not affected by the deflection angle in potential core zone. The decay rates of flow velocity in the transition zone are 1.195, 1.281, 1.439, and 1.532 corresponding to the unilateral deflection angles, 0°, 3°, 6°, and 9°, respectively. The decay rates of velocity in the transition zone are 1.928 and 2.835 corresponding to the bilateral deflection angles 3° and 6°. It is also found that the spread of velocity is stronger in the vertical direction as the deflection angles become smaller. The spread rates of velocity with unilateral deflection wall are higher than those with bilateral deflection walls in the horizontal plane in the pool.
3
Zang, Wei, Xin Cheng Li, Yi Chen, and Yu Ting Luo. "Numerical Study of the inside Flow Field and the Rectangle Channel Impeller of Roto-Jet Pump." Applied Mechanics and Materials 529 (June 2014): 164–68. http://dx.doi.org/10.4028/www.scientific.net/amm.529.164.
Full textAbstract:
By means of ANSYS-CFX, the 3D numerical simulations of flow field for the three hydraulic models are performed. Through comparing the three types of pumps with three different rectangle channel impellers which have different spread angle, blade, the authors draw conclusions: the distribution of the pressure and velocity in the rectangle flow channels with 6° spread angle is well-proportioned, the head and the efficiency of the whole pump can meet the requirement: But the other two types of impeller channels, the distribution of velocity is unstable, there are backflow and big whirlpool. Therefore, the rectangle channel impeller with 6°spread angle is a better type for the Roto-Jet pump.
4
Ingole, Sunil B., and K. K. Sundaram. "Cold Zone Exploration Using Position of Maximum Nusselt Number for Inclined Air Jet Cooling." Archive of Mechanical Engineering 64, no. 4 (December 20, 2017): 533–49. http://dx.doi.org/10.1515/meceng-2017-0031.
Full textAbstract:
Abstract Inclined jet air cooling can be effectively used for cooling of electronics or other such applications. The non-confined air jet is impinged and experimentally investigated on the hot target surface to be cooled, which is placed horizontally. Analysis and evaluations are made by introduction of a jet on the leading edge and investigated for downhill side cooling to identify cold spots. The jet Reynolds number in the range of 2000 ≤ Re ≤ 20 000 is examined with a circular jet for inclination (Θ) of 15 < Θ < 75 degree. Also, the consequence of a jet to target distance (H) is explored in the range 0:5 ≤ H/D ≤ 6.8. For 45 degree jet impingement, the maximum Nusselt number is widely spread. Location of maximum Nusselt number is studied, which indicates cold spots identification. At a higher angle ratio, the angle is the dominating parameter compared to the Reynolds Number. Whereas at a lower angle ratio, the inclined jet with a higher Reynolds number is giving the cooling point away from leading edge. It is observed that for a particular angle of incident location of maximum Nusselt Number, measured from leading edge of target, is ahead than that of stagnation point in stated conditions.
5
Mohabi, A., and M. Hejazi. "The Effect of Nozzle Configuration on Characteristics of Fluidic Excited Jets." Applied Mechanics and Materials 564 (June 2014): 269–74. http://dx.doi.org/10.4028/www.scientific.net/amm.564.269.
Full textAbstract:
Using fluidic self-excited jets increases the rate of fluid mixing and reduces fuel consumption in industry burners (torches) and combustion chambers. The geometry of such jets is an important factor for fluidic jet determination. This study is concerned with investigating the types of fluidic nozzles configuration. The effect of nozzle configuration types was studied on various parameters such as frequency, velocity profile, velocity decay rate, the half angle of jet spread, and entrainment ratio. Maximum frequency and excited oscillation amplitude of fluidic jets were observed in the original geometry configuration. Also, the maximum spread rate and minimum velocity profile were observed in this geometry. Velocity decay rate shows its maximum magnitude in the original geometry configuration. Turbulence intensity reaches its maximum value in this geometry without any internal nozzle, whereas it shows the minimum value at geometry with an additional wall along the internal nozzle. The maximum increase in the half angle of jet spread was seen in the original geometry configuration. In this geometry, entrainment ratio is less than one, while in the geometry to create steady jets, entrainment ratio is more than one.
6
Farrington, R. B. "Infrared Imaging Results of an Excited Planar Jet." Journal of Solar Energy Engineering 115, no. 2 (May 1, 1993): 85–92. http://dx.doi.org/10.1115/1.2930036.
Full textAbstract:
Planar jets are used for many applications including heating, cooling, and ventilation. Generally, a planar jet provides good mixing within an enclosure. In building applications, the jet provides both thermal comfort and adequate indoor air quality. Increased mixing rates may reduce short circuiting of conditioned air, eliminate dead zones within the occupied zone, reduce energy costs, increase occupant comfort, and increase indoor air quality. This article discusses how an infrared imaging system was used to demonstrate how jet excitation affected the spread angle and the jet mixing efficiency. Infrared imaging captures a large number of data points in real time (over 50,000 data points per image) providing significant advantages over single-point measurements. We used a mesh screen with a time constant of approximately 0.3 seconds as a target for the infrared camera to detect temperature variations in the jet. The infrared images show that excitation of the jet caused increased jet spread. Digital data reduction and analysis show changes in jet isotherms and quantify the increased mixing caused by excitation.
7
Pramanik, Shantanu, and Manab Kumar Das. "Computational study of a turbulent wall jet flow on an oblique surface." International Journal of Numerical Methods for Heat & Fluid Flow 24, no. 2 (February 25, 2014): 290–324. http://dx.doi.org/10.1108/hff-01-2012-0005.
Full textAbstract:
Purpose – The purpose of the present study is to investigate the flow and turbulence characteristics of a turbulent wall jet flowing over a surface inclined with the horizontal and to investigate the effect of variation of the angle of inclination of the wall on the flow structure of the wall jet. Design/methodology/approach – The high Reynolds number two-equation κ− model with standard wall function is used as the turbulence model. The Reynolds number considered for the present study is 10,000. The Reynolds averaged Navier-Stokes (RANS) equations are used for predicting the turbulent flow. A staggered differencing technique employing both contravariant and Cartesian components of velocity has been applied. Results for distribution of wall static pressure and skin friction, decay of maximum streamwise velocity, streamwise variation of integral momentum and energy flux have been compared for the cases of α=0°, 5°, and 10°. Findings – Flow field has been represented in terms of streamwise and lateral velocity contours, static pressure contour, vorticity contour and streamwise velocity and static pressure profiles at different locations along the oblique offset plate. Distribution of Reynolds stresses in terms of spanwise, lateral and turbulent shear stresses, and turbulent kinetic energy and its dissipation rate have been presented to describe the turbulent characteristics. Similarity of streamwise velocity and the velocity parallel to the oblique wall has been observed in the developed region of the wall jet flow. A decaying trend is observed in the variation of total integral momentum flux in the developed region of the wall jet which becomes more evident with increase in oblique angle. Developed flow region has indicated trend of similarity in profiles of streamwise velocity as well as velocity component parallel to the oblique wall. A depression in wall static pressure has been observed near the nozzle exit when the wall is inclined and the depression increases with increase in inclination. Effect of variation of oblique angles on skin friction coefficient has indicated that it decreases with increase in oblique angle. Growth of the outer and inner shear layers and spread of the jet shows linear variation with distance along the oblique wall. Decay of maximum streamwise velocity is found to be unaffected by variation in oblique angle except in the far downstream region. The streamwise variation of spanwise integral energy shows increase in oblique angle and decreases the magnitude of energy flux through the domain. In the developed flow region, streamwise variation of centreline turbulent intensities shows increased values with increase in oblique angle, while turbulence intensities along the jet centreline in the region X<12 remain unaffected by change in oblique angles. Normalized turbulent kinetic energy distribution highlights the difference in turbulence characteristics between the wall jet and reattached offset jet flow. Near wall velocity distribution shows that the inner region of boundary layer of the developed oblique wall jet follows a logarithmic profile, but it shows some difference from the standard logarithmic curve of turbulent boundary layers which can be attributed to an increase in skin friction coefficient and a decrease in thickness of the wall attached layer. Originality/value – The study presents an in-depth investigation of the interaction between the jet and the inclined wall. It is shown that due to the Coanda effect, the jet follows the nearby wall. The findings will be useful in the study of combined flow of wall jet and offset jet and dual offset jet on oblique surfaces leading to a better design of some mechanical jet flow devices.
8
Hua, Lin, Hong Li, and Yue Jiang. "Axis-Switching Behavior of Liquid Jets Issued from Non-Circular Nozzles Under Low-Intermediate Pressure." Applied Engineering in Agriculture 37, no. 2 (2021): 367–78. http://dx.doi.org/10.13031/aea.14245.
Full textAbstract:
HighlightsThe flow behavior of water jets discharged from different orifices was investigated.High-speed photography (HSP) was used to obtain surface structures and spread characteristics of water jets.The deformation process in axis switching related to the corner vortices effect of non-circular jets was researched by numerical simulation.The axis switching of non-circular jets enhances entrainment ability of the jet.ABSTRACT. Low-intermediate pressure sprinkler irrigation systems are important research topics in the field of water-saving irrigation. Non-circular nozzles improve spray uniformity at lower pressures and are key components of sprinkler irrigation systems. In this article, the behavior of discharged water jets from nozzles with circular, square, and equilateral triangular orifices designed with the same flow rate was investigated. High-speed photography (HSP) was used to capture jet characteristics in the near field (z<20D). The largest spread angle was obtained for the square jet, which was on average 37% larger than that of the circular jet. In addition, numerical simulations were performed to analyze the axis-switching process using the large-eddy simulation (LES) method and the coupled level-set and volume of fluid (CLSVOF) method. The axis-switching phenomenon was observed in non-circular jets, in which surrounding air mixed with the jet and promoted the formation of thin diaphragm structures. The deformation process that occurs in axis switching is described according to the simulated vorticity and velocity fields. The research results suggest the axis-switching phenomenon is induced by corner vortex motions produced by the polygonal orifice, which accelerate the decay of the axial velocity and increase the jet entrainment rate. Thus, the effect of corner vortices should be considered in the design of polygonal nozzles. Keywords: Axis switching, High-speed photography, Liquid jet, Low-intermediate pressure sprinkler irrigation, Non-circular nozzle, Numerical simulation.
9
Li, Manhou, Zhizhong Shu, Shuwei Geng, and Guangzhao Han. "Experimental and modelling study on flame tilt angle of flame spread over jet fuel under longitudinally forced air flows." Fuel 270 (June 2020): 117516. http://dx.doi.org/10.1016/j.fuel.2020.117516.
Full text
10
Stapelfeldt, Karl, Christopher J. Burrows, and John E. Krist. "Hubble Space Telescope Imaging of the Disks and Jets of Taurus Young Stellar Objects." Symposium - International Astronomical Union 182 (1997): 355–64. http://dx.doi.org/10.1017/s0074180900061775.
Full textAbstract:
We report on Hubble Space Telescope imaging of eleven young stellar objects in the nearby Taurus molecular clouds. The high spatial resolution and stable point spread function of HST reveal important new details of the circumstellar nebulosity of these objects. Three sources (HH 30, FS Tau B, and DG Tau B) are resolved as compact bipolar nebulae without a directly visible star. In all three cases, jet widths near the sources are found to be 50 AU or less. Flattened disk structures are seen in absorption in HH 30 and FS Tau B, and in reflection about GM Aur. Extended envelope structures traced by scattered light are present in HL Tau, T Tau, DG Tau, and FS Tau. The jet in DG Tau exhibits a large opening angle and is already resolved into a bow-like structure less than 3″ from the star.
Dissertations / Theses on the topic "Jet spread angle"
1
Šeda, Libor. "Analýza proudění z vyústky osobního vozu s využitím termoanemometrické sondy." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-231972.
Full textAbstract:
In this master’s thesis there are summarized fundamental findings about air flow velocity measurements and afterwards introduced the measuring track for automobile car vents, measured object and track arrangement and all used components. Velocity field measurement method is how wire anemometry, and apart from 4 main cases measurements of free air jet, there are velocity profiles in piping measured as an input for CFD simulation. Air vent evaluation criteria are described and their assessment is done for specified cases. Further, there is a CFD simulation presented with comparison to experimental data. Uncertainty of flow rate measured and flow rate setting is determined. Improvement points and encountered issues are presented. Visualization and evaluation program coded in MATLAB environment enables easy data display of CTA results and will serve further vent quality assessment.
2
Mead, Ryan M. "Analysis of Flow in a Spray Nozzle With Emphasis on Exiting Jet Free Surface." [Tampa, Fla.] : University of South Florida, 2003. http://purl.fcla.edu/fcla/etd/SFE0000138.
Full text
3
Hong, Chin Tung. "Analysis of flow in a 3D chamber and a 2D spray nozzle to approximate the exiting jet free surface." [Tampa, Fla.] : University of South Florida, 2004. http://purl.fcla.edu/fcla/etd/SFE0000560.
Full text
4
Hsu, Ming-Chieh, and 徐明杰. "Effects of Swirl Numbers、 Flow Rates of Flue Gas and Jet Spray Angles on Combustion Efficiency and Formation of Pollutants in a Boiler." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/96687759252948192354.
Full textAbstract:
碩士國立中山大學
機械工程學系
87
In this research a modified commerical boiler, which burns diesel oil, is used to study the combustion characteristics and pollution of the exhausting products under various operating conditions. In our experiments, the oil-burner designs are modified, and the different equivalence ratios and swirl numbers can be controlled by adjusting fuel-air ratio. The controlling rangesof the various experimental parameters include equivalence ratio from 0.8 to 1.1, swirl number from 0 to 1.0, recirculated flue gas from 0 to 12 %, and jet spray angle including45°、60° and 80°. These controlling variables are used to study effects of the combustion efficiency and pollutant formations; eventually, we certain hope that optimized operating conditions can be found. A photographic technology is used to study the flame structures to help us understand- ing the behaviors of the flame under various operating condition. From the experimental results, we find when the strength of swirl increases, the temperatures along the injection direction of burner increases, but the temperature along the radius direction decreases. At the same time, NO concentration increases near the main combustion region, and decreases in the other region. The temperature in the flue is much lower than in combustiob zoon. The radius distribution of product concentration in flue is quite uniform due to the mixing effect in up- stream. At equivalence ratio0.9, the temperature distribution in combustion zone decrease, when the flow rate of recirculated flue gas increase. When the flow rate of recirculated flue gas increases, the temperature in the flue increase; however, the over- all concentration in any region decreases obviously. Through a series of experimental works, the certain best combinations with higher combustion efficiency and lower NO emission can be found. One of the combination is equivalence ratio at 0.9, the flow rate of recirculated flue gas at 8 %, swirl number at 0.4 and spray angle at 80 degree. The deduction rate of NO is 20~25 %. Flame structures display that when the flow rates of the recirculated flue gas increase, the flame colors in primary com- bustion region changed gradually from white-yellow to orange-red. The flame outside of the primary combustion region exhibits the red color which is due to the formation of CO2 and water vapor. On the other hands, with the increase of swirl, the streamlines of the flame changed gradually from smooth to strongly disturbance
Conference papers on the topic "Jet spread angle"
1
Xu, Qiang, Shiro Takahashi, Noriyuki Takamura, Ryo Morita, Yuta Uchiyama, and Shun Watanabe. "Evaluation of Jet Impact Region and Fluid Force Generated From Ruptured Pipes: 3 — Evaluation of Established Standards." In 2016 24th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/icone24-60317.
Full textAbstract:
Nuclear power plants are designed to avoid damage to their safety installations because of jet impingement when a pipe is ruptured. We have investigated the evaluation method for the design basis of protection of plants against effects of a postulated pipe rupture using the established standard of the American National Standards Institute (ANSI). The steam jet tests using particle image velocimetry and computational fluid dynamics (CFD) analysis were conducted for this verification. Spread angle of steam jet could be visualized. The jet spread angles were lower than 10 deg which was described in the ANSI standard. The ANSI standard was conservative for evaluations of the jet impact region compared to actual test and CFD results. However, it is desirable to use the conservative angle for evaluation of the jet fluid force. We could adequately evaluate the conservative jet fluid forces by the ANSI standard considering the spread suppression region and jet spread angle of 6 deg.
2
Wang, Ting, Sekhar Chintalapati, Ronald S. Bunker, and Ching Pang Lee. "Jet Mixing in a Slot." In ASME 1998 International Gas Turbine and Aeroengine Congress and Exhibition. American Society of Mechanical Engineers, 1998. http://dx.doi.org/10.1115/98-gt-056.
Full textAbstract:
Jet mixing inside a slot has the potential to be applied for cooling in various components in gas turbines. Based on the premise that more uniform flow at the exit of the slot would achieve more uniform cooling downstream of the slot, an experimental program was conducted to focus on investigating the flow mixing behavior inside the slots. Various parameters including orientation angle, inclination angle, slot width, effect of primary flow and slot depth were systematically examined. An array of seven jets with a jet-to-jet spacing of five diameters and velocity ratio of unity was used in the experiment. Experiments were performed by changing the orientation angles of the jets with two inclination angles (90° and 30°). The results indicated that the flow distribution at the slot exit becomes more uniform as the orientation angle was increased from 0° to 60°. Wider slot width brought about high non-uniformity and was clearly undesirable. The optimum slot depth was found to range from 2 to 2.8 times the jet diameter for slots perpendicular to the primary flow (i.e. with 90° inclination angle). The flow field was the most uniform where the shear layers of the two adjacent jets met. Regions of low velocity and high pressure caused non-uniform velocity distribution downstream where the jets met, so deeper slots do not necessarily render better uniformity. When the orientation angle increased from 0 to 30° and 60°, the jets bent toward the wall in the inclined direction caused by the Coanda effect. The presence of the primary flow forced the jet to spread faster in the lateral direction and caused some nonuniform flow pockets at the slot exit. The compound angle configuration (60° jet orientation and 30° slot inclination angles) was discovered as the best choice with four merits: (i) The acceptable uniform flow can be reached as shallow as h/d = 1.0 (slot depth over jet diameter), (ii) The range of the acceptable uniform flow was the broadest (form y/d = 1.0 to y/d = 2.8). (iii) Flow uniformity was the best at the exit, (iv) The total pressure loss was the lowest.
3
Morita, Ryo, Yuta Uchiyama, Shun Watanabe, Shiro Takahashi, Qiang Xu, and Noriyuki Takamura. "Evaluation of Jet Impact Region and Fluid Force Generated From Ruptured Pipes: 1 — Numerical and Experimental Evaluation of Affected Region by Steam Jet." In 2016 24th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/icone24-60341.
Full textAbstract:
Nuclear power plants are designed to prevent the damage of safety installations and human safety due to the jet impingement when a pipe is ruptured. We have investigated evaluation methods for the design basis of protection of plants against effects of postulated pipe rupture using computational fluid dynamics analysis (CFD). The steam jet tests using particle image velocimetry were conducted in order to verify the CFD methods. Spread of steam jet could be visualized. Shapes of steam jet obtained by CFD were almost the same as those by tests. The spread angle of free jet were investigated using CFD, and we have found that the spread angle strongly depends on the inlet pressure. This is thought as the different tendency from Established Standards.
4
Takahashi, Shiro, Qiang Xu, Noriyuki Takamura, Ryo Morita, Yuta Uchiyama, and Shun Watanabe. "Evaluation of Jet Impact Region and Fluid Force Generated From Ruptured Pipes: 2 — Evaluation of Fluid Force Using Computational Fluid Dynamics Analysis." In 2016 24th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/icone24-60316.
Full textAbstract:
Nuclear power plants are designed to avoid damage to their safety installations because of jet impingement when a pipe is ruptured. We have investigated evaluation methods for the design basis of protection of plants against effects of postulated pipe rupture using computational fluid dynamics (CFD) analysis. The steam jet tests obtained using particle image velocimetry (PIV) were conducted in order to verify the CFD analysis. Spread of steam jets could be visualized and the shapes of the steam jets obtained by analysis were almost the same as those by tests. The spread angle of free jet was investigated using CFD analysis. We also measured jet fluid force when a cylindrical structure was installed downstream from the jet nozzle. Steam jet fluid force obtained by analysis was almost the same as that by tests. We judged the CFD analysis to be applicable to evaluation of jet fluid force generated from ruptured pipes.
5
Wang, Wei, Qi Yi, Shengpeng Lu, and Xiaofang Wang. "Exploration and Research of the Impact of Hydrofoil Surface Water Injection on Cavitation Suppression." In ASME Turbo Expo 2017: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/gt2017-63779.
Full textAbstract:
To explore the impact of hydrofoil surface water injection on cavitation suppression, the unsteady cavitation flow around the NACA0066 hydrofoil was simulated by the modified RNG k-ε turbulence model combined with the full-cavitation model. The influence of water injection position and jet angle on cavitation suppression were analyzed. A detailed analysis shows that cavitation suppression effect is closely related to water injection position and jet angle. It is noted that the optimal position is just the vertex position on the upper surface of hydrofoil. Water injection in an appropriate position will increase the velocity gradient in the boundary layer and enhanced the ability of anti reverse pressure gradient, thus weakening the intensity of separation flow. The recirculation zone thickness and the velocity of re-entrant jet are all significantly reduced. For the study of jet angle, the cavitation suppression effect is obvious with jet angles from 145° to 155°. This may due to the high pressure produced by the mixing of jet with the main flow, and the high-pressure zone limit the spread of low pressure from the leading edge to the trailing edge of hydrofoil. This can also explain why the suppression effect is significant at the vertex position on the upper surface.
6
Yao, Jiaxu, Jin Xu, Ke Zhang, Jiang Lei, and Lesley M. Wright. "Effect of Density Ratio on Film-Cooling Effectiveness Distribution and its Uniformity for Several Hole Geometries on a Flat Plate." In ASME Turbo Expo 2017: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/gt2017-63743.
Full textAbstract:
Film cooling effectiveness distribution and its uniformity downstream of a row of film cooling holes on a flat plate are investigated by Pressure Sensitive Paint (PSP) under different density ratios. Several hole geometries are studied, including a streamwise cylindrical hole, a compound-angled cylindrical hole, a streamwise fan-shape hole, a compound-angled fan-shape hole, and double-jet film-cooling (DJFC) holes. All of them have an inclination angle (θ) of 35°.The compound angle (β) is 45°. The fan-shape hole has a 10° expansion in the spanwise direction. In order to have a fair comparison, the pitches are kept as 4d for the cylindrical and the fan-shape holes, and 8d for the double-jet film-cooling holes. The investigated uniformity of effectiveness distribution is described by a new parameter (Lateral-Uniformity, LU) defined in this paper. Effects of density ratios (DR = 1.0, 1.5 and 2.5) on film-cooling effectiveness and its uniformity are focused. Differences among geometries and effects of blowing ratios (M = 0.5, 1.0, 1.5, and 2.0) are also considered. Results show that at higher density ratios, the lateral spread for discrete-hole geometries (i.e., the cylindrical and the fan-shape holes) is enhanced, and the DJFC holes is more advantageous, and the high effectiveness region near the downstream hole exit is larger. Mostly, increased lateral-uniformity is obtained at DR = 2.5 due to better coolant coverage and enhanced lateral spread, but the effects of density ratios on lateral-uniformity are not monotonic in some cases. Utilizing compound angle configuration leads to increased lateral-uniformity due to stronger spanwise motion of the jet. Generally, with higher blowing ratio, the lateral-uniformity for the discrete-hole geometries decreases due to narrower traces, while it for the DJFC holes increases due to stronger spanwise movement.
7
Suzuki, Takayuki, Hiroyuki Yoshida, Naoki Horiguchi, Sota Yamamura, and Yutaka Abe. "Numerical Simulation of Liquid Jet Behavior in Shallow Pool by Interface Tracking Method." In 2020 International Conference on Nuclear Engineering collocated with the ASME 2020 Power Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/icone2020-16213.
Full textAbstract:
Abstract In the severe accident (SA) of nuclear reactors, fuel and components melt, and melted materials fall to a lower part of a reactor vessel. In the lower part of a reactor vessel, in some sections of the SAs, it is considered that there is a water pool. Then, the melted core materials fall into a water pool in the lower plenum as a jet. The molten material jet is broken up, and heat transfer between molten material and coolant may occur. This process is called a fuel-coolant interaction (FCI). FCI is one of the important phenomena to consider the coolability and distribution of core materials. In this study, the numerical simulation of jet breakup phenomena with a shallow pool was performed by using the developed method (TPFIT). We try to understand the hydrodynamic interaction under various, such as penetration, reach to the bottom, spread, accumulation of the molten material jet. Also, we evaluated a detailed jet spread behavior and examined the influence of lattice resolution and the contact angle. Furthermore, the diameters of atomized droplets were evaluated by using numerical simulation data.
8
McClintic, John W., Ellen K. Wilkes, David G. Bogard, Jason E. Dees, Gregory M. Laskowski, and Robert Briggs. "Near-Hole Thermal Field Measurements for Round Compound Angle Film Cooling Holes Fed by Cross-Flow." In ASME Turbo Expo 2015: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/gt2015-43949.
Full textAbstract:
The effectiveness of film cooling from short cooling holes, scaled to engine conditions, has been shown to be dependent on the nature of the internal coolant feed. A common method of supplying coolant to film cooling holes in engine components is through an internal cross-flow, which causes skewed effectiveness profiles on the surface of film cooled parts. For round axial holes, this effect causes coolant jets to more effectively spread across the surface. Additionally, for compound angle round holes, the direction of the cross-flow relative to the direction of injection has a substantial effect on film cooling effectiveness. A cross-flow directed counter to the span-wise direction of coolant injection has previously been shown to cause greater lateral jet spreading than cross-flow directed in-line with the span-wise injection direction. To better understand the phenomena responsible for the improved coolant spreading, two-dimensional thermal field profiles were measured downstream of compound angle film cooling holes fed by an internal cross-flow. A smooth-walled rectangular channel was used to produce an internal cross-flow in both a counter and in-line flow direction. Thermal field cross-section data was collected at three stream-wise locations: 0.7, 3.4, and 8.8 diameters downstream of the holes. Blowing ratios of 0.75 and 1.00 were studied at a density ratio of 1.5. Experiments were performed in a low speed recirculating wind tunnel at high mainstream turbulence with a thick approach boundary layer relative to the film cooling holes. It was found that the improved lateral spreading observed in the coolant jets fed by a counter cross-flow occurred due to the formation of a bulge on the downstream side of the jet.
9
Kang, Yao, Yuzhen Lin, Xiaofeng Wang, Chi Zhang, and Shuangwen Song. "Effects of Sleeve Divergence Angle of Dual-Stage Swirl Cup on the Ignition Performance." In ASME Turbo Expo 2014: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/gt2014-25782.
Full textAbstract:
Due to the effective decrease on the exhaust smoking, pollutant emission and lean blowout limit, the swirl cup has a wide application in the combustor design. The flow field and two-phase atomizing field downstream of the swirl cup are greatly affected by the sleeve. To investigate the influence of the variation of the sleeve geometry on the ignition performance of the combustor used in jet engine with Chinese aviation kerosene RP-3, three dual-stage swirl cup with different sleeve divergence angles, namely 60°, 70°, and 80°, were examined under normal inlet temperature and normal inlet pressure. The first-stage of the swirl cup uses oblique holes as swirler which is in the anticlockwise direction, while that of the second-stage employs radial blades as swirler in the clockwise direction. High speed imaging was used to obtain the transient process of the combustor ignition. Numerical simulation was used to assist the analysis on the experimental results. It was found that the ignition process in the single dome combustor can be divided into four stages, namely 1) the formation of a flame kernel, 2) the upstream propagation of the flame kernel to the swirl cup exit, 3) the flame stabilization in the swirl cup, and 4) the flame spread from the swirl cup to the primary combustion zone. With the sleeve divergence angle increased from 60° to 80°, the size of the central recirculation zone, the divergence angle of the swirl flow, and the spray angle at the swirl cup exit increased, and the lean ignition fuel/air ratio was reduced by 38%.
10
Haydt, Shane, and Stephen Lynch. "Cooling Effectiveness for a Shaped Film Cooling Hole at a Range of Compound Angles." In ASME Turbo Expo 2018: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/gt2018-75726.
Full textAbstract:
Shaped film cooling holes are a well-established cooling technique used in gas turbines to keep component metal temperatures in an acceptable range. One of the goals of film cooling is to reduce the driving temperature for convection at the wall, the success of which is generally represented by the film cooling adiabatic effectiveness. However, the introduction of a film cooling jet-in-crossflow, especially if it is oriented at a compound angle, can augment the convective heat transfer coefficient and dominate the flowfield. The present work aims to understand the effect that a compound angle has on the flowfield and adiabatic effectiveness of a shaped film cooling hole. Five orientations of the public 7-7-7 shaped film cooling hole were tested, from a streamwise oriented hole (0° compound angle) to a 60° compound angle hole, in increments of 15°. Additionally, two pitchwise spacings of P/D = 3 and 6 were tested to examine the effect of hole-to-hole interaction. All cases were tested at a density ratio of 1.2 and blowing ratios ranging from 1.0 to 4.0. Experimental results show that increasing compound angle leads to increased lateral spread of coolant, and enables higher laterally-averaged effectiveness at high blowing ratios. A smaller pitchwise spacing leads to more complete coverage of the endwall, and has higher laterally averaged effectiveness even when normalized by coverage ratio, suggesting that hole to hole interaction is important for compound angled holes. Steady RANS CFD was not able to capture the exact effectiveness levels, but did predict many of the observed trends. The lateral motion of the coolant jet was also quantified, both from the experimental data and the CFD prediction, and as expected, holes with a higher compound angle and higher blowing ratio have greater lateral motion, which generally also promotes hole-to-hole interaction.