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Numerical Simulations of jet flow Inside Launching Box and Design of Pressure Opening the Covers of Missile Launching Box

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Journal of Beijing Institute of Technology 2004年第S1期13卷 54-57页

作者：刘琦郝继光姜毅陈建伟 School of Mechatronics Engineering Beijing Institute of Technology Beijing 100081 China

Numerical simulations are presented for jet flow inside a launching box. The predictions are based on solutions of the unsteady three-dimensional Reynolds-averaged Navier-stokes equations. Since the pressure opening the forward cover is given, the pressure opening the backward cover is designed by analyzing the flow field inside the launching box. The κ -ε turbulent model is presented and the structured meshes are used through the whole computational field.

关键词： launching box the pressure opening the covers jet flow

Numerical study of hydrofoil surface jet flow on cavitation suppression

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排灌机械工程学报 2017年第10期35卷 829-834页

作者： WANG Wei LU Shengpeng XU Ruiduo YI Qi WANG Yayun WANG Xiaofang Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education Dalian University of Technology

Cavitation caused vibration and noise of hydraulic machinery. To some extent,cavitation made fatigue damage in advance. Many scholars found that the re-entrant jets were the reasons of the shedding of cavities. To suppress cavitation,based on the idea of blocking the re-entrant jets,a special surface flow structure of 2D hydrofoil was proposed. The through-hole was made in the proper position of the hydrofoil. The incoming flow can outflow from this jet-hole automatically depending on the pressure difference between pressure side and suction side. Re-entrant jet growth can be weakened by optimizing the jet-hole geometry. Based on the standard k-ε turbulence model and Schnerr & Sauer cavitation model,under different cavitation numbers( σ) and jet-angles( β) for NACA0066( 2D) hydrofoil with 8° angles of attack,cavitation field numerical analysis was carried out. The results show that 2D hydrofoil cavitation flow had a strong unsteadiness. Making a jet-hole at the junction between the re-entrant jet and cavity can effectively minimize cloud cavitation. For a certain cavitation condition,optimal jet-angles( β) can be obtained to control cavitation growth. For the same β,the effects of cavitation suppression were changed with different cavitation numbers( σ). Consequently,suitable jet-angle and jet-position could extend the stable operating range of the hydrofoil.

关键词： hydrofoil cavitation suppression jet flow lift-to-drag ratio

Numerical Experiments of Subsonic jet flow Simulations Using RANS with OpenFOAM

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Open Journal of Fluid Dynamics 2022年第2期12卷 230-247页

作者： Negar Naghash Zadeh Roberto Paoli Department of Mechanical and Industrial Engineering University of Illinois at Chicago Chicago USA Argonne National Laboratory Leadership Computing Facility and Computational Science Division Lemont USA

This study investigates the accuracy of different numerical schemes of OpenFOAM software to simulate compressible turbulent jets. Both pressure-based schemes utilizing the implicit PIMPLE algorithm and density-based schemes relying on AUSM scheme and explicit Runge-Kutta time integration are considered. The results of the numerical tests are compared and validated against data from NASA ARN nozzle geometry. The choice of parameter setting of the schemes is discussed in depth and possible optimization strategies are proposed to increase accuracy of RANS simulations of turbulent jets.

关键词： CFD jet flow Axisymmetric Turbulence RANS OpenFOAM

Numerical Simulation and Experimental Study on Open-end Shock Tube jet flow

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Numerical Simulation and Experimental Study on Open-end Shoc...

Laboratory model study of the effect of aeration on axial velocity attenuation of turbulent jet flows in plunge pool

Asian Simulation Conference/The 6th International conference on system Simulation and Scientific Computing

作者： JIANG Kun, QIAN Linfang, XU Yadong (School of Mechanical Engineering, Nanjing University of Science and Technology, Nanjing 210094)

The open-end shock tube studied is a one-side open-end tube with side slots to discharge the high pressure gases. Its primary function is mitigating the recoil force generated when the high pressure gases rush out of the tube. Numerical simulation is applied to study the shock tube jet flow and analyze the performance of the shock tube. Firstly the flow field with a shock tube was numerically simulated using a CFD code. Experiment is also done to test the simulation results and evaluate the code. The overpressure measured with PCB pressure transducer at the monitored spot is compared with the simulation results, good agreement is seen. At last a new shock tube was designed and tested with the simulation code. The simulation results show that the efficiency for the newly designed shock tube is 0.5% higher than that of the original one and the highest overpressure on the monitored spot decreased by 34.6%.

关键词： numerical simulation shock tube jet flow shock wave

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Journal of Hydrodynamics 2015年第6期27卷 913-918页

作者：邓军张法星田忠许唯临刘斌卫望汝 State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan University

In the laboratory model experiment, the velocities of the jet flow along the axis are measured, using the CQY-Z8a velocity-meter. The velocity attenuations of the jet flow along the axis under different conditions are studied. The effects of the aeration concentration, the initial jet velocity at the entry and the thickness of the jet flow on the velocity attenuation of the jet flow are analyzed. It is seen that the velocity attenuation of the jet flow along the axis sees a regular variation. It is demonstrated by the test results that under the experimental conditions, the velocity along the axis decreases linearly. The higher the air concentration is, the faster the velocity will be decayed. The absolute value of the slope K increases with the rise of the air concentration. The relationship can be defined as K = AC~ ＋ Kb. The coefficient A is 0.03 under the experimental conditions. With the low air concentration of the jet flow, the thinner the jet flow is, the faster the velocity will be decayed. With the increase of the air concentra- tion, the influence of the thickness of the jet flow on the velocity attenuation is reduced. When the air concentration is increased to a certain value, the thickness of the jet flow may not have any influence on the velocity attenuation. The initial jet velocity itself at the entry has no influence on the variation of the velocity attenuation as the curves of the velocity attenuation at different velocities at the entry are practically parallel, even coinciding one with another. Therefore, improving the air concentration of the jet flow and disper- sing the jet flow in the plunge pool could reduce the influence of the jet flow on the scour.

关键词： jet flow air concentration velocity

The　Mechanism　of　Clearing　Away　Cuttings　and　Breaking　Rocks　Using　Pulse　jet　Nozzle

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天然气工业 1995年第4期15卷 103-105页

作者： (Southuest Petroleum Institute)(

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ＴｈｅＭｅｃｈａｎｉｓｍｏｆＣｌｅａｒｉｎｇＡｗａｙＣｕｔｔｉｎｇｓａｎｄＢｒｅａｋｉｎｇＲｏｃｋｓＵｓｉｎｇＰｕｌｓｅ　ＪｅｔＮｏｚｚｌｅＸｉｏｎｇＪｉ－ｙｏｕ．（ＳｏｕｔｈｕｅｓｔＰｅｔｒｏｌｅｕｍＩｎｓｔｉｔｕｔｅ）（ＳｕｂｊｅｃｔＨｅａｄｉｎ...

关键词： Pulse jet flow Pulse pressure jet drilling Rock-breaking mechanism.)

Role of unsteady tip leakage flow in acoustic resonance inception of a multistage compressor

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Chinese Journal of Aeronautics 2023年第10期36卷 165-181页

作者： Xiaohua LIU Zihao WU Changxin SI Jun YANG Xiaofeng SUN School of Aeronautics and Astronautics Shanghai Jiao Tong UniversityShanghai 200240China Key Laboratory(Fluid Machinery and Engineering Research Base)of Sichuan Province Xihua UniversityChengdu 610039China China Three Gorges Investment Management Co.Ltd Shanghai 200124China School of Energy and Power Engineering University of Shanghai for Science and TechnologyShanghai 200093China Research Institute of Aero-Engine Beihang UniversityBeijing 100191China

In previous studies,a theoretical model was developed after Acoustic Resonance(AR)was experimentally detected in a four-stage compressor,and AR inception was proposed to be triggered by an unknown sound source,which is a pressure perturbation of a specific frequency with a suitable circumferential propagation *** present paper,which is not dedicated to the simulation of acoustic field,aims to identify the specific sound source generated by the unsteady tip leakage flow using the unsteady Computational Fluid Mechanics(CFD)*** a comprehensive analysis of an Unsteady Reynolds Averaged Navier-Stokes(URANS)simulation,a pressure perturbation of non-integer multiple of rotor frequency is found at the blade *** the essence of the tip leakage flow is a jet flow driven by the pressure difference between two sides of blade,a simplified tip leakage flow model is adopted using Large Eddy Simulation(LES)in order to simulate the jet flow through a tip *** is found that the convection velocity of shedding vortices fits the expected propagation speed of the sound source,the frequency is also close to one of the dominating frequencies in the URANS simulation,and the resultant combination frequency coincides with the experimentally measured AR *** such a simplified model successfully captures the key physical mechanisms,it is concluded that this paper provides a piece of unambiguous evidence on the role of unsteady tip leakage vortex in triggering the AR inception of the multistage compressor.

关键词： Acoustic Resonance(AR) jet flow Multistage compressor Tip leakage flow Unsteady flow

THE SOLUTION FOR INCOMPRESSIBLE PLANE TURBULENT jet BY USING THE METHOD OF SUCCESSIVE SUBSTITUTION

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Journal of Hydrodynamics 1997年第2期9卷 31-36页

作者： Fan Meng, P.Y. ChouDepartment of Mechanics, Peking University, Beijing 100871, P. R. China

Based on P. Y. Chou's theory of turbulence for incompressible viscous fluids, this paper solves the Reynolds' equations of mean motion and the equations of turbulent fluctuation simultaneously using the method of successive substitution. The comparison of the computed results for incompressible plane turbulent jet with the experimental data is reasonably good.

关键词： turbulence theory jet flow pseudo-spectral method

Experimental Study on Shock Wave Structures in Constant-area Passage of Cold Spray Nozzle

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Journal of Thermal Science 2007年第1期16卷 40-45页

作者： Hiroshi KATANODA Takeshi MATSUOKA Kazuyasu MATSUO Dept.Mechanical Engineering Kagoshima University1-21-40 KorimotoKagoshima890-0065 Japan Takagi Precision Dies Co. Ltd.2-4-1 Ishida-MinamiMinami-kuKitakyushuFukuoka802-0836 Japan Dept.Mechanical Systems and Environmental Engineering The University of Kitakyushu1-1 HibikinoWakamatsukuKitakyushuFukuoka808-0135 Japan

Cold spray is a technique to make a coating on a wide variety of mechanical or electric parts by spraying solid particles accelerated through a high-speed gas flow in a converging-diverging nozzle. In this study, pseudo-shock waves in a modeled cold spray nozzle as well as high-speed gas jets are visualized by schlieren technique. The schlieren photographs reveals the supersonic flow with shock train in the nozzle. Static pressure along the barrel wall is also measured. The location of the head of pseudo-shock wave and its pressure distribution along the nozzle wall are analytically explained by using a formula of pseudo-shock wave. The analytical results show that the supersonic flow accompanying shock wave in the nozzle should be treated as pseudo-shock wave instead of normal shock wave.

关键词： Supersonic flow Pseudo-Shock Wave jet flow Cold Spray