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Three-dimensional transient numerical simulation for intake process in the engine intake port-valve-cylinder system

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Journal of Zhejiang University Science 2003年第3期4卷 309-316页

作者：罗马吉陈国华马元镐 CollegeofEnergyandPowerEngineering HuazhongUniversityofScienceandTechnologyWuhan430074China

This paper presents a KIVA-3 code based numerical model for three-dimensional transient intake flow in the intake port-valve-cylinder system of internal combustion engine using body-fitted technique, which can be used in numerical study on internal combustion engine with vertical and inclined valves, and has higher calculation precision. A numerical simulation (on the intake process of a two-valve engine with a semi-sphere combustion chamber and a radial intake port) is provided for analysis of the velocity field and pressure field of different plane at different crank angles. The results revealed the formation of the tumble motion, the evolution of flow field parameters and the variation of tumble ratios as important information for the design of engine in-take system.

关键词： Internal combustion engine Intake flow transient numerical simulation Dynamic grid generation

Investigation of Self-Priming Process of a Centrifugal Pump with Double Blades

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Journal of Thermal Science 2021年第3期30卷 849-858页

作者： QIAN Heng MOU Jiegang REN Yun ZHU Zhibing LIU Nuojia ZHENG Shuihua WU Denghao College of Mechanical Engineering Zhejiang University of TechnologyHangzhou 310014China College of Metrology&Measurement Engineering China Jiliang UniversityHangzhou 310018China Zhijiang College Zhejiang University of TechnologyShaoxing 312030China

The gas-liquid two-phase flow patterns of a centrifugal pump during the self-priming process were investigated numerically and *** Euler-Euler multiphase model and SST k-ω turbulence model were applied for simulating the self-priming ***,the changes of motor speed and self-priming height were considered in the *** overall transient two-phase flow features and water level distributions were *** showed that the self-priming process was divided into three *** liquid level in inlet-pipe rose in oscillation during self-priming *** variations of water level during self-priming process of numerical simulation and test result agreed *** inlet-pipe(Ver)was filled at 22 s and 24 s respectively numerically and *** bubble cloud circulated in the volute during middle stage of self-priming process,and breakup into smaller bubbles by shear force and tongue,and then discharged into *** bubbles in the outlet-pipe mainly included bubbly flow and slug flow at the last stage of self-priming process,which is morphologically consistent with the test ***,during the self-priming process,the reflux liquid was pressed by blades and fully mixed with gas;that is the way to realizing the function of self-priming.

关键词： self-priming process gas-liquid two-phase flow centrifugal pump gas-liquid mixing and separation transient numerical simulation

A comprehensive fluid-solid coupling dynamic simulation for spatiotemporal distribution of regression rate in hybrid rocket motors

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Chinese Journal of Aeronautics 2024年第9期37卷 100-112页

作者： Tianfang WEI Guobiao CAI Hui TIAN Xiangyu MENG Xianzhu JIANG Xiaoming GU School of Astronautics Beihang UniversityBeijing 100191China Key Laboratory of Spacecraft Design Optimization&Dynamic simulation Technologies Ministry of Education Beijing 100191China

The spatiotemporal distribution characteristics of the regression rate are crucial aspects of the research on Hybrid Rocket Motor(HRM). This study presents a pioneering effort in achieving a comprehensive numerical simulation of fluid dynamics and heat transfer in both the fluid and solid regions throughout the entire operation of an HRM. To accomplish this, a dynamic grid technique that incorporates fluid–solid coupling is utilized. To validate the precision of the numerical simulations, a firing test is conducted, with embedded thermocouple probes being used to measure the inner temperature of the fuel grain. The temperature variations in the solid fuel obtained from both experiment and simulations show good agreement. The maximum combustion temperature and average thrust obtained from the simulations are found to deviate from the experimental results by only 3.3% and 2.4%, respectively. Thus, it can be demonstrated that transient numerical simulations accurately capture the fluid–solid coupling characteristics and transient regression rate. The dynamic simulation results of inner flow field and solid region throughout the entire working stage reveal that the presence of vortices enhances the blending of combustion gases and improves the regression rate at both the front and rear ends of the fuel grain. In addition, oscillations of the regression rate obtained in the simulation can also be well corresponded with the corrugated surface observed in the experiment. Furthermore, the zero-dimension regression rate formula and the formula describing the axial location dependence of the regression rate are fitted from the simulation results, with the corresponding coefficients of determination(R^(2)) of 0.9765 and 0.9298, *** research serves as a reference for predicting the performance of HRM with gas oxygen and polyethylene, and presents a credible way for investigating the spatiotemporal distribution of the regression rate.

关键词： Hybrid Rocket Motor(HRM) transient numerical simulation Fluid-solid couplingheat transfer Spatiotemporal distribution of regression rate Dynamic grid