Numerical Study on Rarefied Gas Flow and Heat Transfer of Microchannel in Slip Flow Regime

• Main Authors: Tai Chung Chieh, 戴中傑
• Other Authors: Tzeng Pei Yuan
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/53849237836251628673

博士 === 國防大學理工學院 === 國防科學研究所 === 102 === The purpose of this research is to study the existing and possible novel models for specifying boundary conditions in flow computations of micro systems. Effective models for solid boundary condition will be explored along with the application focusing on micro-channel flow problem. Systematical examination of gas-surface interaction models will also be performed. The investigation is conducted for the models applied in Direct Simulation Monte Carlo (DSMC) simulation of micro gas flow problem. At first, we investigate the pressure driven flow in microchannel at non-uniform temperature. The major concerns are thermal creep and boundary condition effects on slip velocity. The thermal creep is found to enhance the slip, and adiabatic wall condition decreases the slip velocity. Secondly, we compare the thermal and adiabatic boundary condition in enclosure, and investigate the boundary effect on slip velocity. Thirdly, we employ CLL model that related to wall roughness which is the most realistic gas solid interaction model in DSMC calculation. The influence of changing tangential moment accommodation coefficient (TMAC) on slip velocity and thermal flow is studied. Comparisons of theoretical and calculated TMAC value are performed. Lastly we employ the idea of energy conservation and reflection rule in CLL model to simulate combined adiabatic and roughness effect of wall condition . By this research, the physics of gas-surface interaction in slip flow regime will be better understood. The results of this study will be useful in providing proper boundary treatment for simulation of rarefied gas flow problems, and significant insight for the design of micro/nano system.