Multiscale simulation of non-isothermal microchannel gas flows

JOURNAL OF COMPUTATIONAL PHYSICS

卷:270

Article

Patronis, Alexander¹  Lockerby, Duncan A.¹ 

[1] Univ Warwick, Sch Engn, Coventry CV4 7AL, W Midlands, England

关键词: Multiscale simulation;    Rarefied gas dynamics;    Thermal transpiration;    Thermal creep;    Knudsen compressor;    Knudsen pump;   

DOI  :  10.1016/j.jcp.2014.04.004

来源: Elsevier

【 摘 要 】

This paper describes the development and application of an efficient hybrid continuum-molecular approach for simulating non-isothermal, low-speed, internal rarefied gas flows, and its application to flows in Knudsen compressors. The method is an extension of the hybrid continuum-molecular approach presented by Patronis et al. (2013) [4], which is based on the framework originally proposed by Borg et al. (2013) [3] for the simulation of micro/nano flows of high aspect ratio. The extensions are: 1) the ability to simulate non-isothermal flows; 2) the ability to simulate low-speed flows by implementing a molecular description of the gas provided by the low-variance deviational simulation Monte Carlo (LVDSMC) method; and 3) the application to three-dimensional geometries. For the purposes of validation, the multiscale method is applied to rarefied gas flow through a periodic converging-diverging channel (driven by an external acceleration). For this flow problem it is computationally feasible to obtain a solution by the direct simulation Monte Carlo (DSMC) method for comparison: very close agreement is observed. The efficiency of the multiscale method, allows the investigation of alternative Knudsen-compressor channel configurations to be undertaken. We characterise the effectiveness of the single-stage Knudsen-compressor channel by the pressure drop that can be achieved between two connected reservoirs, for a given temperature difference. Our multiscale simulations indicate that the efficiency is surprisingly robust to modifications in streamwise variations of both temperature and cross-sectional geometry. (C) 2014 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/3.0/).

【 授权许可】

Free