Multiscale flow behaviors of hydrogen and oxygen gas based on the coupled DSMC-SPH approach

J. Ye, J. Yang, J. Zheng, X. Ding, L. Wong, W. Li, C. Chen
Zhejiang University, CN

Keywords: multiscale flow, DSMC-SPH multiscale approach, rarefaction, mass flowrate, Knudsen number

Summary:

With the development of the MEMS technology, the exploration and application of micro-mechanical devices becomes the hotpoint. The flow behaviors researches in the MEMS system become very important. However, the MEMS flow usually presents multiscale effect. The small dimensions encountered in micro devices result in rarefaction of the flow, which necessitates the use of molecular based approaches. The MEMS devices also involve regions with larger dimensions, where the flow is not rarefied but in the continuum regime. In this paper, a novel numerical analysis method combining the direct simulation Monte Carlo (DSMC) method with the smoothed particle hydrodynamics (SPH) method is presented for the multi-scale flow prediction. The continuum regions are treated by SPH method and the rarefied flow region is described by the DSMC method. The validity and accuracy of the new method are given by comparing its results with that of the DSMC method. The computational efficiency is also analyzed and discussed. Using this coupled multiscale approach, the flow behaviors of the hydrogen and oxygen multiscale gas flows in the MEMS device are investigated. Since the multiscale flow is often encountered, the present approach results can provide significant insights for the design and operation of MEMS devices.