Ellipsoidal statistical Fokker-Planck simulation of thermally induced gas flow in a ratchet microchannel

[摘要] We present numerical simulation results of thermally induced gas flow in the gap between a ratchet surface and a moving wall using the recently proposed ellipsoidal statistical Fokker-Planck (ESFP) algorithm. In this algorithm, the evolution of individual molecular velocity is modelled as a continuous stochastic process, and the corresponding Langevin equation is implemented in a particle Monto Carlo manner. The simulation aims at the calculation of the thermally induced shear stress acting on the top wall. In the transition regime, the mechanical power output and thermodynamic efficiency are calculated for various moving speeds of the upper wall and inclination angles of the specular surface. The proposed method facilitates the evaluation of the efficiency of converting transverse heat flux across the channel into the tangential propelling force for this device. The dependence of efficiency of the inclination angle is identified, and the optimal efficiency is found to be not much different from that in the free molecular regime.

[学科分类] 物理（综合）