Numerical Simulation Optimization via DSMC Method for Thermally Induced Flow in Microchannel-Type Knudsen Pumps with Quadrilateral Arrays

A microchannel geometry with different temperature quadrilaterals is proposed, and its pumping capacity is demonstrated, giving its optimal parameters for pumping gas. Numerical simulations of the microchannel are performed using the direct simulation Monte Carlo (DSMC) method. The results show that the mass flow rate of the microchannel increased almost linearly with the temperature difference in the range of 75 to 1200 K. The mass flow rate at a temperature difference of 1200 K is 10 times higher than that at a temperature difference of 75 K. Both the maximum gas flow rate and mass flow rate occur at Kn = 0.3, indicating that the gas pumping capacity is strongest in transitional flow. Also, the dimensionless mass flow rate of this microchannel at the same operating conditions is 62 times higher than that of a conventional rectangular Knudsen pump.