Quantitative numerical analysis of micro-thermal transpiration pump using kinetic theory of gases

The rarefied gas flow in the microscopic thermal transpiration pump fabricated by micro/nano-electro-mechanical systems is investigated. The numerical analysis is carried out by the direct simulation Monte Carlo (DSMC) method of the Boltzmann equation since the thermal transpiration phenomena are unique to the rarefied gas. The values of mass flow rate and pressure difference induced by the device are obtained by the DSMC method. The simulation adopts the three-dimensional numerical model that strictly follows the shape of the microchannel of the fabricated device. The numerical results can reproduce the experimental data by selecting the appropriate values of the Knudsen number and the accommodation coefficient on the surface. The simulation also clarifies the details of the three-dimensional flow structures for a wide range of Knudsen numbers.