GASEOUS FLOW AND HEAT TRANSFER IN MICRO-CHANNEL WITH HEAT FLUX SPECIFIED BOUNDARY CONDITION

Gaseous flows in micro fluidic devices are often characterized by relatively high Knudsen number. For such flows, the continuum approximation is not valid, and direct simulation Monte Carlo (DSMC) may be used to find an appropriate solution. For flows associated with Micro-Electro-Mechanical Systems (MEMS), the Heat Flux Specified (HFS) boundary condition broadly exists. However, problem with HFS boundary condition has not been realized in the simulations of micro channel flows with DSMC method. To overcome this problem, a new technique named as Inverse Temperature Sampling (ITS) is developed. This technique provides an approach to calculate the molecular reflective characteristic temperature from the molecular incident energy and the heat flux at the wall boundary. Coupling with DSMC method, this ITS technique can treat the HFS boundary condition in DSMC method. For sample computations, two-dimensional Poiseuille flows with HFS boundary condition are employed. One calculation is under uniform wall temperature condition and the other is under step-changed wall temperature condition. The results show that the proposed ITS method could accurately simulate the gaseous flow and heat transfer with great spatial resolution.