Binary gas mixtures separation using microscale radiometric pumps

In this paper, we suggest the application of micro-scale radiometric pumps for helium-xenon binary mixture separation. For this purpose, we consider three geometries of radiometric pumps consisting of channels with their bottom or top surfaces periodically patterned with different structures including a simple vane or double isosceles triangular ratchets. In these geometries, the channel surfaces and structures are considered as diffuse reflectors. The temperature is kept constant on the horizontal walls of the channel; thus, radiometric flow is created by subjecting the adjacent sides of the vane/ratchet to constant but unequal temperatures. Numerical simulation is performed using the direct simulation Monte Carlo (DSMC) method. The DSMC simulations are performed at a Knudsen number for mixture based on the vane/ratchet height of around 0.2. The present study has two important aspects. The first is the amount of lateral and vertical separation that can be achieved by using newly designed Knudsen pumps is described. The second is to study the behavior of the flow field in binary gas mixtures. The features of each design in gas separation will be discussed.