https://doi.org/10.1140/epjp/s13360-022-02612-y
Regular Article
Wall conditions effects on rarefied gas flow characteristics in the system of microbeams with different temperatures
School of Mechanical Engineering and Automation, Northeastern University, 110819, Shenyang, China
Received:
25
October
2021
Accepted:
16
March
2022
Published online:
11
April
2022
The rarefied gas flows triggered by temperature fields in the system of microbeams are numerically analyzed to investigate the effects of wall materials (surface accommodation coefficients) and roughness on the gas flow, pressure, Knudsen (thermal) force, and thermal characteristics. The direct simulation Monte Carlo (DSMC) method coupled with the Cercignani–Lampis (CL) gas–surface interaction model imposed on the walls is applied. The variation in wall materials is achieved by changing normal energy accommodation coefficient (NEAC) and tangential momentum accommodation coefficient (TMAC). Moreover, the wall roughness is configured with a series of rectangular obstructions. The results indicate that the macroscopic characteristics of the gas flow are sensitive to the wall materials and wall roughness. Whether the surface of cold beam is rough or not, Knudsen force exhibits an approximately linear increase as NEAC reduces, but nonlinearly decreases with TMAC reducing. In particular, Knudsen force increases by approximately 3.21, 4.41, and 18.23 times at pressures of 155 Pa, 387 Pa, and 966 Pa, respectively, when NEAC varies from 1 to 0. However, Knudsen force can be reversed when TMAC ranges between 1 and 0 (or 2). At the same time, surface roughness weakens the effects of wall materials on Knudsen force. Regarding the variation in Knudsen force owing to the decrease in NEAC (or TMAC), a large Knudsen force is obtained corresponding to the cold beam with smooth (or rough) surfaces.
© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2022
