Heat Transfer in Nanochannel Devices Using DSMC

High speed rarefied gas flows through 2D nanochannels, with inlet Mach number 4.15 and inlet Knudsen number 0.148, are investigated using the Direct Simulation Monte Carlo (DSMC) method. Pressure boundary condition is implemented benefiting from the characteristics theory. We show that high back pressures have large effects in flow configuration, wall heat flux, high temperature region, and high velocity region. In particular, a normal shock appears at the inlet at very large back pressure, and change the upstream condition from supersonic flow to subsonic one. We also show that the results with no pressure condition at outflow, are the same as vacuum outflow condition. In low back pressure, vacuum, and no pressure conditions, the outflow remains supersonic, however it approaches to sonic and subsonic conditions as the back pressure increases. In supersonic outflow cases, expansion waves are clearly observed at the outlet.

Keywords:

Heat Transfer , Nanochannel , Nanodevices , Direct Simulation Monte Carlo (DSMC) method , Boundary Conditions