Heat transfer under rarefied conditions

Understanding the gas-wall or fluid-wall interactions thoroughly is indispensable for temperature control in micro-systems, and has to be studied at a molecular scale. We have developed a multiscale hybrid method that combines the advantages of molecular dynamics (MD) and the stochastic direct simulation Monte Carlo method (DSMC); the accuracy of the interactions at the interfaces by MD, and DSMC in the bulk for low computational costs.

Our studies show that the hybrid MD-DSMC method is as accurate as an MD simulation, for heat transfer problems as well as for surface reactions, but with a large gain in computational speed, and therefore larger domain sizes can be considered. In addition to electronics cooling, this approach also has direct applications for aerospace applications. Together with ESA we are studying heat transfer properties and chemical reactions in the gas-surface interface for the Mars re-entry.