Nanoscale Flow Research Division

Non-Equilibrium Molecular Gas Flow Laboratory

  • Concurrent ProfessorTaku Ohara

In rarefied gas flows and processing plasmas for semiconductor manufacturing and microscale gas flows in the neighborhood of MEMS/MEMS, mean free path of molecules cannot be negligible compared with characteristic lengths of gas flows. Such flows are in strong nonequilibrium due to lack of intermolecular collisions and cannot be considered as a continuum. Therefore, they have to be treated in view of atoms, molecules, ions and electrons. Due to the development of recent microfabrication technology the industrial importance of rarefied gas flow has increased year by year. We study the physical phenomena of such flows and use the knowledge obtained here in industry.

Molecular Gas Dynamics Study of Nanoscale Gas Lubrication

The friction coefficient of a partly polished diamond coating becomes zero as sliding speed is increased, but the mechanism has not been solved. We consider that nanoscale roughness of the partly polished diamond coating may cause high gas pressure between two sliding surfaces and realize this gas lubrication. We clarify the mechanism by the molecular gas dynamics approach.

Development of Numerical Solution for Gas Flow in complicated and Micro-Nanoscale Channel

DSMC method is suitable to solve the transport phenomena in micro-nanoscale channel. However, performing DSMC simulation of gas flow in porous media, which appears in various regions of engineering, e.g., catalytic converters and fuel cells, is difficult because of its complicated surface structure and its slow speed. We develop the high performance numerical solution of such a gas flow.

Research of Non-Equilibrium Plasma

Plasmas for ion thruster and microfabrication of semiconductor devices are generated in rarefied gas and show strong non-equilibrium. The governing equations of plasma are Boltzmann equations and Maxwell equations. We researches physical phenomena in non-equilibrium plasma, and conducts applied industrial research.