Study on Lubrication Theory of Orificed Throttle Based on Molecule Collision

Abstract

Orifice restriction is a traditional form of throttle used in aerostatic guide way. Practically, self-excited vibration or even air hammer phenomenon will appear in gas film interior when supply gas enlarges or the film thickness decreases to micron scale. In order to analyze the process from the pressure inlet to the entrance of completely developed laminar flow, Reynolds Equation coupled with the first order velocity slip is used. Since it has rarefied property, turbulence model and molecular dynamics theory are adopted based on molecular collision theory. This paper reveals the internal cyclone law in gas chamber and the relationship between essence of the shock formation and the gas molecule velocity excitation. Further study shows that, supply pressure, film parameters and chamber parameters have important influences on cyclone phenomenon and shock wave.

Keywords

• orifice throttling
• molecular collision
• shock wave
• cyclone phenomenon