Numerical Study on Viscous Dissipation of Variable Viscosity Fluid in Microscale Gap between Parallel Plates

摘要

The fluid flow in microscale gap between parallel plates is driven by the simultaneous pressure gradient and the movement of the upper plate in the tangential direction. The viscous dissipation of fluid has been studied numerically with the finite volume method. The heights of the studied gaps are 10μm, 40μm, 70μm and 100μm. The lengths are fixed at 25mm. The plates are adiabatic. The flow is laminar with the pressure difference varying from 1 MPa to 10 MPa and the velocity of the moving wall varying from 0 to 20 m/s. The viscous dissipation causes the viscosity falling. The fall of viscosity affects the viscous dissipation inversely, and causes the temperature rises nonlinearly. If the two plates are stationary, the average temperature rise only depends on the pressure difference between the inlet and the outlet, and the geometry and viscosity have no effect on the average temperature rise at the outlet. When one plate moves, the pressure difference, the wall velocity and the gap height have important effect on the average temperature rise.