多尺度传热传质chapter 3.pdf

Multiscale Modeling of Heat and Mass Transfer Chapter 3 Two Phase Flow and Heat Transfer in Non-Microchannel Prof. Qiang Liao Institute of Engineering Thermophysics Chongqing University /cquiet/ 2010.7.10 Chongqing 工程热物理研究所 1/52 Institute of Engineering Thermophysics 1. Taylor Bubble Rising in a Vertical Mini Noncircular Channel Filled with a Stagnant Liquid Schematic of the physical problem in mini triangular and square channels Assumptions: Gas viscosity is negligible Interfacial tension, , is constant Pressure within the bubble is uniform Viscous stress tangential to the bubble interface vanishes 工程热物理研究所 Institute of Engineering Thermophysics Determination of Bubble Profile Assumptions: Gas viscosity is negligible Interfacial tension, , is constant Pressure within the bubble is uniform Viscous stress tangential to the bubble interface vanishes The Young-Laplace equation and force equilibrium: 3 2 1 2 dp dp d  2  2   2   d  d d  1 c        2 1   1 R 1    dz dz dz dz dz dz           Subject to the following boundary conditions: 2 3 d d  d    : 0, 0, 0 u dz