矩形水平通道内液体Poiseuille-Rayleigh-Bénard对流的数值模拟

Numerical Simulation of Poiseuille-Rayleigh-Bénard Convection in a Rectangular Horizontal Channel

本文采用FLUENT软件对底部加热、表面冷却的矩形水平通道内液体的Poiseuille-Rayleigh-Bénard对流进行数值模拟,以有限容积法为基础,研究了在不同Rayleigh数和Reynolds数的情况下液体的流型变化和传热特性。结果表明,在所研究的无量纲数范围内,液体出现纵向流卷形式的二次流,流卷最开始出现在通道入口附近的近壁侧,随着液体的流动逐渐出现在通道的中心,纵向流卷的出现使局部换热系数增加。改变Reynolds数只影响入口段的长度:Ra数的增加会使纵向流卷的个数增加,入口段长度减小。

This article uses FLUENT software to numerically simulate Poiseuille Rayleigh Bénard convection of liquid in a rectangular horizontal channel with bottom heating and surface cooling.Based on the finite volume method,the flow pattern changes and heat transfer characteristics of the liquid at different Rayleigh and Reynolds numbers were studied.The results indicate that within the dimensionless range studied,the liquid exhibits a secondary flow in the form of longitudinal flow coils,which initially appear on the near wall side near the inlet of the channel.As the liquid flows,it gradually appears at the center of the channel,and the appearance of longitudinal flow coils increases the local heat transfer coefficient.Changing the Reynolds number only affects the length of the entry section:an increase in the Ra number will increase the number of longitudinal flow rolls and reduce the length of the entry section.