隔板对流系统中影响流动和传热的压力分布特性

Influence of pressure on flow and heat transfer in partitioned thermal convection

本文采用直接数值模拟(Direct Numerical Simulation, DNS)研究隔板对流系统中的压力分布特性和作用.随着流动失稳,传热通道中纵向压力差与温度漂移和速度同步产生,最终形成隔板相间的压力分布.在隔板对流系统的狭缝和通道中,压力分布分别具有水平和纵向线性分布特性,压力梯度为常值.狭缝中压力分布沿流动方向为顺压分布,传热通道中的压力分布沿流动方向为逆压分布.狭缝中是水平压力驱动的二维泊肃叶流动,流动的速度剖面呈现抛物线型.传热通道中纵向压力差是抵抗温度漂移产生单向浮力而出现的,在b≥4d的条件下流动受纵向合力的影响很小,主要由水平狭缝流动的连续性保持.

The pressure characteristics and effects on the flow in the partitioned thermal convection were studied with the direct numerical simulation （DNS）. With the flow instability, the longitudinal pressure difference between the upper and below plates in the heat transfer channel is synchronized with the temperature drift and the velocity, and finally the pressure alternate distribution between the partitions is formed. The pressure has the linear distribution in the horizontal gaps and the vertical channels in the partitioned convection system, and both pressure gradients are the constant value. The pressure gradient have the same direction with the flow in the horizontal gaps, but the opposite direction in the vertical heat transfer channels. The flow in the gaps is the two-dimensional Poiseuille flow driven by the horizontal pressure gradient, and its velocity profile presents parabolic style. The pressure difference in the vertical heat transfer channels is generated by resisting temperature drift which produce one-way buoyancy. The flow in the vertical channels is affected little by the longitudinal force at the condition of b〉_4d, and is mainly maintained by the continuity of the flow in the horizontal gaps.