管内填充多孔介质强化换热的数值研究

Numerical study of heat transfer enhancement inside tube partially filled with porous

管内填充多孔介质强化换热的基本原理是构造热边界层,增大壁面附近流体的温度梯度,并且流动阻力增幅不大。本文运用数值模拟的方法,模拟填充多孔介质管内的流场和温度场,探讨填充比例φ、渗透率Da以及空隙率ε对管内对流换热的影响规律。研究表明,提高填充比例φ和减小渗透率Da都能明显提高换热效果,但也增加了管内流动阻力。空隙率ε对强化换热作用不大,但高空隙率可以明显降低管内流动阻力,在实际中应选用空隙率较大的多孔介质。

Basic principle of heat transfer enhancement inside tube partially filled with porous medium is re-constructing the thermal boundary layer,increasing the fluid temperature gradient near the wall,and little increase in flow resistance.This paper obtain flow and temperature field by numerical simulation method,analyze affection law of the filling ratio φ,Darcy number Da and porosity ε on the convective heat transfer inside tube.Researches indicate that increase the filling ratio and decrease permeability can significantly improve the effect of heat transfer,but also increased the flow resistance in tube.Porosity have little effect on the enhanced heat transfer,but high porosity can significantly reduce the pipe flow resistance,so in practice,high porosity of porous media should be used.