正弦波温度边界下多孔介质方腔内非热平衡对流传热数值模拟

Numerical investigation of natural convection in a square enclosure filled with porous medium on sinusoidal thermal boundary condition

采用局部非热平衡模型,在方腔左侧壁面温度正弦波变化、右侧壁面温度均一的边界条件下,通过SIM-PLER算法数值研究了固体骨架发热多孔介质方腔内的稳态非达西自然对流,主要探讨了不同正弦波波动参数N及方腔的高宽比M/L对方腔内自然对流与传热的影响规律。计算结果表明:正弦波温度边界使得方腔内的流场出现了复杂的变化,流体及固体区域左侧壁面附近出现了周期性的正负变化的温度场分布,左侧壁面局部Nusselt数出现了周期性的震荡现象;存在一个最佳温度波动参数N=1,此时多孔介质方腔内的整体散热量达到最大值;增加方腔高宽比会显著地削弱方腔内的自然对流传热过程,小高宽比也会在一定的程度上削弱多孔介质方腔内的对流传热。

Steady non-Darcian natural convection in a square cavity filled with heat-generating porous medium is studied numerically by adopting the local thermal non-equilibrium model, with SIMPLER algorithm in the spatial coordinates. The top and bottom walls are adiabatic, the left wall is partially heated and cooled by sinusoidal temperature profiles and the right wall temperature is kept uniform. The heat transfer in the square enclosure is investigated under different value of temperature fluctuant parameter and aspect ratio of the square enclosure. It is observed that the temperature near the left wall and local Nusselt number of the left wall varies periodically because of the sinusoidal boundary condition, there exists an optimal fluctuant parameter of N= 1 which makes the heat transfer rate maximum in the square enclosure. Increasing aspect ratio is bad for natural convection and heat transfer in the square enclosure, also ,low aspect ratio can weaken heat transfer of the square enclosure.