含内热源的多孔方腔自然对流非正交MRT-LBM模拟

为了增强多孔方腔内流体流动与传热效果，采用非正交多松弛格子Boltzmann方法（MRT-LBM）对含有内热源的多孔方腔自然对流传热现象进行了数值模拟。研究了不同冷源布置方案（Scheme A~Scheme F）、内热源结构形式（Case 1、Case 2、Case 3）、内热源位置（a、b）、Darcy数、Rayleigh数等对多孔方腔内流体流动与传热的影响。计算结果表明:冷源布置方案对腔内流体流动与传热具有重要影响，当冷源左右对称布置时，腔内温度场及流场亦对称分布；在高Rayleigh数下采用Scheme A的双上部冷源布置方案能明显提高腔内的传热强度；内热源的形状对腔内对流传热影响很大，高Rayleigh数下，Case 3的布置方式更好。内热源的位置a和b对腔内的传热影响明显，提出了热壁面平均Nusselt数与位置a的拟合关系式，存在最佳的位置a（a=0.25），使得腔内的对流传热最强；热壁面平均Nusselt数亦随b值变化表现出特定的变化规律。随着b值的增加，热壁面平均Nusselt数呈现先增后减再增的趋势。 

Non-orthogonal multiple-relaxation-time lattice Boltzmann simulation of natural convection in porous square cavity with internal heat source

In order to enhance the effect of fluid flow and heat transfer in the porous square cavity, the non-orthogonal multiple-relaxation-time (MRT) lattice Boltzmann method (LBM) is used to simulate the natural convective heat transfer in the porous square cavity with internal heat source. The effects of different cold source arrangements (Scheme A-Scheme F), internal heat source structure (Case 1, Case 2, Case 3), internal heat source location (a, b), Darcy number, and Rayleigh number on fluid flow and heat transfer in square cavity are studied. The calculation results show that the arrangement of the cold source has an important influence on the fluid flow and heat transfer. When the cold source is symmetrically distributed, the temperature field and the flow field in the cavity are also symmetrically distributed; under high Rayleigh number, the double upper cold source arrangement of Scheme A can significantly improve the heat transfer intensity in the cavity; the shape of the internal heat source has a great influence on the convective heat transfer in the cavity. Under the high Rayleigh number, case 3 is arranged better. The positions a and b of the internal heat source have obvious influence on the heat transfer in the cavity. The fitting relationship between the average Nusselt number of the hot wall surface and the position a is proposed, and there is an optimal position a (a=0.25), which makes the convective heat transfer in the cavity strongest; the average Nusselt number of the hot wall surface also shows a specific variation law with the change of b value. With the value of b increases, the average Nusselt number of the hot wall surface increases first, then decreases and finally increases.