Researchers in heat transfer field always attempt to find new solutions to optimize the performance of energy devices through heat transfer enhancement. Among various methods which are implemented to reinforce the thermal performance of energy systems, one is utilizing porous media in heat exchangers. In this study, characteristics of laminar mixed convection in a porous two-sided lid-driven square cavity induced by an internal heat generation at the bottom wall have been carried out by using a numerical methodology based on the finite volume method and the full multigrid acceleration. The two-sided and top walls of the enclosure are assumed to have cold temperature while the remaining walls of the bottom wall are insulated. The working fluid is air so that the Prandtl number equates 0.71. The behavior of different physical parameters is shown graphically so that computations have been conducted over a wide range of pertinent parameters; (10−2≤ Ri ≤10), Darcy number (10−4≤ Da ≤10−1), internal Rayleigh number (0≤ RaI≤104), the porosity (0.2≤ε≤0.8) and the Grashof number (103≤ Gr ≤106). Results revealed that heat transfer mechanism and the flow characteristics inside the enclosure are strongly dependent on the Grashof number. For instance, the best heat transfer rates at the considered values of internal Rayleigh numbers are obtained for a high Grashof number. Furthermore, an increase of internal heat generation (Ra_I) leads to a higher flow and temperature intensities for Grashof numbers ranging from 104 to 106 and a specific Richardson number value. Besides, an increase in porosity values (ε) leads to an obvious decrease in the average Nusselt number. Maximum temperature θmax is optimal for high (ε) value. A correlation expression for the average Nusselt number relative to the internal heat source was established in function of two control parameters such as Darcy and Richardson numbers.

中文翻译：

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填充多孔介质的盖子驱动外壳中的混合对流传热和发热模拟

传热领域的研究人员总是试图寻找新的解决方案，通过增强传热来优化能源设备的性能。在为增强能源系统的热性能而实施的各种方法中，一种是在热交换器中使用多孔介质。本研究采用基于有限体积法和全多重网格加速度的数值方法，研究了由底壁内部发热引起的多孔两侧盖驱动方形腔内的层流混合对流特性。 . 假设外壳的两侧和顶壁具有低温，而底壁的其余壁是绝缘的。工作流体是空气，因此普朗特数等于 0.71。不同物理参数的行为以图形方式显示，以便在广泛的相关参数上进行计算；（10-2≤里≤10), 达西数 (10-4≤大≤10-1), 内部瑞利数 (0≤拉一世≤104), 孔隙率 (0.2≤ε≤0.8) 和 Grashof 数 (103≤格≤106）。结果表明，外壳内的传热机制和流动特性强烈依赖于 Grashof 数。例如，在考虑的内部瑞利数值下，对于高 Grashof 数，可获得最佳传热率。此外，内部热量产生的增加（Ra_一世) 导致 Grashof 数的流量和温度强度更高，范围从104到106和一个特定的理查森数值。此外，孔隙率值的增加（ε) 导致平均努塞尔数明显减少。最高温度θ最大限度是最佳的高（ε） 价值。根据两个控制参数（如达西数和理查森数）建立了平均努塞尔数与内部热源的相关表达式。