The results of a detailed theoretical examination of laminar natural convection heat flow in a triangular porous cavity with significant radiative heat transfer and porosity variations are presented. Two-dimensional laminar incompressible flow was considered, in which the left slant and right walls were at low and high temperature, respectively, and the remaining (top) wall was adiabatic. The Darcy-Brinkman isotropic model was utilized, and the coupled governing equations were solved by a numerical method utilizing finite differences. Visualization of the isotherms and streamlines was achieved using the method of energy flux vectors (EFVs). The impacts of the different model parameters (the Rayleigh number, Darcy number, porosity, and radiation parameter) on the thermo-fluid characteristics were studied in detail. The computations showed that convective heat transfer was enhanced with an increase in the Darcy number (permeability), which also led to intensification in the density of the EFV patterns. The flow accelerated with an increase in the buoyancy effect (Rayleigh number) and the temperatures also increased with greater radiative flux. The average Nusselt number decreased with higher porosity. The simulations are relevant to hybrid porous media solar collectors.

中文翻译：

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多孔三角形罩壳内对流换热的数值模拟和能量通量矢量可视化

给出了在三角形多孔腔中层状自然对流热流的详细理论研究结果，该层具有明显的辐射热传递和孔隙率变化。考虑了二维层流不可压缩流动，其中左斜壁和右壁分别处于低温和高温，而其余（顶壁）是绝热的。利用Darcy-Brinkman各向同性模型，并通过利用有限差分的数值方法求解耦合的控制方程。等温线和流线的可视化使用能量通量矢量（EFV）的方法实现。详细研究了不同模型参数（瑞利数，达西数，孔隙率和辐射参数）对热流体特性的影响。计算表明，对流传热随着达西数（渗透率）的增加而增强，这也导致EFV图案密度的增强。流动随着浮力效应（瑞利数）的增加而加速，温度也随着辐射通量的增加而增加。孔隙率越高，平均努塞尔数越少。该模拟与混合多孔介质太阳能收集器有关。