Goodarzi M, Safaei M R, Oztop Hakan F, Karimipour A, Sadeghinezhad E, Dahari M, Kazi S N, Jomhari N
Department of Software Engineering, Faculty of Computer Science & Information Technology, University of Malaya, 50603 Kuala Lumpur, Malaysia.
Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia.
ScientificWorldJournal. 2014 Mar 20;2014:761745. doi: 10.1155/2014/761745. eCollection 2014.
The effect of radiation on laminar and turbulent mixed convection heat transfer of a semitransparent medium in a square enclosure was studied numerically using the Finite Volume Method. A structured mesh and the SIMPLE algorithm were utilized to model the governing equations. Turbulence and radiation were modeled with the RNG k-ε model and Discrete Ordinates (DO) model, respectively. For Richardson numbers ranging from 0.1 to 10, simulations were performed for Rayleigh numbers in laminar flow (10⁴) and turbulent flow (10⁸). The model predictions were validated against previous numerical studies and good agreement was observed. The simulated results indicate that for laminar and turbulent motion states, computing the radiation heat transfer significantly enhanced the Nusselt number (Nu) as well as the heat transfer coefficient. Higher Richardson numbers did not noticeably affect the average Nusselt number and corresponding heat transfer rate. Besides, as expected, the heat transfer rate for the turbulent flow regime surpassed that in the laminar regime. The simulations additionally demonstrated that for a constant Richardson number, computing the radiation heat transfer majorly affected the heat transfer structure in the enclosure; however, its impact on the fluid flow structure was negligible.
采用有限体积法对正方形封闭腔内半透明介质的层流和湍流混合对流换热的辐射效应进行了数值研究。利用结构化网格和SIMPLE算法对控制方程进行建模。分别采用RNG k-ε模型和离散坐标（DO）模型对湍流和辐射进行建模。对于理查森数范围为0.1至10的情况，对层流（10⁴）和湍流（10⁸）中的瑞利数进行了模拟。将模型预测结果与先前的数值研究进行了验证，观察到了良好的一致性。模拟结果表明，对于层流和湍流运动状态，计算辐射换热显著提高了努塞尔数（Nu）以及传热系数。较高的理查森数对平均努塞尔数和相应的传热速率没有明显影响。此外，正如预期的那样，湍流状态下的传热速率超过了层流状态。模拟还表明，对于恒定的理查森数，计算辐射换热主要影响封闭腔内的传热结构；然而，其对流体流动结构的影响可以忽略不计。
