ABSTRACT

Natural convection from a horizontal plate with identically-heated top and bottom sides, enclosed in gas- or liquid-filled square cavities cooled at sides, is studied numerically. A computational code based on the SIMPLE-C algorithm for pressure-velocity coupling is used to solve the system of the governing conservation equations of mass, momentum and energy. Simulations are performed using the Rayleigh number based on the plate length, the Prandtl number, the cavity width normalized by the plate length, and the distance of the plate from the bottom wall of the enclosure normalized by the cavity width, as controlling parameters. It is found that the heat transfer rate enhances as the Rayleigh number, the Prandtl number and the dimensionless size of the cavity are increased, while it deteriorates as the dimensionless elevation of the plate is increased. Additionally, the heating of the upper side of the plate has an almost imperceptible effect on the heat transfer rate at the lower side of the plate, whereas the amount of heat transferred from the upper side of the plate normally decreases when the lower side of the plate is heated rather than being insulated. Based on the results obtained, suitable dimensionless heat transfer correlations are developed for the entire plate and each heated side.

摘要

数值研究了顶部和底部均被加热的水平板的自然对流，并封闭在侧面冷却的充满气体或液体的方腔中。基于SIMPLE-C算法的压力-速度耦合计算代码用于求解质量，动量和能量的控制守恒方程组。使用基于板长，普朗特数，通过板长归一化的腔体宽度以及通过离腔体宽度归一化的板到外壳底壁的距离的瑞利数作为控制参数，执行模拟。已经发现，随着腔的瑞利数，普朗特数和无因次尺寸的增加，传热速率提高，随着板的无量纲高度的增加而恶化。另外，板的上侧的加热对板的下侧的传热率几乎没有明显的影响，而当板的下侧从板的上侧传递的热量通常减少。加热板而不是绝缘板。基于获得的结果，为整个板和每个受热侧开发了合适​​的无因次热传递相关性。