Interaction of Natural Convective Flows Induced around Multiple Heat Sources and Its Influence on Heat Transfer

对垂直加热板周围的自然对流流动和换热进行了分析和实验研究。主要关注的是由板块产生的热羽流的相互作用，以及它对板块局部热传递的影响。为了分析平板周围的流动场和温度场，在环绕整个平板的计算域内，对动量和能量输运的全椭圆方程进行了数值求解。研究对象是室温下的空气和水，以及由2至6个垂直板组成的阵列。结果表明，椭圆分析能较好地预测羽流相互作用。分析结果还表明，当水板间距大于10mm，空气板间距大于20mm时，一对垂直板之间的诱导流量随着板数的增加而增加。此外，在固定板阵列数量下，板阵列中心部分的流速值比外部部分的流速值大。测量了板的局部换热系数，并与分析结果进行了比较。目前的分析结果与实验数据吻合得很好。在固定间隙下，板的总换热系数随板数的增加而增加。此外，在固定板数的情况下，放置在阵列中心部分的板的系数高于放置在阵列外侧部分的板的系数。这些结果表明，板对之间的流速很大程度上取决于板的数量和位置。这也引起了板间传热系数的显著差异。

Natural Convective flow and heat transfer around a row of vertical heated plates were investigated both analytically and experimentally. Main concerns are directed to an interaction of thermal plumes arising from the plates and also to its influence on the local heat transfer from the plates. In order to analyze the flow and temperature fields around the plates, full elliptic equations for the momentum and energy transport were solved numerically for the computational domain that encloses the whole plates. The investigations were carried out for air and water at room temperature and for the arrays of 2 to 6 vertical plates. The results showed that the present elliptic analysis well predicts the plume interaction. The analytical results also showed that the flow rates induced in between a pair of vertical plates increase with the number of plates when the gaps between the plates are larger than 10mm for water and 20mm for air. Moreover, the flow rates show larger values in the central portion of the plate array than in the outside portion under the fixed numbers of the plate arrays. The local heat transfer coefficients of the plates were also measured and they were compared with the analytical results. The present analytical results coincide fairly well with the experimental data. It was also found that the overall heat transfer coefficients of the plates increase with the number of the plate under the fixed gaps of the plate. Besides, the coefficients of the plates placed in the central portion of the arrays show higher values than those placed in the outer, portion of the arrays under the fixed number of the plates. These results depict that the flow rates in between the pairs of plates depend strongly on the numbers and situations of the plates. This also causes marked differences in the heat transfer coefficients of the plates.