平板太阳能集热器空气夹层内自然对流换热的数值模拟

Numerical Study on Natural Convection Heat Transfer of Air Layer Inside the Flat Plate Solar Collector

本文采用数值模拟技术研究了平板太阳能集热器空气夹层内的自然对流换热,并对影响夹层内自然对流换热的因素进行了分析。结果表明:集热器内自然对流换热热损失随夹层间距的变化而改变,为降低自然对流换热热损失,最佳的空气夹层间距应为3 cm;夹层间距一定时,吸热板温度越高,对流换热系数越大,自然对流换热作用越强;集热器水平放置时,自然对流换热作用最强,热损失最大,当放置角度超过30°后,自然对流换热热损失基本不变。

In this paper,a CFD model was developed to study the natural convection heat transfer of the air layer inside the flat plate solar collector,also the influence factors were analyzed. The results indicated that the spacing of air layer had effects on natural convection heat transfer of the enclosure. In order to reduce the heat loss,the optimal spacing of the air layer should be 3 cm. Furthermore, when the spacing of air layer kept constant,the natural convection heat transfer coefficient would increase with the rise trend of absorber temperature. In addition,when the collector was settled horizontally,the natural convection heat transfer effect was the strongest and the heat loss had the largest value ,while when the inclined angle of the collector exceeded 30℃, the heat loss changed little.