【作者】 郑臻轶； 王建刚； 杨茉； 章立新； 王治云；

【Author】 ZHENG Zhen-yi WANG Jian-gang YANG Mo ZHANG Li-xin WANG Zhi-yun (The College of Power Engineering of USST 200093 )

【机构】 上海理工大学动力学院；

【摘要】 底部加热的方腔内自然对流换热是一个具有广泛工程背景的经典理论模型。该文分别采用二维和三维模型对底部加热的方腔内自然对流换热进行了数值计算,并根据计算结果的比较,探讨了该问题流动和换热的三维效应。所采用的数值方法为具有QUICK差分格式的SIMPLE算法。数值结果表明,随着宽高比增大,对流涡卷的轴向发生改变,从平行于Y轴转变到平行于X轴,即平行于短轴。采用三维模型计算所得到的平均Nu均小于二维模型所获得的结果,而参考文献中给出的经验公式的计算结果介于两者之间。当Ra=5×103和Ra=104时,三维模型平均Nu的计算结果比经验公式的结果大约小10%,二维模型的结果比经验公式的结果分别大17%和10%左右。随着宽高比的加大,三维数值计算得到的平均Nu相应增加,但当Ra=104时,宽高比对其影响变得很小。更多还原

【Abstract】 The nature convection heat transfer in a cavity heated below is a classical theory model with wide engineering background. Two-dimensional and three-dimensional model are used to do numerical simulation about nature convection heat transfer in a cavity heated below. According to the comparing with calculation results, the three-dimensional effect on flow and heat transfer of this problem is analyzed. The SIMPLE algorithm with QUICK scheme is used as numerical method The numerical result suggests that when the transverse aspect ratio increases, the longitudinal rolls become align to the shorter X side. The Nu calculated by three-dimensional model are all smaller than the two-dimensional model’s, and the Nu calculated by empirical equation in a reference is intervenient. When Ra=5×103 or Ra=104, the Nu calculated by three-dimensional model is smaller than the empirical equation’s by 10%, and the two-dimensional result is larger than it by 17% and 10%. When the transverse aspect ratio increases, the gap decreases, when Ra=10000,the influence of transverse aspect ratio upon Nu become weaker.更多还原