中文摘要：

采用两种不同的物性参数处理方法对不同温差下的封闭方腔内自然对流进行数值计算,研究瑞利数Ra从103～106之间时,封闭方腔内空气的流动换热规律,将所得到的数值模拟结果与研究文献做了对比分析,验证了其方法的准确性,同时对比分析了利用多项式考虑气体物性参数随温度变化情况下的数值模拟结果.计算结果表明,在所计算的问题中,小温差下把热物性参数设置为常数可以一定程度上减小计算量,加快计算收敛速度,但在大温差下,物性参数设置为常数计算将造成计算结果相对误差较大.

英文摘要：

The numerical simulation was carried out by two different physical parameters approaches, through the calculating of the natural convection in closed square cavity under difference temperatures, and the analysis of the law of air flow heat transfer in a closed square cavity, with the Rayleigh Numbers in the range of 103to 106. The two approaches were verified to be correct,through the contrastive analysis between the numerical simulation result and and the published data in literature. And at the same time, the polynomial method was employed to analyse the numerical simulation results of the physical parameters under different temperatures. The numerical results show that, in the small temperature difference, constant approximation can reduce computation cost and accelerate the convergence, but it will bring large error for large temperature difference.