圆形封闭水箱非稳态数值模拟

Simulation of unsteady number in round sealed water tank

采用数值方法对圆形封闭水箱内放置两根加热管的二维流动传热进行了非稳态数值模拟,探讨了Ra数从104到107四种情况和封闭水箱的加热管不同摆放位置下的流动和换热;对流场和温度场进行了分析,讨论了不同情况下加热管平均努赛尔数(Nuavg)的变化情况。数值模拟结果表明,随着Ra数增大水箱内的流动表现出了很大变化,决定了传热是导热或者是对流;两个水平加热管在水箱存在最佳的放置距离,这样可以使自然对流情况下的换热达到最好。

The paper carried out a simulation of unsteady number in order to investigate the unsteady natural convection around two heated horizontal cylinders in a round sealed water tank with isothermal walls by using numerical simulation,and studied the flow and heat transfer at different Rayleigh numbers（ 104 to 107） and different position. It also analyzed flow and temperature field and discussed the variation of average Nusselt number（ Nuavg） of heated cylinders in different situations. The simulation result showed that flow changes so much with the growth of Rayleigh number which determines whether the dominant heat transfer is conduction or convection. It is also found that there is always an optimum distance between two cylinders which make heat transfer to reach the best under the situation of natural convection.