盘面温度水平对自由盘层流换热的影响

Effect of temperature level on heat transfer on a free disk with laminar flow

采用数值模拟的方法,研究冷气与盘面的温差(即不同盘面温度水平)导致的冷气密度变化对自由盘盘面换热所产生的影响(采用局部努塞尔数的相对偏差进行衡量),对比不可压空气与可压缩空气的换热计算结果发现:对于自由盘层流,盘面过余温度分布曲线的指数、盘面无量纲最大温差以及旋转雷诺数对盘面局部努塞尔数的相对偏差的影响可以忽略,相对偏差只与盘面无量纲局部温差有关;通过对计算数据进行拟合之后,得到了层流时自由盘盘面局部努塞尔数的相对偏差与盘面无量纲局部温差的计算关联式.

The effect of density variation caused by temperature difference of cooling air and a free disk on the heat transfer of the disk was simulated numerically. The difference of heat transfer between compressible and incompressible cooling air was compared by the local Nusselt number of the free disk. The following conclusions can be drawn on a comparative basis： the relative difference of the local Nusselt number is dominantly controlled by dimensionless local temperature difference, regardless of the influence of the distribution curve exponent of surplus temperature, dimensionless maximal temperature difference and rotating Reynolds number. A correlation formula of relative difference of local Nusselt number and dimensionless local temperature difference was presented by fitting numerical data.