正弦交叉波纹填料三维换热特性的数值模拟

Three-Dimensional Numerical Simulation of Heat Transfer in a Packing with Sinusoidal Cross-Corrugation Channels

为了得到正弦交叉波纹通道填料内部的三维换热特性和边界结构对换热特性的影响,选用了相互交叉的两个相邻正弦波纹板之间的流道作为计算区域。将该含有多个不同流动通道和多个不同单元格的三维区域划分为16829606个非结构化四面体网格,运用低雷诺数k-ε紊流模型并按照实际流动边界条件进行了数值模拟,得到了该流动区域内的三维温度分布,以及填料壁面处的切应力和热流密度的分布。不但了解到该流动区域各流道的流动规律,而且也清楚看到各单元格内的流动规律。结果显示:各通道气流流动主方向的改变对其切应力、热流密度和温度等都有着显著的影响。受横向流动气流的影响,各通道背风面的切应力和热流密度很小并在节点后接近于零,而迎风面的值在中间位置附近达到最大。并对不同的进口空气流速,计算出该交叉波纹通道的蒸发冷却效率随进口速度的变化规律,与参考文献的结果比较验证了结果的可靠性。

In order to obtain the heat transfer performance inside the three-dimensional flow channels and near the side walls in a sinusoidal intersecting corrugated packing,the flow paths between two adjacent sinusoidal corrugated plates were considered as a three-dimensional computational domain.The three-dimensional domain with many different channels and units was meshed with 16829606 unstructured tetrahedral grids and numerically simulated with low Re-number k-εturbulence model under the real flow boundary condition.The three-dimensional temperature distribution in the domain was obtained,meanwhile the shear stress and heat flux on domain walls were calculated.Based on the results,the flow law in channels and units of the whole domain was clear,which showed that the change of the main flow direction in channels greatly influenced on shear stress,heat flux and temperature.Due to the cross flow above a channel,the shear stress and heat flux on the leeward side reached the minimum value with nearly zero behind the node and the maximum value near the middle position on the windward side.Meanwhile,the variation of evaporative cooling efficiency with inlet air velocity was calculated,that is showed to be valid by comparing with references.