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用k- ε双方程模型研究了大宽隙比( 通道宽度与通道间隙之比> 25) 矩形窄缝通道内单相流体的混合对流换热问题。数值模拟结果表明, 大宽隙比窄缝通道内的混合对流存在着与圆管内混合对流相似的“中部热岛”现象,在给定流量下,壁面“热岛”现象随热流密度增大而加强,给定热流时壁面“热岛”随流量增加而减弱
The mixed convection heat transfer problem of a single-phase fluid in a rectangular narrow channel was investigated using a k-ε dual equation model with a large ratio of wide to wide channels (ratio of channel width to channel gap> 25). The numerical simulation results show that there is a “middle heat island” phenomenon that is similar to the mixed convection in the circular tube in the mixed convection in the large-wide gap than in the narrow-passage channel. Under a given flow, the “heat island” phenomenon on the wall increases with the increase of the heat flux. Wall surface “heat island” weakens with increasing flow for a given heat flow