压管式水冷板90°弯管内流动及传热特性研究

Numerical study on the flow and heat transfer characteristics in a 90°-bend extruded pipe setted in water-cooled plate

为优化压管式水冷板中弯管结构,并为微小发热电子器件在水冷板上合理的布局提供指导性意见,通过FLUENT软件,采用RNG k-ε模型,对一款应用于射频功放散热的压管式水冷板“D”形直角弯管处流场及热分布进行三维数值模拟,并通过试验对其结果进行了验证。同时讨论了不同弯曲度和雷诺数对流道内迪恩涡结构、流动阻力及传热特性的影响。结果表明:管道弯曲段压力从外壁到内壁呈梯度减小且总压力损失在弯曲度R/D为1.5~2范围内最小。沿弯管流道方向,“D”形弯管中心线两侧形成迪恩涡,在弯管出口90°截面二次流强度最大。在弯管出口段2D~4D范围内对流换热系数达到极大值,线性拟合得到极大值点位置S2/D与雷诺数Re之间的关系,S2/D=0.0029Re-0.114。研究结果可为微小电子发热器件在水冷板布局提供指导性意见。

In order to optimize the elbow structure and provide guidance for the reasonable layout of micro heating electronic devices in water-cooled plate,a numerical simulation of the flow field and heat distribution in a“D”-shaped bends setted in water-cooled plate,which applied to the heat dissipation of RF power amplifier,is carried out here.Simultaneously,the simulation results are verified by experiments.The effects of different curvature and Reynolds number on Dean Vortex shape,flow resistance and heat transfer characteristics in the channel were studied.The results show that the pressure in the bending section of the pipeline decreases gradually from the outer wall to the inner wall,and a smaller total resistance loss is obtained within the curvature range of 1.5~2.Dean Vortex is formed on both sides of the center line of the“D”shaped elbow along the direction of the elbow channel,and its intensity attains the largest at the 90°section of the bends.The convection heat transfer coefficient reaches the maximum value in the downstream section of the elbow outlet,and the relationship between the position of the maximum point(S2/D)and Reynolds number(Re)is obtained by linear fitting,S2/D=0.00029Re-0.114.The research results can provide guidance for the layout of micro electronic heating devices in water-cooled plate.