天线阵面沸腾换热的数值分析及优化

Numerical Investigation and Optimization on Boiling Heat Exchange of Antenna Surface

为研究雷达天线阵面的冷却降温效果,建立了两相流蒸发冷却模型,并着重分析了沸腾换热在局部高热流密度条件下的换热能力,局部热流高达800kW/m2。采用VOF模型结合用户自定义控制方程,数值计算三维流道内的沸腾传热现象,从气液流动趋势上寻找阻碍换热的因素。结果表明:VOF模型能较好地用于分析气液两相流动中的层状流、泡状流以及气液流动趋势;通过减小弯道处过流面积提高局部流速的方法可以缓解气相在弯道处的汇聚,消除了0.9K的局部过热;对于单侧高热流蒸发的数值分析,蒸发控制方程的调节系数在500左右为宜。温度计算结果与实验结果趋势一致,总体偏差5K左右,数值分析可以用于研究冷板的沸腾换热。

The evaporative cooling of two-phase model was established to cool the antenna surface with partial high heat flux. The analysis was focused on the ability of cooling under the local high heat flux of 800 kw/m2. Using VOF model, as well as the governing equation defined by the user, the computation of the boiling heat exchange in the three-dimensional pipe was performed to study the reason of hindering the heat exchange from the flow of the vapor and liquid. Results show that, the model could be well used in the analysis of stratified flow, bubble flow and the flow trend of vapor and liquid in the two-phase flow. Decreasing the flow area of the curved tube and increasing the local velocity could reduce the converging of the vapor. And the local superheat of 0.9 K was dismissed. The coefficient in the evaporation control equation should be increased to about 500 to ensure the accuracy of simulation in the partial high flux model. The overall error of the numerical result was about 5 K but the tendency of the temperature was similar with the experiment. So, numerical analysis could be used in the study of the boiling heat exchange for the cold plate.