Y型三维微肋管管外池沸腾传热特性

Pool boiling heat transfer performance outside Y-shaped three-dimensional micro-finned tube

为了提高换热管的传热效率,选用1根光滑管和2根不同肋间距的Y型三维微肋管进行了R410A的管外池沸腾传热实验。研究发现,受气泡行为的影响,Y型三维微肋管的管外传热系数随热流密度升高而降低,传热强化效果削弱并逐渐趋于光滑管;提高饱和温度和肋间距可以增大管外传热系数,但在高热流密度下,饱和温度对管外传热系数的影响不大;与其他商用强化管相比,2根Y型三维微肋管的传热系数在热流密度在低于25 kW/m^(2)时更具优势,但在热流密度高于45 kW/m^(2)时强化倍率较低。为了预测Y型三维微肋管的管外表面传热系数,拟合了一个传热关联式,该关联式92.62%的计算值与实验值相对误差不超过30%。

In order to improve the heat transfer efficiency of the heat exchange tube,a smooth tube and two Y-shaped three-dimensional micro-finned tubes with different fin-pitch were selected to carry out the pool boiling heat transfer experiment of R410A outside the tube.The experimental results show that the heat transfer coefficient outside the Y-shaped three-dimensional micro-finned tube influenced by the bubble behavior decreases with the increase of the heat flux,and the heat transfer enhancement effect is weakened and gradually tended to a smooth tube.The raise of saturation temperature and the width of fin-pitch enhances the heat transfer outside the tube,but under the condition of high heat flux,the saturation temperature has little effect on the heat transfer outside the tube.Compared with other commercial enhanced tubes,the heat transfer coefficient of the two Y-shaped three-dimensional micro-finned tubes is more advantageous at the heat flux<25 kW/m^(2),but the enhancement factor becomes lower at the heat flux>45 kW/m^(2).Moreover,in order to predict the external surface heat transfer coefficient of Y-shaped three-dimensional micro-finned tubes,a fitting correlation is adopted.The relative deviation between the calculated value and the experimental value is within 30%.