入射角对径向热管换热器性能影响的数值模拟

Numerical Simulation of Heat transfer Thermal Performance under Various Inclination Angles in Radial Heat Pipe Heat Exchanger

利用FLUENT软件对径向热管换热器壳程进行模拟计算,在入口烟气质量流量不变的基础上,在0°～65°范围内逐渐改变烟气入射角,分析换热量、压降和单位压降换热系数的变化规律。结果显示:随着烟气入射角的增大,入射角小于45°时,换热量偏差基本不变,压降偏差逐渐减小,而单位压降换热系数逐渐增大,并在约45°时达到最大,此时换热器整体性能最好;大于45°后,换热量偏差明显增大;压降偏差急剧增大,压力损失增加,而单位压降换热系数急剧减小,换热器性能恶化。将模拟结果与测试结果进行比较,误差在5%以内。

Abstract： Based on the constant smoke mass flow at the entrance of heat exchanger, the characteristics of the heat transfer rate, pressure drop and heat transfer coefficient of u- nit pressure drop were analyzed as the inclination angles varied between 0° and 65° by simulating the shell side of radical heat pipe heat exchanger with the software FLU- ENT. The results show that, with the increasing of inclination angles less than 45° ,the deviation of heat transfer rate nearly keeps constant, the deviation of pressure drop de- creases gradually and the heat transfer coefficient of unit pressure drop increases gradu- ally and culminates at 45° where the heat transfer performance of the heat exchanger gets its optimum; When the inclination angles exceed 45°,the deviation of heat transfer rate goes up remarkably, the deviation of pressure drop increases significantly with the pressure loss enlarging, and the heat transfer coefficient of unit pressure drop decreases rapidly, so the performance of the heat exchanger deteriorates. The relative error of the simulation results to experimental results is less than 5 %.