一种超临界CO2印刷电路板式换热器热工水力特性数值研究

采用商用CFD软件CFX对应用于超临界CO2(S-CO2)布雷顿循环的一种印刷电路板式换热器(PCHE)热工水力特性进行了数值研究。建立三维数值计算模型进行模拟,将数值计算结果与公开发表的实验数据进行对比,验证了数值方法及模型的适用性。对PCHE传统Z字形的半圆形截面流道结构进行了优化,通过将半圆形截面优化成矩形截面使得PCHE传热面积增加,传热性能得到提升。将优化后的结构应用于S-CO2布雷顿循环中的预冷器,基于预冷器的运行条件研究了其CO2侧和水侧的流动传热性能,并依据计算结果拟合了预冷器两侧流体的传热关联式和流动阻力关联式。

A CFD analysis is conducted to reproduce the micro channel internal flow information in the S-CO2 printed circuit heat exchanger(PCHE)for S-CO2 power cycle with a commercial CFD code ANSYS CFX.By comparing the simulation results with the experimental data published in a thesis,the applicability of the numerical method is verified.In order to improve the thermal hydraulic performance of PCHE,a new structure is developed by changing the conventional semi-circular zigzag flow channel into rectangle zigzag flow channel which can offer more heat transfer area with the same heat exchanger volume.The new structure of rectangle zigzag flow channel is applied to PCHE as a pre-cooler for S-CO2 power system with CO2 flowing in hot side channel and water flowing in cold side channel.Then the hydraulic performance of pre-cooler is studied under the operating condition and the friction factor and heat transfer correlation on both side are developed.