印刷电路板式换热器超临界二氧化碳传热特性分析

Investigation on Heat Transfer Characteristics of Supercritical Carbon Dioxide in Printed Circuit Heat Exchanger

采用数值模拟的方法分析不同热工参数对印刷电路板式换热器内超临界二氧化碳进行换热特性研究。在压力8~12 MPa、质量流速800~2000 kg/(m^(2)·s)和入口温度650~850 K的参数范围内,讨论了压力、温度和质量流速对管内超临界二氧化碳传热特性的影响。研究结果表明:印刷电路板式换热器管内压力升高,传热系数增大;当流体温度升高,管内主流焓值增大,热传递能力增强,传热系数增大;在出口附近区域,随着边界层的厚度沿主流方向增加,传热系数先增大后减小,换热能力降低,传热系数减小;随着质量流速的升高,管内换热能力增强,平均换热系数升高,换热效果强化显著。

The numerical simulation method is used to study the heat transfer characteristics of supercritical carbon dioxide in the printed circuit heat exchanger with different thermal parameters.Within the range of pressure from 8 to 12 MPa,mass velocity of fluid from 800 to 2000 kg/(m^(2)·s)and fluid temperature from 650 K to 850 K,the heat transfer characteristics of supercritical carbon dioxide in the printed circuit heat exchanger are numerically analyzed.The effects of pressure,temperature and mass flow rate on the heat transfer characteristics of supercritical carbon dioxide in tube were discussed.The results show that the pressure in the tube of printed circuit heat exchanger increases and the heat transfer coefficient increases.When the fluid temperature increases,the mainstream enthalpy increases,the heat transfer capacity increases and the heat transfer coefficient increases;In the area near the outlet,as the thickness of the boundary layer increases along the mainstream direction,the heat transfer coefficient first increases and then decreases,the heat transfer capacity decreases and the heat transfer coefficient decreases;With the increase of mass flow rate,the heat transfer capacity in the tube increases,the average heat transfer coefficient increases,and the heat transfer effect is strengthened significantly.