摘要
在质量流速100 kg/(m^2·s),热流密度28~50 kW/m^2,入口压力7.6~8.6 MPa下,对超临界CO2在非均匀热流密度下竖直向上的流动传热规律进行了数值模拟,比较了均匀与非均匀加热的区别,分析了非均匀加热情况下热流密度和入口压力对对流传热系数、浮力效应和加速效应的影响,提出并检验了新的传热关联式。结果表明:与均匀加热相比,非均匀加热局部对流传热系数小,壁温更高;随着热流密度的增大,对流传热系数减小,浮力效应和加速效应增强;高热流密度下,随着入口压力的增大,对流传热系数增大,浮力效应和加速效应减弱;新的传热关联式能较好地预测本文中超临界CO2的传热规律。
The heat transfer characteristics of supercritical CO2 in non-uniform heated vertical upward flow were studied by numerical simulations,under conditions with mass flow rate of 100 kg/(m^2·s),heat flux of 28~50 kW/m^2 and inlet pressure of 7.6~8.6 MPa.The differences between uniform and non-uniform heating were compared.In terms of non-uniform heating,the effects of heat flux and inlet pressure on convective heat transfer coefficient,buoyancy effect and acceleration effect were discussed.Based on the numerical results,a new heat transfer correlation was developed and compared with the present simulation data.The results show that,compared with uniform heating,the local convective heat transfer coefficient is lower and the wall temperature is higher under nonuniform heating.With the increase of heat flux,the convective heat transfer coefficient decreases,while the buoyancy and acceleration effects are more pronounced.Under high heat flux condition,with the increase of inlet pressure,the convective heat transfer coefficient increases,while the buoyancy and acceleration effects decrease.The new heat transfer correlation can predict the heat transfer mechanisms of supercritical CO2 in this study well.
作者
吴家荣
李红智
杨玉
韩万龙
WU Jiarong;LI Hongzhi;YANG Yu;HAN Wanlong(Xi’an Thermal Power Research Institute Co.,Ltd.,Xi’an 710054,China)
出处
《热力发电》
CAS
北大核心
2019年第11期22-29,共8页
Thermal Power Generation
基金
国家自然科学基金项目(51806172)~~
关键词
超临界CO2
非均匀加热管
对流传热系数
浮力效应
加速效应
热流密度
壁温
压力
supercritical CO2
non-uniform heating tube
convective heat transfer coefficient
buoyancy effect
acceleration effect
heat flux
wall temperature
pressure
