竖直圆管内超临界压力低温甲烷传热的数值研究

Numerical Study on Heat Transfer of Supercritical Pressure Cryogenic Methane in Vertical Pipes

李琳 姜文全 李婷婷 杨帆 宿诗雨 石杰峰

Lin Li Wenquan Jiang Tingting Li Fan Yang Shiyu Su Jiefeng Shi

辽宁石油化工大学 机械工程学院，辽宁 抚顺 113001 临沂市自然资源和规划局，山东 临沂 276301 辽宁石油化工大学 石油天然气工程学院，辽宁 抚顺 113001

School of Mechanical Engineering，Liaoning Petrochemical University，Fushun Liaoning 113001，China Linyi Natural Resources and Planning Bureau，Linyi Shandong 276301，China College of Petroleum Engineering，Liaoning Petrochemical University，Fushun Liaoning 113001，China

为了降低超临界压力甲烷管内对流换热的热阻，提高传热过程的稳定性，对竖直管内超临界甲烷的流动与传热过程进行了数值研究，讨论了热流密度、流动方向对流动换热特性的影响，研究了流场、温度场和湍动能变化对传热不稳定性的影响。结果表明，竖直管内超临界甲烷的传热存在不稳定传热现象，在高热流密度下，管内壁温度和平均温度具有不稳定性，在传热恶化区间震荡；在低热流密度下，局部对流传热系数具有不稳定性，在传热恶化区间震荡；在相同的热流密度下，向上流动时的传热不稳定性大于向下流动时的传热不稳定性，是由于向上流动的热影响大于向下流动的热影响，产生的类气膜是传热不稳定的主要因素。

In order to reduce the heat resistance and improve stability of convective heat transfer in liquefied natural gas(LNG) vaporizer, the flow and heat transfer processes of supercritical pressure LNG were analyzed by numerical method in a vertical tube. The influence of heat fluxes and flow directions on heat transfer characteristics was discussed, and the effects of the flow field , the temperature field , and the turbulent kinetic energy changes on the heat transfer instability were investigated.The results show that the heat transfer of supercritical methane in vertical tube is unstable,at high heat flux density, the inner wall temperature and the average temperature of the pipe are unstable and and shock in the heat transfer deterioration range; At the low heat flow density , the local convection heat transfer coefficient is unstable , and it shocks in the heat transfer deterioration range; Under the same heat flux density, the heat transfer instability of upward flow is greater than that of downward flow, because the thermal influence of upward flow is greater than that of downward flow. The gas?like film is the main reason of heat transfer instability.

辽宁省教育厅科学研究经费项目(L2019024)

10.3969/j.issn.1672-6952.2021.05.012