空温式翅片管气化器冷热流体传热特性仿真研究

Simulation Study of Heat Transfer Characteristics of Cold and Hot Fluid Distribution for Air-heating Finned-tube Vaporizers

空温式翅片管气化器通过吸收周围环境的热量使管内低温液体气化,其壁面温度低于附近湿空气冰点时会引起翅片表面结霜问题,严重影响低温系统正常工作。为探究翅片管内、外冷热流体对表面结霜影响的基础科学问题,采用Fluent软件对空温式翅片管气化器冷热流体的传热特性进行数值模拟,获得了翅片管内、外冷热流体与翅片壁面温度分布关系,研究了翅片管内低温液体入口流量和管外吹风速度对其传热特性的影响。结果表明:在管外自然对流条件下,翅片壁面温度沿管内低温液体流动方向(由下往上)逐渐升高,随翅片管内低温液体入口流量的降低而升高;管外向下进口风速为2.0m/s时,与自然对流条件相比,翅片壁面平均温度升高了约17K。

Air-heating finned-tube vaporizers absorb ambient heat to vaporize cryogenic liquid within finned-tubes.When the vaporizer wall’s temperature stays below freezing point of the moist air,the frost comes into being on the finned-tube surface,which seriously influences normal operation of the cryogenic system.In order to explore effects of cold and hot fluid’a distribution inside and outside the finned-tube on the surface frosting,the heat transfer characteristics of cold and hot fluid distribution for air-heating finned-tube vaporizer were numerically simulated with Fluent software and the temperature distributions of cold and hot fluids inside and outside the finned-tube and the finned wall were obtained,including effects of inlet cryogenic fluid’s flowrate in the finned-tube and the air velocity outside the finned tube on the heat transfer characteristics.The results showed that,under the condition of natural convection,the temperature of finned wall increases gradually along the direction of cryogenic fluid(from bottom to top)and increases with the decrease of the inlet flowrate of the cryogenic fluid in the finned-tube.When the downward inlet air velocity outside the finned-tube is 2.0 m/s,the average temperature of the finned wall increases by about 17 K compared with the condition of natural convection.