中文摘要：

采用Fluent多相流混合物模型，通过用户自定义程序（UDF）实现了液氮相变模拟，模拟了不同进口流速对翅片管气化器管内流体换热量、压力降、含气率及汽化体积的影响，并分析了各参数随进口流速改变而变化的原因。由数值模拟可知，翅片管内流体进出口焓差、含气率及单位质量汽化体积随进口流速的增加而减少，而压力降和总换热量随进口流速的增加而增大，其中压力降增大的主要原因是由加速压降引起。

英文摘要：

Using Fluent multiphase mixture model, the phase change simulation of liquid nitrogen was achieved through Us- er - Defined Function （UDF）. The effect of different inlet velocities on fluid heat transfer rate, pressure drop, gas fraction and volume of gasification was simulated, and the variation reasons of parameters with the inlet velocity were analyzed. According to the numerical simulation results, the enthalpy difference, gas fraction and volume of gasification per unit of mass will reduce with the increase of inlet velocity, while the pressure drop and total heat transfer rate will add with the increase of inlet velocity. The increase of pressure drop is mainly caused by the accelerated pressure drop.