基于双流体模型的液氢流动沸腾数值模拟

基于双流体模型，建立了液氢管内流动沸腾的数值模型，在液体Reynolds数67000～660000、壁面热通量16300～317800 W/m²、饱和温度22～29 K、入口过冷度0～8 K的范围内，对管径5.95和6.35 mm的圆管内液氢流动沸腾开展了数值模拟研究，并与试验结果进行了对比。对比显示，液氢流动沸腾传热系数的模拟结果与试验数据的平均误差（MAE）为7.79%，94%的模拟数据都在±20%误差带范围内。

Numerical investigation of hydrogen flow boiling based on two-fluid model

As a kind of clean and efficient renewable energy with high colorific value, liquid hydrogen has been widely used in the fuel cell vehicles, explorer propelling and so on. Besides, liquid hydrogen can also be used for the cooling of devices working in cryogenic environment, for example High Temperature Superconducting (HTS) magnets. During the storage, transport and application, flow boiling of hydrogen can be easily triggered due to its extremely low saturation temperature. Heat transfer performance of hydrogen flow boiling is of significant importance and needs to be carefully studied. In conjunction with the two-fluid model, liquid hydrogen flow boiling model is developed according the Rensselaer Polytechnic Institute (RPI) model. In the model, heat transfer mechanism of hydrogen nucleate flow boiling can be divided into three parts, the evaporative heat transfer, the quenching heat transfer and the single liquid-phase convectional heat transfer. Some key parameters in the hydrogen flow boiling model, such as the bubble nucleation site density, bubble departure diameter and bubble departure frequency are carefully discussed and determined. Simulations of hydrogen flow boiling heat transfer in round tubes are conducted with the Re in 67000—660000, wall heat flux in 16300—317800 W/m², saturation temperature in 22—29 K, inlet subcooling degree in 0—8 K and channel diameter in 5.95—6.35 mm. The simulated flow boiling heat transfer coefficients agree considerably well with the experimental data with the mean absolute error (MAE) of 7.79%. About 94% of the simulated results fall in the ±20% error band. It is reasonable to conclude that the new developed model successfully captures some basic heat transfer mechanisms of hydrogen flow boiling and can be expected to be used for the further study of hydrogen flow boiling heat transfer.