Parametric influence study of cryogenic hydrogen dispersion on theoretical aspect

In this paper, we proposed a theoretical model to study the dispersion of hydrogen. The model given a correlation between the concentration and temperature for cryogenic gases. The model based on adiabatic mixing hypothesis and neglected exterior heat sources, and thought the gas mixture was always at quasi-steady state. Real-gas law was adopted, and thermal physical properties of the gases are obtained from NIST REFPROP database. The concentration curve approximately appears a decreasing straight line, and turns on dew point and ice point, since heat released from water vapor phase change. Compared with liquid hydrogen and liquid natural gas spill experimental data, the model obtained well agreement solutions. Effects of three typical weather conditions (atmospheric temperature, relative humidity and barometric pressure) on hydrogen dispersion were quantitatively studied. It is confirmed that the dispersion is excited in summer, and is depressed in winter and transition seasons with increased ambient temperature. With increased ambient temperature, the effect of increased enthalpy reduction of the dry air components and the effect of the water latent heat are respectively dominate in the 268.15–293.15 K and 293.15–308.15 K ranges. Compared to ambient temperature and barometric pressure, relative humidity has the strongest positive effect on hydrogen dispersion, and the slight dampening effect of barometric pressure could be neglected.