Numerical Simulation Of The Diffusion Behavior Of Hydrogen Cloud Formed By Large-scale Liquid Hydrogen Leakage

Hydrogen has the characteristics of low pollution emissions and high energy density,and is considered to be one of the most promising energy sources.Compared with traditional high-pressure gaseous hydrogen storage methods,liquefied hydrogen storage occupy a smaller volume under the premise of providing the same energy and have higher storage and transportation efficiency.However,in the production,storage,transportation and application of liquid hydrogen,once a liquid hydrogen leakage accident occurs,its flammable,explosive,colorless and odorless characteristics bring great safety risks.Therefore,it is of great significance to study the diffusion behavior of hydrogen cloud caused by liquid hydrogen leakage.Different from the way most scholars using commercial software for numerical simulation,this paper combines the standard k-ε turbulence model,conjugate heat transfer model,atmospheric boundary layer model and liquid hydrogen evaporation model.Based on the OpenFOAM platform,this paper builds a predictable large-scale three-dimensional non-steady-state numerical calculation model of the diffusion behavior of the hydrogen cloud caused by the liquid hydrogen leakage.The large-scale liquid hydrogen leakage experiment carried out by the NASA in 1981 at the white sand Experimental Base is used to verify the procedure.The results show that the prediction results of the program are in good agreement with the experiments,and the procedure can be used to simulate and calculate the diffusion behavior of hydrogen clouds.In order to better understand the diffusion behavior of the hydrogen cloud caused by the liquid hydrogen leakage accident,this paper explores the influence of atmospheric conditions,environmental temperature and leakage quality on the diffusion behavior of the hydrogen cloud.It focuses on the analysis of the changes in the hydrogen concentration of the hydrogen cloud at the symmetry plane over time,as well as the maximum ascent height,the farthest traverse distance,the volume and the hydrogen mass of the hydrogen cloud over time.The difference between combustible cloud cluster and explosive cloud cluster is analyzed.With reference to the storage methods of LNG storage tanks,this article calculates and analyzes the effects of the two protective measures,the protective pool and the protective wall,in order to provide a certain reference for the actual placement of liquid hydrogen storage tanks.The results show that the protective pool can reduce the diffusion range of the hydrogen cloud,but at the cost of extending the dissipating time of the cloud.The protective wall can accelerate the ascent of the hydrogen cloud in the initial stage,which is conducive to the diffusion of the cloud in the high air,but is extremely unfavorable for protection Dissipation of the hydrogen cloud in the wall.