CFD Analysis Of Hydrogen Absorption In Hydrogen Storage Bed And Structural Optimization Based On Genetic Algorithm

With the rapid development of global industrialization,a large amount of traditional fossil energy has been exploited and used,which has caused an energy crisis and a series of environmental problems.The development and utilization of new renewable and clean energy has become an urgent problem for mankind.Among the many new energy sources,since the product of hydrogen energy combustion is water that is non-polluting to the environment.Hydrogen energy has abundant reserves in nature and has received extensive attention from countries around the world in recent years.The storage of hydrogen energy is the key to whether it can be commercialized on a large scale.Metal hydride hydrogen storage has become an important hydrogen storage method due to its large hydrogen storage capacity and high safety.Many scholars at home and abroad have conducted research on it.However,at present,metal hydride hydrogen storage still has problems such as low mass hydrogen storage density and slow hydrogen absorption and desorption rate in the hydrogen storage reaction bed.Therefore,according to the needs of the project,this paper firstly analyzes the heat and mass transfer of the double-layer thin-walled hydrogen storage reaction bed during the hydrogen absorption process to study the changes in the temperature and hydrogen absorption of the hydrogen storage layer.Then the genetic algorithm is used to optimize the structure of the hydrogen storage bed to improve the hydrogen absorption performance of the hydrogen storage bed.The main research is as follows:1 The basic principles of metal hydride hydrogen storage are studied.The hydrogen storage process can be divided into physical adsorption,diffusion,nucleation and growth.This process can also be explained by the alloy P-C-T curve.The kinetic equation of hydrogen absorption for Zr Co alloy is deduced,which provides a theoretical basis for the determination of the energy source term.Perform CFD(Computational Fluid Dynamics)analysis on the hydrogen storage reaction bed,and establish a numerical model of hydrogen absorption in the hydrogen storage bed according to the conservation of mass,momentum,energy conservation equation,hydrogen absorption rate equation and convective heat transfer equation.UDF is used to define the heat source term of the hydrogen absorption reaction,which is loaded by means of compilation,and finally the model is solved by Fluent software.In order to verify the validity of the numerical model,the experimental data of Kang et al.were compared with the simulation results in this paper.2 Based on the established numerical model of hydrogen absorption,the influence of the structural parameters of the double-layer thin-walled hydrogen storage bed and the operating parameters of hydrogen absorption was carried out.In terms of bed structure parameters,the influence of the radius of the cooling pipe,the thickness of the heat transfer fins and the thickness of the hydrogen storage layer on the heat and mass transfer performance of the metal hydride bed is considered.In terms of the operating parameters of hydrogen absorption,the effects of hydrogen supply pressure,cooling fluid temperature and heat transfer fin material on the heat and mass transfer performance of the hydrogen storage reaction bed are studied.Through the study of different influencing factors,it is possible to further explore the heat and mass transfer law of the hydrogen storage bed in the process of hydrogen absorption,and provide a reference for the subsequent optimization of the reaction bed structure.3 Construct an approximate model of the hydrogen storage reaction bed,use the optimal Latin hypercube to collect a certain number of sample points in the space formed by the design variables(cooling pipe radius,heat transfer fin thickness,and hydrogen storage layer thickness),and use the obtained sample points The second-order response surface method is used for fitting the sample points.The function expressions between the temperature of the hydrogen storage layer and the radius of the cooling pipe,the thickness of the heat transfer fins,and the thickness of the hydrogen storage layer are obtained and used as the fitness function.According to the optimization model,the genetic algorithm C program is written,and methods such as adaptive crossover and mutation operators are used to improve the optimization performance of the algorithm.The temperature and hydrogen absorption before and after the optimization of the reaction bed were compared and analyzed to prove the improvement effect of the optimized hydrogen storage performance.