The Study On The Effects Of Geometrical Parameters On Temperature Rise In On-board Gaseous Hydrogen Storage Cylinder During The Fast Filling Process

The carbon fiber reinforced composite cylinder is a popular solution for the on-board hydrogen storage in hydrogen vehicle.The nominal working pressure in cylinder is 70 MPa with a high hydrogen storage density and a good rate of filling-emptying.However,the great increase of temperature of hydrogen gas is related to the compression effects and other related factors,and may affect the mechanical properties of fiber/epoxy composite laminate and increase the probability of danger in refueling.So,a thorough understanding of evolution rule of temperature rise is helpful for the development of the regulation on the control of temperature rise and plays a important role in the safety of hydrogen vehicle.In this paper,computational fluid dynamics(CFD)is used to investigate the evolution of temperature rise in hydrogen storage cylinders with different geometrical parameters during the filling process.The main work in this research is as follows:(1)The filling and the holding process of on-bus hydrogen storage cylinder with different filling rates is simulated,and then the evolution rule of temperature rise is obtained.The temperature distribution in on-bus cylinders with different filling rates is shown.The evolution of temperature rises of hydrogen and solid material in cylinders with different nominal working pressures is explored.The reason for the difference of temperature rise between the hydrogen gas and solid material in different types of cylinders is explained.The effects of filling rates on heat transfer inside cylinder and heat transfer between the layers of solid material are evaluated.The maximum temperature rise of solid material in cylinder with different filling rates is given and further compared.The effect of ambient temperature on the evolution of temperature rise of hydrogen gas in cylinder is analyzed.The proposed time for fast filling in 70 MPa on-bus type III hydrogen storage cylinder is given based on the study of effects of temperature rise.(2)The filling and the holding process of on-board hydrogen storage cylinder with different geometrical parameters is simulated and the evolution rule of temperature rise is further obtained.This paper shows the temperature distribution in cylinder with different thicknesses of external wall,investigates the evolution of temperature rise in cylinders with different thicknesses of external wall,and then obtains the effects of thicknesses of external wall of cylinder on temperature rise in cylinder.The evolution of temperature rises of hydrogen gas and carbon fiber/epoxy composite laminate in cylinders with different inner water volumes is also investigated,and then the effect of inner water volume of cylinder on temperature rises of hydrogen gas,carbon fiber/epoxy composite laminate is obtained.(3)Through theoretical analysis and nonlinear fitting,the evolution rule of temperature rise in cylinder that accounts for the effects of multiple parameters including filling rates and geometrical parameters is obtained.The effect of introduced dimensionless volume-based coefficient on maximum temperature rise is studied.The comprehensive effects of the heat dissipation between the external walls of cylinder and the temperature rise in cylinder on heat transfer during the filling process are reflected by theoretical analysis,and the effects of filling parameters and geometrical parameters on evolution of temperature rise are further obtained.Through nonlinear fitting,the evolution rule of temperature rises in cylinder that accounts for the effects of multiple parameters is obtained,and the results can provide some theoretical guidance for the development of the filling strategy on on-board hydrogen storage cylinder.