Numerical Simulation On Quenching Cooling Uniformity Of Gas Storage For Gas Supply Stations

With the rapid development of auto industry of China and the widespread use of CNG dual fuel power vehicles,the demand for gas cylinders is growing rapidly.Gas cylinders for gas supply stations are an important tool for the storage of natural gas,The large gas cylinders work in fatigue conditions of unloading and loading for a long time,The structural characteristics of cylinders is owning big size,high-mass,the large diameter and thick wall.Gas cylinder's heat treatment is very complicated.On account of the structural characteristics of cylinders,the limits of equipment on the quenching process,it will lead to the result is that quenching cooling of the organization of the gas cylinders is not uniform,the distribution of stress of the bottle is not uniform.The above factors will lead to defects such as body deformity and crack,to ensure the uniformity and the hardenability of gas cylinders is the key of cylinder manufacturing.The different dynamic CCT curves of continuous cooling transformation were determined by DIL805 L Phase transition quenching.Achieve experimental results of the critical transition temperature at different cooling rates of materials.The experimental results provide a practical data basis for subsequent numerical calculation of the quenching process.Namely the internal are intermittent radial sprayed and the outside of the cylinders are sprayed water continuously are taken for water quenching.Establish an orthogonal test program.Determine the scientific and reasonable multi-nozzle layout of the cylinder chamber.With the help of computational fluid dynamics software Fluent,it simulated the flow field and temperature field with coupled method in quenching process.According to the temperature of the monitoring point in the process of simulation,the change of the maximum pressure inside the cylinder,to ensure the intermittent spray time of internal in the quenching process.To get the different results of pressure in this process,the fraction of gas and liquid are compared,and the results of reducing pressure in the process of the intermittent spray water quenching are analyzed.The temperature field of the two processes optimal model and the intermittent spray water quenching model are compared,and the temperature field distribution of the intermittent spray water quenching is obtained.Stress and strain analysis of the cylinder in the Workbench was carried out that were on the basis of the result of the pressure and temperature field data of the stoppage process in Fluent.The principal stress,equivalent stress,equivalent strain,axial stress and circumferential stress of the cylinder were simulated.The variation characteristics of each stress in the cooling process were analyzed.The distribution characteristics of the whole cylinder body at different temperatures were analyzed by equivalent stress.To get the cylinder is easier to deformation and the location of defects.The results show: the quenching process namely the internal are intermittent radial sprayed and the outside of the cylinders are sprayed water continuously can regulate the temperature gradient and pressure in the bottle,to control the pressure inside the bottle within the safe range during the cooling process.;The process can improve the temperature drop rate of the inner wall of the cylinder,and can ensure the quantity of martensitic transformation.