Numerical Simulation Of Cryogenic Treatment Process For Conical Picks

Conical pick is the main vulnerable part of roadheader and shearer,its service life affects the efficiency of roadheader and shearer,so improving its service life is an important content of scientific research of conical pick.The research shows that the mechanical properties and service life of conical pick can be improved by cryogenic treatment.The main purpose of this paper is how to make the parameters of cryogenic treatment,save energy and improve the effect of cryogenic treatment.With the rapid development of computer simulation technology,numerical simulation has become an effective means to predict,guide and analyze experiments.In this paper,the temperature field and stress field of the cryogenic treatment of conical pick are studied by numerical simulation,which can provide reference for the formulation of the cryogenic treatment process of conical pick,and then optimize the process parameters of conical pick.The main research contents and conclusions of this paper are as follows:(1)The finite element analysis model of conical pick is established by ANSYS,and the indirect thermal stress coupling analysis is carried out.The influence of different cryogenic temperature,cryogenic speed and holding time on the thermal stress of conical pick and weld in the process of cryogenic treatment is simulated and calculated,and the change rule of temperature field and stress field of conical pick in the process of cryogenic treatment is analyzed.The results show that with the decrease of the cryogenic temperature,the greater the thermal stress produced by the conical pick,the faster the cryogenic speed,the greater the thermal stress produced by the conical pick,and the longer the holding time,the smaller the thermal stress produced by the conical pick.Through the comparative analysis of the influence of different cryogenic processes on the thermal stress of conical pick,the results show that the minimum thermal stress is produced when the cryogenic speed is 1 ℃/min and the holding time is 2 h.(2)The multi-body parts of conical pick and cryogenic tank are modeled by ANSYS Workbench,the solid model is preprocessed by Fluent software,and the physical model which accords with transient analysis is established based on heat transfer and hydrodynamics.The temperature field of conical pick under different cryogenic temperature is simulated,and its reliability is verified by test.The results show that the established physical model has a certain accuracy,and the numerical simulation results have a high reliability,which can be used for the numerical simulation analysis of the temperature field of the cryogenic treatment of conical pick.On this basis,the pressure outlet boundary is proposed,and the comparison between numerical simulation and free outlet boundary shows that the method can effectively save the amount of liquid nitrogen.(3)With Fluent software,the arrangement and different spacing of conical picks in the cryogenic tank are simulated,and the charge and liquid nitrogen consumption of cryogenic tank are numerically simulated and analyzed.The simulation results show that for SLX-30 type cryogenic tank,the horizontal transverse arrangement of conical pick is the optimal arrangement,and the spacing of 30 mm is the optimal spacing.