Study On Thermal Deformation Issues Of Impeller And Shaft Interference Fit With Thermal Difference Dismantling

The dismantling is the premise of machinery equipment remanufacturing.As the machinery equipment, to achieve high efficiency and economy of the non-destructive dismantling is one of the key questions of remanufacturing.To explore and research the thermal deformation issues in thermal difference dismantling, the methods of theoretical derivation, FEM calculation and dismantling simulation test are used in this dissertation, with the core parts of impeller and shaft in large compressor as the research object.In this dissertation5aim at the thermal difference dismantling issues of the impeller and shaft under interference fit condition, the heat transfer mechanism is researched; the complex constraint feature and the stress distribution characteristics are analyzed with multi-field coupling. Through theoretical analysis and FEM calculation, the loose volume model of the mating surfaces between the impeller and the shaft is built during the temperature difference dismantling process.Besides,the influence of heating temperature,heating time and heating position on the loose volume of mating surfaces interference fit and the deformation of the impeller weakness part is researched.Then we obtained the reasonable heating parameters.What’s more, the influence of heat transfer coefficient, the heating temperature, thermal conductivity and thermal contact resistance on loose volume and optimal heating time is explored, and the main factor which relate to optimal heating time is obtained.The distribution characteristics and variation discipline of the loose volume and stress in axial of impeller and shaft are analyzed during the thermal difference dismantling, the mechanism of constraint release and damage is studied in multi-field coupling.Finally, the dismantling simulation test is done to verify the influence of different stress and fit condition on the work surface damage,and the optimal thermal difference dismantling program is obtained according to the result of the simulation.Based on the above analysis, the method of reduce or eliminate damage from dismantling is used to meet the requirements of remanufacturing.