Abstract:With the low temperature of compression medium for the BOG labyrinth compressor,the cylinder and piston are subjected high temperature loads and stress loads,which has a significant impact on the sealing clearance between piston and cylinder,and indirectly affects the labyrinth sealing performance.Focused on the influence of thermalsolid coupling deformation on labyrinth seal,with the largescale BOG reciprocating compressor as the case study,the cylinder and piston were simulated and analyzed by thermalsolid coupling method using ANSYS Workbench simulation platform.The deformation rule of the cylinder and piston under the action of thermalsolid coupling was investigated,and the effect of the deformation variables on the sealing clearance was discussed.The results show that the maximum deformation of the piston and the cylinder occurs at the stroke end of the upward compression under the action of thermomechanical coupling.The maximum deformation of the cylinder occurs at the top edge of the cylinder and the maximum deformation of the piston occurs at the middle ring of the top end face.The simulation result shows that the sealing clearance deformation of the large BOG reciprocating compressor in the compression process is increased between 0.1 mm and 0.15 mm because of the deformation of piston and cylinder.