Abstract:The study of intestinal robots now at home and abroad is focused on the singlephase liquid flow environment,while there exists food residues in the actual intestine,and the intestinal fluid should be liquidsolid twophase mixed fluid.The operational performance indicators of inner spiral capsule robots in liquidsolid twophase flow,including axial thrust force,circumferential resisting moment and the maximum pressure of pipe wall were numerically calculated by using the computational fluid dynamics (CFD) method,and the calculation results were validated by experiment.The results show that in the liquidsolid twophase flow,with the increasing of the diameter and weight concentration of the solid particles,the axial thrust force and circumferential resisting moment of the robot are decreased and the maximum pressure of pipe wall is increased.The performance indicators of the robot in liquidsolid twophase flow are lower than those in singlephase liquid flow.The experiments prove that adding the solid particles will decrease the operational performance of the inner spiral capsule robot in the liquid pipe.