Abstract:In order to obtain the tip leakage flow characteristics of turbomachines,the leakage flow between coaxial rotating cylinders under circumferential pressure difference was studied.By using a twodimensional,circumferential pressure differential,coaxial rotating cylinder as a model,the analytical solutions for the circumferential flow velocity between cylinders expressed by the nondimensional function of the rotational speed ratio and the radius ratio were obtained by solving the flow control equations.The analytical expression of the circumferential leakage flow,which is jointly caused by the circumferential pressure gradient and cylinder rotation,was derived.The influence of rotational speed ratio,radius ratio,fluid medium and fluid temperature on the leakage flow were determined.The results show that the leakage flow between rotating cylinders is increased with the increase of the rotation speed and decreased with the increase of the radius ratio.When the viscosity of the medium is low,the rotation of the cylinder has little effect on the leakage flow while the circumferential pressure gradient has a great influence on the leakage flow.When the viscosity of the medium is large,leakage flow is impacted greatly by the cylinder rotation while the circumferential pressure gradient impacts the leakage flow less.