Abstract:The seal endface temperature not only affects the endface deformation but also characterizes the friction state of the endface,which is very important for the operation of the seal,especially for the unopened state of the hydrodynamic seal when starting and stopping.The endface temperature distribution of oilgas twophase backflow pumping seal (OGBPS) in open state and unopened state was studied.The thermalstructure coupled numerical analysis model was established in the ANSYS Workbench and a variable condition parameter test was conducted.The effects of the working parameters such as the rotation speed,pressure difference and liquidgas ratio on the end face temperature were analyzed.The results show that the endface temperature only has a slightly increase with the increasing of the rotation speed and the liquidgas ratio in the open state,therefor the OGBPS can work stably and reliably under the variable working conditions.In the unopened state,the endface temperature is increased sharply with the increasing of the rotation speed and pressure difference,but with the increasing of the liquidgas ratio,the end surface temperature is decreased rapidly,and the oilgas twophase medium is conducive to startstop operation.The experiment results are in agreement with the numerical results,which proves the correctness of the numerical calculation.