Abstract:The principle of zeroleakage of upstream gas spiral groove face seals was investigated,based on numerical analysis of film pressure,flow velocity and leakage rate in the cases of low seal pressure.The numerical results indicate that the upstream pumping spiral groove face seal can realize the complete zero leakage of sealed fluid since a circumferential closed high pressure zone can be obtained near the inlet which prevents the inflow of high pressure sealed fluid.The leakage rate is decreases firstly and then increase with the increasing of rotational speed,groove number and film thickness,contrarily increased firstly and then decreased with the increasing of groove depth,spiral angle and groove width ratio,and decreased with the increasing of groove radius.The leakage direction is changed reversely once rotational speed,film thickness and groove number reach certain values.The opening force is increased with the increasing of rotational speed and groove number,and decreased with the increasing of film thickness,and turns from increasing to decreasing with increasing groove depth,spiral angle,groove width ratio and groove radius.