Abstract:As the advanced fourth generation nuclear power reactor technology,the main helium fan of the high-temperature gas-cooled reactor is the key equipment.The object of this study is the labyrinth seal between the main helium fan stages of high-temperature gas-cooled reactor.The leakage characteristics of the labyrinth seal under different inlet and outlet pressure difference,shaft speed,cavity width and tooth width were analyzed by CFD numerical technology.At the same time,a sealing test platform is established to study the influence of shaft speed and inlet pressure difference on leakage characteristics.The results show that the leakage increases obviously and is approximately proportional with the increase of the pressure difference between inlet and outlet.With the increase of rotational speed,the leakage decrease,but the change range is small,when the rotational speed reaches 5 000 r/min,the leakage amount is the smallest.As the increase of the cavity width,the leakage decrease.As the increase of the tooth width,the leakage decrease.