The proportion of oil frictional loss is large in high speed wet rotor generator.The analysis for oil frictional loss related factors is very important for the efficiency optimization of the machine.An aviation high speed wet rotor generator with a rated speed of 30 000 r /min was taken as an example.The 3D flow field in the air gap of the constant rotor was studied by means of computational fluid dynamics.The correctness of the numerical calculation was verified by transverse comparison between analytical and numerical calculations.At the same time,based on the numerical calculation,the influences of the rotor speed,aviation kerosene working temperature,rotor air gap length,the size of the stator slot,the rough height and the cylindrical rotor stator eccentricity and other operation,structure and process factors on the rotor oil frictional loss were analyzed.The results are as follows:the power index of rotor oil frictional loss and speed is 2833 5 after correction;the increase of the operating temperature of the fluid medium is beneficial to reduce the oil frictional loss of the rotor;the air gap length of the fixed rotor has little effect on the oil frictional loss of the rotor,and the selection of its value should give priority to meet the needs of magnetic circuit calculation;the sealing treatment of the notch and the reduction of the width of the notch will reduce the oil frictional loss of the rotor;the existence of rotor outer circle roughness and constant rotor eccentricity will lead to the increase of rotor oil frictional loss.