In compressor, impeller design plays a decisive role in compressor stage characteristics. The main aerodynamic parameters of impeller design, such as flow coefficient, attack angle, slip coefficient, inlet and outlet moment of momentum, are usually calculated or selected according to empirical formula in engineering design. The most important part of the rotor is generally composed of disc, cover and blade. Under the action of the impeller blade, the gas rotates at high speed with the impeller. The pressure of the gas after passing through the impeller is increased due to the centrifugal force and the diffuser flow in the impeller.
Due to the wide speed range of gasoline engine and the large variation of air flow, the shape of the compressor impeller of the turbocharger is a complex three-dimensional curved ultra-thin wall impeller blade, which generally has 12-30 blades arranged in radial curve, and the thickness of the blade is less than 0.5mm. It is made of aluminum by special casting method. The blade shape directly affects the performance of turbocharged engines. The more reasonable the impeller shape angle is, the lighter the mass is, the more sensitive the impeller is to start, and the smaller the inherent defect "response lag" of the turbocharge.