Effect Of Blade Inlet Edge Type And Blade Wrap Angle On Cavitation Characteristics Of Screw Centrifugal Fuel Pump

With the development of the times and the advancement of aviation technology,the aviation industry has put forward requirements for long endurance,high altitude,and hypersonic speed for the performance of aircraft,which puts forward more restrictive requirements for each component of the aircraft.The screw centrifugal fuel pump is the main component of the aircraft’s fuel system and plays an extremely important role in ensuring the aircraft’s stability,high-altitude flight,and long-endurance flight performance.Among them,the high-altitude flight performance of the aircraft has a very close relationship with the cavitation performance of the fuel pump.After the fuel pump cavitation occurs,it is easy to cause insufficient fuel supply and irregular operation of the aircraft.In this paper,the spiral centrifugal fuel pump is independently designed based on the efficiency and cavitation requirements.Using this fuel pump as the research object,the external characteristics,cavitation characteristic curve,and internal flow field characteristics of the fuel pump are numerically simulated based on the RNG k-εturbulence model and the Zwart cavitation model.The experimental verification methods respectively prove the use of this article The accuracy of the turbulence model and cavitation model.A new idea of the influence of the blade inlet sideline type and blade wrap angle on the cavitation performance of the fuel pump is proposed.The new method to improve the cavitation performance of the fuel pump is explored.In order to study the influence of the blade inlet edge profile on the cavitation performance of the fuel pump,a bending coefficient is defined to characterize the degree of curvature of the inlet edge profile.Adjust the bending coefficient to obtain fuel pump schemes with different blade inlet edge types,and adjust the wrap angle to obtain fuel pump schemes with different blade wrap angles.Through numerical simulation,various hydraulic performances of fuel pump schemes with different blade inlet edge types and different blade wrap angles are obtained.The analysis of the results is summarized as follows:(1)The first place where cavitation occurs is the shroud side of the inlet edg e on the back of the blade.As the NPSH_a decreases,the cavitation phenomenon will gradually develop to the side of the impeller hub and the impeller outlet.(2)With the edge-line bending coefficient of the blade inlet decreases,the head and efficiency of the fuel pump increase accordingly.Th e analysis obtains the functional relationship between the relative efficiency and the edge-line bending coefficient of the inlet.(3)With the edge-line bending coefficient of the blade inlet decreases,the necessary cavitation margin of the fuel pump has a trend of first decreasing and then increasing.The function relationship between the relative pump cavitation margin and the inlet edge-shaped bending coefficient is analyzed.When the bending coefficient is 30,the fuel pump cavitation is born late,an d the cavitation performance is the best.(4)As the blade wrap angle increases,the head and efficiency of the fuel pump increase accordingly.Through analysis,the functional relationship between the relative efficiency of the fuel pump and the blade wra p angle is obtained.When the blade wrap angle is 400,the fuel pump cavitation develops slowly,the degree of gas blockage in the flow channel is low,and the cavitation performance is the best.(5)As the blade wrap angle increases,the necessary cavitat ion margin of the fuel pump decreases.Through analysis,the functional relationship between the fuel pump relative to the pump cavitation margin and the blade wrap angle is obtained.