Research On Cavitation And Pressure Pulsation Characteristics Of Centrifugal Aviation Fuel Pump

Aviation fuel pump(hereinafter referred to as fuel pump),as one of the important components of aviation power plant,is widely used in the aerospace field to provide the required fuel for various engines of aviation aircraft.Because the fuel pump is in a high-altitude environment with low temperature and low pressure for a long time,it is more prone to cavitation,which causes problems such as reduced efficiency,reduced performance,and shortened service life.At the same time,cavitation will affect the stability of fluid flow in the pump,resulting in a change in the frequency of pressure pulsation and damage to the stable operation of the fuel pump.The stability of the fuel pump is the key to ensure the long-endurance cruising of the aircraft at high altitude.Therefore,this paper conducts a numerical study on the cavitation and pressure pulsation characteristics of the centrifugal aviation fuel pump.The main contents are as follows:First,the external characteristic curve of the fuel pump and the internal flow under different flow rates are studied under the condition of no cavitation.Research shows that as the flow increases,the head of the fuel pump decreases,and the efficiency first increases and then decreases.The efficiency is highest at 1.2Q,at the same time,it is found that the the operation is the most stable.Secondly,the cavitation characteristics of the fuel pump are studied under cavitation conditions.The research show that: As the NPSHa decreases,the cavitation bubbles first appears in the low-pressure zone at the front end of the suction surface of the long blade,the cavitation bubble diffuses in the corresponding low-pressure zone along the fluid flow direction.When it according to the NPSHc,cavitation bubbles appear in the low pressure area at the front end of the short blade and begins to affect the work of the short blade,resulting in a 3% reduction in head.As the NPSHa continues to decrease,the cavitation bubbles are diffused and connected in the flow channel,and the head drops sharply,which has a serious impact on the performance of the fuel pump.Finally,the pressure pulsation characteristics of the fuel pump under cavitation are studied.The research results show that near the NPSHc,cavitation has a significant impact on the pressure pulsation in the fuel pump.The period of the pressure pulsation at each monitoring point increases,the pressure pulsation signal at low frequencies increases,and the dominant frequency transfer to low frequencies,At the same time,there is a wide band pressure pulsation;The pressure pulsation amplitude at the cavitation bubble attachment site becomes zero,and the pressure pulsation amplitude at the behind of the cavitation bubble and the front of the short blade is significantly increased by cavitation.This study can provide a new theoretical basis for the prevention and monitoring of cavitation in the fuel pump,and provide an effective reference for the optimization of the performance of the fuel pump,and provide certain guidance for the improvement of the efficiency,stability and safety of the fuel pump.