Research On Cleaning Mechanism And Flow Field Characteristics Of Aeroengine Online Wash

As the engine runs,particles in the air will inevitably adhere to the surface of the engine blades,causing engine performance degradation,increasing fuel consumption,and even affecting flight safety in severe cases.Engine on-wing cleaning can effectively remove dirt particles on the blade surface and restore engine performance.However,domestic and foreign scholars are not clear about the mechanism of engine fouling adhesion and on-wing cleaning,and the effect of engine on-wing cleaning is often not ideal.This paper conducts in-depth research on the fouling mechanism,cleaning mechanism,cleaning flow field,cleaning process parameters and equipment of low-pressure compressor blades,which provides a guarantee for improving the propulsion efficiency of aero-engines,and has certain academic and engineering practical values.First,the compressor fouling samples were obtained by cleaning the waste liquid,and the fouling adhesion model was constructed according to the movement and adhesion dynamics of the fouling particles inside the engine.The scratch method was used to test the bonding force of the fouling layer on the blade surface.The elution effect of atomized droplets on the surface fouling layer of engine blades is analyzed,including water wedge,water hammer,erosion and temperature field infiltration,etc.,and a theoretical model for the removal of fouling on the surface of aero-engine blades is established.Secondly,study the impact characteristics of the droplet on the blade surface.The impact pressure of the droplet at the initial moment of impact on the blade is the largest,which is conducive to cleaning the surface of the fouling layer of the blade;the smaller the diameter of the droplet,the smaller the maximum value of the impact force of the droplet.,The earlier the maximum appears;the greater the curvature of the blade surface,the smaller the vertical impact force of the droplet;the heat transfer performance of the droplet on the surface of the high-temperature blade gradually increases along the radial direction from the center of the droplet.Third,the engine lip is modeled based on the reverse scanning technology.Based on this,a cleaning rack with a high degree of matching with the engine lip arc is designed,which verifies the stability of the cleaning rack.Through orthogonal experiments,the nozzle structure parameters that meet the requirements of engine cleaning are optimized.Simulation analysis found that as the jet pressure increases,the cleaning flow field pressure,velocity and wall shear force gradually increase,which helps to improve the cleaning effect;increasing the cooling speed,the cleaning flow field pressure gradually decreases,while the wall shear force The growth rate has slowed down.Based on the characteristics of the cleaning flow field,the best cleaning process parameters are determined as follows: the jet pressure is the best 5MPa,and the cold rotation speed is recommended to be 323r/min.Finally,through the analysis of the cleaning process parameters,the heating vehicle and the liquid supply vehicle are designed separately,so that the parameters of the cleaning fluid meet the requirements of the engine on-wing cleaning manual.Completed the engine on-wing cleaning experiment,and established the EGTM degradation law with engine performance using one-variable linear regression,evaluated the changes in fuel consumption before and after cleaning,estimated that the fuel saved by cleaning 20 aircraft in the fleet was about 469,988 kg,and verified the jet parameters.And the effect of cold rotation speed on the improvement of cleaning effect.