Simulation Study On The Effect Of Burr In Aero-engine Nozzle Swirl Core On Flow Characteristics

Aero engine parts usually produce burr in the process of production and processing.The existence of burr will affect the accuracy and performance of parts.The swirl core studied in this paper will produce a certain amount of burr in the swirl groove and blind hole in the production process.The existence of burr not only reduces the flow rate of the nozzle,but also makes the injection shape unstable,which affects the performance of the engine.In this paper,the influence of the position and quantity of burr in the swirl groove and blind hole on the outlet pressure and mass flow is studied by simulation,and the influence of turbulent kinetic energy and velocity in the flow channel is analyzed,which provides a reference for the subsequent deburring process and test work of swirl core.The specific research contents are as follows:Firstly,the 3D modeling software UG is used to establish the swirl core model,and then the flow channel model of swirl core and auxiliary nozzle assembly is established.The same number of burr is set up in different positions of swirl groove and blind hole of swirl core,and different number of burr is set up in the same position.The established model is meshed and imported into fluent,and relevant conditions are set.The model is simulated under three different pressures.The outlet pressure and mass flow rate of different models are calculated,and the reduction rate of outlet pressure and mass flow rate caused by different positions and different numbers of burrs in the swirl groove and blind hole are calculated.Through the comparative analysis of different pressure,different position and different number of burr in the swirl groove and blind hole on the outlet pressure and mass flow.The influence of burr on turbulent kinetic energy and velocity in the channel was analyzed.The results show that the outlet pressure and mass flow rate decrease by 13.83% and 7.09%respectively at low pressure.Under medium pressure,the biggest reduction rate of outlet pressure and mass flow is near the blind hole.Under high pressure,the decrease rate of outlet pressure and mass flow caused by burr near blind hole is still the largest,which is 14.61% and7.32%.When the number of burr is studied,the influence on outlet pressure and mass flow rate increases with the increase of burr number.The burr near the blind hole has the greatest influence on the turbulent kinetic energy and velocity.When the burr in the blind hole is studied,the burr in the middle of the blind hole wall has the greatest influence on the outlet pressure and mass flow under low pressure.Under medium pressure,the burr in the middle of blind hole wall leads to the largest reduction rate of outlet pressure and mass flow,which are 19.55% and 15.14%.Under high pressure,the biggest reduction rate of outlet pressure and mass flow is the burr in the middle of blind hole wall,which is 21.92% and 16.94%.When the number of burr is studied,the influence on outlet pressure and mass flow rate increases with the increase of burr number.The burr in the middle of the blind hole wall has the greatest influence on the turbulent kinetic energy and velocity.To sum up,under different pressures,the burr near the blind hole in the swirl groove has the greatest influence on the fuel injection.The burr in the middle of the blind hole wall has the greatest influence on the fuel injection.Therefore,more attention should be paid to removing the burr near the blind hole in the swirl groove and the burr in the middle of the blind hole wall.