Turbofan Engine Compressor Performance Under Water Ingestion Conditions

Rapid development of aviation has been witnessed during the last few decades.The growing demand in commercial flight increases the possibility of aircraft encountering inclement weather conditions.Aero engine operating under water ingestion conditions can suffer compressor stall,combustor flameout and engine shutdown which hazards the flight safety.The investigation on the water ingestion is of great interest.A turbofan engine compressor model consisting of fan and four stages compressor is created by ANSYS CFX.Multiphase CFD simulations are conducted to investigate the compressor performance under water ingestion conditions at flight phase of take-off and flight idle.Effect of droplet diameter,injection speed and water to air ratio(WAR)on compressor operating under water ingestion are studied.From the simulation results,it is found that compressor performance is more sensitive to water at flight idle conditions.Fan plays a key role in redistribution of water.WAR has the most significant effect on compressor performance.Droplet diameter and injection speed influence the compressor performance by determining the droplet status reaching fan leading edge.Breakup of the droplet mainly occurs at inlet and fan and the presence of shock wave greatly enhances the breakup process.In terms of thermodynamics,the presence of water has positive effect on compressor performance that pressure ratio and efficiency are increased.Compressor Torque demand will increase when water is ingested into engine.Non-uniform injection has been simulated and the droplet entering the intake under the radius of the splitter proves to be the biggest threat to the turbofan engine.The capability of fan and spinner to move the water outwards varies with the impact position and angle entering the intake.Although the results reflect some aspects of the water ingestion.Multiphase simulation that can account for the water film formation and motion is not conducted due to the computational cost.The influence of intake on droplet trajectory is simulated by conducting the non-uniform injection.Detailed intake design,which is found to be important in droplet breakup is not involved in engine model.