Design Methods and Validation of Turbofan Engine Continuous Hail Ingestion Test

Conduct forward-design research on engine hail ingestion compliance testing. Starting from air-ground disparities, the study addresses key technical challenges in ground-based testing. Under ground static conditions, with the engine in a static state, precise calibration of hail ingestion volume is required, alongside overcoming the technical difficulty of projecting large quantities of hail into the engine. Based on the most stringent spatial environmental criteria from airworthiness regulations, adjustments are made to the hail water content according to the identified disparities. Targeted research on continuous hail projection technology is carried out, employing engineering calculation methods for preliminary design. Cross-sectional frictional pipe flow calculations are used to determine airflow movement, while aerodynamic parameters inform the computation of hail particle forces and motion trajectories. Subsequently, coupled CFD-DEM simulations are applied to reveal the acceleration mechanism of hail. Appropriate mesh and time step sizes were selected based on grid independence and time-step sensitivity studies. Experimental validation of the hail projection apparatus is conducted, analyzing hail projection velocity and radial dispersion. Calculations indicate that the simulated hail velocity exceeds experimental results by 0.3%. Considering both hail projection and air consumption, a hail projection tube length of 4m and a tube diameter of 45mm are selected. Applied to a continuous hail ingestion test on a scaled fan/booster rig, the system successfully projects continuous hail into the inlet. The research results provide an approach for the design of hail projection devices used in continuous hail ingestion tests for aero-engines.