Numerical Simulation of the Aerodynamics of a Scaled Free Jet Altitude Test Facility Model

The widespread adoption of new technologies in aircraft engine testing has accelerated the development of free jet altitude test facilities, necessitating the study of simulations of aerodynamic characteristics. This study utilizes similarity dimensional analysis to construct a scaled model of a free jet altitude test facility. Computational fluid dynamics (CFD) methods are applied to examine the effects of nozzle deflection angle, flow rate, and exhaust diffuser diameter on aerodynamic parameters, such as intake effects, exhaust diffuser performance, and flow field characteristics. The findings reveal a negligible difference (less than 0.9%) in the characteristic parameters between actual atmospheric conditions and the scaled model when the nozzle deflection angle is set to 0° and −10°, enabling accurate atmospheric simulations. Additionally, the total pressure recovery coefficient at the engine inlet and the exhaust diffuser’s efficiency exhibits opposing trends with varying exhaust diffuser diameters, suggesting that a balanced aerodynamic design of the inlet and exhaust systems is crucial for optimal performance. The exhaust diffuser’s ejection coefficient increases with the nozzle’s flow rate, indicating that optimizing the nozzle’s flow rate within a specified range can significantly improve the exhaust diffuser’s performance.