Numerical Study on the Performance of the Ventilation Cooling System for Helicopter Engine Nacelle in Hovering

摘要

The main objective of this work is to investigate, by means of numerical simulation, the performance of the engine nacelle ventilation cooling system of a helicopter in hovering, and to propose a simplified method of evaluating the ventilation cooling performance based on rotor downwash flow by taking the synthetical effect of the nacelle, exhaust ejector and downwash flow into consideration. Using the business CFD software, the influences of the turbulent model (for standard k-ε model, k-ω model, SST model and RNG model), rotor downwash flow, engine heat dissipating capacity, inlet number (single inlet and double inlets), inlet size and inlet position (including single-inlet and double-inlets schemes, total up to six schemes) were analyzed on the flow field and temperature field of the nacelle and the performance of the exhaust ejector. The comparisons between flight test and numerical simulation results were completed. The results reveal that the method can exactly predict the performance of the nacelle. Overall, this study indicates that the calculation has the highest degree of accuracy using standard k-ε model, and it has important impact of rotor downwash flow, engine heat dissipating capacity and inlet arrangement on the performance. The results can be regarded as reference for the design and optimization of the system.