Shaanxi Key Laboratory of Internal Aerodynamic in Aero-Engine, School of Engine and Energy, Northwestern Polytechnical University, Xi’an, Shaanxi, 710129, China
Lighter weight, simpler structure and throat area controllable are the developing trends of aircraft engine exhaust system. To meet these challenges, a new concept of hybrid throat control (TC) nozzle was proposed to improve the control efficiency of throat area (η) by using a rotary valve with secondary injection. The flow mechanism of the hybrid TC nozzle and the effect of aerodynamic and geometric parameters on nozzle performance were investigated numerically. Then the approximate model characterizing the hybrid TC nozzle was established with design of experiment and response surface methodology. The approximate model was used to analysis the coupling effect between parameters and optimized the parameter combination. The results show that the flow area of the nozzle can be restricted effectively by the rotary valve and the secondary flow, and η is bigger than 5.24. Nozzle pressure ratio and secondary pressure ratio are the dominant factors for the nozzle throat area control performance. The optimization of the parameter combination was carried out with penalty function approach, with ratio of throat area control being 30 percent and corrected mass flow ratio of secondary flow being 5 percent The maximize error of the optimization result is 4.13 percent and it verifies the validity and feasibility of the approximate model.