航空并联混合动力涡扇发动机热力循环与工作特性研究

Thermodynamic Cycle and Performance of Parallel Hybrid Turbofan Engine

关键词:  并联混合动力系统  涡扇发动机  热力循环  稳态特性  数值模拟

Key words:  Parallel hybrid propulsion system  Turbofan engine  Thermodynamic cycle  Steady-state performance  Numerical simulation

摘要:

为确定并联混合动力涡扇发动机的能量利用效率，并对不同电功率输入下发动机工作特性与性能参数的变化规律进行研究，本文从理论上对发动机有效循环功的来源进行划分，并由此分别定义并联混合动力涡扇发动机的电能利用率和燃油利用率；使用航空发动机性能仿真软件PROOSIS搭建基于CFM56-7B26发动机的并联混合动力涡扇发动机零维模型，模拟不同电功率输入条件下的发动机稳态性能。研究结果表明：并联混合动力涡扇发动机内涵道的循环类型仍然是基于布雷顿循环的实际循环，输入的电功率对发动机外涵道推力的贡献占比远高于其对内涵道推力的贡献；电能利用率始终明显高于燃油利用率，这也是并联混合动力涡扇发动机实现节能的主要原因；当输入的电功率增加时，发动机的涵道比增加，涡轮前温度与总压比降低，各部件的稳态工作点将发生移动，可能造成部件效率的下降。由于电功率的输入以及电能的高利用效率，并联混合动力涡扇发动机的油耗和能耗均低于常规涡扇发动机。

Abstract:

In order to determine the efficiency of energy utilization and the variation rule of steady-state performance for a parallel hybrid turbofan engine by introducing different amounts of electric power， the source of effective cycle work was analyzed in theory and the efficiency of fuel and electric power were defined respectively. Based on the CFM56-7B26 turbofan engine， a parallel hybrid turbofan engine model was developed using PROOSIS， and the steady-state engine performance at different degrees of hybridization was studied. It is found that the type of core thermodynamic cycle in parallel hybrid turbofan engines is still a real Brayton cycle. The contribution of electric power to the bypass thrust is much greater than that to the core thrust. And the efficiency of electric power is much higher than that of fuel， which is the key factor to save energy for a parallel hybrid turbofan engine. As the degree of hybridization increases， the bypass ratio increases but the turbine inlet temperature and overall pressure ratio decrease. The steady-state operating states of different components are affected with the movement of the steady-state operating point and lead to a possible drop in the efficiency. Because of the electric power supply and its high efficiency， both the fuel and energy consumption of the parallel hybrid turbofan engine are lower than the conventional turbofan engine.