Investigation of overall performance of turbofan engine with pulse detonation combustor in bypass duct

The performance model was established to study the performance of mixed exhaust turbofan engine with pulse detonation combustor (PDC) in the bypass duct. The effects of the total pressure loss of isolator and bypass circulation parameters on the characteristic of PDC and performance of engine were analyzed. Then, the sensitivity analysis of performance parameters was carried out on the influence of the components parameters. The performance of mixed exhaust turbofan engine with PDC in the bypass duct was compared with that of the conventional afterburner turbofan engine at the same design circulation parameters. The results show that to increase the total pressure loss of isolator is beneficial to the improvement of performance because of the improvement of pressure ratio; when fan pressure ratio is constant, with the increasing of bypass ratio, the specific fuel consumption and specific thrust increase; with the increasing of fan pressure ratio, when bypass ratio is 0.2 to 0.4, specific thrust increases first and then decreases. When bypass ratio is 0.4 to 0.5, specific thrust increases first and then remains constant. When bypass ratio is 0.5 to 0.9, specific thrust increases, but the rate of increase reduces. At different bypass ratio, specific fuel consumption decreases with increasing of fan pressure ratio; the performance of engine is more sensitive to the component parameters that directly affect the flow state parameters of the bypass duct; because of supercharging performance of PDC, PDC in the bypass duct only uses part of air flow to organize combustion that can make specific thrust of turbofan engine with PDC in the bypass duct and conventional afterburner turbofan engine are equivalent. Meanwhile, specific fuel consumption can be reduced by 27.7% at design point and 12.8%-26.8% at off-design points. 为研究外涵装有脉冲爆震燃烧室(PDC)的混合排气涡扇发动机性能, 建立其性能模型。研究了隔离段总压恢复系数和外涵循环参数对PDC特性和整机性能的影响; 分析了发动机性能参数对部件参数的敏感性; 在相同设计循环参数下与传统加力涡扇发动机性能进行了对比。结果表明: 提高隔离段总压恢复系数能够增大PDC增压比, 提升发动机性能; 风扇压比一定, 涵道比增大, 发动机耗油率和单位推力增大; 风扇压比增大, 涵道比在0.2~0.4时, 单位推力先增大后减小, 涵道比在0.4~0.5时, 单位推力先增大后基本不变, 涵道比在0.5~0.9时, 单位推力一直增大, 但增幅逐渐减小。不同涵道比下耗油率随风扇压比增大一直减小; 发动机性能对直接影响外涵气流状态参数的部件参数敏感性高; 由于PDC的增压特性, 脉冲爆震外涵加力发动机仅利用外涵部分气流组织燃烧就可使单位推力与传统加力涡扇发动机相当, 且耗油率在设计点降低27.7%, 非设计点降低12.8%~26.8%。