Abstract: The variable cycle engine (VCE) with FLADE (Fan on Blade) is one of the research hotspots for future military and civil aircraft power device， which shows outstanding performance advantages. For evaluating its performance， the method for FLADE component simulation and the steady-state performance simulation model for the double bypass VCE with FLADE are developed. The transient performance simulation model for VCE is also established， which considered the effects of the polar moment of inertia and the component volumes during the dynamic equation constructing. The transient performance at mode transition state of the FLADE VCE between double bypass mode and single bypass mode is discussed， and the influence of geometric parameters on the mode transition state of FLADE VCE is deeply analyzed. It can be concluded that the mode transition characteristic of the double bypass FLADE VCE is only related to the angle of inlet guide vane of FLADE and the area of the FLADE nozzle， and both should be enlarged or closed at the same time. The state of FLADE is on or off which has small impact on airflow of fan bypass and core engine.

Key words: Variable cycle engine；Mode transition；Transient performance

摘要： 为对带FLADE(Fan on Blade)的变循环发动机总体性能进行评估，发展了FLADE部件计算方法以及带FLADE的双外涵变循环发动机稳态性能计算模型，加入反映转子惯性效应和部件容积效应的动力学方程，建立了变循环发动机过渡态性能计算模型。分析了FLADE变循环发动机在双外涵与单外涵模式之间的模态转换过渡态特性，重点研究了几何参数调节及其不同组合形式对FLADE变循环发动机模态转换过程的影响。结果表明，带FLADE的双外涵变循环发动机的模态转换过程只与FLADE导叶角度和FLADE喷管面积有关，且两者应同时放大或关小；FLADE的开/关对风扇外涵气流及核心机的影响较小。

关键词: 变循环发动机；模态转换；过渡态性能