分开排气系统的1种设计方法及其性能研究

针对大涵道比涡扇发动机,开展了其排气系统气动型面参数化设计方法和气动性能的研究。通过控制外涵、内涵喷管流道的中心线形状和流通面积,设计了外涵、内涵分开排气喷管气动型面。采用数值模拟的方法模拟了喷管的流场结构,并分析了外涵落压比和自由流马赫数对喷管推力系数的影响。在自由流马赫数为0.050时,推力系数随外涵落压比的增大而增大,在自由流马赫数为0.785时,推力系数随外涵落压比的增大而减小;在外涵落压比相同时,自由流马赫数越大,核心机舱外罩b段与尾锥b段所受轴向力在喷管总推力中所占比例越大,对喷管推力系数的影响也增大。

A Design Method and Performance Research of Separately Exhaust System

An aerodynamic profile parametric design method of engine exhaust system and aerodynamic performance were investigated for highbypassratio turbofan engine. The bypass duct and core duct of the nozzle were designed by controlling the centerlines and corresponding cross-section area of the two ducts. The nozzle flow field was simulated by CFD, and the influence of bypass nozzle pressure ratio and ambiance Mach number on nozzle thrust coefficient was analyzed. The results show that the nozzle thrust coefficient increase with the rising of bypass pressure ratio when the ambiance Mach number is 0.050, and correspondingly the nozzle thrust coefficient decrease with the rising of bypass pressure ratio when the ambiance Mach number is 0.785. Additionally, the nozzle thrust coefficient increase with the growth of ambiance Mach number. When the bypass nozzle pressure ratio is identical, the bigger the ambiance Mach number is, the larger the proportion of the axial force of B stage of core engine cover cowling and tail-cone is in nozzle total thrust , the more obvious the influences on nozzle thrust coefficient is