轴对称近似等熵压缩流场的乘波前体优化设计

Optimized design of waverider forebody derived from asymmetric near-isentropic compression flow fields

关键词:  等熵压缩  乘波前体~+  优化设计  气动特性

Key words:  Isentropic compression  Waverider forebody~+  Optimized design  Aerodynamic characteristics

摘要:

以升阻比为优化目标,在来流马赫数Ma=2~4及飞行高度H=20km~24km条件下,进行了轴对称近似等熵压缩流场的乘波前体优化设计,通过CFD验证M∞=4优化乘波体的气动特性,并研究了Ma=3优化乘波前体在非设计条件下的气动特性。结果表明:近似等熵压缩下表面的乘波前体在设计条件下具有良好的气流压缩效果,可满足机体/发动机一体化设计的需要;乘波前体升阻比在1.5~1.9之间,纵向压心位置靠后;非设计条件下,压缩波不聚焦,小于设计马赫数升阻比时降低,大于设计马赫数时升阻比略大。

Abstract:

A new kind of waverider forebody with near isentropic lower surface was optimized design.Axsystematic inviscous flow fields of a family of near isentropic surfaces was obtained by solving Euler equation and acted as base flow field,then a family of waverider derived from this base flow field was generated and optimized for maximum L/D at the condition of Ma=2~4 and attitude H=20km~24km,detailed viscous effects were calculated and included within the optimization progress itself.Shape and aerodynamics of waverider forebody were obtained and CFD results for Mach 4 case was verified.Aerodynamics of Mach 3 waverider at off-design condition was also simulated by CFD.This kind of waverider with high pressure recovery could meet the air-breathing requirement of the vehicle with engine integrated design,but the L/D was smaller than common waverider because of large wave drag.Pressure center was also at the aft of the waverider.Pressure wave did not focus at off-design condition.L/D was increased with Mach number.