可压缩管流中真实气体效应的理论分析与数值模拟

为研究超燃冲压发动机冷却通道内复杂碳氢燃料的可压缩流动特性及相关影响因素,本文在典型工况条件下讨论了超声速膨胀流中真实气体效应的影响。基于平衡热力学理论,明确了气体动力学基础导数对可压缩流动的关键影响,并从气体动力学基础导数的角度出发考察了多种碳氢燃料在临界点附近的特性。同时,在数值模拟程序中耦合了立方型状态方程以准确描述超临界碳氢燃料的热物性参数。最后,对超临界条件下的二维超声速膨胀流进行了数值模拟,捕捉到了超声速扩张管道流动中马赫数下降的现象并揭示了其相应的物理机制。此外,参考发动机冷却通道内的典型工况条件,系统考察了不同入口马赫数、压力与温度等不同来流条件下真实气体效应的影响规律。

Theoretical Analysis and Numerical Simulation of Real Gas Effect in Compressible Pipe Flow

To explore the characteristics of compressible flow and influential factors of complex hydrocarbon fuels in the cooling channels for scramjet engines, the role of real gas effect in supersonic expansion flow is revealed under typical operating conditions. The crucial influence of fundamental derivative of gas dynamics is illustrated theoretically within the equilibrium thermodynamics, and the characteristics of various hydrocarbon fuels close to critical point are clarified by exploiting the fundamental derivatives. Meanwhile, the equation of state in cubic forms are coupled with the numerical simulation to accurately describe the thermodynamic properties of the supercritical hydrocarbon fuel. Subsequently, a serial of numerical simulations was conducted for two-dimensional supercritical pipe fluid, which captured and revealed the abnormal decrease of Mach number in supersonic expansion flow. In addition, under typical operating conditions for the cooling channel of scramjet engines, a systematic study is implemented to illustrate the influences of real gas effects for different inlet Mach numbers, pressures and temperatures, respectively.