壁面粗糙度对高超声速进气道气动性能的影响

Effects of Wall Roughness on AerodynamicPerformance of Hypersonic Inlet

关键词:  高超声速进气道  壁面粗糙度  气动特性  起动特性  数值仿真

Key words:  Hypersonic inlet  Wall roughness  Aerodynamic performance  Start performance  Numerical simulation

摘要:

为探究壁面粗糙度对于高超声速进气道气动性能的影响，采用经过校验的数值仿真和理论分析相结合的方法进行研究。结果显示:同一飞行马赫数下，随着壁面粗糙度的增加，进气道的流量系数、总压恢复系数和出口马赫数逐渐降低，而静压比、压差阻力系数、摩擦阻力系数以及起动马赫数则逐渐增大；不同飞行马赫数/不同钝化半径下，进气道性能参数随壁面粗糙度的变化规律相似，均表现出较好的拟合规律，据此获得的拟合公式及光滑壁面进气道的气动性能可预估不同壁面粗糙度下进气道的气动性能；就本文研究的进气道而言，当壁面相对粗糙度从0增加至0.625%时，进气道起动马赫数从4.25增加至4.85。壁面粗糙度增加，导致进气道沿程附面层增厚是进气道气动性能参数出现上述变化规律的主要原因。

Abstract:

In order to study the effects of wall roughness on aerodynamic performance of hypersonic inlet， numerical simulation which had been verified and theoretical analysis were carried out. The results indicated that at the same Mach number ， as the wall roughness increased， the mass flow coefficient， the total-pressure recovery coefficient and Mach number of inlet's exit all declined while the static pressure ratio， the pressure drag coefficient， the friction drag coefficient and the start Mach number all raised. Under different Mach numbers or blunt radius， the aerodynamic performance of the inlet was similar while the wall roughness changed. Through curve fitting， the relationship between each parameter of aerodynamic performance and wall roughness was presented， so that it can be predicted of the aerodynamic and starting performance of the inlet with rough wall according to the smooth one. For this article， the start Mach number of the inlet increased from 4.25 to 4.85 when the relative roughness increased from 0 to 0.625%. Thicker boundary layer because of the wall roughness was the main reason why the aerodynamic performance of the inlet changed partly.