脉冲能量沉积对超声速射流/激波相互作用掺混的控制研究

Mixing Control of Supersonic Jet Interacting with ObliqueShock by Pulsed Energy Deposition

关键词:  超声速射流  射流掺混  激波冲击  脉冲能量沉积

Key words:  Supersonic jet  Jet mixing  Shock wave impingement  Pulsed energy deposition

摘要:

为探究超声速射流掺混增强的有效控制方法，基于二维非稳态雷诺平均Navier-Stokes方程，研究了脉冲能量沉积对超声速射流与斜激波相互作用后增强掺混的控制机理和规律。宽度为5 mm的低密度平面射流同向完全膨胀射入马赫数为2.5的主流中，并与20°压缩斜面所产生的斜激波相互作用。在流场中引入脉冲能量沉积对射流掺混进行控制，并考虑射流马赫数、射流长度、能量沉积位置及激励频率对掺混效果的影响。对比激励流场与基础流场，结果表明：脉冲能量沉积的加入诱导射流形成大尺度涡结构，显著提高射流的掺混效果；能量沉积位置对于不同马赫数射流的掺混增强具有不同的控制效果；激励前后射流宽度的对比表明，脉冲能量沉积的无量纲激励频率在0.22附近时，可使得射流的掺混效果最佳。

Abstract:

The mechanism of intensification for supersonic cocurrent jet mixing interacting with an oblique shock wave by a pulsed energy deposition is revealed on the frame of unsteady Reynolds averaged Navier-Stokes equations as to find out the effective methods to enhance supersonic jet mixing. The perfectly expanded planer supersonic low density jet with width of 5mm is injected into the supersonic Mach 2.5 air stream and interacts with an oblique shock downstream generated by a ramped step with an inclination angle of 20°. The jet mixing is modulated by the pulsed energy deposition, and the effects of jet Mach number, jet length, energy deposition location and frequency on the mixing are discussed. By comparing the baseline and energized flow fields, it is found that the jet mixing is enhanced significantly through the large scale vortices generation induced by energy deposition. The location of the energy deposition is observed as an important factor for the mixing enhancement at different jet Mach numbers. The comparison of jet width with and without energy deposition shows that the largest jet width of the energized flow is realized when the actuation works at the non-dimensional frequency of 0.22.