航空学报 > 2023, Vol. 44 Issue (13): 127832-127832   doi: 10.7527/S1000-6893.2022.27832

高焓激波/湍流边界层干扰直接数值模拟

刘晓东1,2, 刘朋欣1, 李辰1, 孙东1(), 袁先旭1   

  1. 1.空气动力学国家重点实验室,绵阳  621000
    2.西昌卫星发射中心,西昌  615000
  • 收稿日期:2022-07-20 修回日期:2022-08-30 接受日期:2022-09-07 出版日期:2022-09-14 发布日期:2022-09-13
  • 通讯作者: 孙东 E-mail:sundong0523@cardc.cn
  • 基金资助:
    国家重点研发计划(2019YFA0405201);国家数值风洞项目

Direct numerical simulation of high enthalpy shock wave/turbulent boundary layer interaction

Xiaodong LIU1,2, Pengxin LIU1, Chen LI1, Dong SUN1(), Xianxu YUAN1   

  1. 1.State Key Laboratory of Aerodynamics,Mianyang  621000,China
    2.Xichang Satellite Launch Center,Xichang  615000,China
  • Received:2022-07-20 Revised:2022-08-30 Accepted:2022-09-07 Online:2022-09-14 Published:2022-09-13
  • Contact: Dong SUN E-mail:sundong0523@cardc.cn
  • Supported by:
    National Key Research and Development Program of China(2019YFA0405201);National Numerical Windtunnel Project

摘要:

激波/湍流边界层干扰是高速飞行器表面常见的一种流动现象。当前高超声速飞行器的飞行马赫数不断提高,在头部激波后的高温环境中空气可能发生离解,出现高焓激波/湍流边界层干扰。相比于完全气体,高焓流动中化学非平衡效应可能与湍流、激波发生强烈的耦合作用,使流动情况变得更加复杂,目前相关研究较少,缺乏对此类流动的深入认识。选取高超声速楔形体头部斜激波后的高焓流动状态开展高焓激波/湍流边界层干扰直接数值模拟,并与相似工况的低焓流动对比,研究高温化学非平衡效应对流动分离的影响机制和组分扩散带来的影响。结果表明:高温化学非平衡效应对雷诺应力分布和湍动能输运过程的影响不明显;对流动分离影响显著,高焓流动的分离区远小于低焓流动,这可能是来流边界层动量增大和分离泡密度增大共同作用造成的。流动分离非定常分析表明高焓工况流动分离状态为瞬变分离,而低焓工况为平均分离;两者回流面积中的能量都以中低频为主,但低焓工况低频能量占比更大。进一步对高焓工况干扰区内的流向速度脉动和O组分质量分数脉动进行特征正交分解分析,发现分离泡变化过程中的能量主要集中在剪切层,这与低焓流动一致;气体组分的能量模态在分离激波处最高,表明激波是引起组分脉动的主要原因。

关键词: 高超声速, 激波/湍流边界层干扰, 化学非平衡, 直接数值模拟, 非定常流动分离

Abstract:

Shock wave/turbulent boundary layer interaction widely exists in the external flow of hypersonic aircraft. With the increase in the flight Mach number of new hypersonic aircraft, the gas may dissociate in the high-temperature environment after the leading shock, resulting in high enthalpy shock wave/turbulent boundary layer interaction. Compared with perfect gas, the chemical nonequilibrium effect in high enthalpy flow may have a strong coupling effect with turbulence and shock wave, further complicating the flying environment. However, related studies are limited. This study performed direct numerical simulation of high enthalpy shock wave/turbulent boundary layer interaction based on the flow condition after the leading shock of a cone in the hypersonic flight. Compared with the low enthalpy flow under similar conditions, the influence mechanism of high-temperature chemical nonequilibrium effect on flow separation and the influence of component diffusion are studied. The results show that the effects of high-temperature chemical nonequilibrium on Reynolds stress distribution and turbulent kinetic energy transport are not obvious. However, it has a significant impact on flow separation. The separation area of high enthalpy flow is much smaller than that at low enthalpy, possibly due to the increasing momentum of the upstream boundary layer and the increasing density of the separation bubble. Unsteady analysis reveals that the flow separation state under the high enthalpy condition is transient separation while average separation under the low enthalpy condition. The energy in the reverse area under both conditions is mainly low and middle frequency, although the low frequency energy under the low enthalpy condition accounts for a larger proportion. Furthermore, through the proper orthogonal decomposition of the streamwise velocity pulsation and oxygen atoms mass fraction pulsation in the high enthalpy interaction area, it is found that the energy during the separation bubble change mainly concentrates in the shear layer, consistent with the result of low enthalpy. The energy modes of the gas component are the highest at the separation shock wave, indicating that the shock wave is the main cause for the component pulsation.

Key words: hypersonic, shock wave/turbulent boundary layer interaction, chemical nonequilibrium, direct numerical simulation, unsteady flow separation

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