隔板构型对超声速混合层流动及混合特性的影响研究

Effects of splitter plate configuration on flow and mixing characteristics of supersonic mixing layer

关键词:  隔板构型  超声速混合层  混合层生长  涡量分析  混合效率

Key words:  Splitter plate configuration  Supersonic mixing layer  Mixing layer growing  Vortex analysis  Mixing efficiency

摘要:

为进一步揭示超声速来流下混合层流场演化过程物理机制，采用高精度计算方法对超声速来流下混合层流动及生长特性开展数值研究。首先，采用经典算例深入验证了本文所发展计算程序在复杂流场预示方面的精度和可靠性。然后，对四种不同构型隔板下混合层流动及生长机制进行了深入分析。研究结果发现，在典型隔板构型中引入凹腔、楔形角及凸台结构后，整体流场结构变得更为复杂，且诱发了更为剧烈的混合层的涡卷起、配对、合并、旋转等流体物理现象。在典型隔板工况中混合层出现了再层流化现象，而引入凹腔、楔形角及凸台结构后能够有效抑制混合层出现再层流化现象。此外，所有隔板构型工况下湍流转捩区雷诺应力均出现了“多峰值”现象，但典型隔板工况的混合层附近的湍动能明显小于其余工况，同时，典型隔板工况的雷诺应力峰值与分布范围明显小于其余工况。就本文研究工况而言，在出口处楔形角隔板工况的混合效率最高，为0.050；同时其混合层厚度也最大，达到27.9 mm；但楔形角隔板工况的总压损失也最大，为0.22。

Abstract:

In order to further reveal the physical mechanism of the mixing layer and flow field evolution process under supersonic incoming flow， a numerical study， the mixing layer flow and growth characteristics under supersonic incoming flow， is carried out with high-precision computational method. Firstly， the accuracy and reliability of the computational procedure， predicting the complex flow fields， are verified by using classical examples. Then， the flow and growth mechanism of mixing layer under four different splitter plates are analyzed in depth. It is found that the overall flow field structure becomes more complex after the introduction of concave cavity， wedge and step in the typical splitter plate， and induces more violent fluid physical phenomena such as vortex roll-up， pairing， merging and rotation of the mixing layer. In case splitter plate （sp）， relaminarization occurs in the mixing layer. The introduction of cavity， wedge and step can effectively avoid the relaminarization phenomenon in the mixing layer. In addition， the Reynolds stress， in the turbulent transition zone of all cases， shows a phenomenon of “multi-peak”， but the turbulent kinetic energy of the mixing layer in case sp is significantly smaller than that in the rest cases. Peak of the Reynolds stress and distribution range， in case sp， are significantly smaller than those in the rest cases. According to the cases in present study， the mixing efficiency of case splitter plate with strut， at the outlet， is the highest， which is 0.050. At the same time， the mixing layer thickness is also the maximum， which is 27.9 mm. However， the total pressure loss is also the highest， which is 0.22.