宽速域可调进气道密封腔流动特性研究

Study on flow characteristics of adjustable inlet seal chamber with wide speed range

为了满足高超声速飞行器的宽速域进气需求,一般考虑使用可调进气道,此时进气道内部需要安装动密封结构。陶瓷栅片密封凭借其优异的耐磨损性和抗高温氧化能力是最理想的选择。使用陶瓷栅片作为密封件后,密封室内会形成受侧板边界层影响的三维空腔流动。以密封腔模型为基础,提出对密封腔流动和泄漏通道流动解耦化处理,并分别对进气道密封模型和泄漏模型进行了建模。利用数值模拟方法,改变来流边界层厚度以及来流速度研究不同来流条件对长密封腔结构类型流动特性及泄漏规律的影响。分析发现,长密封腔在Ma4.5高超声速来流下表现为开式空腔流动,对边界层厚度以及来流马赫数的变化相较于短密封腔更为敏感;来流马赫数的改变使得密封腔内流动结构变化较大,相应泄漏通道的入口压力分布也存在很大区别。

When the adjustable inlet port is used to meet the demand of wide-velocity air intake of hypersonic vehicle,the dynamic seal structure needs to be installed inside the inlet port.Ceramic grid seals are the ideal choice due to their excellent wear resistance and high temperature oxidation resistance.When the ceramic grating is used as a seal,a three-dimensional cavity flow is formed in the sealing chamber,which is affected by the boundary layer of the side plate.Based on the sealing cavity model,the decoupling of the sealing cavity flow and the leakage channel flow is proposed,and the sealing model and leakage model of the inlet are modeled respectively.The influence of different inlet conditions on the flow characteristics and leakage law of long sealed cavity was studied by changing the inlet boundary layer thickness and inlet velocity using numerical simulation method.It is found that the long sealed cavity behaves as an open cavity flow at Ma4.5 hypersonic flow,and is more sensitive to the changes of boundary layer thickness and incoming Mach number than the short sealed cavity.The change of incoming Mach number makes the flow structure in the sealed cavity change greatly,and the pressure distribution at the inlet of the corresponding leakage channel is also very different.