壁面温度对斜爆震发动机进气道流动特性影响的数值研究

Numerical Study on Effects of Wall Temperature on Flow Characteristics of Inlet of Oblique Detonation Engine

关键词:  斜爆震发动机  进气道  壁面温度  分离区  热边界层  数值模拟

Key words:  Oblique detonation engine  Inlet  Wall temperature  Separation zone  Thermal boundary layer  Numerical simulation

摘要:

为研究壁面温度条件对层流、转捩、湍流状态下斜爆震发动机进气道流场结构、流场参数的影响，选取Ma10级、具有曲面压缩段的斜爆震发动机进气道为研究对象进行数值模拟，对进气道壁面附近激波诱导分离区、热边界层的变化进行了深入探讨。数值模拟结果表明，进气道肩部圆弧过渡段出现的再层流化现象，壁面冷却对其起抑制作用，绝热壁面条件下再层流化程度最为严重。壁面温度的增加有利于延缓流动转捩，同时也导致了分离区尺寸的增加以及转捩、湍流状态下分离区主体位置逐渐前移，进气道内通道的转捩为分离诱导转捩，转捩位置主要受到分离点位置的影响，整体表现为壁面温度增加转捩位置前移。进气道出口顶板侧热边界层厚度随着壁面温度的增加逐渐变厚，转捩状态下热边界层厚度变化可达5%，温度峰值也随着壁面温度的增加逐渐增加，且峰值位置逐渐靠近壁面。壁面温度条件相同时，层流状态下热流、热边界层厚度均较小。转捩、湍流状态下进气道出口顶板侧热边界层较厚，约为层流状态3倍，同时转捩、湍流状态下热边界层厚度相差可达2%。

Abstract:

In order to study the effects of wall temperature on the flow field structure and flow parameters of oblique detonation engine inlet in laminar， transition and turbulent states， an oblique detonation engine inlet with curved compression section at Mach 10 was selected as the research object to conduct numerical simulation， and the changes of shock induced separation zone and thermal boundary layer near the inlet wall were deeply discussed. The numerical simulation results show that the wall cooling can restrain the phenomenon of relaminarization in the circular transition section of the inlet shoulder， and the relaminarization is the most serious under the condition of adiabatic wall. The increase of wall temperature is beneficial to delay the flow transition， and it also leads to the increase of separation area size and the moving forward of the main body of separation zone in transition and turbulent state. The transition in the inlet channel is separation induced transition. The transition position is mainly affected by the position of separation point. The overall performance is that the transition position gradually moves forward with the increase of wall temperature. With the increase of wall temperature， the thickness of thermal boundary layer on the top plate side of the inlet exit gradually thickens. In transition state， the thermal boundary layer thickness changes by up to 5%. The peak temperature on the top plate side of the inlet exit increases with the increase of wall temperature， and the peak position is gradually close to the wall. When the wall temperature is the same， the heat flux and thermal boundary layer thickness is smaller in the laminar flow state. In the transition and turbulent state， the thermal boundary layer on the top side of the inlet exit is thicker， which is about three times that of laminar flow， and the difference of thermal boundary layer thickness between transition and turbulent state can reach 2%.