抽吸腔中心隔板对弯曲壁面边界层抽吸性能影响研究

Study on Performance Impact of Boundary Layer Bleed on Curved Wall with Center Clapboard in Chamber

关键词:  中心隔板  弯曲壁面  边界层  抽吸

Key words:  Center clapboard  Curved wall  Boundary layer  Bleed

摘要:

为了研究抽吸腔内隔板对边界层抽吸性能的影响，在弯曲壁面上均匀分布22个抽吸槽，并在抽吸腔内布置中心隔板，改变抽吸腔出口大小以及入射激波的位置。数值计算采用基于有限体积法的二阶迎风格式来离散二维可压N-S方程，湍流模型采用标准k-ε模型，从流场结构、抽吸流量、弯曲壁面的表面摩擦阻力系数、平均总压恢复系数以及平均马赫数等方面对流场进行了分析。结果表明在弯曲壁面抽吸腔内布置隔板会对抽吸效果产生影响，并且影响程度随抽吸腔出口大小以及激波位置的改变而改变。抽吸腔出口非节流时:布置隔板后，激波位于弯曲壁面中段、后段，抽吸效果均无明显变化，进气道性能亦无明显改变；激波位于弯曲壁面前段时，平均总压恢复系数增加8.33%，质量流量增加3.27%，抽吸效果有所改善，进气道性能也有所增强。抽吸腔出口节流时:布置隔板后，与非节流时相反，当激波位于弯曲壁面前段时，抽吸效果无明显改变，进气道性能不变；当激波位于弯曲壁面中段时，弯曲壁面分离泡的长度减小近2倍，质量流量增加66.15%，抽吸效果显著增强，进气道性能变好；当激波位于弯曲壁面后段时，分离泡长度增加了5倍，分离泡高度增加了近2倍，平均总压恢复系数降低8.33%，同时质量流量也减少1.83%，抽吸效果变差，进气道性能恶化。

Abstract:

An numerical investigation was conducted to study the effects of center clapboard in the chamberon the performance of boundary layer bleeding. The curved wall has 22 bleed slots and the chamber has a center clapboard. The exports size of the bleed chamber and the position of the incident shock wave were changed. Finite Volume Method based on second order upwind was used to discrete two-dimensional compressible N-S equation. Turbulence model is the standard k-ε. The flow field was analysed in some aspects，such as flow field structure，mass flow rate，surface friction coefficient，the average total pressure recovery coefficient and average Mach number. The results show that the center clapboard in the bleed chamber can affect bleed efficiency which changes with the exports size of bleed chamber and the position of incident shock wave. Under the condition of unentrottled: the effect of bleed and the performance of inlet almost unchanged when shock wave was put in the middle/end of the curved wall. However，the average total pressure recovery coefficient increased by 8.33% and mass flow increased by 3.27% when shock wave was put in the front of the curved wall，so bleed effect has been improved and the performance of inlet has also been enhanced. The results are different under entrottled condition. For example，the effect of bleed and the performance of inlet almost unchanged when shock wave was put in the front of the curved wall. But it changed to be better when shock wave was put in the middle of the curved wall.For example，the length of the separated region on the curved wall decreased to half of its previous size and the mass flow increased 66.15%. When shock wave was put in the end of the curved wall，the length of the separated region on the curved wall increased by 5 times，the height of the separated region increased by twice，the average total pressure recovery coefficient decresed by 8.33% and mass flow decreased by 1.83%. So bleed effect and the performance of inlet changed to be worse.