双射流激波针在高超声速下的减阻降热特性OA北大核心CSTPCD
Drag and heat reduction performance of a dual-jet spike configuration in hypersonic flow
严酷的气动力和气动热环境是制约高超声速飞行器发展的两个重要因素,如何高效地降低高超声速飞行过程中的阻力和热流一直是设计者们追求的目标.为此,本文提出了一种结合后向射流和根部逆向射流的双射流激波针新构型.数值模拟研究发现:该构型能够利用后向射流产生的反作用力削减逆向射流附加阻力对减阻效果的影响,因此与无射流和单一射流方案相比,双射流激波针的流场结构显著改变,减阻降热效果极大提高.此外,增大激波针的长径比(L/D)有利于提高双射流激波针的减阻效果,但会使降热性能有所下降:在本文研究中,当激波针长径比从 1 增大到4 时,结构的总阻力系数降低了 71.9%,而钝体总热流增大了 13.7 倍.同时,增大射流总压比PR可以显著降低壁面热流:当逆向射流总压比(PR,o)或后向射流总压比(PR,r)大于 0.4 时,钝体壁面的热流极低并开始出现负值;然而,阻力系数随PR,o和PR,r的变化趋势恰好相反,随着PR,o从 0.2 增大到 0.5,由于逆向射流附加阻力的影响,结构总阻力系数增大了 66.7%,而得益于后向射流的推力作用,结构总阻力系数则降低了 59.3%.
High aerodynamic drag and severe aeroheating are the two most important factors impeding the development of hypersonic vehicles.Thus,how to reduce the drag and heat flux effectively in hypersonic flight has attracted worldwide attention.In this paper,a novel strategy combining a spike and a dual-jet has been proposed for the drag reduction and thermal protection.In this configuration,the reaction force generated by the root jet can balance the additional resistance of the rear jet,and the surface heat flux of the vehicle can also be reduced effectively.The flow characteristics and the drag/heat reduction efficiency is explored by numerical simulations.Meanwhile,the influence of the spike length and the total jet pressure on the drag and heat flux are quantitatively analyzed.The results reveal that flow structures of the dual-jet spike configuration are significantly changed,and the drag and heat reduction efficient is greatly improved compared to the cases with a single jet or without any jet.In addition,increasing the spike length ratio(L/D)is beneficial to improve the drag reduction performance,but has a negative effect on the thermal protection.Specifically,by increasing the spike length,from L/D = 1 to L/D = 4,the drag coefficient of the dual-jet spike configuration is decreased by 71.9%,while the total heat flux on the blunt body is increased by 13.7 times.On the other hand,the wall heat flux can be remarkably reduced by increasing the total jet pressure,and it becomes negative when the total pressure ratio of the opposing jet(PR,o)or that of the rear jet(PR,r)is larger than 0.4.However,the variation tendency of the drag coefficient with the increasing of PR,o and PR,r is completely opposite.Due to the drag induced by the opposing jet,the total drag coefficient of the dual-jet spike configuration is increased by 66.7%from PR,o = 0.2 to PR,o = 0.5.On the contrary,thanks to the thrust generated by the rear jet,the total drag coefficient of the dual-jet spike configuration is decreased by 59.3%from PR,r = 0.2 to PR,r = 0.5.
王俊峰;李珺;罗世彬
中南大学 航空航天技术研究院,长沙 410083
减阻热防护射流激波针高超声速
drag reductionthermal protectionjetspikehypersonic
《空气动力学学报》 2024 (002)
34-46 / 13
国家自然科学基金(52202454);湖南省重点研发计划项目(2021GK2011,2023GK2022)
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