Mach数和壁面温度对HyTRV边界层转捩的影响

典型的高超声速飞行器流场存在着复杂的转捩现象,其对飞行器的性能有着显著的影响。针对HyTRV这款接近真实高超声速飞行器的升力体模型,采用数值模拟方法,研究Mach数和壁面温度对HyTRV转捩的影响规律。采用课题组自研软件开展数值计算,Mach数的范围为3~8,壁面温度的范围为150~900 K。首先对■转捩模型和SST湍流模型进行了高超声速修正:将压力梯度系数修正、高速横流修正引入到■转捩模型,并对SST湍流模型闭合系数β~*和β进行可压缩修正;然后开展了网格无关性验证,通过与实验结果对比,确认了修正后的数值方法和软件平台;最终开展Mach数和壁面温度对HyTRV边界层转捩规律的影响研究。计算结果表明,转捩区域主要集中在上表面两侧、下表面中心线两侧;增大来流Mach数,上下表面转捩起始位置均大幅后移,湍流区大幅缩小,但仍会存在,同时上表面层流区摩阻系数不断增大,下表面湍流区摩阻系数不断减小;升高壁面温度,上下表面转捩起始位置先前移,然后快速后移,最终湍流区先后几乎消失。

Progress in flight tests of hypersonic boundary layer transition

Boundary layer transition(BLT)can cause a sharp rise in heat flux and skin friction,which can seriously affect the flight performance and safety of hypersonic flight vehicles.Therefore,the mechanism,prediction and control of transition have become important issues that must be dealt with for the development of advanced flight vehicles,and it is also a research hotspot of particular interest to major aerospace countries.Compared to other transition research approaches,model flight tests can better present the transition problems under real flight conditions,thus have been carried out extensively over the past 30 years.The United States,Germany,France,Australia,and other countries have carried out transition research based on flight tests,such as the Pegasus wing-glove crossflow transition and the Hypersonic Boundary Layer Transition(HyBOLT)transition control flight test of the United States,the joint research project of the Hypersonic International Flight Research and Experimentation-1(HIFiRE-1)circular cone and the HIFiRE-5 elliptic cone transition flight tests between the United States and Australia,the flight test of compression surface transition of the scramjet forebody(LEA)in France and so on.Although these flight tests suffered various setbacks,they still obtained valuable transition data.Recently,the United States is carrying out the concave-surface transition flight tests of Hypersonic Boundary Layer Transition(BOLT)and BOLT-II.Since its first model flight test mission for verification purpose launched successfully in 2015,several hypersonic BLT flight tests have been conducted by China Aerodynamics Research and Development Center(CARDC).The flight tests have measured valid transition data under flight conditions,obtained the transition front and its dynamical variation on blunt cones at various angles of attack and a lifting body Hypersonic Transition Research Vehicle(HyTRV).The crossflow traveling waves in high-altitude flight were measured for the first time,and our understanding of hypersonic BLT has been greatly improved.

Design and transition characteristics of a standard model for hypersonic boundary layer transition research

To understand fundamental problems in hypersonic laminar-turbulent boundary layer transition for three-dimensional complex vehicles,a new standard model with typical lifting-body features has been proposed,named as hypersonic transition research vehicle(HyTRV).The configuration of HyTRV is fully analytical,and details of the design process are discussed in this study.The transition characteristics for HyTRV are investigated using three combined methods,i.e.,theoretical analyses,numerical simulations,and wind tunnel experiments.Results show that the fully analytic parameterization design of HyTRV can satisfy the model simplification requirements from both numerical simulations and wind tunnel experiments.Meanwhile,the flow field of HyTRV reveals typical transition mechanisms in six relatively separated regions,including the streamwise vortex instability,crossflow instability,secondary instability,and attachment-line instability.Therefore,the proposed HyTRV model is valuable for fundamental researches in hypersonic boundary layer transition.