钝体标模高焓风洞试验和飞行试验相关性的数值分析

Numerical analysis for correlation of standard model testing in high enthalpy facility and flight test

在高焓风洞喷管膨胀流动中,会出现组分和振动能量的非平衡冻结现象,给试验数据的分析、外推和使用带来困难。笔者选择有飞行试验数据的钝锥体ELECTRE作为高焓风洞试验的标模,用热化学非平衡Navier Stokes软件,计算了飞行条件和相应的考虑组分和振动能量的非平衡冻结效应试验条件的模型绕流流场,用双尺度参数ρL和Stanton数,分析试验条件下的热流数据外推飞行条件的问题。研究结果说明:在模型头部区域,保持总焓和双尺度参数ρL不变,热流数据从试验条件外推到飞行条件是可行的;在模型尾部区域,试验条件和飞行条件的Stanton数有较大差别,用双尺度参数ρL把热流数据从试验条件外推到飞行条件有较大误差。最后提出了用CFD设计高焓风洞试验条件的思路,并识别真实气体效应显著改变热流分布的高焓风洞试验能力区域。

There exits the nonequilibrium freezing of the species and vibrational energy , resulting from the rapid expansion of the nozzle flow in high enthalpy facilities. So the data of wind tunnel simulation are full of difficulties with the analysis, extrapolation and use. In present paper, a blunt cone, referred to as ELECTRE, from which flight data exits, has been selected as the standard model for reference testing in hypersonic facilities. The analysis of the extrapolation to flight is done by simulating numerically the flowfields over the standard model under the conditions of the flight and the corresponding experimental simulation in the high enthalpy facility with a thermal and chemical nonequilibrium NavierStokes code. The binary scaling parameter ρL and Stanton number hasbeen taken into account. The result shows that the extrapolation to flight of the heat transfer rate by using the binary scaling and by keeping the total enthalpy the same, is only feasible in the nose region where the dissociation reactions are predominant. For the conical aft part of the standard model large differences in Stanton are observed and binary scaling becomes less accurate. Finally the use of CFD for the design of the experimental conditions has been demonstrated by identifying the regions within the wind tunnel envelope where real gas effects significantly change the heat transfer rate distribution.