高超声速飞行器气动热关联换算方法研究
RESEARCH ON THE CONVERSION METHOD OF AEROHEATING ENVIRONMENT OF HYPERSONIC VEHICLE
-
摘要: 气动热风洞实验是地面研究和预测飞行器气动热环境的重要手段之一, 但由于风洞实验模拟能力的限制, 风洞实验的流场参数和模型的几何尺度都会与实际飞行情况存在一定的差别, 导致地面风洞实验中得到的模型表面气动加热率数据无法直接用于飞行条件下的热环境预测和热防护设计. 以往通过针对具体飞行器的试验结果进行数据拟合后外插的气动热关联换算方法指向性较强, 没有考虑到气动热的具体影响参数, 存在一定局限性, 难以外推应用于其他外形的飞行器. 为解决通过气动热风洞实验数据外推预测飞行条件下气动热的技术难题, 基于无量纲NS方程和边界层理论分析研究了影响气动热的主要参数, 并通过推导化简边界层近似解热流公式, 针对层流流态建立了气动热关联换算方法, 可以考虑当地边界层外缘参数的影响, 具有一定通用性. 在此基础上, 利用建立的方法将Reentry-F飞行器缩比模型的风洞实验数据换算到该飞行器飞行条件下的典型工况, 并与飞行测量结果进行了比较, 外推预测结果与飞行测量结果符合较好, 表明建立的关联方法可以用于气动热风洞实验数据的外推换算.Abstract: Wind tunnel experiment is a key means to research and predict aeroheating for hypersonic vehicles. The flow field parameters and model scales in wind tunnel are different from flight condition, owing to the limitation of its simulation capability. The aeroheating data obtained from wind tunnel experiments can not be directly used for the aeroheating prediction and thermal protection system design in flight condition. So the method of predicting the aeroheating environment on flight condition, by using the wind tunnel experimental data, has been a technically difficult problem. In the past, the correlation and extrapolation method of wind tunnel aeroheating experiment data for specific aircrafts has a strong directionality, because this method is a kind of data fitting based on aeroheating data and does not take into account the specific parameters of aeroheating. It has certain limitations and is difficult to extrapolate to other shapes of aircraft. To solve the problem of the wind tunnel experimental data extrapolation, the main parameters of the influence of aeroheating were analyzed on the basis of the dimensionless Navier-Stokes equations and boundary layer equations, and the correlation and extrapolation method was developed for laminar and turbulence conditions by deducing the approximate solution of the aeroheating. Because the parameters of the local boundary layer edge can be taken into consideration, the correlation method has certain versatility. Then the experimental data of scale model on Reentry-F was obtained from wind tunnel experiments, the correlation analysis and validation for Reentry-F configuration was accomplished, the wind tunnel experimental data was extrapolated to flight condition by the extrapolation method and it agreed well with flight data. It showed that the method can be used for extrapolation of aeroheating experimental data, and multiple points of flight condition can be extrapolated from a few experimental results.