摘要
对载荷辨识方法用于脉冲燃烧风洞模型阻力测量的可行性进行了研究。设计了钝头锥模型阻力测量试验系统,通过突然卸载的方式对系统进行了动态标定,辨识得到了系统结构动力学参数,建立了系统动力学模型。基于脉冲风洞的工作特性,采用斜坡阶跃函数与傅里叶级数之和描述模型的载荷历程,将载荷辨识问题转化为函数参数辨识问题,采取先辨识斜坡阶跃函数参数再用最小二乘方法求傅里叶级数系数的求解策略。通过使理论计算输出在低频段逼近实测输出来确定傅里叶级数的项数。首先通过数值仿真检验了方法的有效性,然后在脉冲燃烧风洞进行了两车试验,基于天平输出对模型阻力进行了辨识,结果与CFD预测值吻合良好。
The feasibility of load identification method used in drag measurements on a model in impulse combustion facilities was discussed. A test system was designed to measure the drag force of a blunt cone model. The system was dynamically calibrated by sudden relief of a preload to excite the system. The dynamic parameters were estimated from the balance out,and a dynamic structural model of the system was established. A ramp-step function plus Fourier series were adopted to model the load history,and the force identification was transformed to the estimation of parameters of the function. A two-step solution skill was proposed,which estimates the parameters of the ramp-step function firstly,and then solves the Fourier coefficients by least square method. The term number of the Fourier series was determined by making the theoretical response approximating to the measured response at low frequency band. The method was validated by numerical simulations at first and then by two experiments in the impulse combustion tunnel. The drag forces of the cone model were identified from the measured balance output and the results agree well with the predictions by the CFD tool.
出处
《振动与冲击》
EI
CSCD
北大核心
2015年第24期202-208,共7页
Journal of Vibration and Shock
基金
国家自然科学基金项目(11372339)
高超声速冲压发动机技术重点实验室基金项目(STSKFKT2012001)
关键词
脉冲风洞
阻力测量
动态标定
载荷辨识
impulse facilities
drag measurement
dynamic calibration
load identification
