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低温风洞运行过程消耗大量液氮和电力,洞体结构产生附加热应力和热变形,建立可靠的低温风洞热力学模型对研究风洞运行安全性和经济性是必不可少的。以低温风洞扩散段为方法研究对象,建立有限元热力学模型,为提高热力学模型和实际模型的相关性,使用响应面法对有限元热力学模型多个参数进行修正。通过对比分析温度、应力监测点试验数据和仿真数据的差别,确定驻室锥形体内表面对流换热系数为待修正参数;使用中心复合试验设计生成有限元热分析样本空间,以温度、应力监测点试验数据和仿真数据的残差均方和为考核指标,在样本空间内对残差均方和进行非线性回归分析,建立残差均方和的响应面模型;以所有监测点残差均方和总和为目标函数,在样本空间内进行多目标非线性优化分析,得到最优解;验证修正后的热力学模型,结果表明:(1)基于响应面法的热力学模型修正是可行的;(2)修正后的热力学模型分析数据与试验数据吻合性提高,并且适用于其它降温试验。
Low temperature wind tunnel operation consumes a large amount of liquid nitrogen and electricity, additional thermal stress and thermal deformation of the hole structure, and establish a reliable low-temperature wind tunnel thermodynamic model is essential for the study of wind tunnel operation safety and economy. Taking the low-temperature wind tunnel diffusion section as the research method, a finite element thermodynamic model was established. In order to improve the correlation between the thermodynamic model and the actual model, several parameters of the finite element thermodynamic model were modified by response surface method. By comparing and analyzing the differences between the test data and the simulation data of the temperature monitoring points and the monitoring data, the convective heat transfer coefficient inside the conical body is determined as the parameter to be corrected. The central composite experimental design is used to generate the finite element thermal analysis sample space. The temperature and stress monitoring Point test data and the residuals of the simulation data were used as evaluation indexes. Non-linear regression analysis was performed on the sum of squares of residuals in the sample space to establish the response surface model of the sum of residuals. The residuals of all the monitoring points And the sum of the square and the sum as the objective function, the multi-objective nonlinear optimization analysis is performed in the sample space to obtain the optimal solution. The modified thermodynamic model is validated. The results show that: (1) the thermodynamic model modification based on the response surface method is feasible; 2) The revised thermodynamic model analysis data is in good agreement with the experimental data and is suitable for other cooling experiments.