电弧风洞高焓流动模拟及壁面催化效应研究

HIGH ENTHALPY FLOW SIMULATION AND WALL CATALYTIC EFFECT IN ARC-HEATED WIND TUNNEL

  • 摘要: 对电弧风洞高焓流动进行模拟时,基于其高温复杂流场特性,对比不同热化学模型、壁面催化条件、流场一体化及分体计算等多种数值计算条件下,电弧风洞内部、出口流场特性及典型模型壁面热流分布。结果表明,模型距离喷管出口较近时,流场分体计算可以提高计算效率,但是模型距离喷管出口较远时,则必须采用一体化计算保证计算精度,数值模拟单温度热平衡模型计算得到的等热流模型表面热流高出双温度热非平衡模型6.99%。同时对电弧风洞高焓流动壁面催化效应开展研究,通过X射线扫描电镜对3组类型热流传感器表面元素成分进行分析,研究热流传感器表面催化属性对气动热测量的影响。结果表明,壁面催化效应会显著增加试验模型表面气动热环境,采用无氧铜基体的塞式量热计进行电弧风洞热流测量时,其表面会被氧化成CuO,数值模拟壁面采用有限催化条件γ=0.022时计算结果与试验结果更接近,也与文献中CuO的催化复合系数匹配。

     

    Abstract: In the simulation of high enthalpy flow in an arc-heated wind tunnel, based on the characteristics of complex flow field at high temperature, the flow parameters in the inner and outlet of the nozzle, and the heat flux distribution on the wall of the typical model were compared under various numerical calculation conditions, such as different thermochemical models, wall catalytic conditions, flow field integrated and separated calculation. The numerical simulation results show that the surface heat flux of the single temperature heat equilibrium model is higher than that of the double temperature heat non-equilibrium model by 6.99%. When the test model is close to the nozzle outlet, the separated calculation of flow field can improve the simulation efficiency. However, the integrated calculation must be adopted to ensure the numerical accuracy when the test model is far away from the nozzle outlet. At the same time, the wall catalytic effect has been studied at the high enthalpy flow in arc-heated wind tunnel. The surface elements of 3 types of heat flux sensors were analyzed by X-ray scanning electron microscopy, and the influence of surface catalytic properties of heat flux sensors on aerodynamic heat measurement was studied. The results indicate that the wall catalytic effect can significantly increase the surface heat flux of the test model. Combining the numerical simulation results with the test measurement results of slug calorimeter, it shows that when the slug calorimeter with oxygen free copper matrix is used for arc-heated wind tunnel heat flux measurement, its surface will be oxidized to CuO. The numerical simulation results with limited catalytic wall condition γ=0.022 are closer to the experimental results. It is also consistent with the catalytic recombination coefficient of CuO in the literature.

     

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