连续式跨声速风洞流场湍流度测试实验研究

Experimental investigation of turbulence intensity measurement in continuous transonic wind tunnel

  • 摘要: 使用恒温式热线风速仪(CTA)完成了0.6m连续式跨声速风洞换热器入口至试验段流场湍流度测量;采用二维热线探头旋转方法,完成了换热器入口至稳定段出口的低速流场三维湍流度分布测试;采用一维探头连续变热线过热比方法,完成了试验段跨声速流场湍流度测试,测试流场速度最高马赫数为1.5。研究结果表明:换热器段和稳定段是重要的降湍部段,均可降低湍流度90%以上;稳定段阻尼网从3层增加至5层,可降低稳定段湍流度50%,可降低试验段湍流度17%;采用CTA连续变热线过热比方法可以获得试验段可压流场的扰动图(反映了试验段流场的扰动特征)和湍流度值,马赫数为0.4的流场扰动图呈一阶线性特征,马赫数为0.7的流场扰动图呈现双曲线特征。实验结果可为连续式跨声速风洞流场湍流度评估和优化提供依据。

     

    Abstract: The constant temperature anemometer is used for turbulence intensity measurement from the entrance of the heat exchanger to the test section in a 0.6 m continuous transonic wind tunnel. Two dimensional hot wire probes were rotated to measure the three dimensional turbulence intensity in the flow field from the entrance of the heat exchanger to the exit of the setting chamber. One dimension hot wire probes were used for turbulence intensity measurement in transonic flow of test section, with the method of continuous varying hot wires over heating ratio, where the maximum testing flow velocity was Ma1.5. Test results show that, the heat exchanger and the setting chamber paly important roles in damping turbulence intensity, each of which could reduce the turbulence intensity by more than 90%; when the screens in the setting chamber are added from 3 to 5 layers, the turbulence intensity of setting chamber could be decreased by 50%, and could be decreased by 17% in the test section; using the continuous varying hot wires over heating ratio method, the fluctuation diagrams and turbulence intensity are acquired in the test section. The fluctuation curve is of the straight line type at Mach number 0.4, and the fluctuation curve is of the hyperbola type at Mach number 0.7, which present the fluctuation characteristics in the flow field. Experiment results are useful for flow turbulence evaluation and optimization in the continuous transonic wind tunnel.

     

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