航空学报 > 2017, Vol. 38 Issue (11): 121236-121236   doi: 10.7527/S1000-6893.2017.121236

可压缩流湍流度变热线过热比测量方法

杜钰锋, 林俊, 马护生, 熊能   

  1. 中国空气动力研究与发展中心, 绵阳 621000
  • 收稿日期:2017-03-13 修回日期:2017-06-13 出版日期:2017-11-15 发布日期:2017-06-12
  • 通讯作者: 林俊 E-mail:1415776643@qq.com

Measurement technique for turbulence level in compressible fluid by changing overheat ratio of hot-wire

DU Yufeng, LIN Jun, MA Husheng, XIONG Neng   

  1. China Aerodynamics Research and Development Center, Mianyang 621000, China
  • Received:2017-03-13 Revised:2017-06-13 Online:2017-11-15 Published:2017-06-12

摘要:

开展了可压缩流中湍流度测量技术的研究,以满足高速风洞高精度试验能力的需求。以对流换热规律为基础,从理论上对可压缩流中热线金属丝热平衡关系式进行了推导,以此为基础,详细推导了恒温热线风速仪的响应关系式,得到了质量流量和总温灵敏度系数的显式表达式,建立了可压缩流中湍流度的求解方法。在马赫数为0.3~0.6范围内进行了湍流度测量试验,以响应关系式为数学模型,利用双曲线拟合方法对试验数据进行了拟合分析,求解得到了马赫数在0.3~0.6范围内流场湍流度约为0.3%~0.6%。对热线输出电压进行了频谱分析,根据频谱特性,利用低通滤波对频域信号进行了处理,有效降低了时域信号脉冲尖峰对湍流度求解的影响,滤波后求解得到马赫数在0.3~0.6范围内流场湍流度约为0.1%~0.3%,与前期测量结果相符。试验结果证明了所建立理论方法的正确性及利用恒温热线风速仪变过热比方法测量可压缩流湍流度的可行性。

关键词: 可压缩流, 湍流度, 恒温热线风速仪, 过热比, 响应关系式, 双曲线拟合, 低通滤波

Abstract:

Turbulence level is important in high speed wind tunnel experiments. Research on measurement techniques for turbulence level in compressible fluid is carried out to satisfy the need of tests with high accuracy in high speed wind tunnel. Based on the law of heat convection, response function of constant temperature hot-wire anemometer is derived in detail. Sensitivities of mass flux and total temperature are obtained, and the algorithm for the turbulence level in compressible fluid is built. Turbulence level measurement tests are carried out with Mach number varying from 0.3 to 0.6. Using the response function proposed above as a mathematical model, the data are fitted based on the hyperbola fitting method. The turbulence level is around 0.3%-0.6% when the Mach number varies from 0.3 to 0.6. The frequency spectrum of the hot-wire output voltage is analyzed. According to the characteristics of the frequency spectrum, the signal is processed using low-pass filtering, and the effect of voltage spike in the time domain on the solution for turbulence level is reduced effectively. The turbulence level is around 0.1%-0.3% after filtering with Mach number ranging from 0.3 to 0.6, and the results are almost the same with results obtained previously. The results validate correctness of the solution for turbulence level and feasibility of application of the technique of changing the overheat ratio of the constant temperature hot-wire anemometer for turbulence level in compressible fluid.

Key words: compressible fluid, turbulence level, constant temperature hot-wire anemometer, overheat ratio, response function, hyperbola fitting, low pass filtering

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