可压缩流体热线探针校准方法研究

Investigation of calibration method for hot-wire probe in compressible flow

在可压缩流体中利用热线技术进行湍流度测量时,其输出不仅与脉动速度有关,而且也与流体温度、密度紧密相关。因此,需要在与高速可压缩流体特征相似的校准装置中,在使用前对热线探针进行准确校准。本文提出了可压缩流体热线探针校准方法,建立了热线校准(工作)数学模型,并利用自建的热线校准风洞开展了热线校准实验和湍流度测量风洞试验验证,结果表明:热线校准方法可行,校准数学模型合理可靠,热线探针校准精度较高,湍流度测量结果可信,基本可满足高速可压缩流体湍流度测量的工程需要。

The output of hot-wires is related to fluctuation velocities, and is closely related to fluid temperature and density when a hot-wire technology is used to measure turbulence intensity in compressible fluid. Therefore, hot-wire probes should be accurately calibrated before being used in a calibration facility, which has similar characteristics as those in high speed compressible fluid. In this paper, a calibration method for hot-wire probes in compressible flow is proposed, and a mathematical model of hot-wires for calibrations and measurements is established. Calibration experiments of hot-wire probes are conducted, and an experiment of turbulence intensity measurements is carried out in a wind tunnel with self-building hot-wire calibration. The result indicates that, the calibration method is feasible, and the mathematical model is reasonable and reliable. The calibration accuracy for hot-wire probes is high, and the results of turbulence intensity measurements are credible. The engineering requirements for hot-wire probe measurements in compressible flow are basically satisfied.