低温风洞极低露点原位在线测量技术研究

Research on ultra low dew point in-situ on-line measurement technology for cryogenic wind tunnel

面向低温风洞极低露点原位在线测量需求,开展了基于激光吸收光谱的宽温域、高精度、极低露点原位在线测量技术研究。分析了激光吸收光谱露点测量技术原理,开展了吸收谱线选型、光谱参数标定和光谱信号处理方法研究,测量了低温平台原位在线露点和0.3 m低温引导风洞露点,并与冷镜式露点仪比较了测量精度。研究结果表明:激光吸收光谱露点测量技术可以实现宽温域、高精度、原位在线露点测量,露点测量范围–100~30℃,测量误差小于1℃,测量时间低于1 s,可满足低温风洞极低露点测量需求。

To achieve wide temperature domain,high precision and ultra low dew point in-situ on-line measurement in the cryogenic wind tunnel,a technology based on the laser absorption spectrum is developed.In the method,the principles of laser absorption spectroscopic technology for dew point measurement are analyzed firstly.Then the absorption spectroscopic selection,spectral parameter calibration and spectral signal processing are provided.The experiments are carried out on the low temperature platform and in the 0.3 m cryogenic wind tunnel,which are compared to the chilled-mirror dew-point hygrometer measurement.The experimental results show that the developed technology can achieve wide temperature domain,high precision and in-situ on-line dew point measurement.The measurement range is from–100℃to 30℃,the error is less than 1℃,and the time is less than 1 s.It can be used for ultra low dew point in-situ on-line measurement in the cryogenic wind tunnel.