可调谐二极管激光吸收光谱技术测量风洞流速

Fluid velocity measurement of supersonic wind tunnel with tunable diode laser absorption spectroscopy

基于对水蒸气的吸收谱线在超音速流场的多普勒效应,结合HITRAN数据库,选取适合当前环境的吸收谱线7181.1558 cm-1,结合超音速风洞装置建立起一套基于可调谐二极管激光吸收光谱(TDLAS)技术的实验装置,测量对应频移,分析反演出流场速度,实验结果表明,在高速环境下,系统测量流速为563.06 m/s,线性误差为5.09%,效果良好,从而为对激波管等高速脉冲设备的进一步测量实验打下了良好基础。

Tunable diode laser absorption spectroscopic （TDLAS）technology applies the wavelength tunable character- isties of diode lasers to the absorption spectroscopy of the selected absorption line. Based on the absorption line of wa- ter vapor, combined with HITRAN database, the frequeney is chosen which fits the cun＇ent environment （7181. 1558cm^-1）, experiment equipments are set up, the according frequency shift of the chosen frequency is meas- ured and the fluid velocity is calculated. Experiments results show that velocity measurement is 563.06m/s,with the linear error of 5.09%, which builds good foundation for the next series of＂ experiments under transient environments of high velocity such as shock tube.