High-precision measurement of the temperature of methanol and ethanol droplets using spontaneous Raman scattering

Abstract.

The temperature of liquid methanol and ethanol is demonstrated to be determined by a non-intrusive laser technique in sprays. The method is based on spontaneous Raman scattering, namely the shape and spectral position of the OH stretching band, which is temperature dependent. The accuracy achieved in this way is about ±2 °C. Thus, it could be applied to precise evaporation studies in sprays. Furthermore, it is demonstrated that this technique can be performed with moderate spectral resolution, although the spectral shape of a Raman line used for temperature determination. Hence, several other vibrational Raman lines can be recorded simultaneously along a line by using a spatially resolving optical multichannel analyzer. This yields the possibility to obtain additional spatially resolved information, e.g., air/fuel ratio, vapour/liquid mass fraction, or gas temperature, simultaneously.