Liquid phase temperature determination in dense water sprays using linear Raman scattering.

Area of Science:

• Physical Chemistry
• Thermodynamics
• Spectroscopy

Background:

• Accurate temperature measurement is vital for understanding water spray dynamics.
• Non-equilibrium conditions in sprays, where liquid and vapor temperatures differ, pose a significant challenge for traditional measurement techniques.

Purpose of the Study:

• To develop and validate a method for determining the temperature of liquid water droplets in sprays.
• To differentiate liquid water temperature from surrounding water vapor temperature, especially in non-equilibrium spray scenarios.

Main Methods:

• Utilizing linear Raman scattering to analyze the OH-stretching vibration band of water.
• Deconvoluting the Raman band into five Gaussian peaks, each corresponding to specific intermolecular interactions (hydrogen bonding).
• Implementing a signal processing technique to eliminate interference from water vapor Raman signals.

Main Results:

• The intensity of each Gaussian peak in the Raman spectrum is demonstrably dependent on temperature and the phase of water.
• Successful isolation of liquid water Raman signals from water vapor signals was achieved.
• The method allows for the determination of liquid water droplet temperature even when it differs from the vapor temperature.

Conclusions:

• Linear Raman scattering provides a viable method for measuring liquid water temperature in sprays.
• The technique is particularly valuable for studying non-equilibrium sprays where thermal equilibrium between phases is not achieved.
• This advancement facilitates a deeper understanding of heat and mass transfer processes in sprays.