Simultaneous 2D temperature and velocity measurement using a one-color-camera PLIF method combined with a physically...

Area of Science:

• Fluid dynamics
• Optical diagnostics
• Laser-induced fluorescence

Background:

• Accurate simultaneous temperature and velocity measurements are crucial for understanding complex multi-phase flows.
• Existing laser-induced fluorescence (LIF) methods face challenges with image misalignment and thermal effects, particularly at phase boundaries.
• High measurement deviations (30°C-50°C for temperature, 77.6% for velocity) limit the application of LIF in multi-phase flows.

Purpose of the Study:

• To develop a time-resolved two-color LIF method for simultaneous 2D temperature and velocity measurements in multi-phase flow.
• To enhance measurement accuracy by addressing temperature deviations from image misalignment and velocity calculation errors due to thermal processes.
• To improve the reliability of LIF-based diagnostics in complex, coupled thermal-flow environments.

Main Methods:

• A time-resolved two-color laser induced fluorescence (LIF) technique utilizing a temperature-sensitive dye molecule for simultaneous temperature and velocity tagging.
• Implementation of a one-color-camera system to minimize temperature deviation caused by image misalignment at phase boundaries.
• Introduction of a physically constrained temperature tagging method to mitigate velocity calculation errors influenced by thermal diffusion and convection.

Main Results:

• The one-color-camera system reduced temperature deviation from 30°C-50°C to below 10°C near the two-phase flow boundary, achieving a high contrast ratio (0.41-0.43).
• The physically constrained temperature tagging method decreased relative velocity deviation from 77.6% to below 10%.
• Demonstrated significant improvement in the accuracy of simultaneous temperature and velocity measurements in multi-phase flow.

Conclusions:

• The proposed LIF method offers a robust solution for accurate 2D temperature and velocity measurements in complex multi-phase flows.
• The developed techniques effectively address key error sources, enhancing the applicability of LIF diagnostics.
• This advancement is vital for detailed studies of phenomena involving strong coupling between temperature and velocity in multi-phase systems.