Multipoint gas-liquid phase detection method based on a thin-film optical waveguide

Area of Science:

• Optoelectronics
• Fluid Dynamics
• Materials Science

Background:

• Gas-liquid phase detection is vital across various industries.
• Existing methods face limitations in complex environments like curved tubes or near machine walls.
• High-speed visualization is often difficult in such confined spaces.

Purpose of the Study:

• To develop an effective phase detection method using a film-based optical waveguide.
• To investigate the sensor's performance with single droplets, droplet evaporation, and thin-film liquid flow.
• To enable multipoint, high temporal resolution phase detection in challenging industrial settings.

Main Methods:

• Development of a thin, flexible film optical waveguide with multi-light paths and multi-microsensors.
• Utilizing the intensity of reflected light, modulated by refractive index changes between gas and liquid, for phase identification.
• Analyzing sensor response to single droplet impacts, evaporation, and high-speed airflow-induced liquid flow.

Main Results:

• The optical waveguide effectively distinguishes between gas and liquid phases based on reflected light intensity.
• The sensing principle is analogous to established optical fiber probing techniques.
• The method demonstrated capability for simultaneous local multipoint and high temporal resolution phase detection on smooth surfaces.

Conclusions:

• The proposed film-based optical waveguide sensor offers a viable solution for gas-liquid phase detection.
• It can diagnose dispersed two-phase flow in hard-to-visualize areas, such as inside machines or curved tubes.
• This innovative sensor technology has significant potential for industrial process monitoring and diagnostics.