New method for bubble/slug velocity measurement in small channels

Area of Science:

• Fluid dynamics
• Two-phase flow measurement
• Sensor technology

Background:

• Gas-liquid two-phase flow in small channels presents measurement challenges.
• Capacitive four-terminal detection (C4D) is a potential technique for such flows.
• Coupled capacitances can interfere with accurate measurements.

Purpose of the Study:

• To develop a novel method for measuring bubble/slug velocity in small channels.
• To introduce a new C4D sensor design overcoming capacitive interference.
• To validate the proposed method's accuracy and effectiveness.

Main Methods:

• Development of a new C4D sensor utilizing capacitive reactance elimination.
• Construction of a bubble/slug velocity measurement system with two C4D sensors.
• Application of cross-correlation technique for velocity determination.
• Experimental validation using prototypes with diameters 1.82 mm, 2.65 mm, and 2.96 mm.

Main Results:

• Capacitive reactance elimination effectively mitigates coupled capacitance effects.
• The proposed method successfully measures bubble/slug velocity in small channels.
• Velocity measurement accuracy was demonstrated to be satisfactory across prototypes.
• Maximum relative errors in velocity measurements were consistently below 5%.

Conclusions:

• The capacitive reactance elimination principle is effective for C4D measurements in two-phase flows.
• The developed system provides accurate bubble/slug velocity measurements in small channels.
• The method offers a reliable solution for analyzing gas-liquid two-phase flow dynamics in micro-scale systems.