This study is focused to develop a sensor for measurement of void fraction in two-phase flow. A special device to control the void fraction named Styrofoam simulator is designed, which simulates the air bubble by use of Styrofoam. Because the permittivity of Styrofoam is negligible compared to that of water, it is shown that a Styrofoam is suitable for simulation of air bubble. Three kinds of electrodes were designed and compared to provide the performance of sensors in the Styrofoam simulator. The test facility of water-air bubbly flow was designed and constructed to verify the performance of sensor. Three kinds of circular electrode shapes were compared in the test facility to choose the sensor can effectively measure the impedance of water-air bubbly flow. The conductance probe that has coaxial-cylindrical pipe type electrodes was proved to be the best candidate for void fraction sensor. The resistance increased with the increase of the void fraction while the capacitance decreased with the increase of the void fraction. The resistance of water contributes the most part of the total impedance. The impedance values in void fraction 0-10% were similar to those of theoretical equation.
展开▼
