성층류 수위 측정을 위한 링 타입 임피던스 센서 설계

Abstract

It is very important issues to monitor the phase distribution, void fraction and water level for effective design and analysis of system in various engineering fields such as chemical and nuclear industry. For these reasons various measurement techniques have been proposed, for example, radiation, micro wave, ultrasonic, and electrical impedance method. However, most techniques have limitations in terms of economic point of view and also these are difficult to apply to the case of the rapid change of phase distributions. The probe level meter which has been widely used for water level measurement tends to disturb the flow fields, in case of ultrasonic level meter water level measurement can be hard when numerous bubbles forms in the interface of two phases. This study considers electrical impedance method which does not disturb the flow field and is simple to design. In this work, a ring-type sensor was designed to measure the water level in the stratified regime. Prior to loop experiments, as a reference the relationship between the electrical signal and normalized water level was constructed based on numerical calculation and this relationship was compared with static phantom experiments. In addition, a designed ring-type sensor was installed in the horizontal test section and sensor signals for various water levels created by a variety of flow rate conditions were measured. By applying these measured signals to precalculated lookup table, corresponding water levels were evaluated. Also, these results were successfully compared with those of images captured by high-speed camera.