Development And Application Of Two Phase Flow Optical Fiber Probe

Due to the application in the various fields,the study of two-phase flow system is becoming the subject of scholars worldwide.In general,almost every process industry has the application of gas and liquid two-phase.From nuclear reactors monitoring to industrial process control sensors,two-phase flow research is a very important part.Air and water can co-exist in a flow or a fluid as it undergoes a phase change due to condensation or evaporation.The nature of the fluid during its flow is complex and cannot be explained clearly,but we can understand the flow by some basic parameters that indicate properties of the flow.Void fraction is one of these parameters.The behavior of the two-phase flow can be understood and explained by developing means for measuring the void fraction in the two-phase flow.If the void fraction can be accurately measured,the control system and the monitoring system will be improved.In nuclear power plants,water is used as a neutron moderator coolant,so void fraction is important for assessing two-phase flow parameters.In this paper,the method of measuring the void fraction and bubble velocity in the two-phase flow by optical fiber probe is studied deeply.The calibration experiment of the void fraction measurement is carried out,and the fiber probe measurement system is applied to the steam generator simulation bench.The main work is as follows:(1)Design a optical fiber probe for measuring the void fraction in the gas-liquid two-phase flow and built a measurement system including fiber probes,lasers and photo detectors;(2)Design and build experimental bench,carry on fiber optic probe calibration experiment,and analyze the performance of optical fiber probe;(3)The fiber probe measurement system is applied to the steam generator simulation platform to measure the void fraction under different working conditions,and analyze the causes of various phenomena.The experimental results show that the average error of the fiber probe is 5.707%(absolute value).The error is within the acceptable range and the probe can be used in measurement.