Measurement Of Void Fraction Using Wire Mesh Sensor

The main concern of this research is the study of two phase flow using wire mesh sensor(WMS),which consist of air bubbles submersed in water in reactors cores.The understanding of these such flow activities is paramount to finding out about the efficiency of the process and for safety concerns.This knowledge is also important to control and monitor the flow at the spot or online.The employed method is based on the conductivity and permittivity principle,and it was chosen because of the cheapness of the circuitry involved for implementation,as compared to other imaging techniques.Keeping this in mind,it provides an excellent temporal and spatial resolution for measurement.To fulfill this requirement,a small testing glass section with wire mesh wires was designed and developed.The circuits were tested and then PCBs were made accordingly.To prevent environmental noises and electromagnet disturbance,the apparatus was shielded to the best of ability,in accordance with the available resources.A wire mesh sensor with sixteen inputs and outputs respectively was made and put in a vertical glass section with water and air filled inside.The bubbles were generated by external means and the signal interference was noted in the collection section.The main system included wire mesh,the circuit for excitation,the circuit for data collection and data acquisition card connected to a computer.The signals were collected by a data acquisition card and further manipulated in a software program.The data was first taken in the Lab VIEW software and then transferred to MATLAB for analysis and image reconstruction.The results were compared with a high speed camera which was linked in synchronization with the software.In these circuit designs,the maximum efficiency was ensured while keeping the cost low.The results were satisfying but can be improved if resolution is raised by increasing the number of cross sections in the sensor.The sensor is surrounded by glass so that the high speed camera could also be used to compare results.The use of the high speed data acquisition card also enabled to deal with real time acquisition without any problem.Unfortunately,this facility could not be tested in rigorous conditions like high temperature and pressure because of limited resources.The conclusions drawn from these experiments are that wire mesh sensors indeed provide temporal resolution of about 1000 frames/s with a good spatial resolution and is also cheaper in comparison with other techniques.