Estimation Of Void Fraction In Fuel Bundle Using The Wire-Mesh Sensor

Two-phase flow exists in most of the thermodynamic engineering environments.The measurement of gas-liquid two-phase flow in the thermodynamic and hydraulic engineering experiments between fuel assemblies of nuclear power plants is of great significance.According to acquisition resolution and acquisition speed,mesh sensors have more advantages than resistive and ultrasonic sensors.And in the strict sealing of the fuel assembly special working environment.the optical sensor is difficult to work.The measurement of gas-liquid two-phase flow in the thermal hydraulic test of fuel assembly in PWR is of great significance for studying the flow characteristics between rods and heat transfer characteristics of cladding under specific working conditions.When the traditional two-phase flow measurement method is applied to the measurement of cavitation share and bubble velocity distribution between fuel assemblies,there are some limitations such as insufficient spatial resolution or high measurement cost.In view of the above problems,this paper develops a mesh wire sensor suitable for two-phase flow measurement of fuel assembly,including design of excitation circuit and receiving circuit.data acquisition program and image reconstruction program,and design of simulation experiment section of fuel assembly.Different from the traditional wire sensor,the fuel rod body is used as the excitation electrode in this design,which further improves the spatial resolution of the measurement.In order to test and verify the designed mesh sensor,a simulated fuel module test bench was designed and manufactured.A two-phase flow environment between fuel assemblies is simulated by generating rising bubbles in a rectangular experimental section with rod bundles.In this project circuit designed is the most important part.Circuit design has been improved.The circuit designed is optimized for power,cost and complexity.The control was performed using the micro-controller,ithout using any shift registers or multiplexers.The circuit is simple and have fast response time and low noise.