Measurement of void fraction in pipes by nuclear transmission based techniques

Abstract In this study, the application of nuclear transmission based techniques to the measurement of two-phase flow was evaluated and the experiment setup was described. Because neutrons are appreciably affected by interaction with hydrogen atoms, techniques based on transmission of thermal and fast neutron are particularly suitable for use with water or any other hydrogenous fluids. Based on the effective of water for gamma-rays attenuation on mass basis, transmission technique based on measuring of total gamma-rays has been examined. The beams of fast neutrons, thermal neutrons and gamma-rays emitted from 252Cf neutron source of strength 1.3 × 107 n/s were used. Void fraction is measured for steady-flow regimes in a horizontal air–water flow. Results are evaluated and the strength and limitations for each technique are given and discussed.