High-frame rate imaging of two-phase flow in a thin rectangular channel using fast neutrons

• Published in: Applied radiation and isotopes Vol. 90; pp. 122 - 131
• Main Authors: Zboray, R., Mor, I., Dangendorf, V., Stark, M., Tittelmeier, K., Cortesi, M., Adams, R.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.08.2014
• Subjects: Bubble size; Bubble velocity; Fast neutron radiography; High frame rate; Two-phase flow; Bubble velocity; Bubble size; Two-phase flow; Fast neutron radiography; High frame rate
• ISSN: 0969-8043; 1872-9800
• DOI: 10.1016/j.apradiso.2014.03.023

We have demonstrated the feasibility of performing high-frame-rate, fast neutron radiography of air–water two-phase flows in a thin channel with rectangular cross section. The experiments have been carried out at the accelerator facility of the Physikalisch-Technische Bundesanstalt. A polychromatic, high-intensity fast neutron beam with average energy of 6MeV was produced by 11.5MeV deuterons hitting a thick Be target. Image sequences down to 10ms exposure times were obtained using a fast-neutron imaging detector developed in the context of fast-neutron resonance imaging. Different two-phase flow regimes such as bubbly slug and churn flows have been examined. Two phase flow parameters like the volumetric gas fraction, bubble size and mean bubble velocities have been measured. The first results are promising, improvements for future experiments are also discussed. •Fast neutron radiography of air–water two-phase flows in a thin channel is performed.•High frame rate imaging is performed using an optical detection system.•Gas volume fraction and bubble sizes have been estimated.•Bubble velocities are estimated by optical flow algorithm based on image sequences.•Spectral, scatter corrections of the raw images are done based on MC simulations.