Vertical distribution of the void fraction, using X-ray attenuation measurements, for different flow regimes in a horizontal pipe

L. Rossi (1) , R. de Fayard (1) , S. Kassab (1)

1 CEA-DES (ex-DEN) - CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire)

METERO is an experimental facility built by the French Atomic Energy Commission (CEA) aimed atstudying adiabatic air-water flows in horizontal pipes. The physical insight and the experimental dataprovided by METERO experiments support the validation of MCFD (NEPTUNE CFD) and System(CATHARE-3) codes as a part of the NEPTUNE project developed jointly by EDF, CEA, AREVA NPand IRSN. [Bottin et al International Journal of Multiphase Flow 60 (2014) 161179] have proposed aflow map of the different regimes encountered in the METERO experiments, i.e. stratified flows, slugflows, plug flows, stratified dispersed bubbly flows and dispersed bubbly flows. Following this work,we investigate the vertical distribution of void fraction integrated horizontally using X-ray attenuationmeasurements.After a description of the experiments and the measurements' method, we discuss the evolution of thevertical distribution of the void fraction in horizontal pipes and derived statistics such as the ratio of theair and water phase velocities. Different flow regimes and their transitions (e.g. slug, plug, and bubblyregimes) are explored by varying the water and air superficial velocities.

Domains: Nuclear Experiment [nucl-ex]; Nuclear Theory [nucl-th]

L. Rossi, R. de Fayard, S. Kassab. Vertical distribution of the void fraction, using X-ray attenuation measurements, for different flow regimes in a horizontal pipe. NUTHOS 11th - International Topical Meeting on Nuclear Thermal Hydraulics, Operation and Safety, Oct 2016, Gyeongju, South Korea. ⟨cea-02439449⟩