Quantitative evaluation of void wave propagation in oscillatory flow by using neutron radiography

Critical Heat Flux (CHF) is a very important designing factor of boiling systems, such as boiler and so on. Under flow instabilities condition, such as density wave oscillation, the CHF value is drastically decreased with an increase of oscillatory amplitude and oscillatory period, and the wall heat capacity becomes a very important parameter. In order to clarify this phenomenon, it is important to understand the void wave propagation under oscillatory flow conditions. In this investigation, the quantitative measurement of the void fraction in boiling two-phase flow under oscillatory flow condition was conduced by using the neutron radiography. The measurement results of the void fraction have been evaluated by the comparing with the calculation results of the lumped parameter model. (author)