Experimental investigations on single-phase convection and steam-water two-phase flow boiling in a vertical rod bundle

Heat transfer coefficient correlations of water subatmospheric vaporization in a channel of a smooth plate heat exchanger, based on Vaschy-Buckingham theorem

“…The maximum error of the acquisition system is 0.02%. The uncertainties of the data are estimated by assuming that the instrumental error was uniformly distributed and could be estimated by Eq.11 as in [23] cited by [16].…”

CFD Analysis of Subcooled Flow Boiling in 4 × 4 Rod Bundle

“…In Equation (11), 𝐶 and 𝐶 are constant. The turbulence dispersion force and coefficient of Lahey et al (1993) [21] are given by…”

“…Thus, it was necessary to react sensitively to the fluid velocity, and in the next step, excessive bubble prediction is prevented through a nuclear boiling suppression factor. By taking in account the enhancement factor of forced convection and the suppression factor of nucleate boiling, a new correlation in terms of boiling number, Reynolds number, and Martinelli number was found to be effective in predicting two-phase-flow boiling heat transfer coefficients [11]. Analytical studies using various turbulence models for rod bundles in various shapes have also been conducted.…”

Parametric effects on the flow redistribution in ballooned bundles evaluated by magnetic resonance velocimetry

“…As the water level rises, a dispersed two-phase flow is created with steam generated from evaporated water at the triple interface of solid-liquid-vapor and droplets generated by bursting and spattering at this interface and by shearing between liquid and steam. While we find some studies investigating flow boiling and its fluid dynamics [2][3][4], which is the predominant heat transfer phenomenon in a LOCA during the pre-dryout condition, this dispersed flow plays a very important role in the cooling of the fuel assemblies' parts that are still not immersed in water. For this reason, several reflooding experiments have been performed in the past [5] but also more recently [6,7] with the evolution of measurement techniques, especially concerning clad ballooning as we discuss in the next paragraphs.…”