Experimental and numerical investigation of local bubble parameters for subcooled flow boiling in a pressurized annulus

The wall boiling models adopted in the Computational Multi-Fluid Dynamics (CMFD) tools rely on empir-ical correlations for closures, which causes considerable uncertainties in their results. Thus, well-defined experimental data for local boiling parameters are essential for the development and validation of the wall boiling constitutive models. This paper presents new experimental data on the local bubble parame-ters and the wall temperatures along the heated tube for the subcooled flow boiling under high-pressure conditions. The radial distributions of the bubble parameters, namely, void fraction, bubble velocity, in-terfacial area concentration, and Sauter mean diameter were measured at multiple elevations to evaluate their development along the flow. Furthermore, the experimental data set was utilized to validate physi-cal models for predicting subcooled flow boiling using a CMFD code. The source of discrepancies between the experimental and calculated results were analyzed and possible directions for research in subcooled flow boiling under high-pressure conditions were defined.(c) 2022 Published by Elsevier Ltd.