Applicability of novel critical heat flux criteria to high pressure subcooled flow CFD simulations

A novel criterion for departure from nucleate boiling is compared with conventional criteria in the computational fluid dynamics code Star-CCM+, using an experimental dataset from the Large Water Loop at Skoda, Czech Republic and from Bettis Thermal and Hydraulics Laboratory. The experimental data consists of subcooled flow boiling measurements at high temperature, high pressure conditions for both fuel bundle and pipe geometries. We compare the results obtained by Macek & Vyskocil using the NEPTUNE_CFD code to our results using two untuned boiling models that are broadly implementable, and compare the sensitivity of each criterion to the two boiling models examined. We find that the criterion’s reliance on understanding the bubble growth time poses a serious challenge to applying the criterion to legacy experiments and real world applications, where high fidelity measurements are unavailable or impractical to obtain. There is some evidence that the criterion might be useful under some circumstances, but is not generally applicable. • Novel DNB criteria were tested against conventional criteria with Star-CCM+ CFD code. • Critical triplet criterion does not predict CHF as well as conventional criteria. • Current bubble growth time models are insufficient for being used in CFD codes. • All criteria showed some sensitivity to the choice of boiling model and geometry.