الفهرس Only 14 pages are availabe for public view
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Abstract
The critical heat flux (CHF) phenomenon has been extensively investigated over the past four decades, as it constitutes the most important operational limit for various heat transfer units including water-cooled nuclear reactors and fossil-fueled boilers. The operating conditions in these applications are designed to maintain heat fluxes lower than the critical heat flux for preventing potential failure by overheating or burnout. For subcooled flow, CHF is a condition in which a small increase in heat flux leads to abrupt wall overheating caused by the transition from nucleate to film boiling. In this study, a model for predicting the CHF was improved in order to minimize the CHF prediction error. This was done by using different correlations to calculate the critical wall-void fraction. The results of the model using each of these correlations were studied in order to determine the best one and its range of applicability. It was found that using some correlations to calculate the void fraction will improve the prediction quality of the CHF model. The results were improved in the range of ± 20%