ISSN Online: 2379-1748
ISBN Flash Drive: 978-1-56700-518-9
5th Thermal and Fluids Engineering Conference (TFEC)
IMPROVED CRITICAL HEAT FLUX CORRELATION FOR REFRIGERANT FLOWIN CIRCULAR MICROTUBES
Abstract
A new improved CHF correlation using critical quality and a modified measure of subcooling is developed for refrigerant flow in circular microtubes. The correlation showed a MAE of only 3% with R134a and 12% with R123 data, respectively. Nine different correlations were tested against the R134a data. Among the preexisting correlations, the Shah and the Zhang correlation performed well for R134a with a MAE of 16% and 19%, respectively. In general, the conventional scale correlations performed better than the microchannel correlations. Compared to the microscale correlations, the accuracy of the conventional scale correlations were impacted by critical quality. The proposed new correlation and updated version of the Wojtan-Thome
and Basu correlation were trained on the R134a dataset. All the correlations were compared against the independent R123 dataset and the new correlation fared better than the existing correlations in the literature.