Improved methodology for deriving the critical heat flux look-up table

Title: Improved methodology for deriving the critical heat flux look-up table
Authors: Tanase, Aurelian
Date: 2007
Abstract: A literature review on critical heat flux (CHF) prediction methods confirmed that the CHF look-up table (LUT) has many advantages over the other prediction methods: it covers the widest range of flow conditions, it is the most accurate CHF prediction method and it is computationally very efficient. The LUT has been included in the major thermalhydraulics and safety analysis computer codes. The LUT accuracy has increased over the years, although several areas have been identified where further improvements are desirable. These areas include (i) the screening of the experimental data, (ii) effect of the heated channel diameter and length on the CHF, and (iii) difficulties in predicting the CHF in the limiting quality region in LUT, at low flow/low pressure conditions and in the very high dryout quality range. This thesis describes the various improvements that have been made to the LUT derivation. In addition to the improvements in the LUT derivation methodology, a new visual analysis technique that allows simultaneous LUT trend visualization and comparison in all parametric directions has been developed. Based on the findings and improvements in the LUT derivation methodology, a new version of the LUT has been developed. The error analysis revealed that refined data screening and removal of outliers is an effective method for improving the CHF LUT accuracy. Because the majority of the experimental data were obtained for diameters close to the standard 8 mm ID, a better correction of diameter effect on the CHF does not significantly affect the overall LUT accuracy, although it appears to be very important at specific conditions such as low flow or extreme diameters.
CollectionTh├Ęses, 1910 - 2010 // Theses, 1910 - 2010
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