Measurement of Drypatch Spreading and Post-Dryout Temperatures in a 3-Rod Bundle Cooled by Freon-12 in Vertical and Horizontal Orientations

摘要

Post-dryout (PDO) temperatures and drypatch spreading have been measured in a 3-rod segmented bundle cooled by Freon-12. The bundle was tested both vertically and horizontally at mass fluxes ranging from 1 to 4 Mg.m exp -2 .s exp -1 . It was found that rod spacers 25 cm upstream of the end of the heated length caused considerable local CHF enhancement immediately downstream, resulting in a reduction of axial drypatch spreading. The fully developed PDO temperature data were successfully correlated using a high pressure water correlation. A correction term to account for partially developed PDO conditions was developed. This correction term was found to be applicable to high pressure water data from tubes and 37-rod bundle. The overall equation fitted the vertical Freon-12 PDO termperature data with rms error of 6.5% and the horizontal data with an rms error of11.9%. (Atomindex citation 11:559148)