Use of fundamental condensation heat transfer experiments for the development of a sub-grid liquid jet condensation model

Abstract

Condensation on liquid jets is an important phenomenon for many different facets of nuclear power plant transients and analyses such as containment spray cooling. An experimental facility constructed at the Pennsylvania State University, the High Pressure Liquid Jet Condensation Heat Transfer facility (HPLJCHT), has been used to perform steady-state condensation heat transfer experiments in which the temperature of the liquid jet is measured at different axial locations allowing the condensation rate to be determined over the jet length. Test data have been obtained in a pure steam environment and with varying concentrations of noncondensable gas. This data extends the available jet condensation data from near atmospheric pressure up to a pressure of 1.7MPa. An empirical correlation for the liquid side condensation heat transfer coefficient has been developed based on the data obtained in pure steam. The data obtained with noncondensable gas were used to develop a correlation for the renewal time as used in the condensation suppression model developed by Young and Bajorek.This paper describes a new sub-grid liquid jet condensation heat transfer model. In the current work, mass and energy balance equations are solved in a marching scheme in each sub-grid node along the path of the jet trajectory. Jet specific condensation heat transfer closure relations are used. The jet sub-grid method has been implemented as a boundary condition in an in-house version of the sub-channel analysis code COBRA-TF (COBRA-IE). COBRA-IE fluid nodes provide the required vapor and noncondensable gas conditions for the heat transfer solution. The sub-grid model solves the liquid side heat transfer and the condensation rates for each volume in the sub-grid solution. These terms are summed along all of the sub-grid cells that pass through each COBRA-IE control volume to provide mass and energy transfer rates for the COBRA-IE solution. Results using the new jet injection boundary condition show an improved ability to simulate jet condensation experimental data.