INVESTIGATION OF HEAT TRANSFER PHENOMENA DURING DIRECT CONTACT CONDENSATION IN THE PRESENCE OF NON CONDENSABLE GAS BY MEANS OF LINEAR RAMAN SPECTROSCOPY

Condensation in the presence of non condensable gases is one of the dominating processes which determine the thermohydraulic behaviour in the primary system of a pressurized water reactor during a postulated loss of coolant accident. On this account experiments have been performed at the LAOKOON test facility at the Technische Universität München to study the effect of non condensable gases on direct contact condensation at stratified steam/water flow. The paper presents the experimental setup and the measurement techniques for the heat transfer determination, especially the linear Raman spectroscopy. This laser measurement technique allows the simultaneous investigation of concentration profiles in the vapour phase and water temperatures in the liquid phase. Furthermore the fog density in the vapour phase can be estimated, if homogenous condensation occurs in the boundary layer. The results of experiments with different system parameters are presented and the possibilities and difficulties of the linear Raman spectroscopy will both be discussed. Fig.1: Results from linear Raman spectroscopy in the investigation of direct contact condensation at stratified flow nitrogen signal H2O vapour signal H2O liquid signal fog signal Raman spectra liquid phase (row 256)