Effect of Non-Condensation Gas on Heat Transfer of Direct Contact Condensation

Abstract The small modular pressurized water reactors adopt a safety relief system to provide overpressure protection for the reactor coolant system. During this process, the mixed gas is discharged into the suppression water tank, causing direct contact condensation. The fraction of the non-condensable gas has a significant impact on the heat transfer. A visual experimental device was established to conduct the experiments of direct contact condensation within the mixed gas mass flux in the range of 177∼425 kg/m2s and the non-condensable gas mass fraction in the range of 0∼20% by using type I multi-holes sparger. The jet plume shapes for the pure steam condensation and mixed gas condensation are investigated in the condensation oscillation zone and jet stable condensation zone. The heat transfer area of pure steam and mixed gas condensation is obtained based on the jet plume shape at the interface. An empirical correlation of the heat transfer coefficient of direct contact condensation with a function of a dimensionless steam mass flux and a driving potential for the condensation process and steam mass fraction is developed and verified with different experimental data. The results show that the empirical correlation of the heat transfer coefficient applies to pure steam and mixed gas, and the error of the model is within ±50%.