An Experimental Study of Droplet Entrainment in the Horizontal Stratified Flow

The objective of this study is to carry out experiments for droplet entrainment of stratified flow condition in a horizontal rectangular channel to extend the database. By using the experimental data, an empirical correlation for droplet entrainment is proposed applicable to horizontal stratified flow. Droplet entrainment in a horizontal stratified flow is a major phenomenon that can occur in a hot leg pipe during Loss of Coolant Accident (LOCA) in a PWR nuclear power plant. The droplets entrained in the hot leg move to the steam generator (SG) together with the droplets generated from the reactor. In the SG, the evaporation of droplets causes the pressure increases in the upper head of reactor. This interferes with the injection of the emergency core cooling water into the reactor during the reflood period, which greatly affects the safety of the fuel rods. However, up to now, the experimental study on the droplet entrainment in the horizontal stratified flow has been limited to few researchers at the CEA in France and Tulsa university. Droplet entrainment experiments were performed by applying liquid film extraction method in order to extend experimental database for entrainment fraction.