A study on the rewetting of a hot surface, using low pressure, subcooled liquid

This study presents the experimental work carried out to simulate the rewetting behavior of a vertical annular channel with a heated rod at top flow rewetting conditions. A specifically designed and built experimental facility has been used to simulate the two-phase water flow phenomena at atmospheric conditions and low pressures at different degrees of inlet sub-cooling. Experiments have been conducted at atmospheric and steam conditions up to 3 bar with inlet sub-cooling in the range of 0-50°C. The initial surface temperature of the rod varies from 200 to 550 °C while the liquid flow-rate is steady and equals to 10-3 m³min^-1. The main objective of this study is to identify the effect of low pressure steam environment in combination with inlet sub-cooling on the rewetting process. It appears that the rewetting velocity increases with an increase in pressure and inlet sub-cooling and decreases with an increase in the initial surface temperature. In addition, this study proposes a new rewetting correlation and discusses the effect introduced by the channel diameter on the rewetting phenomena.