| Abstract: | Uncovered-bundle heat transfer tests under high-pressure boil-off conditions were conducted in ranges of pressure from 3 to 12 MPa, heat flux from 3.3 to 18 W/cm2 and vapor Reynolds number from 10000 to 62000. There existed two boil-off patterns depending on bundle power, low-power boil-off and high-power boil-off. Though existing steam cooling heat transfer correlations fitted approximately the low-power boil-off test data, they underpredicted considerably the high-power boil-off test data. Intermittent droplet cooling effect in the froth region was fairly larger in high-power boil-off than in low-power boil-off. The FLECHT correlation was modified to account for the intermittent droplet cooling effect in the froth region by using the test data. The modified correlation was in approximate agreement with the high-power boil-off test data as well as the lower-power boil-off test data. |
