Abstract
Film boiling heat transfer coefficients are obtained and the vapor film behavior is visualized through a series of quenching experiments. The test section is of a downward heated curved surface of which the curvature radius and edge angle are 990 mm and 9.88°, respectively. The copper having the Biot number less than 0.1 in the film boiling regime, heat transfer coefficients are determined without considering conduction in the test section. A total of seven thermocouples are installed near the outer surface of the test section. The test results are compared with those from the laminar film boiling analysis and a previous experiment with the same edge angle. Higher heat transfer coefficients than are predicted by laminar film boiling analysis are measured since the concentric interfacial waves limit the increase in the vapor film thickness by way of an intermittent breakup allowing the heated surface to be rewetted.
