HEAT TRANSFER TO MIXTURES OF HIGH PRESSURE STEAM AND WATER IN AN ANNULUS Part VI. A preliminary study of heat transfer coefficient and heater surface temperature at high steam qualities

摘要

Measurements of heat transfer coefficient near the exit of an annular test section showed the transition from "fast" to "slow" burnout to be a sharply defined point. At a mass flowrate of 0.6 x 106 lbs ft-2 hr-1, it occurred at 75 per cent exit quality at 500 psia and at 82 per cent exit quality at 1000 psia. In the "slow burnout" region, the burnout detector was found to operate at an excess temperature of approximately 100°F.nIn the post burnout region the experimental heat fluxes necessary to give a particular surface temperature were up to 40 per cent lower than that to be expected from the steam alone, assuming thermal equilibrium. This suggested that most of the heat transferred was used in superheating the steam rather than in evaporating the water.