HEAT TRANSFER AND HYDRODYNAMICS OF SUBCOOLED INVERTED ANNULAR FLOW FILM BOILING ON A SINGLE ROD HEATER

Heat transfer during inverted annular flow boiling of a subcooled liquid was studied in this work. An experiment was set up to simulate flow downstream of a quench front during the reflooding phase of a dried out nuclear core in a loss of coolant accident. Steady-state, subcooled flow film boiling experiments were conducted inside an annular cross section consisting of a single stainless steel rod heater, 71 cm in height and 1.11 cm in diameter, which was placed concentrically within a tube of diameter 1.59 cm. The quench front location was stabilized near the test section inlet using a "hot patch". The hot patch consisted of a 2.5 cm-long cartridge heater inserted within the inner diameter of the heater tube. All tests were performed with PF-5060 as the test fluid, with mass flux ranging from 200 to 810 kg/m(2)s, inlet subcooling ranging from 12 to 27 degrees C, and wall superheat ranging from 200 to 305 degrees C. The fluid temperature, wall temperature, and pressure were measured at various axial locations. Fluid temperatures in the radial direction were also measured at several axial locations. The data obtained from these experiments were used to determine the wall heat transfer coefficient and liquid side heat transfer rate.