Unsteady heat transfer during subcooled film boiling

Effect of Coating by a Carbon Nanostructure on Heat Transfer with Unsteady Film Boiling

“…The primary purpose of the stand is to obtain new experimental data, which are necessary for simulation of cooling of the reactor core during post accident reflooding, as well as processes that may lead to the occurrence of a vapor explosion. A detailed description of the stand can be found in the previous publications, e.g., [12,13].…”

“…It is found that in water subcooled by ΔT sub > 20-30 K, microbubble boiling occurs when the samples made of materials with very different properties (stainless steel, nickel, and copper) are cooled. As far as is known, the temperature of a cooled ball is measured in such experiments at the center and at several points on the surface rather than at one point only in [7][8][9][10][11][12][13]. The presence of several surface thermocouples enables us to determine reliably the temperature of occurrence of the intensive cooling mode, the velocity of the cooling front propagation over the surface, and the rate of the ball cooling.…”

“…It should be noted that, when the temperature is measured at a single point (in the center of the ball or at some distance from its surface) in experiments on unsteady cooling, particular caution is needed during interpretation of the measurement results, especially at a low thermal conductivity of the metal. Such errors become unavoidable if the thermocouples are mounted directly on the sample surface, provoking an early transition to a high-intensity film boiling regime, which is discussed in [13].…”

Pressure influence on film boiling of mixtures

“…In the stand upper part a coil (2) of a high frequency induction heater (3) is placed; the lower part is is filled with a cooling liquid, the temperature of which is maintained at a predetermined level by means of a thermostat (8) (8) and a coil pipe (7) immersed in the liquid. The heating zone is separated from the liquid by thin metal diaphragm (5), (5), which protects the cooling medium against heat radiation. At the experiment beginning a metal sphere (tested sample) (1) is mounted inside the coil (2) by means of the lever-type displacement system (4).…”

“…Over the past 10 years, our research team has conducted an extensive series of experimental work on various liquids and metals under different conditions [5][6][7][8][9][10]. The compressed results are shown in Table 1 and 2.…”