| An experimental investigation of subcooled flow film boiling of Freon-113 over horizontal cylinders was undertaken. Experiments were performed for liquid velocities ranging from 0.78 m/s to 3.05 m/s, and for liquid subcooling ranging from 55.3°C to 72.6°C. Simultaneous wall temperature measurements were recorded using five miniature thermocouples embedded in the heater.;A two-dimensional nonlinear inverse heat conduction problem (IHCP) was formulated based on the well-posed hyperbolic heat conduction equation, to estimate the surface heat flux, given measured heater temperatures. Based on the transient surface heat flux estimates and the measured wall temperature fluctuations, solid-liquid and pseudo contacts were identified. Contact parameters such as duration of contact, energy removed per contact, and wall temperature depression per contact were extracted from the data. The results showed that the contacts were not periodic. No clear trend was evident in the data. Correlation of the data was impossible due to the large scatter present.;Boiling curves based on both "apparent" and "corrected" heat fluxes were compared to emphasize the importance of internal heat conduction in the heater. The effect of the thermal properties of the heater was investigated using computer simulations. It showed that the lava core was unaffected by short duration contacts. The lava core acts as an energy storage medium. Analysis of the nucleate-film boiling showed that the heater was capable of sustaining simultaneous nucleate and film boiling on its surface.;An analytical flow film boiling model was also developed. Though this model does not include heat transfer in the wake of the heater and the effects of solid-liquid or pseudo contact, it is still a major improvement over all existing analytical models. However, these limitations of the model resulted in poor agreement between predicted wall temperatures and those experimentally measured. |
