Convection-driven cavity formation in ice adjacent to externally heated flammable and non-flammable liquids

A parametric experimental study on melting of ice adjacent to liquids exposed to various heat fluxes from above was conducted in order to understand the role of liquid properties in formation of cavities in ice. In previous experiments related to in situ burning (ISB) of crude oil contained in ice, the convective motion in the fuel layer was identified as a key parameter determining the amount of the ice melting. An experimental setup was designed to measure the melting rate of the ice and penetration speed of the liquid similar to the lateral cavity formation problem observed in ISB experiments. Lateral cavity formation is identified as a key factor reducing the removal efficiency of ISB. The experiments were conducted in a transparent glass tray (70 mm × 70 mm × 45 mm) with a 20 mm thick ice wall (70 mm × 50 mm × 20 mm) placed on one side of the tray. Liquids in the tray (water, n-pentane, dodecane, n-octane, m-xylene, and 1-butanol) that were adjacent to the ice wall were exposed to varying heat fluxes mimicking flame heat feedback from a pool fire. The results of ice melting rate among different liquids were found to vary significantly. The exposure of the liquids to the radiative heat flux led to temperature difference between the liquid and the ice, thereby creating a heat transfer pathway towards the ice that provided the required energy for the melting. It is suggested that Marangoni-driven convection caused by the temperature gradient near the ice and below the free surface of the liquid is influential in the ice melting. A scaling analysis of the surface flow was undertaken to elucidate the influence of surface tension effect (Marangoni convection). It was found that the surface flow velocity obtained from the surface tension effect at the liquid free surface correlates well to the melting front velocity.