Heptane slick pool fires on water with inserted high-temperature heat pipes

The coupled heat transfer and combustion dynamics of floating fuel slicks play a critical role in governing flame behavior and burning characteristics. This study investigates the use of vertically inserted high-temperature heat pipes (HTHPs) at the burning surface of a 10 mm thick floating n-heptane slick. HTHPs (150 mm length, 30 mm diameter) with liquid metal working fluid are investigated under varying number (N = 1, 2, 3) and immersion depths (him = 5–20 mm). Experimental analysis quantifies the dominant thermal pathways, including radiation, nucleate boiling, and conduction at key interfaces of the pool surface, the HTHP immersed wall, and the fuel/water interface. Flame height increases with the number of HTHPs but decreases with greater immersion depth, peaking at 90 cm for N = 3 at him = 5 mm, which is a 44.3 % rise over baseline. The HTHP evaporator reaches isothermal temperatures of 400–550 °C, enabling effective vapor transport, while the bottom immersed section remains below the vapor flow transition temperature (181 °C) when immersed at 5–10 mm. Radiative heat fluxes from both the flame and the HTHP wall increase with N while nucleate boiling is enhanced by increasing the heat pipe wall exposure. An energy-based mass loss model efficiently captures experimental trends and reflects dynamic burning configurations. These findings demonstrate that phase change-driven heat transfer devices can modify the thermal feedback in n-heptane slick burning, providing mechanistic insights into heptane slick pool fire combustion with thermally conductive devices.