Influence of Edge-Limited Hot Surfaces on Accidental Ignition and Combustion in Ship Engine Rooms: A Case Study of Marine Diesel Leakage

To extend initial ignition-related fire prevention in ship engine room, this work presents a case study of marine diesel leakage for identifying accidental ignition by hot surface. Based on a self-designed experimental platform, a full-scale innovative experimental arrangement was conducted for diesel leakage-related hot surface ignition (HSI) tests in a ship engine room. A series of parameters (e.g., heat transfer, evaporation mode, ignition position, ignition delay time, flame instability, and combustion behavior) for improving the initial HSI of diesel leakage on an edge-limited hot surface were analyzed. A transient sequence corresponding to a change in leakage flow rates ranging from 7.5 mL to 25 mL was tested, and hot surface temperatures (HSTs) were adjusted between 390 °C to 525 °C. Puffing motion accelerated the mixing of HSI-driven vapors with fresh air, which was affected by the edge-based limitation and HSTs. The case study identified the effects of hot surface shape and the most important combinations of HSI-driven combustion characteristics for estimating initial ignition responses. Based on this current work, prediction models were proposed for determining the HSI height of marine diesel for varying leakage flow rates and HSTs. The results indicate that HSI height increases with leakage flow rate and HSI position is influenced by edged hot surfaces, leading the vertical centerline to shift towards the side of the edge structure. The results also revealed that the ignition delay time of diesel leaked onto an edged hot surface decreases as leakage flow rate increases. This change causes the initial HSI to occur earlier, potentially creating an extra risk in ship engine rooms.