Effects of ventilation system design on flame behavior and smoke characteristics for mitigating marine engine room fire hazards

Abstract

Engine room fires are one of the most harmful types of ship fires, the development of which is closely related to the design of marine ventilation system. In this paper, a full-scale numerical study of ship's engine room fire is carried out using a fire dynamics simulator, and the effects of vent layout and air velocity on the flame behavior, smoke stratification and diffusion are investigated. The three-dimensional model of the engine room is built based on the ocean-going training ship Yukun of Dalian Maritime University. First, the variations of flame behavior under different air vent layouts and wind speeds are explored, and a mathematical model is derived to quantify the flame deflection angle. Then, the effects of ventilation conditions on the smoke stratification in the cabin are analyzed, and the characteristics of hot smoke diffusion are revealed. The results show that a higher ventilation velocity is beneficial to the rapid cooling of the ship's engine room, and the symmetric ventilation layout of Method 3 with a central intake on the upper side and a bottom exhaust on both sides is more conducive to the safety of the engine and other heat source equipment in a fire. This study provides references to the design and optimization of ventilation systems on ships, which can improve the safety of the important equipment in the engine room and prevent further expansion of fire.