Abstract: The fire experiments were carried out in a 3 m (length) × 3 m (width) × 3.5 m (height) confined cabin with square double oil pools with side lengths of 10, 15, 20 cm, respectively, at different spacings to investigate the variation law of combustion rate. The results show that the double oil pool fire in the confined compartment can be divided into three typical combustion stages: initial, stable and extinguished, and the dimensionless spacing S/L of different oil pools shows a parabolic relationship with the combustion rate and the threshold value of S/L at the peak of mass loss rate is between 0.70 and 0.85, which is obviously different from the development of double fires in open space and tunnel semi-enclosed space. On this basis, a prediction model for the dimensionless heat release rate in a confined compartment with a modified spacing S is given.

Key words: sealed ship engine room, double fire sources, fire source distance, mass loss rate