INFLUENCE OF VIBRATION ENVIRONMENT OF SHIP ENGINE ROOM ON COMBUSTION CHARACTERISTICS OF SMALL-SCALE POOL FIRES

Abstract

The vibration environment generated by various operating equipment in ship engine room can significantly affect the heat transfer and combustion characteristics of pool fires. In this paper, with n-heptane as fuel, the combustion characteristics and heat transfer characteristics of pool fire under vibration frequencies of 0 Hz, 3 Hz, 5 Hz, 7 Hz, 8 Hz, and 9 Hz are studied for pool with diameters of 6 cm, 10 cm, 15 cm, and 20 cm. By comparatively analyzing the changes in quality change, flame geometry shape, temperature field and heat transfer characteristics, it is found that the vibration environment changes the typical evolution characteristics of pool fire combustion. The high vibration frequency (> 3 Hz) changes the typical development characteristics of the pool fire in the static environment, and its stable combustion phase disappears. Except in precombustion phase, the mass burning rates increase as the vibration frequency increases. The flame height is positively correlated with the vibration frequency. Additionally, the Heskestad model of flame height is developed, and coupling relationships between flame height and heat release rate, pool diameter and vibration frequency are established. At the same time, a vibration correction factor is proposed, and the heat transfer model is developed.