Numerical computation and characteristic analysis on the center shift of fire whirls in a ship engine room fire

The existence of fire whirls in some ship engine room is studied by using the basic elements of the fire whirls formation. The temperature characteristic of fire whirls are used to study the path shift of fire whirls and the result is nearly circular. The center shift angular velocity of fire whirls is analyzed with the least square fitting in the conditions of the constant wind velocity and the variable wind velocity from four sides. In the situation of the constant wind velocity, the result shows that the center shift angular velocity of fire whirls comply with the change regularity of a cube polynomial with different wind speed. When the wind velocity is more than 6.58 m/s, it strongly affects the change rate of the center shift angular velocity. However, in the situation of variable wind velocity, when the change rule of wind velocity follow increasing or descending regularity, the change law of the center shift angular velocity is proportional to the size of the wind velocity, but when the wind velocity is random variation, the change fluctuation of center shift angular velocity is comparatively small. Computational results have important significance for the structure fireproofing, fire evaluation and shipping design.

► For the first time, we studied the existence of fire whirls in some ship engine room. ► We study the path shift of fire whirls by using its temperature characteristic. ► The path shift of fire whirls is nearly circular. ► The center shift angular velocity is analyzed with the least square fitting. ► The relation between the wind velocity and the center shift angular velocity is studied.