Effects of nozzle diameter on marine fuel injection and deflagration performance

Abstract

The marine fuel injection and deflagration performance with different nozzle diameters in large compartments are researched in this work. The results show that marine fuel could quickly form a stable fuel spray field. Increasing nozzle diameter dramatically enhances the fuel spray concentration and aggravates the fuel spray deflagration degree, resulting in rapid increases in flame propagation speed, deflagration overpressure, and deflagration temperature. A larger nozzle diameter causes the deflagration flame to propagate further forward. With the increase of deflagration time, the flame propagation speed shows a trend of first rising and then decreasing, with fluctuations. When the nozzle diameter is small, the overpressure declines toward the back. In the case of large nozzles (≥0.8 mm), the overpressure distribution in the compartment fluctuates greatly, with a tendency to increase first and then decrease. Furthermore, deflagration peak overpressure ascends linearly with the logarithm of fuel spray concentration. The peak deflagration overpressure is 1.875 MPa with 1.0 mm nozzle diameter. The deflagration temperature is highest at the center of the deflagration. The research results can guide the assessment and prevention of fire and deflagration accidents on ships.