Combustion Behavior Characteristics of Transformer Jet Fire with Multiple Factors

Transformer jet fire is one of the most serious types of substation fire accidents, which often causes heavy casualties and property losses and even causes other secondary disasters, further expanding the impact of thermal disasters. Compared with the jet fire formed by the leakage of gaseous combustibles during production, transportation, and storage, the research on the combustion behavior of transformer jet fire under multiple factors, such as flame shape and flame height, is relatively scarce. This study used the research method of combining experimental research with theoretical analysis. Flame shape and flame height of transformer jet fire under different vessel diameters (5, 8, and 10 cm), opening diameters (5, 10, and 15 mm), and filling rate (60, 80, and 100%) were measured and analyzed. The results show that jet momentum and flame buoyancy are the main reasons for the change in flame shape characteristics. The transformer jet fire development process can be divided into three typical stages of full development, stable jet, decay, and extinguish. The flame height increases with the increase of the opening diameter and container diameter, and increases first and then decreases with the increase of filling rate. The functional relationship between the flame height and the 0.2 power of the characteristic Froude number is established. The research results provide reliable theoretical guidance and data support for transformer fire prevention and control.