Experimental Study on Combustion Characteristics of Transformer Oil Pool Fire with Different Scales

Abstract

To study the combustion characteristics of transformer oil pool fire with different sizes, transformer oil pool fire experiments with diameters of 40cm, 50cm, and 60cm are carried out to analyze the evolution laws of flame height, fire plume temperature, and oil temperature of oil pool fire with different diameters. The results show that the ignition process of the transformer oil pool can be divided into three typical stages: initial growth stage, full development stage, and extinguished stage. According to the characteristics of combustion rate and flame height, the full development stage is subdivided into the stable combustion stage and boiling combustion stage. The flame height of the boiling combustion stage is about 1.1 times higher than that of the stable combustion stage. With the increase of diameter, the range of intermittent flame area of oil pool fire with three diameters increases by 1.2 times. The heat transfer analysis of the full development stage shows that the oil temperature presents the phenomenon of temperature stratification. There is a boiling layer below the liquid level. Its temperature is about 330 °C and its thickness is about 2.3 mm. The oil temperature under the boiling layer decreases in a gradient, and the boiling layer thickness and temperature have no significant correlation with the oil pool diameter.