Abstract:

In order to definite the effect of pebble size of bedding on the fire characteristic parameters of KI25X transformer oil, combustion experiments of small-scale KI25X transformer oil with different sizes of pebbles of bedding immersed were carried out. Combustion characteristic parameters such as the combustion mass loss rate, flame height, and axial temperature of the plume were measured, and the effect of the initial liquid level height of KI25X transformer oil and bedding size on combustion characteristics was considered. The results show that when the initial liquid level of KI25X transformer oil is higher than the bedding, the mass loss rate of KI25X group in the quasi-steady state combustion stage shows an overall trend of decreasing with increasing size, and that of kerosene group decreases with decreasing initial liquid level. The flame height in the quasi-steady state shows a trend of increasing first and then slightly decreasing with the increase in the size of the pebbles. This might be due to the combined effect of the capillary effect and heat insulation effect. The relationship between axial temperature rise and pebble size is reflected in the change of the axial temperature rise correction coefficient of plume K. With the increase in pebble size, K first decreases and then gradually increases.

Key words: transformer oil, pebble size, combustion, flame height, axial temperature of plume