In this paper, the combustion characteristics of small-scale oil pool fire under multi gradient static low pressure are studied by means of field experiment and numerical simulation.The characteristic parameters such as flame height and flame axis temperature of oil pool fire under different fire source diameter and pressure are analyzed. The results show that the flame shape shows the characteristics of decreasing tip width, increasing carbon black particles and weakening flame oscillation frequency with the decrease of ambient air pressure. Under the same air pressure, the average height of flame is positively correlated with the diameter of oil pool; Under the same oil pool diameter, the average flame height has a negative correlation with the pressure. The quantitative function relationship between dimensionless flame height and combustion rate, fire source diameter and ambient air pressure was obtained. The flame axis temperature can be divided into fast rising stage and stable stage.When the oil pool diameter is the same, the peak value of flame axis temperature increases first and then decreases.

pool fire, low pressure, flame height, flame temperature, FDS