Combustion Characteristics And Image Parameters Of Small-scale Oil Tank

With the rapid development of national economy, demand for oil increases day by day, all countries are speeding up the national strategic petroleum reserve. In different regions of China, oil reserves are also rising. So how to ensure the safety of oil storage tank is an urgent problem which cries for solution. Oil has the property of flammable and explosive. Once fire break out in tank, it will be difficult to put out. The fire not only cause great economic losses, but also poses serious threat to personnel security and environmental pollution. Normally the oil tank areas are built in the outdoor, so the wind will have impact on the fire, such as the fire tilts, the radiation and thermal steam flow between adjacent tanks changes. The entrainment between the flame and surrounding environment strengthens; the spread of fire accelerates. Research on tank fire is concentrated in quiescent ambient air mainly, so it is urgent to studying the combustion characteristics of tank fire under wind, and the result will provide theoretical basis for actual fire prevention and control.According to accident investigation, in the tank fire, the top of the tank ruptures, which is completely opened accounts for40%in all tank fire cases, and there is part of the top rupture and so on. In this paper, we carries out research on combustion characteristics of different opening oil tank fire under wind.We use small tanks to simulating different conditions of actual tank fire. And studying combustion characteristics and image parameters of oil tank fire. The experiment sets various conditions:two liquid levels, different opening factors and different wind speeds. Through the results, we can study how different elements effect on the combustion parameters such as the burning rate, radiation fraction, flame temperature, and image parameters (length, angle and flame height).In the experimental design, a tank with10cm high and15cm diameter was used in the experiment. In order to simulate the rupture at the top of tank, this paper designed five openings, such as full open,3/4opening factor,1/2opening factor,1/4opening factor and1/8factor(opening factor refers to the ratio of the open area to full open area). And in order to simulating tank fire under different storage conditions, experiment designed two levels:6cm and8cm.In order to simulating tank fire under different wind velocities, experiment designed five velocities:0m/s,0.5m/s,1.0m/s,1.5m/s,2.0m/s,2.5m/s. It was carried out in the wind tunnel of State Key Laboratory of Fire Science. The burning rate of fuel was collected by electronic balance; the flame temperature was measured by shield thermocouples and the heat radiation in upwind and downwind were measured by the radiation flux, flame image data was acquired by DV camera.Opening sizes affect the development process of tank fire, in order to investigating how the opening factor affects the combustion characteristics of tank fire, we set a dimensionless parameter. With analyzing the experimental data and establishing the relationship between the opening factor and burning rate, fitting the relationship between the opening factor and flame length, then we can get the influence of opening factor on combustion characteristics and image parameters. Analyzing the combustion characteristics and image parameters under two liquid levels, then we can get the relationship between the liquid level and combustion parameters. Under the wind, flame starts to tip over, heat exchange between the flame and the surface or surrounding environment changes. Dealing the experimental data, fitting the relationship between wind speed and flame angle, dimensionless flame height and combustion characteristics, then we can get the influencing rule of wind speed on image parameters.