Numerical Simulation Study On The Transmission Of High-viscosity Oil Of Tank Export

In the process of storage, high viscous crude oil gradually dissipate heat to external environment, the oil temperature decreased, the viscosity increased, and liquidity became poor. This result that the conveying of oil became difficult when needed to sending again. To reduce the viscosity of crude oil, an electric heating appliance was set at the bottom of oil tank to heat crude oil. And a screw conveyer was installed in the outlet of oil tank, the mechanical force of that promoted the flow of crude oil, and further improve the conveying efficiency of crude oil. Based on FLUENT software platform, the temperature field distribution of crude oil inside the tank and the flow behavior of crude oil were simulated. The differences of velocity field and temperature field distribution of crude oil were analysed comparatively when the position of heater and the parameters of screw conveyor were different. In order to further reduce energy consumption and save the production cost, the method that combining solar and electricity was adopted to heat the crude oil. Therefore, a set of solar collector which was suitable for oil tank was designed, and the thermal properties of the solar collector were researched through experiments.The simulation results show that in heating process, firstly the crude oil around the heater heats up, whose density lowers, the difference of density cause the natural convection. Overall, the oil near the heater flows upward, then flows down when reaching the top of oil tank, eventually form a large circle, continuously transfer heat to the tank. Ultimately the crude oil in the tank is in a relatively uniform temperature range. The distribution of temperature field and velocity field of crude oil varies with the location of the heater. When the center of the heater is0.1m away from the bottom and0.3m away from the wall, the heating effect is best. When the screw shaft rotates, the helicoid produces axial thrust force and a force along the helicoid to crude oil, the fluid near the spiral blades rotates with the blades, and the speed is relatively large. Meanwhile, the fluid between the two blades forward flow at a small speed. The comparative analysis of the distribution of fluid velocity field when the screw pitch and rotate speed of spirochete is different shows that the best screw pitch of big spirochete is150mm, the best screw pitch of small spirochete is60mm, and optimal rotate speed of screw shaft is240r/min.Experimental results show that the temperature of the ceramic plate, the heat pipe and the glass cover-plate increases(decreases) along with the increase(reduces) of the solar radiation, at the same time the temperature of each part changes with the real-time weather. The temperature distribution of ceramic plate is uneven, the temperature on both sides of the ceramic plate is slightly lower than that of the middle. The higher the temperature of the glass cover-plate is, the more the heat loss of heat collector is, the lower the thermal efficiency is. The temperature of water within the heat exchange tube increases along with the increase of solar radiation, the temperature no longer change after reaching the highest. The temperature of water within the heat exchange tube rise up by20.7℃, which is smaller than that of the current heat collector, so the heat collector has much room for improvement.