Abstract
Research on thermal behaviors under the synergy of mechanical stirring and tubular heating can reveal the effect mechanism of mechanical stirring, and determine the optimal stirring parameters. In this paper, the physical and mathematical models of heat transfer in crude oil storage tank under the synergy of tubular heating and mechanical stirring are established, the sliding grid technique is used to model the stirring impeller, which are further numerical calculated by the FVM. Our outcomes demonstrate that through the enhancement of convection, mechanical stirring significantly changes the thermal behaviors and enhances the heat exchange. Precisely, for a 1,000 m3 crude oil storage tank, the stirring of 350 rpm can increase the average velocity by 329%, the heating rate by 89%, and rise the average crude oil temperature from 42.311 °C to 42.586 °C during 2 h of heating. However, the higher crude oil temperature will cause a 1,613 W increase in heat loss power. The heating efficiency has also increased by 10%. Furthermore, mechanical stirring can promote a more uniform temperature distribution. Thus, the volume ratio in the low-temperature region decreases by 10% and that in the high-temperature region increases by 26%. The temperature variance decreases from 4.517 °C2 to 0.275 °C2. However, the velocity and temperature fields are almost the same under different stirring rates. With increasing stirring rate from 100 rpm to 700 rpm, the average heating rate can only increase by 0.026 °C/h, and temperature variance decreases from 0.596 °C2 to 0.086 °C2. With increasing stirring rate, the efficiency of the heating tube does not change significantly. The optimal stirring rate is determined as 350 rpm based on the fitting curve of temperature variance stabilization time and the comprehensive effect.
Published Version
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