Effect of mechanical stirring on the tubular heating process of crude oil

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 pa-per, 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 be-haviors and enhances the heat exchange. Precisely, for a 1,0 0 0 m 3 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 degrees C to 42.586 degrees C during 2 h of heating. However, the higher crude oil tem-perature 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 degrees C 2 to 0.275 degrees C 2 . 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 degrees C/h, and temperature variance decreases from 0.596 degrees C 2 to 0.086 degrees C 2 . With increasing stirring rate, the efficiency of the heat-ing 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.(c) 2023 Elsevier Ltd. All rights reserved.