Analysis of Multi-Field Synergy and Frictional Entropy Generation in Stirred Kettles
Chemical mixing kettles are one of the essential equipment widely used in the chemical industry for mixing,stirring,heating,and cooling various liquid and powdery materials to meet the demands of the production process.The current study conducted a three-dimensional numerical simulation of the flow field inside the stirred kettle using computational fluid dynamics methods to analyze the flow characteristics due to the rotation of the stirring paddle.The synergistic relationship between the pressure and velocity fields inside the chemical stir-ring kettle was explored through the angle between the pressure and velocity fields,and the irreversibility of the flow inside the stirring kettle was revealed through the frictional entropy generation.The results show that the ve-locity and pressure fields have the maximum average synergistic angles when the stirring paddle speed is 60 r/min.The average synergistic angle decreases with the increase of the stirring paddle speed,the smaller the syner-gistic angle is,the larger the viscous dissipation of the fluid is,and the larger the flow resistance is generated.The frictional entropy generation of the flow field is mainly concentrated in the vicinity of the stirring paddle,and the average entropy generation rate shows an exponential increase with the increase of the rotational speed of the stir-ring paddle.The cyclonic flow generated by the rotation of the stirring paddle is gradually increased and attenua-ted along the axial direction of the two sides of the paddle,and the increase in the rotational speed of the stirring paddle also implies the increase of the cyclonic flow intensity.