The Role of Baffles Installed Inside Magnetic Stirred Reactors and Determination of Relevant Data

   Magnetic Stirred Reactor Sometimes, baffles are added to the vessel wall. The functions of these baffles are as follows: First, when the viscosity of the material is relatively low, the high-speed rotation of the agitator generates a tangential flow under the influence of centrifugal force, which causes the liquid to be flung toward the vessel walls and rise along the vessel’s periphery, while the liquid level in the center naturally drops, forming a large depression inside the magnetic stirrer reactor—this phenomenon is referred to as "whirlpool formation." Materials caught in the whirlpool rotate closely along with the搅拌 shaft and fail to achieve adequate mixing. If the mixture contains multiple phases, phase separation or layering may occur. Second, when the material has high viscosity, a large amount of air is drawn into the liquid surface, reducing the apparent density of the liquid and causing the搅拌 shaft to vibrate due to varying forces acting upon it. Therefore, "whirlpool formation" should generally be avoided as much as possible.

　　To eliminate the vortex formation described above, baffles—typically four in number—can be installed around the inner wall of the magnetic stirrer reactor. These baffles redirect the tangential flow of the material into either an axial or radial flow. After the baffles are installed, the impeller’s stirring action causes the spiral-shaped concave flow observed in the liquid’s longitudinal cross-section to be blocked by the baffles, thereby transforming it into a vertical up-and-down flow perpendicular to the liquid surface. As a result, the liquid is forced to adopt an axial flow pattern, and the concave regions naturally disappear. Of course, certain internal components of the magnetic stirrer reactor, such as coils and flow-guiding cylinders, can also play a role similar to that of baffles to some extent.

　　In industrial applications, the installation of baffles should be carried out under full-baffle conditions. Under a given rotational speed, if additional attachments are added yet the shaft power remains constant, this constitutes the full-baffle condition. Typically, four baffles installed radially at widths equal to one-twelfth or one-tenth of the equipment diameter can adequately meet the mixing requirements.