Stirring can be an independent unit of fluid mechanics, such as liquid-liquid mixing, solid-liquid suspension, gas-liquid or thermal, liquid-liquid dispersion, etc., and often other unit operations such as heat transfer, Absorption, extraction, crystallization, etc. and the necessary means of chemical reaction processes.
The agitation process brings the various parts of the agitated liquid close to a homogeneous state. The agitation process can make the parts of the agitated liquid close to a homogeneous state, can increase the effective contact area of the dispersed phase, can reduce the liquid film resistance around the dispersed phase, and increase the relative speed to increase the heat transfer rate. The influencing factors of the agitation process are complicated and numerous, but the characteristics of the agitation process are nothing more than the use of a stirrer or other means to make the fluid flow state inside the device, and achieve various operational purposes in the flow state. Therefore, to understand the mixing process, it is necessary to know the causal relationship between the fluid flow state in the equipment and various mixing purposes. Metallurgy should consider the flow state of the fluid and heat transfer, and what is the relationship between mass transfer, particle refinement and dispersion.
Based on this point of view, it is convenient to classify the agitation process by the phase of the agitation medium. This allows the mixing process to be divided into two major categories, homogeneous and heterogeneous. The former is agitation of the mutual solution, and the latter includes agitation of the non-intermediate solution, agitation of the gas-liquid phase, and agitation of the solid-liquid phase. When the viscosity of the stirring medium is relatively high, its flow state is special, so it is generally classified as a stirring of a high viscosity liquid.