Agitation is a kind of commonly use

Agitation is a kind of commonly used industrial process engineering, widely used in petroleum, chemical industry, light industry, medicine and other industrial process [1], the effect of mixed is to promote fusion, dispersed reaction between several kinds of uneven material (such as liquid-liquid mixing, gas-liquid mixing, solid-liquid mixture, gas liquid solid three phase hybrid, etc.), components to form a uniform system, namely mixing is to weaken system needed by the inhomogeneity of processing, inhomogeneity can be concentration, one of the phase or temperature, and secondary effects such as mass transfer, reaction and product properties are often a target key [2] in practical engineering applications, The first to use this technology is the chemical industry, due to its excellent effect and the similarities between various industries, petroleum, sewage treatment and other industries have gradually learned from this technology, and has been effectively used. Among them, gas-liquid stirred tank is widely used in wastewater treatment, aerobic fermentation, gas-liquid reaction and other process industries. In fact, they provide good gas dispersion and can guarantee satisfactory mass and heat transfer characteristics, especially under turbulent conditions [3].Along with the industry's rapid development, stirred tank in the actual use of more and more widely, and the mixing equipment design work mostly rely on experience and semi-empirical correlations, this is due to the complexity in stirred tank in the process of mixing multiphase system, operating conditions, the complexity of the boundary conditions, and the turbulent fluid process, delivery process, the instability of local mixing process, makes the experimental flow measurement method can only get a small amount of information, it is difficult to through the experiment data within the mixing tank on detailed mathematical description of the characteristics of flow field, so as to make the theory instruction system comprehensive enough, cause waste of materials, increasing the cost of [4-5]. Due to the inherent complexity of multiphase systems, it is often difficult to design, optimize and scale up such reactors [6]. With the rapid development of computational fluid dynamics (CFD) technology, the velocity field in gas-liquid system has been studied by CFD simulation. Detailed information about the temperature and concentration fields can be obtained. It can predict the details and turbulence characteristics of the fluid flow under different working conditions in the numerical simulation of the multiphase reactor, which greatly makes up for the defects of the data obtained by the experimental method, and provides a basis for the design and optimization of the multiphase reactor. The most important advantage of CFD is that it consumes less resources and can simulate more complex processes. At present, the application in stirred tank simulation is more and more, and the simulation results are more practical, which greatly reduces the time cost and economic cost.