As significant process equipment for ensuring production, stirred tanks are mainly used for operation units such as mixing, dissolution, crystallization, extraction, mass transfer, and heat-transfer in various industries, including medicine, dye, food, metallurgy, wastewater treatment, and synthetic materials [
1,
2,
3]. The flow information of the fluid is the basis for investigating the energy, quality, and reaction process in the vessel, and it determines the output and energy consumption of products in industrial production. The stirring effect depends on the type of impeller, the physical properties of the medium, and the baffle structure.
In general, when dealing with low viscosity materials, the rotation speed increases and the flow is in a turbulent state. The centrifugal force and the inner wall of the stirred tank work in conjunction to enhance the circular motion of the medium and form a vortex on the free liquid surface, thereby weakening the mixing effect (
Figure 1). Through the baffle settings, most of the tangential flow caused by the rotation of the impeller is converted into more efficient axial and radial flow, which can minimize the formation of the central vortex and effectively disrupt the flow of circulating fluid [
4]. Researchers in the relevant field have conducted a number of experiments and numerical simulations [
5]. Ying F et al. [
6] used PIV experiments to compare and analyze the baffled and non-baffled stirred tank. The addition of baffles increased the convective circulation of the main body and created favorable conditions for the diffusion of a small-scale structure under the stirred tank. Atibeni R et al. [
7] compared the effects of different width baffles and up and down triangular baffles on the suspended particle stirred tank. Kamla Y et al. [
8] evaluated the power consumption in the Rushton turbine agitator at different baffle inclinations. After conducting a dynamic analysis of turbulent flow in a stirred tank, Ammar M et al. [
9] found that the power number strongly depended on the baffle length. Lin et al. [
1] investigated the effect of the baffle structure and groove size on dimethyl fumarate spherical agglomerates and found that with the increase of baffle width, the strain rate and turbulent dissipation rate increased, rendering an increase in the collision rate of aggregates. Vitor et al. [
10] compared vertical tube baffles with traditional jacket and helical coil heat-transfer methods; the former eliminated eddy currents and had higher heat exchange efficiency. Several scholars have described the effect of the special-shaped baffle design. Soliman et al. [
11] analyzed the heat and mass transfer behavior of a novel heterogeneous stirred tank reactor with serpentine baffles, which could effectively improve the selectivity and yield of the reactor during the exothermic liquid–solid diffusion-controlled catalytic reaction process. Shen et al. [
12] installed a “V”-shaped horizontal baffle at the height of the impeller, and such a structure could reduce energy consumption and improve the mixing effect during the mixing process of liquid–liquid two-phase flow. Bukhari et al. [
13] evaluated the coefficient of variation (COV) of a fractal baffled stirred tank, which improved the mixing efficiency compared with ordinary baffles. In a six-blade Rushton turbine stirred tank, Foukrach et al. [
14] quantified and characterized the effect of baffle shape on the flow field and power consumption and found that increasing the baffle curvature could reduce power consumption.
Scholars have conducted experimental and model studies on the hydrodynamic characteristics of stirred tanks, such as stirring speed and turbulence intensity. On the premise of not changing the shape and working conditions of the impeller, the baffle plate provides an effective method for strengthening the stirring. However, the standard baffle structure affects the stirring speed and mixing uniformity while also increasing the energy consumption. Despite the fact that several scholars having explored the sawtooth, there is a scarcity of reports on the influence mechanism of the sawtooth shape, the relative tooth height, and the relative tooth width on the stirring flow field. In the present study, numerical simulations and PIV experiments were performed to investigate the effects of sinusoidal sawtooth baffles on the fluid velocity field distribution, particle concentration distribution, and power consumption in a stirred tank equipped with a six-blade turboprop (PBTD).