Laser-doppler anemometry in a baffled mixing tank

Experiments were conducted for extremely high turbulent mixing operation in a standard geometry, baffled mixing tank. Three components of the mean and root-mean-square velocities were measured by using a laser-Doppler anemometer. The impeller ratation rate, the impeller type, and the impeller location were considered. Water was mixed with polystyrene by a six-bladed Rushton turbine impeller and a four-bladed inclined paddle impeller at 100, 200, and 400 revolutions per minute rotation rates. The impellers were located at one-half or one-third of the liquid height in the tank. Due to the complexity of flow in a baffled mixing tank, there are still several fundamental modeling and computational difficulties in simulating the flow. Thus, these experimental data based on the sophisticated and extensive measurements may improve fundamental modeling methods. The results show that the flow patterns depend on the impeller type. The effect of the impeller location on the flow was small. The axial direction of the flow was caused by the baffles. The flow was three-dimensional, rotational periodic, and statistically random. This information successfully characterizes the flow in the baffled mixing tank.