This example project involved analysis of mixing of two streams of the same fluid in a pipe (Figure 1). CFD was employed to examine the mixing characteristics of the two streams. A red dye was injected in the side stream and tracked to assess the extent of mixing. The results in Figure 2 indicate that when injected into the main pipe, the side stream resides in the lower half of the main stream and does not mix well. CFD methods can be employed to perform a "what-if" study. A dual-bladed mixing element (Figure 3) was added to break and mix the side stream. The mixing element spreads the side stream fluid more uniformly in the main stream. As a result, the injected stream does not reside in the lower half of the main stream. Mixing is improved by the introduction of the mixing element as depicted by the dye concentration in Figure 4. CFD methods can be employed successfully to analyze and optimize mixing of streams in various configurations.
Figure 1 - Original Design
Figure 2 - Mixing Obtained with Original Design
Figure 3 - Design Modified by Addition of Mixing Element
Figure 4 - Mixing Obtained with Modified Design