Serpentine mixer mixing

To illustrate what is possible in 3D, consider the serpentine mixer that was modeled in Chapter 10. The idea is that at the inlet there are two streams entering, and one of them contains a different chemical. The objective is to mix the chemicals in as short a distance as possible. Because mixing by diffusion is slow, chimneys and turns are inserted to enhance the mixing and make it occur in a shorter distance. This was solved by Zachery Tyree when he was a senior chemical engineering student at the University of Washington (Neils et al., 2004). 

Figure 7.6 Serpentine mixer used for the generation of eluent gradients with LC EOF pumps. (A) Inlet of serpentine mixer displaying two distinct fluid flows (B) non-uniform fluorescent intensity profile along the channel cross-section (C) outlet of serpentine mixer displaying the fully mixed flows (D) equalized fluorescent intensity profile along the channel cross-section.

A serpentine mixer (Fig. 8.18) can be used to mix two chemicals in a shorter length than happens in a straight channel. Figure 8.19 shows a typical solution for a Reynolds number of 1.0 and Peclet number of 1000. Comparing these data with those for a T-sensor (Fig. 8.17) shows that the total length/width necessary has been reduced from 250 to 19.6 when the variance is 2.6 X 10". ... 

Another aspect of the serpentine mixer is to define how much mixing occurs for a given pressure drop. The flow solution gives the pressure drop and the variance gives the mixing. Table 8.4 shows results at different velocities for the serpentine mixer. 

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