# Numerical and Experimental Investigations of a Micromixer with Chicane Mixing Geometry
## 3 Results and Discussion
### Verification  
In this section, the experimental results were compared with simulation results. The simulation figures were obtained using a volume rendering tool in CFD-Post software. All points with mass fraction were divided into 10 semi-transparent slices according to the experimental pictures. Figure 11 shows the comparison between experimental results (left side) and simulation results (right side).  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Volume** & **Reynolds** & **Intensity of** & **Pressure** & **Mixing** & **Input Power** & **Mixing** \\
**Flow Rate** & **Number** & **Mixing** & **Drop** & **Cost** & **Coefficient** & **Energy Cost** \\ \hline
**mL/min** & **-** & **-** & **Pa** & **1/Pa** & **-** & **-** \\ \hline
0.05 & 1.3 & 0.33 & 1.07 & 30.37 & 74,590.93 & 2295.11 \\
0.1 & 2.6 & 0.24 & 2.15 & 11.04 & 13,598.50 & 573.78 \\
0.5 & 13.0 & 0.15 & 11.34 & 1.35 & 351.15 & 22.95 \\
0.7 & 18.2 & 0.15 & 16.41 & 0.91 & 174.47 & 11.71 \\
1 & 25.9 & 0.15 & 24.75 & 0.62 & 88.36 & 5.74 \\
1.5 & 38.9 & 0.19 & 40.80 & 0.46 & 47.43 & 2.55 \\
2 & 51.9 & 0.25 & 59.10 & 0.42 & 36.00 & 1.43 \\
3 & 77.8 & 0.40 & 102.10 & 0.39 & 25.37 & 0.64 \\
4 & 103.7 & 0.48 & 155.00 & 0.31 & 17.11 & 0.36 \\
5 & 129.7 & 0.52 & 219.70 & 0.24 & 12.00 & 0.23 \\
6 & 155.6 & 0.43 & 336.97 & 0.13 & 6.89 & 0.16 \\
7 & 181.5 & 0.61 & 404.00 & 0.15 & 7.14 & 0.12 \\
8 & 207.5 & 0.72 & 515.00 & 0.14 & 6.47 & 0.09 \\
10 & 259.3 & 0.80 & 789.00 & 0.10 & 4.61 & 0.06 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Mixing cost and mixing energy cost for the chicanes micromixer at different volume flow rates.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & **Reynolds** & **Pressure** & **Intensity of** & **Mixing** & **Cost** \\
**Micromixer** & **Number** & **Drop** & **Mixing** & **Cost** & **Coefficient** \\ \cline{2-5}  & **-** & **Pa** & **-** & **1/Pa** & \\ \hline Longitudinal vortex generators & 64 & 10,000 & 1.00 & 0.01 & [39] \\ Opposite T-junction & 50 & 93 & 0.11 & 0.12 & [40] \\
45 Y-junction & 50 & 94 & 0.13 & 0.14 & [40] \\
135 Y-junction & 50 & 95 & 0.14 & 0.14 & [40] \\ cross T-junction & 50 & 99 & 0.16 & 0.17 & [40] \\ Serpentine micromixer with simple T-joint inputs & 45 & 10,000 & 0.35 & 0.20 & [41] \\ Serpentine micromixer with tangentially aligned inputs & 45 & 12,000 & 0.44 & 0.26 & [41] \\
3D serpentine crisscross SAR micromixer & 50 & 40,000 & 1.00 & 0.003 & [42] \\
3D serpentine SAR micromixer & 50 & 40,000 & 0.90 & 0.002 & [43] \\ Chicanes micromixer & 52 & 59 & 0.25 & 0.42 & Present study \\ \hline \hline \end{tabular}
\end{table}
Table 2: Comparison of mixing cost of the chicanes micromixer with other micromixers without chicanes geometry.  
In general, in the case of stratified flow (Re = 13) there are no vortices and the interface between species is distinct. The small area of color gradient can be explained using a small \"bend\" of the flow due to the curvature of the flow direction after its entrance into the meander element. This vortex structure is growing together with increasing Reynolds numbers. In the case of Re = 78 and Re = 260, the vortex structure becomes qualitatively different due to the formation of the recirculation area directly after the extension.  
It is conspicuous, that the interface between species of both the experimental and simulation results matches in all cases. Thus, it can be assumed that the simulation results generally agree with the experimental ones. The deviation between the simulation and the experimental results can be explained due to the inaccuracy of the micromixer production, i.e., differences between the real geometrical model of the micromixer and ideal geometrical model.