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Figure 11. Mesh Sensitivity Analysis
Figure 11 shows the pressure coefficient drop over one turn with different mesh densities. The pressure drop given by the fine mesh is the most accurate. This is because as the mesh get finer, the truncation error is reduced and provide more accurate result. However, as the mesh get finer, the computational times also increase. To determine is it worth extra time to obtain further accuracy, mesh sensitivity analysis is carried out. Pressure coefficient drop for three meshes is about the same. Hence it is concluded that coarse mesh is good enough to provide reasonable result.
Figure 12. Reynolds Number Effect on Pressure Coefficient Drop
It is important to take a look at the effect of Reynolds number on the results as water treatment plant built by AguaClara varies geographically. The flow rate into water treatment plant is different for different location. Reynolds number is changed by changing the inlet velocity boundary condition. The normal flow rate is of Reynolds number of 10,000. From figure 12, it is seen that the pressure coefficient drop changes only a little with big changes in Reynolds number. In other word, the pressure coefficient drop is not sensitive to the Reynolds number of the system. This is a good thing because the design of the
Figure 13. Clearance Height Effect on Pressure Coefficient Drop and Maximum Velocity
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