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Simulation

This section explains the settings to run the crescent pump simulation.

Create Monitoring Points

In a crescent pump simulation, inherent flow ripples are caused by the pumping mechanism, which are of interest in the analysis. Hence, monitoring points are created after the pumping chamber. The steps to create the monitoring points are as follows:

1. On the Geometric Entities Panel toolbar, click four times Create a Monitoring Point , to create Points Point 01, Point 02, Point 03 and Point 04.
2. Rename the Points and specify their Position values as shown in Table 6.13 in the Geometry Tab of Properties Panel refer, Figure 6.343

Points	Rename as	Position values
Point 01	outlet_top	-0.03, -0.0185, -0.025
Point 02	outlet_bottom	-0.03, -0.0185, -0.04
Point 03	inlet_top	0.0245, -0.028, -0.025
Point 04	inlet_bottom	0.0245, -0.028, -0.04

Table 6.13 - Rename monitoring points

Note: Monitoring points need to be created before running the simulation for recording data refer, . The position of a Points may also be dragged to a new location using the Select in Toolbar and the Left Mouse Button.

 

Figure 6.343 - Create monitoring point

Figure 6.344 - Monitoring points

 

Transient simulation

1. Click Simulation Panel.
2. Define Number of Iterations and Result Saving Frequency to 50 and 510. The Number of Revolutions, Simulation Time (Duration) and the Number of Time Steps are automatically preset by the Crescent module (see, Figure 6.345) .
3. After you save the project, click Start to run the simulation.
4. The result files are saved as .sres in the working folder (Example : "crescent_510.sres"). The number of result files depends on the Result Saving Frequency.

´	Note:  The Result Saving Frequency option in the Simulation Panel is set to a small value (say 5 or 10) before running the simulation to obtain better animations.

 

The residuals are displayed under the Residual Tab in the Plot Panel refer, Figure 6.346

Figure 6.345 - Simulation settings

Figure 6.346 - Residuals-Crescent

 

Note: The default Converge Criterion is 0.03 for the Crescent pump simulations. The residuals are lower compared to a Converge Criterion is 0.1 for other transient simulations to achieve better mass balance. When the residuals for all the variables drop by 1.5 orders or the maximum Number of Iterations is reached, the calculation proceeds to the next time-step.