After the calculation starts, the Solver Monitor dialog provides you with the current status of the solution. You can also monitor the goal changes and view preliminary results at selected planes. In the bottom pane of the Info window Flow Simulation notifies you if inappropriate results may occur. In our case, the message “A vortex crosses the pressure opening” appears to
inform you thatthere is a vortex crossing the opening surface at which you specified the pressure boundary condition. In this case the vortex is broken into incoming and outgoing flow components. When flow both enters and exits an opening, the accuracy of the results is diminished.Moreover, there is no guarantee that convergence (i.e., the steady state goal) will be attained at all. Anyway, in case a vortex crosses a pressure opening the obtained results become suspect. If this warning persists we should stop the calculation and lengthen the ball valve outlet pipe to provide more space for development of the vortex. It is also expedient to attach the ball valve inlet pipe to avoid the flow disturbance caused by the valve’s obstacle to affect the inlet boundary condition parameters.
Since the warning persists, click File > Close to terminate the calculation and exit the Solver Monitor.
You can easily extend the ball valve inlet and outlet sections by changing offset distance for the Inlet Plane and Outlet Plane features. Instead, we will simply clone the project to the pre-defined 40 degrees - long valve configuration.
Cloning the Project
1 Click Flow Simulation > Project > Clone Project. 2 In the Project Name, type Project 2.
3 In the Configuration to Add the Project list, select Select.
4 In the Configuration list, select 40 degrees - long valve. 5 Click OK.
6 Flow Simulation has detected that the model was modified. Confirm the both warning messages with Yes.
The new Flow Simulation project, attached to the 40 degrees - long valve configuration, has the same settings as the old one attached to the 40 degrees - short valve so you can start the calculation immediately.
In the Flow Simulation Analysis tree, right-click the root Project 2 item and select Run. Then click Run to start the calculation.
When the calculation is finished, close the Solver Monitor dialog box.
Let us now see the vortex notified by Flow Simulation during the calculation, as well as the total pressure loss.
Viewing Cut Plots
1 Right-click the Cut Plots icon and select Insert. The Cut Plot dialog box appears.
The Cut Plot displays results of a selected parameter in a
selected view section. To define the view section, you can use SolidWorks planes or model planar faces (with the additional shift if necessary). The parameter values can be represented as a contour plot, as isolines, as vectors, or in a combination (e.g. contours with overlaid vectors).
2 In the flyout FeatureManager design tree, expand the Valve item and select Plane2. Its name appears in the Section Plane or Planar Face list.
3 In the Cut Plot dialog box under Display, in addition to displaying Contours , select Vectors . 4 Under Contours, select the Velocity
(X) as the displayed parameter. 5 Under Vectors, set the Vector
Spacing to 0.012 m and the Arrow size to 0.02 m.
6 Click OK .
The new Cut Plot 1 item appears in the Flow Simulation Analysis tree.
However, the cut plot cannot be seen through the non-transparent model. In order to see the plot, you can hide the model by clicking Flow Simulation > Results > Display > Geometry. Alternatively, you can use the standard SolidWorks Section View option.
1 Click View > Display > Section View. Under Section 1 specify Plane2 as a Reference Section Plane/Face and click OK .
2 In the Flow Simulation Analysis tree, right-click the Computational Domain icon and select Hide.
Now you can see a contour plot of the velocity and the velocity vectors projected on the plot.
For better visualization of the vortex you can scale small vectors: 1 In the Flow Simulation Analysis tree, right-click the
Cut Plot 1 icon and select Edit Definition.
2 Under Vectors click the Adjust Minimum and Maximum and change the Minimum value to
2 m/s.
By specifying the custom Minimum we change the vector length range so that the vectors in areas where velocity is less than the specified Minimum value will appear as if it is equal to Minimum. This allows us to visualize the low velocity area in more detail.
3 Click OK to save the changes and exit the Cut Plot dialog box. Immediately the cut plot is updated.
You can easily visualize the vortex by displaying the flow relative to the X axis. For that, you can display the x-component of velocity in a two-color palette and set the value, separating two colors, at zero.
1 In the graphics area, double-click the palette bar or right-click on it and select Edit. 2 Under Settings using the slider set Number of
Levels to 3.
3 In the Maximum box type 1. 4 In the Minimum box type -1. 5 Click OK .
Now the distribution of the Velocity (X) parameter is displayed in red-blue palette so that all the positive values are in red and all the negative values are in blue. This means that the blue area show the region of reverse flow, i.e. half of the vortex.