Estimating the Overall Erosion Rate
Create a field function and report to estimate the overall erosion rate.
To obtain an estimate of the erosion rate in g/hr for the whole restrictor, it is necessary to create a field function that multiplies the computed erosion rate in each boundary face by the face area.
To estimate the overall erosion rate:
- Right-click the node and select .
- Rename the User Field Function 1 node to Overall Erosion Rate.
-
Edit the
Dimensions property and set
Mass to
1 and
Time to
-1 as shown.
- Click OK.
- Set the Function Name to OverallErosionRate.
-
Edit the
Definition property and enter the following definition in the dialog:
$ErosionRate * mag($$Area)
-
Click
OK.
The completed Properties window appears as shown below.
It is possible to report the overall erosion rate in units other than kg/s by creating a user-defined unit. This is demonstrated by creating a unit for g/hr. The conversion factor is:
1 g/hr = 2.777778 x 10-7 kg/s
-
Right-click the
node and select
from the pop-up menu.
- Rename the Units 1 node to g/hr.
- Select the g/hr node and set Description to g/hr.
- Edit the Dimensions property and set Mass to 1.
- Set Time to -1.
- Click OK.
-
Enter the
Conversion property as
2.777778E-7.
The completed Properties window is as shown below.
Create a report that uses the field function and unit:
- Right-click the Reports node and select .
- Rename the Sum 1 node to Overall Erosion Rate.
- Set the Scalar Field Function to Overall Erosion Rate.
- Click the right half of the Parts property, expand Regions and Fluid nodes and select Restrictor.
-
Set the
Units to
g/hr using the drop-down menu.
The completed Properties window appears as shown below.
-
Right-click the
Overall Erosion Rate report node and select
Run Report from the pop-up menu.
See the Output window for the report result. A typical value is 1.858468e-01 g/hr .
The predicted quantity is for a quarter annulus only. To get the full erosion rate for the real case, it is necessary to multiply by 4. This gives a predicted erosion rate of 0.75 g/hr for the whole component.