Excel-Worksheet Predicts Control Valve Hydrodynamic Noise
Reference 1 includes a simplified method for predicting hydrodynamic noise developed by H. D. Baumann, an internationally recognized control valve expert who has spent many years investigating control valve noise mechanisms and theory. Reliable valve noise test data is difficult to find unless you are a valve manufacturer and then you tend not to share it. I did find 18 noise tests that I believe to be reliable, and using this simplified noise prediction method, average errors from test data ranged from minus 2.5 to plus 3.7 dB(A). Control valve noise prediction methods normally claim accuracy of plus or minus 5 dB(A). IEC 60534-8-4:2015 gives two example calculations.
For Example 1, this simplified method calculates a predicted a sound pressure level that is 1.3 dB(A) lower and for Example 2, 1.7 dB(A) lower.
Reference 1 suggests that the method is simple enough to be implemented with a pocket calculator or one of the many calculator apps available for cell phones. A sample hand calculation is included in the article to demonstrate this claim. Several people have contacted me saying that it would be easier to have an Excel-worksheet for this proposed method. This should be easy to construct, but so far as I know, no one has actually done it, at least not to share with others. The balance of this article describes how to construct such an Excel sheet. Reference 1 lists the calculation steps and shows the formulas used in a conventional format. Screen 1 is an Excel-worksheet that implements the calculations described in Reference 1. To construct the worksheet, start by entering the text shown in black, all of which is simply plain text. Column D, Rows 7 through 9, 12 through 16 and 19 is where the user’s process and valve data are entered. The numbers shown in red are the sample process and valve data that were used in the sample calculation of Reference 1. To test the worksheet, if you enter these sample data you should get the calculation results shown in green on Screen 1.
How to Construct the Excel-Sheet
The formulas for all the calculations rely on the cells in Column D having the names to their left in Column C. To name them, highlight both Columns C and D, rows 7 through 33. Select the “Formulas” tab, select “Create from Selection” then check “Left column” and click “OK.” Now all the cells in Column D, Rows 7 through 33 will have the names in the cells to their left. This makes it possible for all the formulas to use the actual names of each variable, for example, the inlet pressure, P_1, appears in all the formulas that depend on it as “P_1” instead as simply “D7.” You can do this in one step. Excel will ignore any cells that have nothing in them. Finally, enter the formulas shown on Screen 2 (column D) in the appropriate cells. This requires great care for the Excel-sheet to work properly. If you have accurately entered the process and valve data, and the formulas, you will get the calculated results shown in green on Screen 1.
As an option you can add an additional column of noise calculations by entering the formulas shown on Screen 3 in Column E. The process and valve parameters for this column of calculations would be entered in Column E. If you choose to perform the above step, it will be extremely easy to extend the worksheet to include any number of calculations that you choose. For example, if you want to add another eight calculations to the worksheet, do the following:
Extend the Worksheet
- Select Column E, cells 21 through 33.
- Copy these cells (ctrl + C).
- Click on Cell F21 and drag the pointer to M21
- Paste (ctrl + P)
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