Verification Case 2
PRODUCT: AFT Fathom
TITLE: FthVerify2.fth
REFERENCE: Piping Handbook, 7th Ed., 2000, McGraw-Hill, Mohinder L. Nayyar, P.E., Ed., Tadeusz J. Swierzawski, Author, Page B.375-381, Example B8.1
FLUID: Water
ASSUMPTIONS: N/A
RESULTS:
| Parameter | Swierzawski | AFT Fathom |
| Pressure drop (psid) | 61.48 | 61.33 |
DISCUSSION:
The exit loss factor of 1.0 is modeled as part of the exit Assigned Flow.
The overall pressure drop in AFT Fathom is obtained by subtracting the discharge pressure (438.67 psia) from the supply (500 psia). It is also displayed in the General Results list at the top of the Output window. Finally, the pressure difference is given in the Junction Deltas table at the top of the Output window. The junction delta was setup in the Output Control window.
On page B.380 the Piping Handbook calculates the Flow Resistance Coefficients as 9.77 as shown in the table on that page. However, if one adds up the individual K factors, 9.84 is obtained, not 9.77. To better match the overall resistance assumed for the handbook calculation, the tee K factor was therefore reduced from 0.33 to 0.26 so that a K factor of 9.77 is obtained.
The difference in the final answer (61.48 vs. 61.33) is mostly due to round-off errors in the handbook calculations. If more digits are saved in the handbook calculations, the answer will be much closer to 61.33.
