Verification Case 63
PRODUCT: AFT Fathom
TITLE: FthVerify63.fth
REFERENCE: Roland Jeppson, Analysis of Flow in Pipe Networks, 1976, Publisher Ann Arbor Science, Page 94
FLUID: Water
ASSUMPTIONS: Assume water at 70 deg. F.
RESULTS:
| Pipe Flow Rate (ft3/sec) | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
| Jeppson | 0.533 | 0.662 | 1.338 | 0.699 | 0.639 | -0.129 | 0.828 |
| AFT Fathom | 0.5352 | 0.6636 | 1.3417 | 0.7008 | 0.6409 | -0.1284 | 0.8291 |
| Pipe Head Loss (feet) | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
| Jeppson | 1.306 | 17.384 | 15.563 | 2.201 | 8.127 | 0.38 | 13.474 |
| AFT Fathom | 1.303 | 17.390 | 15.569 | 2.192 | 8.124 | -0.372 | *13.460 |
| Node EGL (feet) | 1 | 2 | 3 | 4 |
| Jeppson | 98.7 | 81.3 | 96.9 | 99.1 |
| AFT Fathom | 98.7 | 81.31 | 96.88 | 99.07 |
| Node pressure (psig) | 1 | 2 | 3 | 4 |
| Jeppson | 8.1 | 0.56 | 7.32 | 8.28 |
| AFT Fathom | 8.095 | 0.566 | 7.307 | 8.256 |
* AFT Fathom results combine two pipes, as discussed below
** Note that AFT Fathom represents head loss on pipes with reverse flow as a negative. Jeppson represents it as positive regardless of the direction.
DISCUSSION:
Jeppson's method of applying pump data is to lump it into a pipe, whereas AFT Fathom's method is to place pumps at boundaries between pipes. Pumps are therefore a specific node (or junction) in AFT Fathom. To accommodate Jeppson's method, the pipe which contains the pump is split into two equivalent pipes in AFT Fathom. Where the split is made will have no impact on the results.
Because there is one pump in the example, there is one additional pipe in the AFT Fathom model. AFT Fathom pipes 7 and 8 together represent Jeppson pipe 7.
Jeppson presents results in terms of HGL. However, Jeppson's method assumes EGL and HGL are essentially the same because of minimal velocity. Therefore, Jeppson results are presented in the results shown above as EGL.
Slight differences in property and calculation constants that were assumed, as well as potential differences from Jeppson's solution tolerances, which are not known, may also contribute to differences in the solution results. Examples are the specific value of water density and gravitational constant.
