Verification Case 59
PRODUCT: AFT Fathom
TITLE: FthVerify59.fth
REFERENCE: Roland Jeppson, Analysis of Flow in Pipe Networks, 1976, Publisher Ann Arbor Science, Page 84-85
FLUID: Water
ASSUMPTIONS: Assume water at 70 deg. F.
RESULTS:
| Pipe Flow Rate (ft3/sec) | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
| Jeppson | 0.841 | 0.666 | 1.334 | 0.573 | 0.761 | 0.175 | 0.398 |
| AFT Fathom | 0.8411 | 0.6664 | 1.3336 | 0.5726 | 0.761 | 0.1748 | 0.3979 |
| Pipe Head Loss (feet) | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
| Jeppson | 3.15 | 17.63 | 15.46 | 1.5 | 11.42 | 0.674 | 3.24 |
| AFT Fathom | *3.125 | 17.535 | 15.387 | 1.484 | *11.373 | 0.664 | *3.210 |
| Node EGL (feet) | 1 | 2 | 3 | 4 |
| Jeppson | 114.2 | 96.6 | 112 | 113.5 |
| AFT Fathom | 114.23 | 96.7 | 112.08 | 113.57 |
| Pump Head (feet) | 1 | 2 | 3 |
| Jeppson | 17.36 | 18.46 | 21.78 |
| AFT Fathom | 17.36 | 18.46 | 21.78 |
* AFT Fathom results combine two pipes, as discussed below
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 are three pumps in the example, there are three additional pipes in the AFT Fathom model. AFT Fathom pipes 1 and 8 together represent Jeppson pipe 1. Similarly, AFT Fathom pipes 5 and 9 represent Jeppson pipe 5, and AFT Fathom pipes 7 and 10 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.
The printed Jeppson results also give pressures at junctions/nodes 1-4. However, pressures can only be determined if elevation data is given for these locations, of which there is no information in the problem statement. Therefore no comparison is made to pressure.
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.
Note this model uses fluid properties from the AFT Standard fluid library. The AFT Standard fluid library was updated in AFT Fathom 12, thus the AFT Fathom results will be slightly different for this verification case when compared to previous versions of AFT Fathom.
