Verification Case 63

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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.

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