View Model Problem Statement
PRODUCT: AFT Fathom
TITLE: FthVerify62.fth
REFERENCE: Roland Jeppson, Analysis of Flow in Pipe Networks, 1976, Publisher Ann Arbor Science, Page 137-139
FLUID: Water
ASSUMPTIONS: Assume water at 70 deg. F.
RESULTS:
| Pipe Flow Rate (ft3/sec) |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
| Jeppson |
19.8 |
10.37 |
4.89 |
4 |
2.66 |
4.13 |
4.44 |
4.6 |
| AFT Fathom |
19.798 |
10.375 |
4.891 |
4.003 |
2.656 |
4.131 |
4.439 |
4.601 |
| Pipe Flow Rate (ft3/sec) |
9 |
10 |
11 |
12 |
13 |
14 |
15 |
16 |
| Jeppson |
13.67 |
2.4 |
4.07 |
6.07 |
1.64 |
1.11 |
5.47 |
1.6 |
| AFT Fathom |
13.667 |
2.402 |
4.066 |
6.066 |
1.638 |
1.108 |
5.468 |
1.598 |
| Pipe Flow Rate (ft3/sec) |
17 |
18 |
19 |
20 |
21 |
22 |
23 |
24 |
| Jeppson |
0.4 |
1.33 |
2.83 |
4.83 |
4.07 |
2.59 |
1.41 |
3.07 |
| AFT Fathom |
0.402 |
1.336 |
2.836 |
4.836 |
4.068 |
2.591 |
1.409 |
3.066 |
| Pipe Flow Rate (ft3/sec) |
25 |
26 |
27 |
28 |
29 |
30 |
31 |
32 |
| Jeppson |
3.11 |
3.07 |
2.57 |
6.98 |
2.48 |
8.02 |
10.26 |
12.26 |
| AFT Fathom |
3.112 |
3.067 |
2.573 |
6.975 |
2.483 |
8.019 |
10.262 |
12.262 |
| Pipe Flow Rate (ft3/sec) |
33 |
34 |
35 |
36 |
37 |
38 |
39 |
40 |
| Jeppson |
2.94 |
1.06 |
17.21 |
0.63 |
8.06 |
11.69 |
4.5 |
12.03 |
| AFT Fathom |
2.944 |
1.056 |
17.206 |
0.635 |
8.064 |
11.699 |
4.494 |
12.033 |
| Pipe Flow Rate (ft3/sec) |
41 |
42 |
43 |
44 |
45 |
46 |
47 |
48 |
| Jeppson |
12.55 |
8.16 |
29.73 |
26.58 |
19.58 |
2.48 |
4.96 |
9.74 |
| AFT Fathom |
12.548 |
8.160 |
29.731 |
26.581 |
19.571 |
2.480 |
4.964 |
9.745 |
| Pipe Head Loss (feet) |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
| Jeppson |
10.59 |
2.97 |
0.69 |
24.57 |
0.22 |
17.43 |
10.04 |
16.17 |
| AFT Fathom |
10.562 |
2.961 |
0.686 |
24.513 |
0.214 |
17.385 |
10.019 |
16.129 |
| Pipe Head Loss (feet) |
9 |
10 |
11 |
12 |
13 |
14 |
15 |
16 |
| Jeppson |
11.3 |
3.01 |
16.9 |
2.29 |
2.86 |
1.01 |
0.86 |
4.1 |
| AFT Fathom |
11.275 |
2.997 |
16.852 |
2.274 |
2.845 |
1.003 |
0.851 |
4.066 |
| Pipe Head Loss (feet) |
17 |
18 |
19 |
20 |
21 |
22 |
23 |
24 |
| Jeppson |
0.1 |
1.45 |
0.52 |
1.02 |
12.69 |
10.46 |
1.07 |
7.29 |
| AFT Fathom |
0.098 |
1.438 |
0.518 |
1.007 |
12.650 |
10.428 |
1.062 |
7.251 |
| Pipe Head Loss (feet) |
25 |
26 |
27 |
28 |
29 |
30 |
31 |
32 |
| Jeppson |
15 |
7.28 |
5.16 |
61.39 |
0.81 |
7.89 |
1.46 |
5.16 |
| AFT Fathom |
14.939 |
7.259 |
5.143 |
61.221 |
0.802 |
7.869 |
1.449 |
5.137 |
| Pipe Head Loss (feet) |
33 |
34 |
35 |
36 |
37 |
38 |
39 |
40 |
| Jeppson |
6.73 |
0.92 |
8.03 |
0.05 |
5.99 |
2.82 |
1.53 |
13.17 |
| AFT Fathom |
6.698 |
0.914 |
8.007 |
0.046 |
5.967 |
2.811 |
1.519 |
13.145 |
| Pipe Head Loss (feet) |
41 |
42 |
43 |
44 |
45 |
46 |
47 |
48 |
| Jeppson |
9.54 |
4.9 |
17.75 |
9.48 |
7.77 |
6.41 |
25.04 |
2.63 |
| AFT Fathom |
9.521 |
4.886 |
17.720 |
9.461 |
7.743 |
6.383 |
24.986 |
2.619 |
DISCUSSION:
The problem statement does not include any reservoirs or pressure junctions, and hence no EGL or pressure results can be obtained. Since AFT Fathom always displays EGL and pressure results, there must be a pressure. Thus junction 1 was chosen as a pressure junction and assigned a surface elevation of 200 feet. The particular value chosen does not affect the results.
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.
Results differ slightly between AFT Fathom and Jeppson. The head loss formula used by Jeppson differs from AFT Fathom. Jeppson's formula is more common to the water industry, and assumes the head loss is proportional to flow rate to some power near but less than 2. AFT Fathom assumes it always proportional to flow rate to the power of 2. These differences affect the results to some degree.
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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