Verification Case 27
PRODUCT: AFT Fathom
TITLE: FthVerify27.fth
REFERENCE: Michael R. Lindeburg, P.E., Mechanical Engineering Review Manual, 7th Ed., Professional Publications, Page 5-6, Example 5.6
FLUID: Air
ASSUMPTIONS: Air is at 70 deg. F, inlet pressure is 5 inches of water, gauge, wall roughness is 0.00538 inches
RESULTS:
Parameter | Lindenburg | AFT Fathom |
Velocity (feet/min) | 2200 | 2170 |
Pressure loss(in. water per 100 feet) | 0.5 | 0.4867 |
DISCUSSION:
The reference solves the problem using a chart. No roughness data for the duct is given. Using the chart on page 5-7 of the reference, a representative roughness was determined as follows: for a 12 inch duct at 3000 feet/min, the pressure drop is 1 inch of water per 100 feet. This information was entered into the AFT Pipe Sizing Utility (PSU, part of the Engineering Utility Suite) to obtain an effective duct roughness. A value of 0.00538 inches was obtained, and this was used in AFT Fathom. Results from PSU are given below.
Slight differences in predictions above result from the reference's round-off errors and reading the solution from a chart.
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PSU Results
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Friction Factor = 0.01788
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Epsilon = 0.00538 inches
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Hazen-Williams Factor = 110.390
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Input Parameters
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Delta Pressure = 1.000 in. H2O std.
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Velocity = 3000 feet/min
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Vol. Flow Rate = 39.270 ft3/sec
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Mass Flow Rate = 2.941 lbm/sec
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Reynolds Number = 306548
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Geometry: Cylindrical Pipe
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Diameter = 12 inches
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Area = 0.78540 ft2
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Wetted Perimeter = 37.699 inches
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Length = 100 feet
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Fluid = Air @ 1 atm (vapor)
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Temperature = 70 deg. F
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Density = 0.0749 lbm/ft3
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Dynamic Viscosity = 0.04398 lbm/hr-ft
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