TFS · Hydraulic & Fluid Applications · Problem 8PDFSolution in PDF ↓
TFS · Hydraulic & Fluid Applications · Problem 8
Problem & Solution
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Topic: Pump system — Room temperature atmospheric air flows at 100 feet per second in a 400 foot long nominal 3-inch schedule 40 threaded steel pipe containing 12, 90 degree long radius elbows and 2 gate valves.
Approach: So we want to get P1 minus P2 by itself.
Key values: 0.075 pound force per cubic foot be done with it but if you don, 0.075 pound force per cubic foot absolutely no surprises there all right so what, 100 feet per second in a 400 foot long nominal 3
Reference: look up in the reference handbook
✅ Answer: A
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Student questions asked in live office hours about this problem
OH 51
Q: In a Bernoulli equation problem for air flowing in a pipe with fittings, what are the appropriate assumptions for room temperature, absolute roughness of steel, and whether to interpolate air properties?
A: Room temperature can be assumed as any reasonable value (68-75°F) unless specified; the absolute roughness of steel (0.002 ft) is the average from the Moody diagram range and is material-specific, not universal; and kinematic viscosity/density values don't need interpolation from air tables because the answer choices have large enough differences that estimates are sufficient to save time on the exam.