Verification Case 4
PRODUCT: AFT Arrow
MODEL FILE: AroVerify4.ARO
REFERENCE: Crane Co., Flow of Fluids Through Valves, Fittings, and Pipe, Technical Paper No. 410, Crane Co., Joliet, IL, 1988, Page 4-9, example 4-16
GAS: Air
ASSUMPTIONS: Example does not specify the heat transfer conditions, so it was assumed isothermal in this model.
RESULTS:
| Parameter | Crane | AFT Arrow |
| Static pressure drop (psi) | 2.61 | 2.68 |
| Volumetric flow rate at inlet (ft3/min) | 20.2 | 20.2 |
| Volumetric flow rate at outlet (ft3/min) | 20.9 | 20.9 |
| Velocity inlet (ft/min) | 3367 | 3368 |
| Velocity outlet (ft/min) | 3483 | 3485 |
Note: The AFT Standard library fluid for air was updated in Arrow 10, which may cause some results to differ from those obtained in previous versions.
DISCUSSION:
Crane does not make a distinction between static and stagnation pressure, and it appears that static pressure is usually assumed. Therefore, the inlet pressure of 65 psig was assumed to be static pressure.
Note that the Crane formula underpredicts the pressure drop (by about 3%), which in most applications is not conservative.
