Verification Case 15
PRODUCT: AFT Arrow
MODEL FILE: AroVerify15.ARO
REFERENCE: William S. Janna, Introduction to Fluid Mechanics, PWS Publishers, Belmont, CA 1983, Pages 317-319, example 8.8
GAS: Air
ASSUMPTIONS: 1) Adiabatic flow, 2) Perfect gas
RESULTS:
| Parameter | Janna | AFT Arrow |
| M2– Mach number at exit | 0.14 | 0.14 |
| P2– Pressure at exit (psia) | 9.63 | 9.84 |
| T2– Temperature at exit (deg. R) | 528.8 | 528.9 |
DISCUSSION:
As specified, inlet conditions are known and outlet conditions need to be determined. With the known inlet conditions, an implied mass flow rate exists. To pose the problem in AFT Arrow terms, a few simple calculations are needed to obtain the mass flow rate. Once obtained, it is applied as a flow demand at the exit.
The problem states that the inlet velocity is 100 ft/s, P1 = 15 psia, T1 = 530 R. From the ideal gas law, density, and mass flow rate are:
With this flow rate at the exit, the predictions agree very closely.
