Question

7-9. Products of combustion enter the afterburner (station 6) at a rate of 230 lbm/sec with the following properties: T%-1830°R, P638 psia, M6-0.4, y 1.33, cp 0.276 Btu/(lbm.°R), and R 53.34 ft Ibf/(lbm "R). Assume a calorically perfect gas and B 0.95. a. Determine the flow area at station 6 in square feet. b. With the afterburner off, determine the area (ft) of the exhaust nozzle's choked throat (station 8) for P8//%-0.97 c. With the afterburner on, determine the afterburner fuel flow rate (lbm/sec) and the area (ft) of the exhaust nozzle's choked throat (station 8) for Ps Pr6-0.94 and Ts 3660 R. Assume that the gas leaving the operating afterburner (part c) is a calorically perfect gas with y-1.3, cp- 0.297 Btu/(lbm R), and the same gas constant. Also assume the properties at station 6 do not change and hR 18,400 Btu/lbm 0.94 and Is

Answer 1

2. 830 으:33 (0.4) L+ 32 슛6 46 3.03 ニ|1+ 의33@4) YRT 2. Ve: 1412 26 ft/sec

460 6 .093 142 A= choked nozzle , /1-1 VYRT 2_ 2 1-3 3 " Y+1 46 18 始 S 0,82 338.83

RTe 230 36.84 S3.34x1s080 2 He= 1566.125 14 t-b Pt R3.3 4x3 66 x1o 1212.6 Se C Mメ Ve - 4 23 o = 1.329x10 × 1212,67 × Ae