Question

Air modeled as an ideal gas enters a combustion chamber at 20 lbf/in.2

and 70°F through a

rectangular duct, 5 ft by 4 ft. If the mass flow rate of the air is 830,000 lb/h, determine the

velocity, in ft/s.​

Answer 1

The answer is "
`112.97 \ (ft)/(s)`"

Step-by-step explanation:

Air flowing into the
`p_1 = 20 \ (lbf)/(in^2)`

Flow rate of the mass
`m = 230.556 (lbm)/(s)`

inlet temperature
`T_1 = 700^(\circ) F`

Pipeline
`A= 5 * 4 \ ft`

Its air is modelled as an ideal gas Apply the ideum gas rule to the air to calcule the basic volume v:

`\to \bar{R} = 1545 \ ft (lbf)/(lbmol ^(\circ) R)\\\\ \to M= 28.97 (lb)/(\bmol)\\\\ \to pv=RT \\\\\to v= \frac{\frac{\bar{R}}{M}T}{p}`

`= ((1545)/(28.97)(70^(\circ)F+459.67))/(20) * (1)/(144)\\\\=9.8 (ft3)/(lb)`

`V= (mv)/(A)`

`= (230.556 (lbm)/(s) * 9.8 (ft^3)/(lb))/(5 * 4 \ ft^2)\\\\= 112.97 (ft)/(s)`