Find the Exit Temperature of the Air in the Compressor

[Northbysouth]

Homework Statement

Air enters a compressor operating at steady state with a pressure of 14.7 lbf/in², a temperature of 80°F and a volumetric flow rate of 18 ft³/s. The air exits the compressor at a pressure of 90 lbf/in². Heat transfer from the compressor to its surroundings occurs at a rate of 9.7 Btu per lb of air flowing. The compressor power input is 90 hp. Neglecting kinetic and potential energy effects and modeling air as an ideal gas, determine the exit temperature in °F.

Homework Equations

The Attempt at a Solution

I suspect that I need to use:

Q_cv+m'₁(h₁+v²₁/2) = m'₂(h₂ + v²₂/2) + W_cv

Is Q_cv = 9.7 Btu/lb and W_cv= 90 hp?

 

[SteamKing]

How do you expect to find v?