- #1

jasoncurious

- 8

- 0

Known data:

P(initial)=100kPa

P(final)=800kPa

Temperature(constant)=30°C

Mass flow rate=120kg/min=2kg/s

Since the velocity, elevation and work done is not mentioned, I assume that W(out), KE and PE=0.

Thus the equation:

m(h1+KE1+PE1)+W(in)=m(h2+KE2+PE2)+W(out) is reduced to:

**mh1+W(in)=mh2**

Then,

**W(in)=mh2-mh1**

I have tried looking for the values for h1 and h2 at the ideal gas table(since the air has high temperature and low pressure with respect to its critical properties), but then I realized that both of them are the same, which led to W(in) been 0 (which is impossible). My friend mentioned the "state postulate", others use the PVln(P1/P2) to determine the work done.

I want to know if my attempt is the right one, if not, then what's the right way of doing this question. Your help will be greatly appreciated. God bless you all.