Any thoughts on the method to calculate this?

Consider a cylinder fitted with a piston which contains saturated Steam at 30°C with 80% quality.

Let this vapor be compressed in a reversible adiabatic process until the pressure is 10 bars in

superheated conditions .Determine the work per kilogram of the steam for this process. Assume the

system is open

We need two parameter at state 2 to calcualte h2. We have pressure P2 second one can be? It is given that the steam is superheated at state 2. So I would use 1 MPa superheated steam table and search for S1 value( or interpolate) and find corresponding h2.

Hi,

I am not 100% sure about this problem, because, it is given that the system is open even though the arrangement is piston-cylinder. Usually, piston-cylinder arrangement is considered as closed system.

But my approach is as follows,

To calculate work done per kg in the above problem, we need to know the enthalpies at the state 1 and state 2.

I would calculate enthalpy and entropy at state 1. That is x=0.8

h1 = hf + x(hg-hf) [at 30 C]

s1 = sf + x(sg-sf) [at 30 C]

It is given that the process is reversible adiabatic. Hence, assuming s1=s2.

we can calculate the enthalpy from s2 and P2=10 bar.

W = h2-h1.

------------ X ---------- X ---------

I am also not sure about the heat input required to convert remaining 20% wet steam to steam.