Solving Homework: Find Final State, Mass, Work & P-v Diagram

[JasonHathaway]

Homework Statement

A tank has a saturated liquid at 0.2 MPa. An amount of heat is transferred until the pressure in the tank became 0.1 MPa. If the volume of the tank 1 m³. Determine:

1- The final state of the water

2- The mass of the vapor in the tank

3- The work

4- The process on P-v diagram

Homework Equations

V=C (Volume is constatnt)
m (mass) = Volume (V) / Specific volume (v)

The Attempt at a Solution

v1=vf |_{P=0.2 MPa} = 0.8857 m³/kg

v1= v2=0.8857 m^3/kg

At P1=0.1 MPa, v2=0.8857 m³/kg: vf < v2 < vg

The water is mixture of saturated liquid and saturated vapor --> The final state of the water


m=V/v = (1/0.8857) = 1.13 kg --> The mass of the vapor in the tankWork is zero since the volume is constant --> The work

P-v diagram: http://i.imgur.com/Kz0cVVP.jpg

 

[Chestermiller]

There seems to be some missing information, like the total amount of water in the tank. Please write out the exact statement of the problem.

Chet

 

[JasonHathaway]

That's the exact statement of the problem. I guess we have to assume that the tank is full of water, which means that the volume of water is 1 m³.

 

[HallsofIvy]

You said the tank contained a "saturated liquid". What is a saturated liquid?

 

[Chestermiller]

Assuming that the tank is full, what is the specific volume of saturated liquid water at a saturation pressure of 0.2 MPa? What is the specific volume of saturated liquid water at a saturation pressure of 0.1 MPa?

Chet