DiFerrara

oh nice links thanks I understand better this story of dry, you open my eyes hahah

I'll try it, thanks for the advice !

thanks for the links, before start calcul first I think all work interaction is of the expansion type and only thermal energy change is significant.

For the initial property, I know the volume and pressure. with this information I go to the "saturated water and steam table" the look the properties of this condition

I find for 5 bar presasure :

151.85 C boiling point, 2.669 kg/m³ steam density, 2.3289 kJ/kg K specific heat, 2747.54 kJ/kg specific enthalpy of steam, 640.12 kJ/kg specific enthalpy of liquid water, 2107.42 kJ/kg latent heat of vaporization

- the mass of steam in the system ? steam density x volume initiale <=> 2.669 kg/m³x 0.8 m³= 2.1352 kg for the mass of steam

I'm here, the problem is I didn't understand what means "80% dry to a final state of 2 bar"

thanks for the help

Hi scienceforums !

it's my first time in this forum. I need your help for a problem in thermodynamics. I just started this field so my knowledge it's limit for now. My problem :

Steam in a cylinder-piston arrangement expands from an initial condition of 5 bar, 80% dry to a final state of 2 bar, dry saturated steam.

The initial volume of steam is 0.8 m³. The process of expansion can be represented by a straight line on the p-V diagram.

the mass of steam in the system ? [kg]

the work done by the system ? [kJ]

the change in energy of the system ? [kJ]

the heat absorbed by the system ? [kJ]

Maybe it's a simple problem but really I tried, nothing to do... I'm waiting your help...