Question

A piston–cylinder device contains steam initially at 1 MPa, 450°C. Steam is allowed to cool at constant pressure until it becomes saturated vapor.

• Find the internal energy (u) on the initial and final states.
• Find the specific volume (v) on the initial and final states.
• Find the boundary work associated with the transformation.
• Write the conservation of energy equation, and simplify it. Deduce the amount of heat transferred per unit mass.
• Represent the process on P-v diagram, showing the saturation line.

Answer 1

Given that State i Pia impa ?= 450°C Stile 2 saluraled ivopuur - P2= lapu from superhented steal table of wuler A at p= impa > Tsut = 179.990 T1=4500 > sut water exists as super healed Steum at stule 1 at palapa, TE 4500 =)

hi- 33 713 174 , = 304.0.4 ks at stale a V . 0,= 0.330 45 milleg water exista as saturated vapour .: at p= 1 NIPU, m=i => ha= ny = 2777.1 1 :: uerug = 2582.7 II Una vy - 019 436 [ from saleruled steam table of walêt by pressure] Boundary work = par ; : p2-4) - 10001 011943 6 -0.330 CSW -. - 136.09 kJ W =-136.09 kJ ene ve sign indicates work done un system. from conservation of energy Q = Auth A (M₂="1) + P 0₂-01) 92 +PqQz) 4, +90) hech,. . = 2779.1 – 3371-3 -594.2 k Ilic

.. ilug : Q = -5.94.2 kJ Eve' sign in di wies AE 59х+m the heat loan from t salurated vapour - line Suturaled tip line