Solution Found!
Answer: Applying the Energy BalanceA piston-cylinder
Chapter 3, Problem 66P(choose chapter or problem)
A piston-cylinder assembly contains ammonia, initially at a temperature of \(-20^{\circ} \mathrm{C}\) and a quality of 50%. The ammonia is slowly heated to a final state where the pressure is 6 bar and the temperature is \(180^{\circ} \mathrm{C}\). While the ammonia is heated, its pressure varies linearly with specific volume. Show the process of the ammonia on a sketch of the p–y diagram. For the ammonia, determine the work and heat transfer, each in \(\mathrm{kJ} / \mathrm{kg}\).
Questions & Answers
QUESTION:
A piston-cylinder assembly contains ammonia, initially at a temperature of \(-20^{\circ} \mathrm{C}\) and a quality of 50%. The ammonia is slowly heated to a final state where the pressure is 6 bar and the temperature is \(180^{\circ} \mathrm{C}\). While the ammonia is heated, its pressure varies linearly with specific volume. Show the process of the ammonia on a sketch of the p–y diagram. For the ammonia, determine the work and heat transfer, each in \(\mathrm{kJ} / \mathrm{kg}\).
ANSWER:Step 1 of 3
We have to determine the work and heat transfer.
The work done can be found using the expression,
where,
and
are the specific volume of ammonia
at -20 oC and 180 oC
=
the initial pressure in bar
From table A-13, 1.5038
kg/m3 ,
0.6233 kg/m3 at -20 oC and
kg/m3 at 180 oC and
bar
Hence,
= 0.30513 kg/m3
Thus,
Therefore, the amount of work done is 10,498.64 kJ/kg.