05 kg of air contained inside a piston-cylinder device with

Question

Problem 1:

0.5 kg of air, contained inside a piston-cylinder device, with an initial pressure of 6 bar and initial volume of 0.15 m³ undergoes a thermodynamic cycle consisting three processes as follows:

Process 1-2: 100 kJ of heat is added to the device in an isobaric manner during which the internal energy increases by 40 kJ

Process 2-3: Air cools at constant volume and the internal energy decreases by 50 kJ

Process 3-1: Compression of air via a polytropic process (PV^1.3 = constant).

(a) Draw the cycle on a P-V diagram.

(b) Find the pressure (bar) and volume (m³) at states 2 and 3.

(c) Find the heat transfer (kJ), work (kJ), and internal energy change (kJ) for each process in the cycle.

(d) What is the net heat transfer (kJ) and net work (kJ) for this cycle?

Problem 2:

R-134a vapor initially at 60 psia and 120^oF (State 1) is contained within a piston-cylinder device. The refrigerant is cooled at constant volume until its temperature reaches 25^oF (State 2) and is then compressed isothermally to a pressure of 45 psia (State 3).

(a) Locate the state points on appropriately labeled P-v and T-v diagrams.

(b) Determine the specific volume (ft3/lbm), specific internal energy (Btu/lbm) and specific enthalpy (Btu/lbm) at each state.

Problem 3:

A 0.8 m3 rigid vessel initially contains a saturated liquid-vapor mixture of water at 90^oC. The water is heated until it reaches its critical point.

(a) Indicate the process on a P-v diagram.

(b) What is the mass (kg) of liquid water at the initial state?

(c) Determine the volume (m³) occupied by vapor at the initial state.

Answer 1

Answer the following questions, by providing solutions for each part in a Microsoft paper by showing the whole computation part all along with proper concepts and formulas. Q1. A vapor primarily at 60 psia and 120oF (State 1) is contained in a piston-cylinder device. The refrigerant is cooled at constant volume till its temperature reaches 25oF (State 2) and is then compressed isothermally to the pressure of 45 psia (State 3). a) Set the state points on properly labeled P-v and T-v diagrams. b) Find out the specific volume (ft3/lbm), specific internal energy (Btu/lbm) and specific enthalpy (Btu/lbm) at each and every state. Q2. A 0.8 m3 rigid vessel initially includes a saturated liquid-vapor mixture of water at 90oC. The water is heated till it reaches the critical point. a) Point out the process on P-v diagram. b) Determine the mass of liquid water at initial state? c) Find out the volume occupied by vapor at the initial state.