Chapter 5, Problem 5.53P

Two kilograms of air within a piston-cylinder assembly execute a Carnot power cycle with maximum and minimum temperatures of 750 K and 300 K, respectively. The heat transfer to the air during the isothermal expansion is 60 kJ. At the end of the isothermal expansion the volume is 0.4 m³. Assuming the ideal gas model for the air, determine (a) the thermal efficiency. (b) the pressure and volume at the beginning of the isothermal expansion, in kPa and m3, respectively.

Air in a piston-cylinder assembly undergoes a Carnot power cycle. For the process numbers used in this problem refer to Figure 5.13 in the textbook and the figure below for a T-s diagram. The isothermal expansion and compression occur at 840 K and 295 K respectively. The pressures at the beginning and the end of the cycle are p1 = 400 kPa and p4 = 100 kPa, respectively. Assuming the ideal gas model for both constant and variable heat capacity, cp = 1.005 kJ/kg·K and k = 1.40 determine:   a) the pressures p2 and p3.   b) the heat transfer and work for each process.   c) the thermal effici ency.

2.Find the minimum work done per Kg of air in a cycle according to the following processes: a. Isothermal expansion from state 1 to state 2. b. Constant volume compression from state 2 to state 3. c. Constant pressure compression from state 3 to the initial state. Data: P1= 350 KPa V1 = 1 m3 /Kg T3 = 16500 C d. Represent the work on a p-V diagram.

6.14

Two kilograms of air within a piston–cylinder assembly executes a Carnot power cycle with maximum and minimum temperatures of 700 K and 300 K, respectively. The heat transfer to the air during the isothermal expansion is 60 kJ. At the end of the isothermal expansion the volume is 0.4 m3. Assume the ideal gas model for the air. Determine the thermal efficiency, the volume at the beginning of the isothermal expansion, in m3, and the work during the adiabatic expansion, in kJ.

Thermodynamics subject power cycles. Show the ts diagram and complete and step by step solution. Bix the final answer.

A quantity of water within a piston-cylinder assembly executes a Carnot power cycle. During isothermal expansion, the water is heated from saturated liquid at 45 bar until it is a saturated vapor. The vapor then expands adiabatically to a pressure of 2 bar. (1) Sketch the cycle on a P-v diagram. (2) Evaluate the work per unit mass (W/m) and heat transfer per unit mass (Q/m) for process 4-1 (Isothermal Expansion), in kJ/kg. (3) Evaluate the thermal efficiency.

The first step of a thermodynamic cycle is an isobaric process with increasing volume. The second is an isochoric process, with decreasing pressure. The last step may be either an isothermal or adiabatic process, ending at the starting point of the isobaric process. Sketch a graph of these two possibilities, and comment on which will have greater net work per cycle.

7. A piston-cylinder assembly undergoes a cycle consisting of the following three processes: Process 1-2: Compression with constant internal energy Process 2-3: Constant-volume cooling to p3 100 kPa, V₂ = 0.1 m³ Process 3-1: Constant-pressure expansion with W31 = 12 kJ Sketch the cycle on a p-V diagram, labeling each of the states and indicating the process directions with arrows. If the work for the entire cycle is Wcycle = -20 kJ and changes in kinetic and potential energy are negligible, determine: a) The volume at state 1 [0.2 m²] b) The work and heat transfer for process 1-2 [-32 kJ, – 32 kJ] c) Is this cycle a power cycle or a refrigeration cycle? Explain.