Name of the College : Valliammai Engineering College
Subject : Engineering Thermodynamics
Website : valliammai.co.in
Document Type : Question Bank
Department : Mechanical Engineering
Semester : III
Degree : B.E
Question Bank : https://www.pdfquestion.in/uploads/valliammai.co.in/1764-Engineering%20Thermodynamics.pdf
Engineering Thermodynamics Question Paper
DEPARTMENT OF MECHANICAL ENGINEERING
QUESTION BANK
ME 6301 – ENGINEERING THERMODYNAMICS
UNIT I
BASIC CONCEPT AND FIRST LAW
PART – A
1. What do you understand by pure substance?
2. Define thermodynamic system.
3. Name the different types of system.
Related : Valliammai Engineering College NE701 Mobile Application Development M.E Question Bank : www.pdfquestion.in/2763.html
4. Define thermodynamic equilibrium.
5. What do you mean by quasi-static process? 6. Define Path function.
7. Define point function.
8. Explain homogeneous and heterogeneous system.
9. What is a steady flow process?
10. Prove that for an isolated system, there is no change in internal energy.
11. Indicate the practical application of steady flow energy equation.
12. Explain Mechanical equilibrium.
13. Explain Chemical equilibrium.
14. Explain Thermal equilibrium.
15. Define Zeroth law of Thermodynamics.
16. What are the limitations of first law of thermodynamics?
17. What is perpetual motion machine of first kind?
18. Differentiate between Microscopic and Macroscopic?
19. Differentiate Quasi static and non Quasi static process?
20. Differentiate reversible process and irreversible process?
PART – B
1. a) A rigid tank containing 0.4m3 of air at 400 kPa and 30oC is connected by a valve to a piston cylinder device with zero clearance. The mass of the piston is such that a pressure of 200 kPa is required to raise the piston. The valve is opened slightly and air is allowed to flow into the cylinder until the pressure of the tank drops to 200 kPa. During this process, heat is exchanged with the surrounding such that the entire air remains at 30oC at all times. Determine the heat transfer for this process.
b) A reciprocating air compressor taken in 2m3/min air at 0.11MPa, 293K which it delivers at 1.5 Mpa, 384 K to an after cooler where the air where the air is cooled at constant pressure to 298 K. the power absorbed by the compressor is 4.15 kW. Determine the heat transfer in (i) the compressor (ii) the cooler. State your assumptions.
2. In a turbo machine handling an incompressible fluid with a density of 1000kg/m3 the conditions of the fluid at the rotor entry and exit are as given below:
1. Inlet Exit
Pressure 1.15 MPa 0.05MPa
Velocity 30 m/sec 15.5 m/sec
Height above datum 10 m 2m
If the volume flow rate of the fluid is 40 m3/s, estimate the net energy transfer from the fluid as work.
3. Three grams of nitrogen gas at 6 atm and 160oC is expanded adiabatically to double its initial volume and then compressed again at constant volume to its initial state. Calculate the work done on the gas. Draw the p-V diagram for the process. Specific heat ratio of nitrogen is 1.4.
4. Describe steady flow energy equation and ? deduce suitable expression for the expansion of gas in a ga turbine with suitable assumptions. ? apply the equation to a nozzle and derive an equation for velocity at exit. ? Derive the suitable expression for the ideal compressor and specify the assumptions onder which such equation is aplicable.
5. a) Air expands isentropic process through a nozzle from 784 kPa and 220oC to an exit presssure of 98 kPa. Detrmine the exit velocity and the mass flow rate, if the exit area is 0.0006m2.
b) In an air compressor, air flows steadily at the rate of 0.5 kg/sec. At entry to the compressor, air has a pressure of 105 kPa and specific volume of 0.86 m3/kg and at exit of the compressor those corresponding values are 705 kPa and 0.16 m3/kg. neglect kinetic and potential energy change. The internal energy of air leaking the compressor is 95 kJ/kg greater than that of air entering. The cooling water in the compressor absorbs 60 kJ/sec. of heat from the air. Find power required to drive the compressor.
6. Air contained in the cylinder and piston arrangement comprises the system. A cycle is completed by four process 1-2, 2-3, 3-4 and 4-1. The energy transfers are listed below. Complete the table and determine the network in kJ. Also check the validity of the first law of thermodynamics.
Process Q (kJ) W (kJ) ?U (kJ)
1-2 40 ? 25
2-3 20 -10 ?
3-4 -20 ? ?
4-1 0 +8 ?
7. Calculate the power developed and diameter of the inlet pipe, if a gas enters into the gas turbine at 5 kg/sec, 50 m/s with an enthalpy of 0.9MJ/kg. the heat loss to the surrounding is 0.025 MJ/kg. the heat loss to the surrounding is 0.025 MJ/kg. the heat loss to the surrounding is 0.025 MJ/kg. assume 100 kPa and 300 K at the inlet.
8. a. Define the following terms: ? Thermodynamics ? Macroscopic approach ? Continuum b. A gas of mass 1.5 kg undergoes a quasistatic expansion, which follows a relationship P=a+bV, where ‘a’ and ‘b’ are constants. The initial and final pressures are 1000 kPa and 200 kPa respectively and the corresponding volumes are 0.2 m3 and 1.2 m3. The specific internal energy of the gas is given by the relation U = (1.5PV – 85) kJ/kg, where P is in kPa and V is in m3. Calculate the net heat transfer and the maximum internal energy of the gas attained during expansion.
9. a) Define enthalpy. How is it related to internal energy? b) A fluid is confined in a cylinder by a spring loaded, frictionless piston so that the pressure in the fluid is a linear function of the volume (p = a + bV) where U is in kJ, p is in kPa and V in cubic meter. If the fluid changes from an initial state of 170 kPa, 0.03 m3 to a final state of 400 kPa, 0.06 m3, with no work other than that done on the piston, find the direction and magnitude of the work and heat transfer.
10. The electric heating system used in many houses consists of simple duct with resistance wire. Air is heated as it flows over resistance wires. Consider a 15 kW electric heating system. Air enters the heating section at 100 kPa and 17oC with a volume flow rate of 150 m3/min. if heat is lost from the air in the duct to the surroundings at a rate of 200 W, determine the exit temperature of air.
UNIT II
SECOND LAW AND AVAILABILITY ANALYSIS
PART – A
1. Define Clausius statement.
2. What is Perpetual motion machine of the second kind?
3. Define Kelvin Planck Statement.
4. Define Heat pump.
5. Define Heat engine.
6. What are the assumptions made on heat engine?
7. State Carnot theorem.
8. What is meant by reversible process?
9. What is meant by irreversible process?
10. Explain entropy?
11. Define availability.
12. Define available energy and unavailable energy.
13. Explain the term source and sink.
14. What do you understand by the entropy principle?
15. What are the important characteristics of entropy?
16. What is reversed Carnot heat engine? What are the limitations of carnot cycle?
17. Why Rankine cycle is modified?
18. Name the various vapour power cycle.
19. Define efficiency ration.
20. Define overall efficiency.