Anna University B.E Aeronautical Propulsion (AE2255) 4th Semester 2011 Question Paper

Anna University old, model, previous and latest years question papers >> AE2255 Propulsion, Fourth Semester (4th) B.E Aeronautical Engineering 2011 Question Paper: 

Want to get old, previous years and latest question papers of Anna University, Chennai ? You can find even sample and model question papers of Anna University and various universities in India. Have a look at this post which contains the latest year 2011 Anna University question paper conducted in the month April/May 2011, for the B.E/B.Tech Degree Examination. This question paper is useful for those students who are preparing for Fourth semester AE2255 Propulsion for the course Aeronautical Engineering. Part A consists of 10 Questions and Part B has 5 questions of either or choice with a weight-age of 16 marks each. Use the question paper for your upcoming exams to score high marks.

Anna University, Chennai
Question Paper Code : 11113
B.E./B.Tech. Degree Examination, April/May 2011 
Aeronautical Engineering 
AE2255 Propulsion
Fourth Semester 
(Regulation .2008)
Time : Three hours
Maximum: 100 marks
Use of gas tables permitted Answer ALL questions.
PART A (10 x 2 = 20 marks)

1. What are the advantages of closed cycle gas turbine cycle?
2. Water injection at inlet of a gas turbine engine increases thrust. Comment on the statement.
3. Draw T-S diagram for the inlet during low speed high thrust operation of a gas turbine engine.
4. Differentiate between subcritical arid Supercritical modes of inlet operation.
5. Define pattern factor. What is the desired range of this parameter?
6. What are the functions of dilution zone in combustion chamber of a gas turbine engine?
7. Define nozzle efficiency.
8. What is the need for variable area nozzle for supersonic operation?
9. What are the advantages of the axial flow compressor over the centrifugal flow compressor?
10. Define degree of reaction of an axial flow compressor.

PART B (5 x 16 = 80 marks)

11. (a) (i) Explain the working principle of Brayton cycle with regeneration. (6)

(ii)    In a gas-turbine plant working on Brayton cycle the air at the inlet is at 300 K, 0.1 MPa. The pressure ratio is 6.25 and the maximum temperature is 1073 K. The turbine and compressor efficiencies are each 80%. Find (1) compressor work per kg of air, (2) turbine work per kg of air and (3) turbine exhaust temperature.    (6)

(iii)  What is the effect of pressure ratio on the Brayton cycle efficiency?  (4)

Or

(b) (i) Draw a neat diagram of turbofan engine with axial flow compressor and explain its working principle.    (8)

(ii) What ii an afterburner and why is;it. used? Draw the T-S diagram of an ideal turbojet engine with an afterburner; explain the state points in the T-S diagram.    (8)

12. (a) (i) A jet plane travels through air with a speed of 285 m/s an altitude of 6000 m, where the pressure is 40 kPa,  the temperature is 261 K. The air leaves the diffuser of the engine of this airplane with a velocity of 100 m/s. Determine the pressure' and temperature of air leaving the diffuser, and the ratio of the inlet to exit area of the diffuser, assuming isentropic flow.    (8)

(ii) Performance wise highlight the requirements of a good inlet. Draw the streamline patterns along with T-S diagram for a subsonic inlet under varying speed operations.    (8)

Or

(b) (i) Discuss the effect of shock waves in supersonic inlets.

Schematically describe the working principle of internal compression and external compression type of supersonic inlets. (8),

(ii) An aircraft is flying at an altitude where the ambient static pressure is Po = 10 kPa and flight Mach number is Mo = 0.85. The total pressure at the engine face is measured to be P12  = 15.88 kPa . Assuming compression in the inlet is adiabatic and y = 1.4, calculate (1) the inlet total pressure recovery (2) the inlet adiabatic efficiency and (Ti) the non-dimensional entropy rise caused by the inlet.    (8)

13. (a) (i) Discuss the main factors of importance in assessing combustion chamber performances    (10)

(ii) Explain flame tube cooling of a gas turbine combustion chamber. (6)

Or

(b) (i) Discuss the classification of gas turbine combustion chambers.

Explain, with sketches.    (10)

(ii) Write down: any two methods of flame stabilization with sketches.

(6)

14. (a) (i) Plot Mach number, static temperature, static pressure and static density variations along the longitudinal axis of a convergent-divergent nozzle, when it flows full. Explain the variations.    (6)

(ii) A de Lavel nozzle has to be designed for an exit Mach number of 1.5 ; with exit diameter of 200 mm. Find the required ratio of throat area/exit area. The reservoir conditions are given as Po =10 bar, To =20 Deg C. Find also the maximum mass flow rate through the nozzle. What will be the exit pressure and temperature?   (10)

Or

(b) (i) Write short notes on the following :

(1) Variable area nozzle.    (4)

(2) Losses in nozzle. (4)

(ii) A converging-diverging nozzle operates at an atmospheric pressure of 68.95 KPa. It has a minimum area of 0.1393 m^2 and an exit area of 0.2786 m^2. The inlet total pressure, and temperature are 241.3 KPa and 611.1 K, respectively. The effective specific heat ratio is 1.34, and the nozzle efficiency is 98 percent. Find the exit velocity and mass flow rate.    (8)

15. (a) (i) What do you understand by degree of reaction in an axial flow compressor? Prove that degree of reaction A in an axial flow compressor is given by

A = (tan B1 - tan B2)Ca / 2U    (8)           [ Note: Read B as Beta]

(ii) Draw a neat diagram of axial flow compressor and explain functions of all parts and its working principle    (8)

Or :

(b) (i) A sixteen-stage axial flow compressor is to have a pressure ratio of 6.3. Tests have shown that a stage total-to-total efficiency of 0.9 can be obtained for each of the first six stages and 0.89 for each of the remaining ton stages. Assuming constant work done in each stage and similar stages find the compressor overall total-to-total efficiency. For a mass flow rate of 40 kg/s determine the power required by the compressor. Assume an inlet total temperature of 288 K                            (8)

(ii) Discuss the factors affecting stage pressure rise of an axial flow compressor with suitable sketches.    (8)

Share This