Name of the College : Noorul Islam College of Engineering
University : Anna University
Degree : B.E
Department : Aeronautical Engineering
Subject Code/Name : AE 1009 – Aero Engine Maintenance & Repair
Year : 4th
Semester : 7th
Document Type : Question Bank
Website : niceindia.com
Download Model/Sample Question Paper :https://www.pdfquestion.in/uploads/niceindia.com/3057-AE_1009_AERO_ENGINE_MAINTENANCE_AND_REPAIR.pdf
Aero Engine Maintenance & Repair Question Paper
1. What is operating principle of jet engine? :
Air is collected and accelerated rearwards to a high velocity and the reaction due to this is transmitted to the aircraft as a forward thrust.
Related : Noorul Islam College of Engineering AE1401 Finite Element Materials B.E Question Bank : www.pdfquestion.in/3062.html
2. What is the difference between propeller propulsion and jet propulsion? :
Both are forms of reaction propulsion but jet engine produces its thrust by accelerating small amount of air at high velocity & the propeller moves large mass of air at low velocity.
3. Does jet engine propel the aircraft by causing gas stream to push on the atmosphere? :
No
4. What are relative spheres of operation for propeller propulsion and jet propulsion? :
300-400 m.p.h. for propeller & 500 and above for jet.
5. For what sphere of operation are by-pass and fan engine suitable? :
They provide higher propulsive efficiency
6. Can a propeller be drive by a turbine engine? :
Yes
7. What form does the compressor usually take ? :
Centrifugal (single and two stage) and axial (single spool and twin spool)
8. What form does the turbine usually take? :
Single stage turbine ,two stage turbine ,multi stage turbine
9. Is there any difference between the air flow through a propeller turbine engine and jet engine? :
Jet engine drives only compressor where as propeller turbine engine drives compressor and propeller.
10. What is the temp of air entering the combustion chamber? :
250 to 400 degree C
11. What is the gas temp at the entry of turbine? :
About 600 degree C
12. How much pressure drop occurs across the combustion chambers? :
1-2 p.s.i.
13. Are the air velocity in an axial compressor as high as those produced in a centrifugal type? :
No
14. Why do some jet engines have a double sided centrifugal compressor? :
To allow air to enter the compressor by front and rear intake, and and reduce the compressor dia.
15. What is the reason for the guide vanes fitted into some compressor air intakes? :
For equal air distribution to compressor rotor and minimize the possibility of blade stalling
16. What type of bearing is used to support the main bearing shaft? :
Antifriction bearing are used.For front and rear the roller bearing are used and for centre ball bearing are used.
17. What are two spool compressors ? :
Two halves of a multistage axial flow compressor,each half being driven independently by separate turbine.
18. What is interconnectors? :
Flame Tubes joining adjacent combustion chambers so that air pressure are equalized and allow light up to be passed to all tubes during starting.
19. How does the turbine transmit power to the compressor? :
19.Directly or through reduction gear
20. How is turbine blade attached to the disk.
By “fir-tree” attachment.
21. Why are turbine blades with extended roots sometimes used? :
To deal with high rim temp. problems.
22. How much should be turbine blade tip clearance? :
0.04 to 0.06 inch
23. Why is a bullet or inner cone fitted inside the exhaust unit behind the turbine? :
For smooth flow of gas and also act as heat insulator plate
24. How is the gas flow from the circular combustion chamber outlets spread across the annulus formed by the turbine stator blades? :
Sheet metal nozzles are shaped to provide a smooth change in crosssection from circular at the inlet end to part- annular at exit.
25. Give a simplified explanation of the working of a single-stage turbine? :
26. What is two stage turbine? :
Each stage consists of a set of stationary guide vanes and a rotor carrying a set of blades.The first stage is high and the second stage is low.
27. Explain the air flow of single stage centrifugal compressor? :
28. Explain ,the air flow through a multi-stage axial-flow compressor? :
29. What is the max r.p.m of a turbine engine? :
Depends upon the type of compressor. Usually around 12,500
30. Factors on which propeller reduction gear depends? :
Depends upon r.p.m. of turbine driving propeller and propeller diaeter