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Lesson 11: PREVIOUS YEAR ON COMPRESSOR ( ESE Mechanical)
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Previous year Questions on Compressors are discussed in this video.

Deepali Namdeo
I have done my bachelor's in mechanical engineering from M.I.T.S Gwalior. Currently I am Design Engineer at Cameron, a Schlumberger Company.

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2 months ago
Contact me on 7977012627
1. PREVIOUS YEAR ESE&GATE OBJECTIVE QUESTIONS COVERED PREVIOUS YEAR QUESTIONS ON COMPRESSORS ESE MECHANICAL PRESENTED BY DEEPALI NAMDEO

2. About ME GATE Qualified. I also have an experience of 11 months teaching Engineering subjects like Industrial, Thermodynamics, SOM, HMT. Currently working as a Design Engineer at "Cameron-A Schlumberger Company" B.tech with honors from M.I.T.S Gwalior. I am pursuing my Post graduate Diploma in Design Engineering for Oil and Gas Industry

3. 1. A centrifugal compressor is suitable for which of the following? [IES-2008] (a) High pressure ratio, low mass flow (b) Low pressure ratio, low mass flow (c) High pressure ratio, high mass flow (d) Low pressure ratio, high mass flow 1. Ans. (d) 2. Match List-I (Name of equipment) with List-II (Pressure ratio) and select the correct answer using the code given below the lists: [IES-2007] List-I List-II A. Fan B. Blower C. Centrifugal air compressor D. Axial flow air compressor Codes:A 2.2.5 3.4 4.10 2 134(b)1 234 1 2 43(d) 2 43 2. Ans. (b)

4. Which of the following can be the cause/causes of an air-cooled compressor getting overheated during operation? 1.Insufficient lubricating oi 2.Broken valve strip. 3.Clogged intake filter. Select the correct answer using the code given below: (a) Only 3 3. IES-20061 (b) Only 1 and 2 (c) Only 2 and 3 (d) 1, 2 and:3 3. Ans. (d) 4. Which type of valves is generally used in reciprocating refrigerant [IES-2006] compressors? (a) Mushroom valve (c) Plate valve (b) Puppet valve (d) Throttle valve 4. Ans. (c)

5. 5. Reciprocating compressors are provided with (a) Simple disc/plate valve (c) Spring-loaded disc valve [IES-2000] (b) Poppet valve (d) Solenoid valve 5. Ans. (a) Which one of the following statements is correct? In reciprocating compressors, one should aim at compressing the air (a) Adiabatically (b) Isentropically (c) Isothermally (d) Polytropically 6. [IES-2004] 6. Ans. (c)

6. 7. [IES-2002 Roots blower is an example of: (a) Reciprocating (positive displacement) compressor (b) Rotary (positive displacement) compressor (c) Centrifugal compressor (d) Axial compressor 7. Ans. (b) -8. Match List-I (Refrigeration equipment) with List-II (Characteristic) and select the correct answer: IES-2002] List-I List-II 1. Capillary tube 2. Both compressor and motor enclosed Compressor in a shell or casting 3. Both compressor and motor enclosed in a shell or casing with a removable cylinder cover 4. Driving motor of enclosed in a shell or casing and connected to the shaft driving A. Hermetically sealed compressor B. Semi-hermitically sealed C. Open type compressor D. Expansion device Codes: A 1 432(b)234 1 342(d) 2 431 -8. Ans. (b)

7. -9. The capacity of an air compressor is specified as 3 m/min. It means that the IES-2000] compressor is capable of: (a) Supplying 3 m3 of compressed air per minute (b) Compressing 3 m3 of free air per minute (c) Supplying 3 m3 of compressed air at NTP (d) Compressing 3 m3 of standard air per minute 9. Ans. (b) -10. Which one of the following pairs of features and compressors type is NOT correctly matched? (a) Intake and delivery portsVane compressor back flow and internal compression is attained by [IES-2000] compression cylindrical rotor set to discharge: Reciprocating compressor pressure, slow eccentric casing (b) Intermittent requires receiver, produces high (c) Continuous flow, radial now,Centrifugal compressor much higheir handles large volum speed and lubrication problems : speed and fitted into design of aero- engine (d) Successive pressure drops through contracting Axial flow compressor passages, blades : are formed from a number of circular arcs, axial now 10. Ans. (c)

8. .11. When a burnt out hermetic compressor is replaced by a new one, it is desirable to include in the system a large drier-cum strainer also. This is to be placed in (a) Liquid line (b) Suction line (c) Hot gas line (d) Discharge line IES-1999 11. Ans. (d) 12. Assertion (A): A reciprocating air compressor at sea level would deliver a [IES-1998] greater mass of air than a compressor on a mountain Reason (R): The compressor ratings are given for "free air". (a) Both A and R are individually true and R is the correct explanation of A (b) Both A and R are individually true but R is not the correct explanation of A (c A s true but R is false (d) A is false but R is true 12. Ans. (b)

9. IES-13. What is the preferred intercooler pressure for a two stage air compressor working between the suction pressure ps and the delivery pressure pd? (a) (ps + pd)/2 (b) (p pd)/2 (d) (p. +pa) [IES-2006] (c) (ps x p)12 IES-13. Ans. (c) IES-14. When are shock waves formed in air compressors? (a) Mach number<0 (b)Mach number> 0.9 (c) Mach number-2 (d) Mach number changes suddenly from one value to another IES-2006] IES-14. Ans. (b) IES-15. Assertion (A): In multi-stage compressors, the polytropic efficiency is [IES-2005] always greater than the isentropic efficiency. Reason(R): Higher the pressure ration, the greater is the polytropic efficiency. (a) Both A and R are individually true and R is the correct explanation of A (b) Both A and R are individually true but R is not the correct explanation of A (c) A is true but R is false (d) A is false but R is true IES-15. Ans. (b)

10. 16.When a refrigerator system is started from ambient conditions, the evaporator temperature decreases from ambient temperature to design value. This period is known as a pull-down period. The power requirement of compressor during pull-dow n (a) Decreases continuously (c) Remains constant [IES-2003] (b) Increases continuously (d) Increases and then decreases Ans. (b) 17.If n is the polytropic index of compression and Pi is the pressure ratio for a three-stage compressor with ideal inter-cooling, the expression for the total work of three stage is: [IES-2001] 3n Pi Il Pi Ans. (d)