Q.1

Which of the following statement is correct relating to rocket engines ?

  • The combustion chamber in a rocket engine is directly analogous to the reservoir of a super sonic wind tunnel
  • The stagnation conditions exist at the combustion chamber
  • The exit velocities of exhaust gases are much higher than those in jet engine
  • all of the above
Q.2

A closed cycle gas turbine consists of a

  • compressor
  • heating chamber
  • cooling chamber
  • all of these
Q.3

Maximum work is saved in a two stage reciprocating air compressor with incomplete intercooling.

  • Agree
  • Disagree
Q.4

Which of the following statement is correct as regard to centrifugal compressors?

  • The flow of air is parallel to the axis of the compressor.
  • The static pressure of air in the impeller increases in order to provide centripetal force on the air.
  • The impeller rotates at high speeds.
  • The maximum efficiency is higher than multi-stage axial flow compressors.
Q.5

The efficiency of roots blower __________ with the increase in pressure ratio.

  • decreases
  • increases
  • does not change
Q.6

In a centrifugal compressor, the highest Mach number leading to shock wave in the fluid flow occurs at

  • diffuser inlet radius
  • diffuser outlet radius
  • impeller inlet radius
  • impeller outlet radius
Q.7

In a gas turbine, air is obtained from the atmosphere and compressed in an air compressor.

  • True
  • False
Q.8

A closed cycle gas turbine works on

  • Carnot cycle
  • Rankine cycle
  • Ericsson cycle
  • Joule cycle
Q.9

In reciprocating air compressors, isothermal efficiency is used for all sorts of calculations.

  • Correct
  • Incorrect
Q.10

The mass of gas turbine per kW developed is about __________ as that of an I.C. engine.

  • same
  • one-half
  • one-fourth
  • one-sixth
Q.11

A machine used to raise the pressure of air is called

  • gas turbine
  • I.C engine
  • compressor
  • air motor
Q.12

In a four stage compressor, if the pressure at the first and third stage are 1 bar andbar, then the delivery pressure at the fourth stage will be

  • 1 bar
  • 16 bar
  • 64 bar
  • 256 bar
Q.13

The ratio of the net work obtained from the gas turbine plant to the turbine work is known as

  • compression ratio
  • work ratio
  • pressure ratio
  • none of these
Q.14

A machine used to raise the pressure of air is called

  • gas turbine
  • I.C engine
  • compressor
  • air motor
Q.15

The operation of lifts, rams and pumps make use of compressed air.

  • Yes
  • No
Q.16

In a centrifugal compressor, the air enters the impeller axially and leaves the vane radially.

  • Yes
  • No
Q.17

In open cycle turbo-jet engines used in military aircraft, reheating the exhaust gas from the turbine by burning, more fuel is used to increase the

  • thrust and range of aircraft
  • efficiency of the engine
  • both (a) and (b)
  • none of these
Q.18

The clearance, in a single stage, single acting reciprocating air compressor does not effect the workdone on the air and the power required for compressing the air.

  • True
  • False
Q.19

Euler's equation can be used for

  • radial flow compressors
  • axial flow compressors
  • pumps
  • all of these
Q.20

The intercooler pressure, for minimum work required, for a two stage reciprocating air compressor, is given by (where p1 = Intake pressure of air, p2 = Intercooler pressure, and p3 = Delivery pressure of air)

  • p2 = p1 x p3
  • p2 = p1/p3
  • p2 = p1 x p3
  • p2 = p3/p1
Q.21

In a centrifugal compressor, the ratio of the __________ to the blade velocity is called slip factor.

  • inlet whirl velocity
  • outlet whirl velocity
  • inlet velocity of flow
  • outlet velocity of flow
Q.22

The overall efficiency of the compressed air system is the

  • ratio of shaft output of the air motor to the shaft input to the compressor
  • ratio of shaft input to the compressor to the shaft output of air motor
  • product of shaft output of air motor and shaft input to the compressor
  • none of the above
Q.23

The compressed air may be used

  • in gas turbine plants
  • for operating pneumatic drills
  • in starting and supercharging of I.C. engines
  • all of the above
Q.24

The intercooler pressure, for minimum work required, for a two stage reciprocating air compressor, is given by (where p1 = Intake pressure of air, p2 = Intercooler pressure, and p3 = Delivery pressure of air)

  • p2 = p1 x p3
  • p2 = p1/p3
  • p2 = p1 x p3
  • p2 = p3/p1
Q.25

The process, which causes the air to enter the impeller blades of a centrifugal compressor at __________ velocity (without effecting the mass of air to flow and velocity of flow) is known as prewhirl.

  • reduced
  • increased
Q.26

A jet engine has

  • no propeller
  • propeller in front
  • propeller at back
  • propeller on the top
Q.27

In gas turbines, the work input with intercooling is __________ the work input with no intercooling.

  • less man
  • more than
Q.28

Gas turbine as compared to internal combustion engine

  • can be driven at a very high speed
  • produces uniform torque
  • has more efficiency
  • all of these
Q.29

Air motors work on the cycle which is the reverse of the reciprocating air compressor cycle.

  • Agree
  • Disagree
Q.30

A rocket engine uses __________ for the combustion of its fuel.

  • surrounding air
  • compressed atmospheric air
  • its own oxygen
  • none of these
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