Module 3

Question 1

types of compressor

Answer 1

CENTRIFUGAL FLOW
AXIAL FLOW

Question 2

(?) are dedicated components that sucks air (intake) from the atmosphere, compresses it in the combustion chamber to be used for combustion.

Answer 2

COMPRESSORS

Question 3

The (?) is a single or two stage unit employing an impeller to accelerate the air and a diffuser to produce the required pressure rise.

Answer 3

CENTRIFUGAL FLOW COMPRESSOR

Question 4

(?) have a single or double-sided impeller and occasionally a two-stage, single sided impeller is used, as on the Rolls-Royce Dart.

Answer 4

CENTRIFUGAL FLOW COMPRESSORS

Question 5

The (?) rotates in ball and roller bearings and is either common
to the turbine shaft or split in the center and connected by a coupling, which is usually designed for ease of detachment.

Answer 5

Impeller Shaft

Question 6

The (?) centers around the impeller, diffuser and air intake system.

Answer 6

construction of the compressor

Question 7

The (?) consists of a forged disc with integral radially disposed vanes on one or both sides forming convergent passages in conjunction with the compressor casing.

Answer 7

IMPELLER

Question 8

The clearance between the (?) is an important factor, as too small a clearance will set up aerodynamic buffeting impulses that could be transferred to the impeller and create an unsteady airflow and vibration.

Answer 8

impeller and the diffuser

Question 9

The (?) is a multi-stage unit employing alternate rows of rotating (ROTOR) blades and stationary (STATOR) vanes.

Answer 9

AXIAL FLOW COMPRESSOR

Question 10

rows of rotating blades

Answer 10

ROTOR

Question 11

stationary vanes

Answer 11

STATOR

Question 12

to accelerate and diffuse the air until the required pressure rise is obtained.

Answer 12

AXIAL FLOW COMPRESSOR

Question 13

The (?) is a multi-stage unit as the amount of pressure increase by each stage is small.

Answer 13

COMPRESSOR

Question 14

a stage consists of a row of rotating blades followed by a row of stator vanes.

Answer 14

COMPRESSOR

Question 15

As the pressure ratio is (?) the incorporation of variable stator vanes ensures that the airflow is directed onto the succeeding stage of rotor blades at an acceptable angle.

Answer 15

increased

Question 16

From the front to the rear of the compressor, from the low to the high
pressure end, there is a gradual reduction of the air (?) between the rotor shaft and the stator casing.

Answer 16

ANNULUS AREA

Question 17

With regard to the advantages and disadvantages of the two types, (?)

Answer 17

the centrifugal compressor is usually more robust than the axial compressor and is also easier to develop and manufacture. The axial compressor however consumes far more air than a centrifugal compressor of the same frontal area and can be designed to attain much higher pressure ratios.

Question 18

Since the air flow is an important factor in determining the amount of thrust, this means the axial compressor engine will also give (?).

Answer 18

more thrust for the same frontal area

Question 19

This, plus the ability to increase the pressure ratio by (?), has led to the adoption of axial compressors in most engine designs.

Answer 19

addition of extra stages