3B2 Ch 4

Question 1

When are vibration accelerometers used on gas turbines?
Select one:

a.
If journal or tilt-pad bearings are used

b.
To trip the turbine on rapid acceleration

c.
To control the ramp speed on start-up

d.
On the largest industrial machines

e.
With anti-friction bearings

Answer 1

e.
With anti-friction bearings

Question 2

The nozzles in a gas turbine are usually made from which materials?
1. Ferrite steel
2. Inconel
3. Aluminum alloy
4. Hastelloy
Select one:

a.
1, 2

b.
1, 3

c.
2, 3

d.
2, 4

e.
1, 4

Answer 2

d.
2, 4

Question 3

In a single can combustor, what is decreased by the presence of interconnected tubes?
Select one:

a.
Number of igniters used

b.
Number injectors required

c.
Complexity of the turbine

d.
Pressure differences in each tube

e.
Number of flame tubes required

Answer 3

d.
Pressure differences in each tube

Question 4

In a simple gas turbine, how high might the combustion temperatures be?
Select one:

a.
1500ºC

b.
1700ºC

c.
1800ºC

d.
2000ºC

e.
2200ºC

Answer 4

d.
2000ºC

Question 5

What is an advantage of the can-annular combustor design?
Select one:

a.
More uniform outlet temperatures

b.
Multiple igniters ensure combustion

c.
Fuel lines distribute fuel more rapidly

d.
More efficient use of space

e.
If one quits, the other will keep working

Answer 5

a.
More uniform outlet temperatures

Question 6

The advantages of centrifugal over axial compressors include which of the following?
1. High capacity
2. Short length
3. High flow rates
4. Strength
5. Adjustable flow
Select one:

a.
1, 2

b.
2, 3

c.
3, 4

d.
4, 5

e.
2, 4

Answer 6

e.
2, 4

Question 7

What is the regenerator of a gas turbine cycle?
Select one:

a.
Second combustor

b.
Heat exchanger

c.
Vessel used to transfer heat from the exhaust gas to the working fluid before compression occurs

d.
Component that increases the pressure of the working fluid in the system

e.
Component that increases the temperature of the combustor’s outlet

Answer 7

b.
Heat exchanger

Question 8

What is the maximum temperature that combustion chamber gas can reach in a modern gas turbine?
Select one:

a.
1550°C

b.
1570°C

c.
1650°C

d.
1670°C

e.
1750°C

Answer 8

c.
1650°C

Question 9

In axial flow compressors, where does compression occur?
Select one:

a.
In the stationary blades

b.
In the rotating blades

c.
In both stationary and rotating blades

d.
By the use of nozzle blocks between stages

e.
In only the moving blades

Answer 9

c.
In both stationary and rotating blades