PHEP Ch.12 Intakes, Conduits and Surge Chambers

Question 1

And most hydroelectric developments the head and water flow will:

Remain steady
Fluctuate
Stabilize the load
Determine the hydraulic radius

Answer 1

Fluctuate

Question 2

Intake design has a large effect on:

Velocity
Volume
Head
All three

Answer 2

All three

Question 3

A partially clogged trash rack will:

Cause an increase in head
Cause a decrease in the effective head
Have no effect on velocity through the open portions of the rack
Improve efficiency because of an increase in velocity through the open portions of the rack

Answer 3

Cause a decrease in the effective head

Question 4

Wood-stave pipe would probably not be used for:

High-line conduit
Pressure conduit
Non-pressure conduit
Heads above 500 feet

Answer 4

Heads above 500 feet

Question 5

An open conduit system implies:

The presence of a free surface
The use of a control volume
No drop in hydraulic gradient
A minimum hydraulic radius

Answer 5

The presence of a free surface

Question 6

The best canal cross-section from a hydraulic point of view is defined as:

The least-expensive canal cross-section
The section with minimum roughness coefficient
The one that has a minimum wetted perimeter
The one that has a maximum area for a given flow

Answer 6

The one that has a minimum wetted perimeter

Question 7

The least efficient type of high-line conduit is that type which:

Has the least effect on the available head
Has the greatest effect on the available head
Has the smallest wetted perimeter for a given flow and velocity
Has the least amount of bends and internal protuberances

Answer 7

Has the greatest effect on the available head

Question 8

Steel pipe is used more extensively than any other type of pipe for penstock construction because:

It can be riveted
It can be welded
It is better able to withstand changes in static and dynamic pressures
Of the degree of flexibility it offers in satisfying design criteria in all of the above areas

Answer 8

Of the degree of flexibility it offers in satisfying design criteria in all of the above areas

Question 9

One of the major advantages of using pressure tunnel in a power conduit system is that:

It permits full use of the available head
It permits full use of the best hydraulic radius
It offers less resistance to flow
Expansion joints can be eliminated

Answer 9

It permits full use of the available head

Question 10

Positive water-hammer pressure caused by a sudden decrease in the demand for water can be eliminated by:

A relief valve
A pressure-regulator
A surge tank
Any one of the above

Answer 10

Any one of the above

Question 11

Negative water-hammer pressure is created by:

A sudden deceleration in water flow through the penstock
A sudden decrease in the demand for water
A sudden increase in the demand for water
A faulty operating pressure regulator

Answer 11

A sudden increase in the demand for water

Question 12

Which of the below conditions would probably not cause the water level in the riser of a differential surge tank to fall?

A sudden load increase
Conduit velocity insufficient to supply the demand for water
Negative surge waves
A load rejection

Answer 12

A load rejection

Question 13

Pumped Storage type of hydroelectric developments implies a capability for:

Improving load factors on inter-connected power system steam plants
Providing a wider range of power system reverse capacity
Improved peak load operation
All of the above

Answer 13

All of the above

Question 14

The best hydraulic rectangular cross-section occurs when: (B = bottom width, Y = water depth)

Y = 2B
Y = B
Y = B/5
Y = B/2

Answer 14

Y = B/2

Question 15

Penstock velocities may range from:

6 to 20 FT/SEC
5 to 10 FT/SEC
20 to 40 FT/SEC
None of these answers

Answer 15

6 to 20 FT/SEC