Ch. 10 PHEP hydraulic turbines: water power wheels

How much head would be required to develop 10,000 hp from a turbine operating at 80% efficiency from a stream with a flow of 100 cu. ft./sec?

1100 ft.

What is the best speed of rotation in rpm for a pelton whee 54in in diameter, on which the net head is 625ft?

360

For most reaction turbines, greatest efficiency is obtained when the wicket gates are:

80%-90% open

Water hammer:

Can damage a penstock if not kept within reasonable limits

Power available at the nozzle varies:

Directly with the head and quantity of water

Net head most nearly means:

Gross or static head less the frictional losses in ft.

A draft tube:

Increases the effective head of the turbine

Which of the below factors would not generally contribute to cavitation damage?

Little or no variation in effective head

Pelton wheels:

May use two or more jets per wheel to obtain increased power

A Kaplan turbine:

Propeller blades adjust automatically to maintain best efficiency for gate position and variations in head.

The purpose of an auxiliary needle is to:

Provide a means for reducing flow to an impulse wheel rapidly while reducing the flow more slowly through the penstock

Readings from a pressure gauge on the crown plate of a reaction turbine give a good indication of the:

Seal-ring effectiveness

Which of the following would not be found on a reaction turbine?

Stripper

To deliver the same amount of power, a smaller diameter runner is required for a reaction turbine than an impulse wheel because:

The entire circumference of the runner of the reaction turbine is being acted on by the water stream.

Which of the following would not be used with a pelton wheel?

Wicket gates