Hydraulic Turbines and Hydroelectric Power Generation

What is the main function of turbines?

Convert thermal energy into mechanical energy
Convert electrical energy into mechanical energy
Convert mechanical energy into hydraulic energy
Convert hydraulic energy into mechanical energy (correct)

What is the term used to describe the electric power obtained from the hydraulic energy?

Hydroelectric power (correct)
Thermal power
Electric power
Hydraulic power

What is the Gross Head of a turbine?

The head race level minus tail race level when no water is flowing (correct)
The efficiency of a turbine
The head loss due to friction between penstocks and water
The head available at the inlet of the turbine

Which term is used interchangeably with 'effective head' for a turbine?

Net head (B) Signup and view all the answers

What are losses caused by bend, pipe fittings, and entrance of penstock collectively known as?

Frictional losses (C) Signup and view all the answers

In the equation H = Hg - hf, what does 'hf' represent?

Friction head loss between penstocks and water (D) Signup and view all the answers

What is the main difference between an inward radial flow turbine and an outward radial flow turbine?

Direction of water flow (B) Signup and view all the answers

Which type of turbine is a Pelton wheel?

Tangential flow impulse turbine (C) Signup and view all the answers

What is the function of the casing in a Pelton turbine?

Prevent splashing of water (B) Signup and view all the answers

Why is a breaking jet used in a Pelton turbine?

To stop the runner quickly (B) Signup and view all the answers

What is controlled by a spear in the nozzle of a Pelton turbine?

Amount of water striking the runner (C) Signup and view all the answers

How are the buckets of a Pelton wheel shaped to deflect the water jet?

$160^{ ext{o}}$ (A) Signup and view all the answers

What part of a Pelton wheel divides the jet into two equal parts before it strikes the buckets?

$90^{ ext{o}}$ splitter (A) Signup and view all the answers

What describes a tangential flow impulse turbine like a Pelton wheel?

$180^{ ext{o}}$ water flow (D) Signup and view all the answers

Which material is NOT typically used for making the buckets of a Pelton wheel?

$180^{ ext{o}}$ splitter (C) Signup and view all the answers

What is the mathematical expression for hydraulic efficiency?

Power at shaft/Power supplied at inlet (B) Signup and view all the answers

Which type of turbine is identified by having only kinetic energy at the inlet?

Impulse turbine (A) Signup and view all the answers

What does volumetric efficiency measure?

Volume of water striking the runner (D) Signup and view all the answers

In a reaction turbine, what happens to the pressure energy as water flows through the runner?

Changes into kinetic energy (C) Signup and view all the answers

Which type of turbine is enclosed in an air-tight casing?

Tangential flow turbine (C) Signup and view all the answers

What is the definition of mechanical efficiency?

Power at shaft of the turbine/Power delivered by water to the runner (C) Signup and view all the answers

'Specific speed' is a classification criterion based on what aspect of hydraulic turbines?

Energy available at inlet (A) Signup and view all the answers

What is the primary reason for a decrease in power as water flows over the vanes of a turbine?

Hydraulic losses (D) Signup and view all the answers

'Overall Efficiency' is defined as the ratio of what variables?

'Power available at shaft' to 'Power supplied at inlet' (C) Signup and view all the answers

'Volumetric Efficiency' measures the ratio of what volumes?

'Water striking the runner' to 'Water supplied to turbine' (B) Signup and view all the answers

What is the purpose of the draft-tube in a turbine system?

To create a negative head at the outlet of the runner (A) Signup and view all the answers

In the design of a Pelton wheel, what is determined as 5 times the diameter of the jet?

Width of the buckets (D) Signup and view all the answers

Who is the modern Francis Turbine named after?

J.B. Francis (D) Signup and view all the answers

What type of turbine is a Francis Turbine?

Mixed flow type turbine (A) Signup and view all the answers

What is the speed ratio for a Francis Turbine?

$u1 / \sqrt{2gH}$ (C) Signup and view all the answers

In an inward flow reaction turbine, where does the water enter and leave?

Enters radially, leaves axially (C) Signup and view all the answers

'Hub' or 'boss' in an axial flow reaction turbine serves as what?

Blade attachment point (C) Signup and view all the answers

'Flow ratio' for a Francis Turbine is expressed as?

$Vf1/ \sqrt{2gH}$ (B) Signup and view all the answers

What happens to the speed of the turbine when the load on the generator decreases?

The speed of the turbine increases. (A) Signup and view all the answers

How does the centrifugal governor respond when the speed of the generator increases?

It rotates at an increased speed. (D) Signup and view all the answers

What is the role of the fly-balls in the centrifugal governor system?

To respond to changes in centrifugal force. (D) Signup and view all the answers

When the sleeve moves upward, what happens to the piston rod of the control valve?

It moves downward. (A) Signup and view all the answers

What effect does closing valve V have on the rate of flow of water to the turbine?

Decreases it. (C) Signup and view all the answers

How does increasing the area of flow of water at the outlet of the nozzle affect the speed of the turbine?

Increases it. (D) Signup and view all the answers

What is the purpose of a draft-tube in a turbine?

Convert kinetic energy into useful pressure energy (B) Signup and view all the answers

What is the main function of governing in a turbine system?

Regulate the flow rate through the turbines (C) Signup and view all the answers

Which type of draft-tube is known to be most efficient?

Conical draft-tubes (C) Signup and view all the answers

What happens if a reaction turbine is not fitted with a draft-tube?

Water freely discharges into the tail race (B) Signup and view all the answers

Why is it important to keep the speed of a turbine constant?

To ensure constant power generation by the generator (C) Signup and view all the answers

How does governing help in maintaining constant speed of a turbine?

By regulating flow through the turbines based on load conditions (B) Signup and view all the answers

What drives the gear pump in an oil pressure governor for a Pelton turbine?

The power obtained from the turbine shaft (B) Signup and view all the answers

Which element is responsible for driving the centrifugal governor in governing a Pelton turbine?

Centrifugal governor or pendulum (D) Signup and view all the answers

What part of an oil pressure governor receives power from the turbine shaft?

The gear pump also called oil pump, which is driven by the power obtained from turbine shaft (B) Signup and view all the answers