What is the primary function of a surge tank in a hydraulic system?
A Store energy
B Increase flow rate
C Absorb pressure surges
D Absorb water
Surge tanks are used to absorb sudden pressure surges (water hammer) in a hydraulic system, preventing damage to pipelines and equipment by maintaining pressure stability during rapid flow changes.
What is the main purpose of a hydraulic gate in a dam?
A Store water
B Regulate water flow
C Generate electricity
D Measure pressure
Hydraulic gates in dams are used to regulate the flow of water, controlling how much water is released downstream. They help manage water levels and prevent overflow during heavy rainfall or flooding.
In a Pelton wheel, what is the function of the buckets?
A Convert kinetic energy into mechanical energy
B Store hydraulic energy
C Direct water into the turbine
D Convert kinetic energy to pressure energy
In a Pelton wheel, the buckets are designed to catch high-velocity water jets, converting the kinetic energy of the water into mechanical energy by causing the turbine to rotate.
What is cavitation in hydraulic systems?
A Increased pressure
B Increased fluid velocity
C Reduced flow rate
D Formation of vapor bubbles due to low pressure
Cavitation occurs when local pressure in a pump or turbine falls below the vapor pressure of the fluid, causing vapor bubbles to form. These bubbles collapse violently, causing damage to equipment.
How is water hammer typically caused in a pipeline system?
A Increased water velocity
B Sudden closure of a valve
C High water temperature
D Long pipe length
Water hammer occurs when a valve is suddenly closed, causing a rapid change in water flow. This creates a pressure wave that can damage pipes, valves, and other components in the system.
What is the role of a spillway in a dam structure?
A Increase pressure
B Store excess water
C Release excess water safely
D Regulate flow
A spillway allows controlled release of excess water from a reservoir to prevent overflow and structural damage to the dam. It helps maintain safe water levels during heavy rainfall or snowmelt.
What is “head loss” in a hydraulic system?
A Loss of fluid density
B Loss of pressure due to valve restriction
C Loss of fluid temperature
D Loss of energy due to friction or turbulence
Head loss occurs when energy is lost due to friction between the fluid and pipe walls or due to turbulence in the system. This loss results in a decrease in available pressure and flow rate.
In a Francis turbine, what is the primary energy conversion?
A Kinetic energy to pressure energy
B Kinetic energy to mechanical energy
C Pressure energy to kinetic energy
D Mechanical energy to kinetic energy
In a Francis turbine, water enters radially and flows axially through the turbine blades, where kinetic energy is converted into mechanical energy. It efficiently handles medium-head conditions and is widely used in hydroelectric plants.
What does the specific speed of a turbine indicate?
A The turbine’s rotational speed
B The speed of the water entering the turbine
C A measure of the turbine’s performance characteristics
D The turbine’s flow capacity
Specific speed is a dimensionless number used to classify turbines based on their performance. It helps in selecting the appropriate turbine type for a given flow, head, and speed condition in a hydroelectric plant.
What is the primary cause of energy dissipation in a hydraulic jump?
A Abrupt velocity reduction
B Change in water pressure
C Increased flow depth
D Increased water speed
A hydraulic jump occurs when high-velocity water abruptly slows down, causing energy dissipation. The water depth increases and turbulence forms, leading to energy loss that reduces flow velocity and pressure.
What does a flow control system regulate in a hydraulic system?
A Water temperature
B Fluid viscosity
C Turbine speed
D Water flow rate
A flow control system regulates the rate at which water or fluid moves through pipes, channels, or turbines. It ensures that the system operates within its design limits, preventing excessive flow or pressure.
What type of pump is typically used for high-pressure, low-flow applications?
A Centrifugal pump
B Reciprocating pump
C Gear pump
D Diaphragm pump
A reciprocating pump is ideal for high-pressure, low-flow conditions. It works by using a piston to create suction and pressure, delivering a fixed volume of fluid in each cycle, making it efficient in such scenarios.
What is the main function of guide vanes in a Kaplan turbine?
A Convert pressure energy to mechanical energy
B Regulate water flow to the runner blades
C Increase turbine efficiency
D Store hydraulic energy
Guide vanes in a Kaplan turbine control the flow of water entering the runner blades. By adjusting the angle of the vanes, they ensure optimal energy extraction from the water, improving efficiency under varying flow conditions.
What is the characteristic feature of an impulse turbine like the Pelton wheel?
A Water jets strike the blades to generate power
B Water enters through guide blades
C Water pressure decreases as it passes through
D Water flows axially through the blades
In an impulse turbine, like the Pelton wheel, high-velocity water jets strike specially designed buckets or blades. The force of the jets causes the turbine to rotate, converting kinetic energy into mechanical energy.
What is a typical result of cavitation in hydraulic turbines?
A Increased efficiency
B Increased pressure
C Noise and vibration
D Increased flow rate
Cavitation in turbines causes the formation of vapor bubbles due to low pressure. When these bubbles collapse, they generate noise and vibrations that can damage turbine components and reduce operational efficiency.