Fluid Machineries Hydraulic Turbines

Agnor River

River in Luzon that supplies water to the Ambuklao, Binga, and San Roque hydropower plants.

Ambuklao Hydropower Plant

A hydroelectric plant in Luzon supplied by the Agno River.

Binga Hydropower Plant

A hydroelectric plant in Luzon supplied by the Agno River.

San Roque Hydropower Plant

A hydroelectric plant in Luzon supplied by the Agno River.

Magat River

River that powers the Magat Hydroelectric Power Plant.

Magat Hydroelectric Power Plant

A hydroelectric plant powered by the Magat River.

Angat River

A major river source supplying water to the Angat Hydroelectric Power Plant.

Angat Hydroelectric Power Plant

A hydroelectric plant supplied by the Angat River.

Casecnan River

River used for the Casecnan Hydroelectric Power Plant.

Taan River

River in Nueva Vizcaya used for the Casecnan Hydroelectric Power Plant.

Nueva Vizcaya

A province where the Casecnan and Taan Rivers are located.

Casecnan Hydroelectric Power Plant

A hydroelectric plant utilizing water from the Casecnan and Taan Rivers.

Specific Speed (Ns)

Also referred to as the shape factor, is an important non-dimensional parameter governing the selection of the type of pump or turbine to be used. For turbines, it is the speed at which a particular turbine will develop 1 kW power under a head of 1 m.

Power Specific Speed (Nps)

For hydraulic turbines, is a non-dimensional parameter often used to determine the runner best suited for a given operating range.

Specific Diameter (Ds)

Is a non-dimensional parameter used to decide upon the type of turbine to be used.

Spouting Velocity (Vo)

The ideal (isentropic) velocity of the jet.

Generator Efficiency (ηg)

The ratio of the generator output power to the turbine brake power.

Overall Turbine Efficiency (ηt)

The ratio of the shaft output to the power available at the turbine inlet.

Mechanical Efficiency (ηm)

The ratio of the shaft output to the runner output. This accounts for the mechanical losses.

Hydraulic Efficiency (ηh)

Is the ratio of the power developed by the runner to the theoretical power generated by the turbine.

Turbine Power (Pt)

The theoretical power generated by the turbine.

Head Loss Due to Friction (HL)

The friction losses in the penstock.

Effective Head (He)

The head available at the turbine inlet. This is the difference between the gross head and the friction losses occurring in the flow passage, from the reservoir to the turbine inlet.

Gross Head (Hg)

The difference between the headrace elevation and the tail race elevation when there is no flow.

Very Low Head Turbine

When head is less than 15 m. Example: Propeller turbine.

Low Head Turbine

When head is between 15–60 m. Example: Kaplan turbine.

Medium Head Turbine

When head is between 60–250 m. Example: Francis turbine.

High Head Turbine

When head is above 250 m. Example: Pelton wheel.

Tangential Flow Turbine

A turbine in which water strikes the buckets of the runner tangent to the path of rotation. Example: Pelton turbine and Turgo turbine.

Axial Flow Turbine

A turbine in which water enters and flows parallel to the axis of the turbine shaft. Example: Kaplan turbine, propeller turbine.

Mixed Flow Turbine

A turbine in which the direction of flow is partly radial and partly axial. Water enters the blade radially and comes out axially or parallel to the turbine shaft. Example: Francis turbine.

Impulse Turbine

Generally uses the velocity of water to move the runner. As the water strikes the buckets, the runner rotates with the water exiting on the downside of the turbine housing. commonly used for high head and low flow applications. Example: Pelton, Cross Flow, and Turgo turbine.

Reaction Turbine

A turbine which develops power from the combined action of the pressure and velocity of water. The runner is placed directly in the water stream flowing over the blades rather than striking them. They are generally used for low head and high flow applications. Example: Kaplan, Francis, and Propeller turbine.

Accumulator

A container which stores fluids under pressure as a source of hydraulic power. It may also be used as a shock absorber.

Actuator

A device which converts hydraulic power into mechanical force and motion. (Examples: hydraulic cylinders and motors.)

Affinity Laws

Allow the output of a turbine to be predicted based on model tests.

Axis

An imaginary line about which a body rotates.

Blade

Is the individual component responsible for extracting energy from the velocity of the water jet and uses it to do mechanical work on a rotating output shaft.

Braking Jet

The jet of water produced by the brake nozzle.

Cavitation

A phenomenon which occurs when the pressure at a point in a hydraulic system is lowered below the vapor pressure of the oil in the system. This allows bubbles of oil vapor to form in the oil. If this occurs at the pump inlet, the quick pressure rise inside the pump forces these bubbles to collapse violently. This can cause erosion of metal parts, noise, and vibration.

Control Gate

A barrier that regulates the flow of water entering the penstock.

Dam

A concrete structure that impounds water for irrigation and hydropower purposes.

Deflectors

Serve to bend the jet away from the runner at reduced loads to avoid a high-speed increase.

Design Head (Hd)

Is the net head at which peak efficiency is desired. This head should preferably approximate the weighted average head, but must be so selected that the maximum and minimum heads are not beyond the permissible operating range of the turbine. This is the head which determines the basic dimensions of the turbine and therefore of the power plant.

Duct

A channel or tube for conveying fluid.

Efficiency

The ratio of the useful work performed by a machine or process to the total energy expended or heat taken in.

Forebay or Pre-dam

Is a small reservoir where water is temporarily stored. It is used to trap sediment and debris to ensure that clean water enters the penstock.

Francis Turbine

Is an inward flow reaction turbine having radial discharge at outlet.

Generator

A device that converts mechanical energy to electrical energy. An arrangement of magnets spinning inside a coil of wire to produce electricity.

Guide Bearing

The function of the turbine guide bearing is to resist the mechanical imbalance and hydraulic side loads from the turbine runner thereby maintaining the turbine runner in its center position in the runner seals.

Head Cover

Supports the weights of guide vanes and confines the vibrations and unnecessary movements of the wicket gates.

Head Water

Water level at supply reservoir.

Hub

The part of the runner to which blades are mounted.

Hydraulic Efficiency

It is the ratio of the power developed by runner to the power supplied at the inlet of the turbine.

Hydraulic Turbine

Is a prime mover that converts the kinetic energy and potential energy of flowing water into mechanical power for the purpose of driving an electrical generator or other machinery.

Hydroelectricity

Is electricity produced from hydropower.

Hydropower

The process of generating electricity by capturing the potential energy of falling water through the use of a water wheel (turbine) to mechanically spin rotating magnets which create electrical current that can be distributed to users by transmission lines.

Large Hydropower

The U.S. Department of Energy defines large hydropower as facilities that have a capacity of more than 30 megawatts.

Small Hydropower

The U.S. Department of Energy defines small hydropower as facilities that have a capacity of 100 kilowatts to 30 megawatts.

Micro Hydropower

A plant has a capacity of up to 100 kilowatts. Also can produce enough electricity for a home, farm, ranch, or village.

Jet

A fluid stream issuing from an orifice or nozzle.

Kaplan Turbine

Is a propeller type water turbine with adjustable blades which are reversible. Mainly designed for low head water applications.

Draft Tube

The conically shaped conduit with the smaller end attached to the turbine discharge. It slows down the high discharge velocity water coming from the runner as it discharges to the tail race.

Guide Vanes

The movable vanes used to control the angle of water striking the runner blades.

Francis Runner Blades

The heart of the Francis turbine, the blades are designed so that the upper part uses the reaction force of the water while the lower part uses the impulse action of the water. These two forces combined make the runner rotate.

Kaplan Runner Blades

The heart of the Kaplan turbine, blades are adjustable for optimum angle of attack to ensure maximum power output.

Spiral Casing

A winding conduit from the penstock to the runner, the cross-sectional area of which decreases uniformly to keep the fluid velocity constant.

Stay Vanes

Parts that direct the water to the guide vanes. They are stationary blades that reduce the swirling of water due to radial flow (for Francis turbine only).

Nose Cone

The end component of the runner that reduces losses (for Kaplan turbine only).

Maximum Head (Hmax)

Is the gross head difference in elevation between the maximum forebay level without surcharge and the tailrace level without spillway discharge. Under this condition, hydraulic losses are negligible and may be disregarded.

Minimum Head (Hmin)

Is the net head resulting from the difference in elevation between the minimum forebay level and the tailrace level minus losses with all turbines operating at full specified gate opening.

Mechanical Efficiency

It is the ratio of the power available at turbine shaft to the power available at turbine runner.

Motor

A device that converts electrical energy to mechanical energy.

Overall Efficiency

It is the ratio of the power available at the turbine shaft to the power available from the jet.

Pelton Turbine

Is a tangential flow impulse turbine that uses double curved buckets to capture the jet of water. It is primarily used for high heads.

Brake Nozzle

The part that produces a jet directed at the back of the buckets. This is opened when there is a need to slow down or stop the turbine.

Buckets

Cups or bowls attached to the runner which take the impact of water from the nozzle causing the runner to rotate.

Casing

The outer cover in which the turbine is placed so that water cannot splash outside the surroundings.

Nozzle

Is provided at end of penstock and its main function is to increase the velocity of the water jet striking the buckets of the turbine.

Spear

The conical needle provided within the nozzle, its main function is to control the amount and speed of water striking the buckets.

Splitter

The dividing wall which separates each bucket of a Pelton turbine into two hemispherical parts.

Penstock

A closed conduit or channel that conveys the flow of water from the forebay to the turbine.

Pentrough

An open usually planked or boarded trough or tank from which water falls onto a waterwheel.

Propeller

A mechanical device for driving a boat or aircraft, consisting of a revolving shaft with two or more broad, angled blades attached to it.

Reservoir

A large natural or artificial enclosure used as a source of water supply in a hydraulic system.

Runaway Speed

The speed at full flow and no shaft load.

Runner

A rotating circular disc on the periphery of which the buckets (Pelton) or blades (Francis/Kaplan) are mounted with equal spacing between them.

Scroll Casing

A spiral casing with a decreasing area to make sure that water flows into the central portion of the Kaplan turbine at uniform velocity.

Shaft Seal

Prevents water leakage between main shaft and head cover.

Slit Sluice

Is a chamber that collects the mud and through which the mud is discharged.

Sluice Gate

A sliding gate used to control the flow of water.

Specific Speed

The speed at which the turbine will run when developing one unit power under a unit head.

Spillway

The structure or portion of a larger structure that is used to release excess water over or around a dam.

Stator

The stationary part of a rotary system found in electric generators and electric motors. Its main purpose is to keep the field aligned.

Surge Tank

Is a standpipe connected to the penstock and open to the atmosphere so that the water will always be at atmospheric pressure.

Tail Water

The water level downstream of the powerhouse or dam.

Tailrace

The downstream channel that carries water away from a dam or powerhouse.

Trash Rack

A screen that prevents leaves, branches, and other water contaminants from entering the penstock.

Turbine Shaft

The rotating element, usually circular in cross section, which is used to transmit power from the turbine runner to the generator shaft and generator rotor.

Turbine

A rotary engine that converts the energy of a moving stream of water, steam, or gas into mechanical energy.