Last updated: November 25, 2017. Question: What does a windmill standing on a sandcastle have in common with a massive ocean liner, a hydroelectric dam, or a transatlantic jet? Answer: They all use turbines—machines that capture energy from a moving liquid or gas. In a sandcastle windmill, the curved blades are designed to catch the wind's energy so they flutter and spin. In an ocean liner or a jet, hot burning gas is used to spin metal blades at high speed—capturing energy that's used to power the ship's propeller or push the plane through the sky.
Turbines also help us make the vast majority of our electricity: turbines driven by steam are used in virtually every major power plant, while wind and water turbines help us to produce. Wherever energy's being harnessed for human needs, turbines are usually somewhere nearby. Let's take a closer look at these handy machines and find out how they work!
Photo: A cutaway model of a steam turbine used to generate electricity in a power plant. This one is an exhibit at the Think Tank science museum in Birmingham, England.
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What is a turbine? Photo: A prototype gas turbine produced for a high-efficiency power plant. Each of the metal wheels is a separate turbine stage designed to extract a bit more energy from a high-speed gas. You can see how big this turbine is by looking at the little man dressed in white sitting on the middle of the machine. Photo taken at the National Energy Technology Laboratory, Morgantown courtesy of. A windmill is the simplest kind of turbine: a machine designed to capture some of the from a moving fluid (a liquid or a gas) so it can be put to use.
As the wind blows past a windmill's sails, they rotate, removing some of the wind's kinetic energy (energy of movement) and converting it into mechanical energy that turns heavy, rotating stones inside the mill. The faster the wind blows, the more energy it contains; the faster the sails spin, the more energy is supplied to the mill.
Adding more sails to the windmill or changing their design so they catch the wind better can also help to capture more of the wind's energy. Although you may not realize it, the wind blows just a bit more slowly after it's passed by a windmill than before—it's given up some of its energy to the mill! The key parts of a turbine are a set of blades that catch the moving fluid, a shaft or that rotates as the blades move, and some sort of machine that's driven by the axle.
In a modern, there are typically three propeller-like blades attached to an axle that powers an electricity. In an ancient waterwheel, there are wooden slats that turn as the water flows under or over them, turning the axle to which the wheel is attached and usually powering some kind of milling machine. Impulse and reaction turbines Turbines work in two different ways described as impulse and reaction—terms that are often very confusingly described (and sometimes completely muddled up) when people try to explain them. So what's the difference?
Impulse turbines In an impulse turbine, a fast-moving fluid is fired through a narrow nozzle at the turbine blades to make them spin around. The blades of an impulse turbine are usually bucket-shaped so they catch the fluid and direct it off at an angle or sometimes even back the way it came (because that gives the most efficient transfer of energy from the fluid to the turbine). In an impulse turbine, the fluid is forced to hit the turbine at high speed.
Artwork: A Pelton water wheel is an example of an impulse turbine. It spins as one or more high-pressure water jets (blue), controlled by a valve (green), fire into the buckets around the edge of the wheel (red). Lester Pelton was granted a patent for this idea in 1889, from which this drawing is taken.
Artwork from by Lester Pelton, courtesy of US Patent and Trademark Office. Artwork: An impulse turbine like this works when the incoming fluid hits the buckets and bounces back again.
The exact shape of the buckets and how the fluid hits them makes a big difference to how much energy the turbine can capture. Imagine trying to make a wheel like this turn around by kicking soccer balls into its paddles. You'd need the balls to hit hard and bounce back well to get the wheel spinning—and those constant energy impulses are the key to how it works. The tells us that the energy the wheel gains, each time a ball strikes it, is equal to the energy that the ball loses—so the balls will be traveling more slowly when they bounce back. Also, tells us that the momentum gained by the wheel when a ball hits it is equal to the momentum lost by the ball itself; the longer a ball touches the wheel, and the harder (more forcefully) it hits, the more momentum it will transfer. Water turbines are often based around an impulse turbine (though some do work using reaction turbines). They're simple in design, easy to build, and cheap to maintain, not least because they don't need to be contained inside a pipe or housing (unlike reaction turbines).
Reaction turbines In a reaction turbine, the blades sit in a much larger volume of fluid and turn around as the fluid flows past them. A reaction turbine doesn't change the direction of the fluid flow as drastically as an impulse turbine: it simply spins as the fluid pushes through and past its blades. Wind turbines are perhaps the most familiar examples of reaction turbines. Photo: A typical reaction turbine from a geothermal power plant. Water or steam flows past the angled blades, pushing them around and turning the central shaft to which they're attached.
The shaft spins a generator that makes electricity. Photo by Henry Price courtesy of.
Artwork: A reaction turbine like this is much more like a propeller. The main difference is that there are more vanes in a turbine (I've just drawn four blades for simplicity) and often multiple sets of vanes (multiple stages), as you can see in the photos of the steam and gas turbines at the top of this page. If an impulse turbine is a bit like kicking soccer balls, a reaction turbine is more like —in reverse. Let me explain! Think of how you do freestyle (front crawl) by hauling your arms through the water, starting with each hand as far in front as you can reach and ending with a 'follow through' that throws your arm well behind you. What you're trying to achieve is to keep your hand and forearm pushing against the water for as long as possible, so you transfer as much energy as you can in each stroke.
A reaction turbine is using the same idea in reverse: imagine fast-flowing water moving past you so it makes your arms and legs move and supplies energy to your body! With a reaction turbine, you want the water to touch the blades smoothly, for as long as it can, so it gives up as much energy as possible.
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There are plenty of helpful hints and guides throughout too helping you get to grips with 'snapping' when you draw rectangles, circles and other shapes. There's a refreshing lack of technical jargon in SketchUp Pro and unfamiliar terms to beginners such as the 'Extrude' tool have been renamed to the more obvious 'Push/Pull' for example.
My memories software. The water isn't hitting the blades and bouncing off, as it does in an impulse turbine: instead, the blades are moving more smoothly, 'going with the flow.' Thinking backwards Photo: Turbines and propellers work in exactly opposite ways. Propellers use energy to make a fluid move (air, in the case of a plane, or water, in a ship or ); turbines harness energy when a moving fluid flows past them. Left: Propeller photo by Tech.
Pyle courtesy of. Photo: Turbine blades are shaped in a similar way to propeller blades but are typically made from high-performance because the fluid flowing past them can be very hot. Photo of a turbine blade exhibited at Think Tank, the science museum in Birmingham, England.
You might have noticed that wind turbines look just like giant —and that's another way to think of turbines: as propellers working in reverse. In an, the engine turns the propeller at high speed, the propeller creates a backward-moving draft of air, and that's what pushes—propels—the plane forward. With a propeller, the moving blades are driving the air; with a turbine, the air is driving the blades. Turbines are also similar to. In a pump, you have a spinning paddle wheel that sucks water in through one pipe and throws it out from another so you can move water (or another liquid) from one place to another. If you take a water pump apart, you can see the internal paddle wheel (which is called an impeller) is very similar to what you'd find inside a water turbine.
The difference is that a pump uses energy to make a fluid move, while a turbine captures the energy from a moving fluid. Turbines in action Broadly speaking, we divide turbines into four kinds according to the type of fluid that drives them: water, wind, steam, and gas. Although all four types work in essentially the same way—spinning around as the fluid moves against them—they are subtly different and have to be engineered in very different ways. Steam turbines, for example, turn incredibly quickly because steam is produced under high-pressure. Wind turbines that make turn relatively slowly (mainly for safety reasons), so they need to be huge to capture decent amounts of energy. Gas turbines need to be made from specially resilient because they work at such high temperatures.
Water turbines are often very big because they have to extract energy from an entire, dammed and diverted to flow past them. They can turn relatively slowly, because is water is heavy and carries a lot of energy (because of its high mass) even when it flows at low speeds. Water turbines Photo: A giant Francis reaction turbine (the orange wheel at the top) being lowered into position at the in Washington State, USA. Water flows past the angled blades, pushing them around and turning the shaft to which they're attached.
The shaft spins an electricity generator that makes power. Photo by courtesy of. Water wheels, which date back over 2000 years to the time of the ancient Greeks, were the original water turbines. Today, the same principle is used to make electricity in hydroelectric power plants.
The basic idea of hydroelectric power is that you dam a to harness its energy. Instead of the river flowing freely downhill from its hill or mountain source toward the sea, you make it fall through a height (called a head) so it picks up speed (in other words, so its potential energy is converted to kinetic energy), then channel it through a pipe called a penstock past a turbine and generator. Hydroelectricity is effectively a three-step energy conversion:. The river's original potential energy (which it has because it starts from high ground) is turned into kinetic energy when the water falls through a height. The kinetic energy in the moving water is converted into mechanical energy by a water turbine.
The spinning water turbine drives a that turns the mechanical energy into electrical energy. Different kinds of water turbine are used depending on the geography of the area, how much water is available (the flow), and the distance over which it can be made to fall (the head). Some hydroelectric plants use bucket-like impulse turbines (typically Pelton wheels); others use Francis, Kaplan, or Deriaz reaction turbines.
The type of turbine is chosen carefully to extract the maximum amount of energy from the water. Wind turbines These are covered in much more detail in our separate article on. Photo: A typical wind turbine, in Staffordshire, England. The tower is 50m (150ft) off the ground because the wind moves faster when it's clear of ground-level obstructions.
The rotor blades are 15m (50ft) in diameter and, with a huge sweep, capture up to 225kW (kilowatts) of energy. Steam turbines Steam turbines evolved from the that changed the world in the 18th and 19th centuries. A steam engine burns coal on an open fire to release the heat it contains. The heat is used to boil water and make steam, which pushes a piston in a cylinder to power a machine such as a railroad locomotive. This is quite inefficient (it wastes energy) for a whole variety of reasons. A much better design takes the steam and channels it past the blades of a turbine, which spins around like a propeller and drives the machine as it goes.
Steam turbines were pioneered by British engineer Charles Parsons (1854–1931), who used them to power a famously speedy motorboat called Turbinia in 1889. Since then, they've been used in many different ways.
Virtually all generate electricity using steam turbines. In a coal-fired plant, coal is burned in a furnace and used to heat water to make steam that spins high-speed turbines connected to electricity generators. In a, the heat that makes the steam comes from atomic reactions. Unlike water and wind turbines, which place a single rotating turbine in the flow of liquid or gas, steam turbines have a whole series of turbines (each of which is known as a stage) arranged in a sequence inside what is effectively a closed pipe. As the steam enters the pipe, it's channeled past each stage in turn so progressively more of its energy is extracted.
If you've ever watched a kettle boiling, you'll know that steam expands and moves very quickly if it's directed through a nozzle. For that reason, steam turbines turn at very high speeds—many times faster than wind or water turbines. Read more in in main article on. Gas turbines Airplane jet engines are a bit like steam turbines in that they have multiple stages. Instead of steam, they're driven by a mixture of the air sucked in at the front of the engine and the incredibly hot gases made by burning huge quantities of kerosene (petroleum-based fuel). Somewhat less powerful gas turbine engines are also used in modern railroad locomotives and industrial machines.
See our article on for more details. Turbines for kids? How do you explain something as complex as a turbine to a young child?
All that stuff up above about reaction versus impulse turbines, stages, swimming backwards, and so on is bound to confuse. Photo: Imagine your hand could capture the energy in running water and your body your transform it into a more useful form.
That would make you a kind of turbine. Actually it's easy to explain turbines very simply—and here's how you do it. Take your child into a bathroom or kitchen and get them to hold their hand under a cold tap. Turn on the water a little bit (just a trickle).
Now, to their surprise, turn it on really hard and get them to keep their hand there. 'Can you feel the force of the water hitting your hand? The moving water has a lot of energy and power in it.
Imagine you are a machine that could catch the energy and use it to do something useful, like making electricity. That's what a turbine is. It's a machine that catches energy from a moving liquid (like water) or gas (like air) and helps us do something useful. So a wind turbine is just a machine that catches air with its propeller, turns a generator hidden inside, and makes electricity. The more energy there is in the air, the more power a wind turbine can make. It's just like the water.
The harder it's hitting your hand, the more energy it has, so the more energy you could catch and turn into power. A wind turbine is built very high up in the air because the wind (the air) moves much faster there. That's like turning the tap on harder. It means the wind turbine can catch and make more power for us. Different types of turbines catch different types of fluids (liquids or gases). So while a wind turbine or a windmill catches air, a steam turbine catches hot steam made from burning something like coal, and a water wheel (which is just a water turbine) catches water.
All turbines do the same job: they capture energy (the energy in the moving liquid or gas) and turn it into a form we can use (movement in a machine or electricity). Turbines are energy-catching machines.' Turbines—child's play really! Find out more On this website.
Books. by S M Yahya. Tata McGraw-Hill Education, 2010. A detailed (944-page) and very wide-ranging textbook covering the use of turbines for power production, fans and propellers, and similar energy-conversion technologies.
by Janet Ramage. Oxford/New York: Oxford University Press, 1997. A more general book about energy concepts—useful for basic background reading. Articles.
by G. Pascal Zachary. IEEE Spectrum, May 1, 2007. How small water turbines are proving effective for generating renewable energy in remote parts of Africa.
There are two main types of hydro turbines: impulse and reaction. The type of hydropower turbine selected for a project is based on the height of standing water—referred to as 'head'—and the flow, or volume of water, at the site. Other deciding factors include how deep the turbine must be set, efficiency, and cost. Terms used on this page are defined in the glossary. Impulse Turbine The impulse turbine generally uses the velocity of the water to move the runner and discharges to atmospheric pressure.
The water stream hits each bucket on the runner. There is no suction on the down side of the turbine, and the water flows out the bottom of the turbine housing after hitting the runner. An impulse turbine is generally suitable for high head, low flow applications. A pelton wheel has one or more free jets discharging water into an aerated space and impinging on the buckets of a runner. Draft tubes are not required for impulse turbine since the runner must be located above the maximum tailwater to permit operation at atmospheric pressure. A Turgo Wheel is a variation on the Pelton and is made exclusively by Gilkes in England.
Impulse And Reaction Turbines
The Turgo runner is a cast wheel whose shape generally resembles a fan blade that is closed on the outer edges. The water stream is applied on one side, goes across the blades and exits on the other side. Cross-Flow A cross-flow turbine is drum-shaped and uses an elongated, rectangular-section nozzle directed against curved vanes on a cylindrically shaped runner. It resembles a 'squirrel cage' blower. The cross-flow turbine allows the water to flow through the blades twice.
Impulse Turbine Design
The first pass is when the water flows from the outside of the blades to the inside; the second pass is from the inside back out. A guide vane at the entrance to the turbine directs the flow to a limited portion of the runner. The cross-flow was developed to accommodate larger water flows and lower heads than the Pelton. Reaction Turbine A reaction turbine develops power from the combined action of pressure and moving water. The runner is placed directly in the water stream flowing over the blades rather than striking each individually.
Reaction turbines are generally used for sites with lower head and higher flows than compared with the impulse turbines. A Francis turbine has a runner with fixed buckets (vanes), usually nine or more.
Water is introduced just above the runner and all around it and then falls through, causing it to spin. Besides the runner, the other major components are the scroll case, wicket gates, and draft tube. Kinetic Kinetic energy turbines, also called free-flow turbines, generate electricity from the kinetic energy present in flowing water rather than the potential energy from the head. The systems may operate in rivers, man-made channels, tidal waters, or ocean currents. Kinetic systems utilize the water stream's natural pathway. They do not require the diversion of water through manmade channels, riverbeds, or pipes, although they might have applications in such conduits.
Kinetic systems do not require large civil works; however, they can use existing structures such as bridges, tailraces and channels. Learn more about hydropower technology.
There are two main types of hydro turbines: impulse and reaction. The type of hydropower turbine selected for a project is based on the height of standing water—referred to as 'head'—and the flow, or volume of water, at the site.
Other deciding factors include how deep the turbine must be set, efficiency, and cost. Terms used on this page are defined in the glossary. Impulse Turbine The impulse turbine generally uses the velocity of the water to move the runner and discharges to atmospheric pressure. The water stream hits each bucket on the runner. There is no suction on the down side of the turbine, and the water flows out the bottom of the turbine housing after hitting the runner. An impulse turbine is generally suitable for high head, low flow applications.
A pelton wheel has one or more free jets discharging water into an aerated space and impinging on the buckets of a runner. Draft tubes are not required for impulse turbine since the runner must be located above the maximum tailwater to permit operation at atmospheric pressure. A Turgo Wheel is a variation on the Pelton and is made exclusively by Gilkes in England. The Turgo runner is a cast wheel whose shape generally resembles a fan blade that is closed on the outer edges.
The water stream is applied on one side, goes across the blades and exits on the other side. Cross-Flow A cross-flow turbine is drum-shaped and uses an elongated, rectangular-section nozzle directed against curved vanes on a cylindrically shaped runner. It resembles a 'squirrel cage' blower. The cross-flow turbine allows the water to flow through the blades twice. The first pass is when the water flows from the outside of the blades to the inside; the second pass is from the inside back out.
A guide vane at the entrance to the turbine directs the flow to a limited portion of the runner. The cross-flow was developed to accommodate larger water flows and lower heads than the Pelton. Reaction Turbine A reaction turbine develops power from the combined action of pressure and moving water. The runner is placed directly in the water stream flowing over the blades rather than striking each individually. Reaction turbines are generally used for sites with lower head and higher flows than compared with the impulse turbines.
A Francis turbine has a runner with fixed buckets (vanes), usually nine or more. Water is introduced just above the runner and all around it and then falls through, causing it to spin. Besides the runner, the other major components are the scroll case, wicket gates, and draft tube. Kinetic Kinetic energy turbines, also called free-flow turbines, generate electricity from the kinetic energy present in flowing water rather than the potential energy from the head. The systems may operate in rivers, man-made channels, tidal waters, or ocean currents. Kinetic systems utilize the water stream's natural pathway.
They do not require the diversion of water through manmade channels, riverbeds, or pipes, although they might have applications in such conduits. Kinetic systems do not require large civil works; however, they can use existing structures such as bridges, tailraces and channels. Learn more about hydropower technology.
Higher efficiency and reliability for any thermal cycle requirements GE Oil & Gas Reaction Steam Turbines are based on a modular turbine design to ensure reliability with highest performance. The machines are customized using pre-engineered, field-proven stator and rotor components optimized and tailored to the thermal cycle requirements to provide higher efficiency over the entire operating range.
Inlet sections are selected from a large array of modules, with progressive temperature capabilities up to 565°C/1050°F to satisfy from the smallest to the largest power output requirements. The turbine exhausts are selected from a large array of backpressure and condensing modules available with either a radial or axial configuration. The low pressure stages are selected from a set of families of three-dimensional stages having variable or fixed speed capabilities to best match the specific application. The Intermediate pressure portion is composed of sub-modules to match specific plant process requirements. They are engineered and built to provide excellent fit in a wide range of oil and gas applications, including urea, ammonia, ethylene, methanol, refinery, syn-fuels, process air, GTL, and LNG/FLNG. They also cover a variety of power generation applications, including combined cycles, cogeneration, waste-to-energy, and biomass, geothermal, and solar. GE Oil & Gas as digital industrial company is harnessing the power of data to help our customers make better and quicker decisions and to make their operations and equipment as productive and efficient as they can be.
Thanks to the digital twin approach and advanced sensors designed for on-line continuous steam turbines monitoring, it is now possible to benefit from digital solutions able to reduce commissioning time, increase working hours and optimize maintenance intervals. These features are already embedded in new turbines, while can be also applied on installed machine as small control panel upgrade. SC/SAC Series These single-flow turbines use both impulse and reaction blades for top efficiency over a wide range of operating conditions. Used in condensing configurations, they can have sliding and/or fixed pressure control, up to two controlled or six uncontrolled extractions, axial or radial (up/down) exhaust, and can be base or foundation mounted. SNC/SANC Series These turbines have the same features as the SC/SAC series, but are designed for backpressure configurations with dedicated exhaust modules. A5/A9 Series These single-casing steam turbines provide the most effective solution for small reheat, very compact design applications.
They are configured with a central admission and back-to-back flow path to reduce temperature gradients and minimize thermal stress. Other features include bleeds and an extraction IP section, axial exhaust, sliding and/or fixed pressure control.
SG Series SG series turbines, in single or double flow configuration, feature a unique design and materials to withstand direct geothermal steam conditions such as saturated or slightly superheated steam, corrosive contaminants, and low pressure. Options include, governing impulse or reaction blades, steam chest partializing system to deal with well depletion, inlet pipe mounted trip and control valves, and axial or radial (up/down/lateral) exhaust.
SDF Series SDF double flow turbines have impulse and reaction blades designed to accommodate low pressure steam. They can be used like the low pressure body of a two casing turbine, or like a stand-alone turbine for low pressure steam conditions. Used in condensing configuration, they have sliding and/or fixed pressure control, and radial (up/down) exhaust and are typically used as a revamp option. More Information. Specifications SC/SAC SNC/SANC A5/A9 SG SDF Power 2 to 100 MW 2 to 100 MW 20 to 100 MW 5 to 100 MW 5 to 100 MW Speed 3,000 to 15,000 3,000 to 15,000 3,000 to 3,600 rpm 3,000 and 3,600 rpm 3,000 to 15,000 rpm Rated steam conditions 140 bar (2,030 psi) 565°C (1,050°F) 30 bar (435 psi) 300°C (572°F) Arrangement Single casing Condensing LP stages Up to 31” (50Hz) Up to 25” (60Hz) Up to 31” (50Hz) Up to 25” (60Hz) Up to 26” (50 Hz) Up to 23” (60 Hz) Up to 26” (50 Hz) Up to 25” (60 Hz) Max. Backpressure 60 bar (870 psi) Design standard API 612 API 612.