Shopping on line can be easy, simple and save you lots of money. It can also take a lot of your time, frustrate you, and result in unwanted purchases. Now the same can be said for regular high street shopping, but with the vast opportunity presented by the Internet it will pay you to spend a few minutes reading this and understanding how to better optimize your Turbine shopping experience:

1. Compare - without doubt the biggest advantage that the Turbine offers shoppers today is the ability to compare thousands of Turbine at a time. This is a great thing, but not necessarily all the time! Too much can be daunting at times so take advantage of the great comparison sites and where possible let them do the hard work for you.

2. Research - if it has been said it will be on the internet. Ignorance is no longer a justifiable reason for buying the wrong thing. Take the time to research in detail everything that you could possible want to know about

3. Testimonials - don't know anybody that has bought a Turbine? Wrong! If the Turbine is good the internet will let you know. Use the Internet as a friend and get testimonials before you buy.

4. Questions - Got a question about Turbine then search the Forums, FAQ's, Blogs etc. Don't be afraid to ask .....

5. Reputation - Never heard of the company selling Turbine? Don't worry, no reason why you should know every company in the world, but you know someone that does! Use the internet to find out what people are saying about Turbine and build up a picture of their reputation for sales, returns, customer service, delivery etc.

6. Returns - still worried that even after all of the above your Turbine wont be what you want? Check out the returns policy. There is so much competition now that someone, somewhere is bound to offer the terms that you are comfortable with.

7. Feedback - happy with your Turbine then let people know, after all you are depending on others people input in your buying decision, so why not give a little back.

8. Security - check for the yellow padlock on the Turbine site before you buy, and the s after http:/ /i.e. https:// = a secure site

9. Contact - got a question about Turbine, or want to leave a comment then check out the sites contact page. Reputable companies have them and respond.

10. Payment - ready to pay for your Turbine, then use your credit card or PayPal! Be aware of companies that don't accept them, there may be genuine reasons but given the huge amount of choice you have when buying online there is no reason at all not to buy via credit card or PayPal.

steam turbine with the case opened.

A turbine is a rotary engine that extracts energy from a fluid flow. Claude Burdin (1788-1873) coined the term from the Latin turbinis, or vortex during an 1828 engineering competition. Benoit Fourneyron (1802-1867), a student of Claude Burdin, built the first practical water turbine.

The simplest turbines have one moving part, a rotor assembly, which is a shaft with blades attached. Moving fluid acts on the blades, or the blades react to the flow, so that they rotate and impart energy to the rotor. Early turbine examples are windmills and water wheels.

Gas turbine, steam turbine, and water turbine turbines usually have a casing around the blades that focuses and controls the fluid. The casing and blades may have variable geometry that allows efficient operation for a range of fluid-flow conditions.

A device similar to a turbine but operating in reverse is a compressor or pump. The axial compressor in many gas turbine engines is a common example.

Theory of operation

A working fluid contains potential energy (pressure head (hydraulic)) and kinetic energy (velocity head). The fluid may be compressibility or incompressible fluid. Several physical principles are employed by turbines to collect this energy:

Impulse turbines These turbines change the direction of flow of a high velocity fluid jet. The resulting impulse spins the turbine and leaves the fluid flow with diminished kinetic energy. There is no pressure change of the fluid in the turbine rotor blades. Before reaching the turbine the fluid's pressure head is changed to velocity head by accelerating the fluid with a nozzle. Pelton wheels and Steam turbines use this process exclusively. Impulse turbines do not require a pressure casement around the runner since the fluid jet is prepared by a nozzle prior to reaching turbine. [Newton's laws of motion#Newton.27s second law

Reaction (physics) turbines These turbines develop torque by reacting to the fluid's pressure or weight. The pressure of the fluid changes as it passes through the turbine rotor blades. A pressure casement is needed to contain the working fluid as it acts on the turbine stage(s) or the turbine must be fully immersed in the fluid flow (wind turbines). The casing contains and directs the working fluid and, for water turbines, maintains the suction imparted by the draft tube. Francis turbines and most steam turbines use this concept. For compressible working fluids, multiple turbine stages may be used to harness the expanding gas efficiently. [Newton's laws of motion#Newton.27s third law

Turbine designs will use both these concepts to varying degrees whenever possible. Wind turbines use an airfoil to generate Lift (force) from the moving fluid and impart it to the rotor (this is a form of reaction). Wind turbines also gain some energy from the impulse of the wind, by deflecting it at an angle. Banki turbines are designed as an impulse machine, with a nozzle, but in low head applications maintain some efficiency through reaction, like a traditional water wheel. Turbines with multiple stages may utilize either reaction or impulse blading at high pressure. Steam Turbines are usually more impulse while Gas Turbines more reaction type designs. At low pressure the operating fluid medium expands in volume for small changes in pressure. Under these conditions (termed Low Pressure Turbines) blading becomes strictly a reaction type design with the base of the blade solely impulse. The reason is due to the effect of the rotation speed for each blade. As the volume increases, the blade height increases, and the base of the blade spins at a slower speed relative to the tip. This change in speed forces a designer to change from impulse at the base, to a high reaction style tip.

Classical turbine design methods were developed in the mid 19th century. Vector analysis related the fluid flow with turbine shape and rotation. Graphical calculation methods were used at first. Formulas for the basic dimensions of turbine parts are well documented and a highly efficient machine can be reliably designed for any fluid flow condition. Some of the calculations are empirical or 'rule of thumb' formulae, and others are based on classical mechanics. As with most engineering calculations, simplifying assumptions were made.

Velocity triangles can be used to calculate the basic performance of a turbine stage. Gas exits the stationary turbine nozzle guide vanes at absolute velocity Va1. The rotor rotates at velocity U. Relative to the rotor, the velocity of the gas as it impinges on the rotor entrance is Vr1. The gas is turned by the rotor and exits, relative to the rotor, at velocity Vr2. However, in absolute terms the rotor exit velocity is Va2. The velocity triangles are constructed using these various velocity vectors. Velocity triangles can be constructed at any section through the blading (for example: hub , tip, midsection and so on) but are usually shown at the mean stage radius. Mean performance for the stage can be calculated from the velocity triangles, at this radius, using the Euler equation:



\Delta\;H = U\cdot \Delta\;Vw/g

Whence:

\left (\frac{\Delta\;H}{T}\right) = \left(\frac{U}{\sqrt{T-->\right)\cdot\left(\frac{\Delta\;Vw}{g\cdot\sqrt{T-->\right)

where:

g =\, acceleration of gravity \Delta\;H = enthalpy drop across stage T =\, turbine entry total (or stagnation) temperature U =\, turbine rotor peripheral velocity \Delta\,Vw = delta whirl velocity

The turbine pressure ratio is a function of \left(\frac{\Delta\;H}{T}\right) and the turbine efficiency.

Modern turbine design carries the calculations further. Computational fluid dynamics dispenses with many of the simplifying assumptions used to derive classical formulas and computer software facilitates optimization. These tools have led to steady improvements in turbine design over the last forty years.

The primary numerical classification of a turbine is its specific speed. This number describes the speed of the turbine at its maximum efficiency with respect to the power and flow rate. The specific speed is derived to be independent of turbine size. Given the fluid flow conditions and the desired shaft output speed, the specific speed can be calculated and an appropriate turbine design selected.

The specific speed, along with some fundamental formulas can be used to reliably scale an existing design of known performance to a new size with corresponding performance.

Off-design performance is normally displayed as a turbine map or characteristic.

Types of turbines



Uses of turbines Almost all electrical power on Earth is produced with a turbine of some type. Very high efficiency turbines harness about 40% of the thermal energy, with the rest exhausted as waste heat.

Most jet engines rely on turbines to supply mechanical work from their working fluid and fuel as do all nuclear ships and power plants.

Turbines are often part of a larger machine. A gas turbine, for example, may refer to an internal combustion machine that contains a turbine, ducts, compressor, combustor, heat-exchanger, fan and (in the case of one designed to produce electricity) an alternator. However, it must be noted that the collective machine referred to as the turbine in these cases is designed to transfer energy from a fuel to the fluid passing through such an internal combustion device as a means of propulsion, and not to transfer energy from the fluid passing through the turbine to the turbine as is the case in turbines used for electricity provision etc.

Reciprocating piston engines such as aircraft engines can use a turbine powered by their exhaust to drive an intake-air compressor, a configuration known as a turbocharger (turbine supercharger) or, colloquially, a "turbo".

Turbines can have incredible power density (with respect to volume and weight). This is because of their ability to operate at very high speeds. The Space Shuttle's main engines use turbopumps (machines consisting of a pump driven by a turbine engine) to feed the propellants (liquid oxygen and liquid hydrogen) into the engine's combustion chamber. The liquid hydrogen turbopump is slightly larger than an automobile engine (weighing approximately 700 lb) and produces nearly 70,000 horsepower (52.2 megawatt).

Turboexpanders are widely used as sources of refrigeration in industrial processes.

Shrouded Tidal turbines An emerging renewable energy technology is the shrouded tidal turbine enclosed in a Venturi effect shaped shroud or duct producing a sub atmosphere of low pressure behind the turbine, allowing the turbine to operate at higher efficiency (than the Wind turbine design#Axial momentum and the Betz limit Betz Limit of 59.3%) and typically 3 times higher power output Brian Kirke's PhD Thesis than a turbine of the same size in free stream.

As shown in the CFD (Computational Fluid Dynamics) generated figure here it can be seen that a down stream low pressure (shown by the gradient lines) draws upstream flow into the inlet of the shroud from well outside the inlet of the shroud. This flow is drawn into the shroud and concentrated (as seen by the red coloured zone). This augmentation of flow velocity corresponds to a 3-4 times increase in energy available to the turbine. Therefore a turbine located in the throat of the shroud is then able to achieve higher efficiency, and an output 3-4 times the energy the turbine would be capable of if it were in open or free stream. For this reason shrouded turbines are not subject to the properties of the Betz Limit.

Considerable commercial interest has been shown in recent times in shrouded tidal turbines as it allows a smaller turbine to be used at sites where large turbines are restricted. Arrayed across a seaway or in fast flowing rivers shrouded tidal turbines are easily cabled to a terrestrial base and connected to a grid or remote community. Alternatively the property of the shroud that produces an accelerated flow velocity across the turbine allows tidal flows formerly too slow for commercial use to be utilised for commercial energy production.

While the shroud may not be practical in wind, as a tidal turbine it is gaining more popularity and commercial use. A shrouded tidal turbine is mono directional and constantly needs to face upstream in order to operate. It can be floated under a pontoon on a swing mooring, fixed to the seabed on a mono pile and yawed like a wind sock to continually face upstream. A shroud can also be built into a tidal fence increasing the performance of the turbines.

Cabled to the mainland they can be grid connected or can be scaled down to provide energy to remote communities where large civil infrastructures are not viable. Similarly to tidal stream open turbines they have little if any environmental or visual amenity impact.

External links

steam turbine with the case opened.

A turbine is a rotary engine that extracts energy from a fluid flow. Claude Burdin (1788-1873) coined the term from the Latin turbinis, or vortex during an 1828 engineering competition. Benoit Fourneyron (1802-1867), a student of Claude Burdin, built the first practical water turbine.

The simplest turbines have one moving part, a rotor assembly, which is a shaft with blades attached. Moving fluid acts on the blades, or the blades react to the flow, so that they rotate and impart energy to the rotor. Early turbine examples are windmills and water wheels.

Gas turbine, steam turbine, and water turbine turbines usually have a casing around the blades that focuses and controls the fluid. The casing and blades may have variable geometry that allows efficient operation for a range of fluid-flow conditions.

A device similar to a turbine but operating in reverse is a compressor or pump. The axial compressor in many gas turbine engines is a common example.

Theory of operation

A working fluid contains potential energy (pressure head (hydraulic)) and kinetic energy (velocity head). The fluid may be compressibility or incompressible fluid. Several physical principles are employed by turbines to collect this energy:

Impulse turbines These turbines change the direction of flow of a high velocity fluid jet. The resulting impulse spins the turbine and leaves the fluid flow with diminished kinetic energy. There is no pressure change of the fluid in the turbine rotor blades. Before reaching the turbine the fluid's pressure head is changed to velocity head by accelerating the fluid with a nozzle. Pelton wheels and Steam turbines use this process exclusively. Impulse turbines do not require a pressure casement around the runner since the fluid jet is prepared by a nozzle prior to reaching turbine. [Newton's laws of motion#Newton.27s second law

Reaction (physics) turbines These turbines develop torque by reacting to the fluid's pressure or weight. The pressure of the fluid changes as it passes through the turbine rotor blades. A pressure casement is needed to contain the working fluid as it acts on the turbine stage(s) or the turbine must be fully immersed in the fluid flow (wind turbines). The casing contains and directs the working fluid and, for water turbines, maintains the suction imparted by the draft tube. Francis turbines and most steam turbines use this concept. For compressible working fluids, multiple turbine stages may be used to harness the expanding gas efficiently. [Newton's laws of motion#Newton.27s third law

Turbine designs will use both these concepts to varying degrees whenever possible. Wind turbines use an airfoil to generate Lift (force) from the moving fluid and impart it to the rotor (this is a form of reaction). Wind turbines also gain some energy from the impulse of the wind, by deflecting it at an angle. Banki turbines are designed as an impulse machine, with a nozzle, but in low head applications maintain some efficiency through reaction, like a traditional water wheel. Turbines with multiple stages may utilize either reaction or impulse blading at high pressure. Steam Turbines are usually more impulse while Gas Turbines more reaction type designs. At low pressure the operating fluid medium expands in volume for small changes in pressure. Under these conditions (termed Low Pressure Turbines) blading becomes strictly a reaction type design with the base of the blade solely impulse. The reason is due to the effect of the rotation speed for each blade. As the volume increases, the blade height increases, and the base of the blade spins at a slower speed relative to the tip. This change in speed forces a designer to change from impulse at the base, to a high reaction style tip.

Classical turbine design methods were developed in the mid 19th century. Vector analysis related the fluid flow with turbine shape and rotation. Graphical calculation methods were used at first. Formulas for the basic dimensions of turbine parts are well documented and a highly efficient machine can be reliably designed for any fluid flow condition. Some of the calculations are empirical or 'rule of thumb' formulae, and others are based on classical mechanics. As with most engineering calculations, simplifying assumptions were made.

Velocity triangles can be used to calculate the basic performance of a turbine stage. Gas exits the stationary turbine nozzle guide vanes at absolute velocity Va1. The rotor rotates at velocity U. Relative to the rotor, the velocity of the gas as it impinges on the rotor entrance is Vr1. The gas is turned by the rotor and exits, relative to the rotor, at velocity Vr2. However, in absolute terms the rotor exit velocity is Va2. The velocity triangles are constructed using these various velocity vectors. Velocity triangles can be constructed at any section through the blading (for example: hub , tip, midsection and so on) but are usually shown at the mean stage radius. Mean performance for the stage can be calculated from the velocity triangles, at this radius, using the Euler equation:



\Delta\;H = U\cdot \Delta\;Vw/g

Whence:

\left (\frac{\Delta\;H}{T}\right) = \left(\frac{U}{\sqrt{T-->\right)\cdot\left(\frac{\Delta\;Vw}{g\cdot\sqrt{T-->\right)

where:

g =\, acceleration of gravity \Delta\;H = enthalpy drop across stage T =\, turbine entry total (or stagnation) temperature U =\, turbine rotor peripheral velocity \Delta\,Vw = delta whirl velocity

The turbine pressure ratio is a function of \left(\frac{\Delta\;H}{T}\right) and the turbine efficiency.

Modern turbine design carries the calculations further. Computational fluid dynamics dispenses with many of the simplifying assumptions used to derive classical formulas and computer software facilitates optimization. These tools have led to steady improvements in turbine design over the last forty years.

The primary numerical classification of a turbine is its specific speed. This number describes the speed of the turbine at its maximum efficiency with respect to the power and flow rate. The specific speed is derived to be independent of turbine size. Given the fluid flow conditions and the desired shaft output speed, the specific speed can be calculated and an appropriate turbine design selected.

The specific speed, along with some fundamental formulas can be used to reliably scale an existing design of known performance to a new size with corresponding performance.

Off-design performance is normally displayed as a turbine map or characteristic.

Types of turbines



Uses of turbines Almost all electrical power on Earth is produced with a turbine of some type. Very high efficiency turbines harness about 40% of the thermal energy, with the rest exhausted as waste heat.

Most jet engines rely on turbines to supply mechanical work from their working fluid and fuel as do all nuclear ships and power plants.

Turbines are often part of a larger machine. A gas turbine, for example, may refer to an internal combustion machine that contains a turbine, ducts, compressor, combustor, heat-exchanger, fan and (in the case of one designed to produce electricity) an alternator. However, it must be noted that the collective machine referred to as the turbine in these cases is designed to transfer energy from a fuel to the fluid passing through such an internal combustion device as a means of propulsion, and not to transfer energy from the fluid passing through the turbine to the turbine as is the case in turbines used for electricity provision etc.

Reciprocating piston engines such as aircraft engines can use a turbine powered by their exhaust to drive an intake-air compressor, a configuration known as a turbocharger (turbine supercharger) or, colloquially, a "turbo".

Turbines can have incredible power density (with respect to volume and weight). This is because of their ability to operate at very high speeds. The Space Shuttle's main engines use turbopumps (machines consisting of a pump driven by a turbine engine) to feed the propellants (liquid oxygen and liquid hydrogen) into the engine's combustion chamber. The liquid hydrogen turbopump is slightly larger than an automobile engine (weighing approximately 700 lb) and produces nearly 70,000 horsepower (52.2 megawatt).

Turboexpanders are widely used as sources of refrigeration in industrial processes.

Shrouded Tidal turbines An emerging renewable energy technology is the shrouded tidal turbine enclosed in a Venturi effect shaped shroud or duct producing a sub atmosphere of low pressure behind the turbine, allowing the turbine to operate at higher efficiency (than the Wind turbine design#Axial momentum and the Betz limit Betz Limit of 59.3%) and typically 3 times higher power output Brian Kirke's PhD Thesis than a turbine of the same size in free stream.

As shown in the CFD (Computational Fluid Dynamics) generated figure here it can be seen that a down stream low pressure (shown by the gradient lines) draws upstream flow into the inlet of the shroud from well outside the inlet of the shroud. This flow is drawn into the shroud and concentrated (as seen by the red coloured zone). This augmentation of flow velocity corresponds to a 3-4 times increase in energy available to the turbine. Therefore a turbine located in the throat of the shroud is then able to achieve higher efficiency, and an output 3-4 times the energy the turbine would be capable of if it were in open or free stream. For this reason shrouded turbines are not subject to the properties of the Betz Limit.

Considerable commercial interest has been shown in recent times in shrouded tidal turbines as it allows a smaller turbine to be used at sites where large turbines are restricted. Arrayed across a seaway or in fast flowing rivers shrouded tidal turbines are easily cabled to a terrestrial base and connected to a grid or remote community. Alternatively the property of the shroud that produces an accelerated flow velocity across the turbine allows tidal flows formerly too slow for commercial use to be utilised for commercial energy production.

While the shroud may not be practical in wind, as a tidal turbine it is gaining more popularity and commercial use. A shrouded tidal turbine is mono directional and constantly needs to face upstream in order to operate. It can be floated under a pontoon on a swing mooring, fixed to the seabed on a mono pile and yawed like a wind sock to continually face upstream. A shroud can also be built into a tidal fence increasing the performance of the turbines.

Cabled to the mainland they can be grid connected or can be scaled down to provide energy to remote communities where large civil infrastructures are not viable. Similarly to tidal stream open turbines they have little if any environmental or visual amenity impact.

External links



Turbine, Inc.
William and Janet of California. Photos, information, interest pages, and links.

Turbine Engine
Turbine, Inc. - The world's premier creator and operator of massive, persistent online worlds that foster powerful social gaming communities. ... Turbine has developed a state-of ...

Turbine - Wikipedia, the free encyclopedia
A turbine is a rotary engine that extracts energy from a fluid flow. Claude Burdin (1788-1873) coined the term from the Latin turbo, or vortex, during an 1828 engineering ...

Turbine Services (wind/hydro) Ltd
Servicing of wind turbines, and installation and servicing of micro-hydro energy systems. Benefits of the systems, including pdf format technical documents.

Turbine Motor Works Ltd
Formed in 1988, Turbine Motor Works is a member of the Kruses Capital Group of companies, which also includes Turbine Component Works, TAMRO, Inventory Management Works and Air ...

Login to Sales Turbine System | Sales Turbine
Corpdata Limited

Welcome to the Turbine
You need at least Macromedia Flash 6 to view certain aspects of The Turbine website. You can download it for ...

Turbine Site - Turbine
Apache Turbine Web Application Framework. Turbine is a servlet based framework that allows experienced Java developers to quickly build web applications.

The Lord of the Rings Online™: Shadows of Angmar™ > Home Page
The official community site for The Lord of the Rings Online™: Shadows of Angmar™ ... WESTWOOD, MA - July 31, 2008 - Turbine, Inc. announced today its partnership with Warner ...

Turbocharger Turbine page
Gas Turbine Projects Page ... You are visitor number: (Counter reset 29/3/02) Below are a selction of companies who have been particularly useful or generous.

 

Turbine



 
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