Turbines Definition and 84 Threads

  1. D

    B Could solar sails be used as turbines for power generation?

    It seems as though two advantages to using a solar sail turbine system instead of solar panels would be (1) the sails may not degrade as quickly as the solar panels, and (2) a sail turbine system may be lighter than a solar panel (and therefore less expensive to launch into orbit). The drawback...
  2. S

    Why not use positive displacement turbines?

    Positive displacement pumps are used a lot in the industry for pumping water or other liquids. So why is it not used as turbines in hydropower plants?
  3. aladinlamp

    A Betz Law & Submerged Turbines: Is it Applicable?

    Hi, is Betz law fully applicable for hydro, hydrokinetic submerged turbines, since air is compressible but water is not ?
  4. H

    Why do we need stators in compressors or turbines?

    Hey Everybody! I was wondering why do we need Stators in compressors and turbine, for instance the goal of compressor is to increase the outlet pressure, so that the combustion is effective, but why we don't put just Rotors and no stators in the compressor (or Turbine).
  5. I

    Why do wind turbines pitch their blades?

    Hi all. I'm new to this forum and to wind turbine technology in general, and I watched one of these one-minute videos explaining why wind turbines pitch their blades but it doesn not make sense to me. Why don't you just get a bigger generator? You'd get more energy for the same blades, same...
  6. S

    Why does air have to be compressed first in gas turbines?

    In all gas turbines air is first compressed using a compressor and then head added in a combustor and finally the hot pressurized air is expanded in nozzles to convert air contained energy to kinetic energy which can be harvested and transferred in the form of thrust or shaft rotation. My...
  7. S

    Confusion about energy conversion mechanisms in gas turbines

    Hello Gents, I am very confused about the working principle of gas turbines. I understand that air is first compressed in a compressor to obtain high pressure air at the inlet of turbine, but before air is introduced to the turbine, first it has to be heated to very high temperatures through...
  8. hagopbul

    De-icing the wind turbines in Texas

    Summary:: how we can de ice the turbine in case of sudden frezzing like what happened in texas hello all : i was watching the news and saw the news talking about frezzing of wind farms in texas state , and losing about 35% of the energy due to that problem can we use the following methods to...
  9. S

    Condensation-Expansion Turbines

    I am working on a project involving a steam expansion-condensation turbine. I am the only one in on the project and I am unsure of how to start. I am trained in chemical engineering and have a black box understanding of what turbines do, but have no clue about the actual design or mechanism...
  10. S

    Feasibility of stratopheric wind turbines?

    1/2" kevlar rope has a breaking strength of 31,000 lbs and weighs 7.8 lbs/100 ft. = 116 kg/km So a a bit over metric ton gets you up to 10 km altitude. 2 metric tons at a 30 degree angle. Still gives you 25,000 pounds potential drag without breaking the rope. Working strength is...
  11. jeffinbath

    B Why do modern wind turbines have 3 blades?

    Conventional Wind turbines now have 3 blades. I assume this is a matter of average air pressure. 1)Would a future wind turbine working on Mars with about 1% of Earth’s air pressure need to have many more blades? 2) Would all those Victorian windmills have been any more efficient with 3 sails...
  12. I

    B Traffic Turbines - Free Energy or Cost Exchange?

    I saw a video on FaceBook today that showed traffic turbines. They supposedly generate "free" energy from the traffic that passes by them causing them to spin. Just because I'm curious, I was wondering if this energy isn't really free, but is in exchange of a minuscule drag put on the passing...
  13. C

    Electrical Miniature Turbines for a solar collector

    I have a satellite dish converted to a solar collector. It isn't very big, just a small scale prototype at the moment. I have measured just over 300 degrees Celsius at the focus point. I am considering either using a sterling engine or a steam turbine to generate some electricity. The problem...
  14. Al_Pa_Cone

    Steam and Gas Turbines - The Rankine Cycle

    <<Moved from another forum, thus no template filled out.>> I am having some trouble trying to relate a question given in my distance learning lessons to the equivelent question in my assignment. The assignement question is: 1(a) Superheated steam at a pressure of 40 bar and a temperature of...
  15. S

    Bernoulli Equation and its application to turbines and pumps

    Hi, I have never found a satisfactory explanation for why the Bernoulli equation is not valid when the streamline passes through a turbine, pump or another work transferring device. I have read many books that simply state this limitation without providing a convincing reason. Bernoulli...
  16. P

    A question about condensing turbines

    I want to know that whether in case of condensing turbines, the Latent heat of the steam part that will be condensed will be converted into power or not. In that case, condensing turbines can produce more power with the same temperature and pressure difference.
  17. J

    Calculating Steam Flow in a Nuclear Power Plant Turbine System

    I have a thermodynamics question I'm having difficulty with... I have a steam generator heated by a 39MW nuclear reactor that powers two 4.5MW turbine generators. It produces dry saturated steam at 330psig, and enters the turbine at those conditions. It exits the turbine to a condenser...
  18. S

    Why multiple turbines drive a single generator

    A common sense questions. Can anyone care to provide their insights?
  19. K

    Why wind turbines don't have their dynamos closer to ground?

    Why don't the electric generator mount closer to the ground. The advantage I can think is that it is easy to maintain(no need to climb) and reduce weight(reduce tower cost), however the extended shaft will cost more. Does the longer shaft cost out weight the easier maintenance and generator...
  20. P

    Automotive Gas Turbines in Cars: Efficiency, Power & More

    I know that this topic has already been covered (kind of) in a separate forum post, but it became rather confused and there were many differing and contradicting opinions/supposed facts, so I just want to clarify a few things. Firstly, are gas turbines more or less efficient (useful mechanical...
  21. S

    I Pinwheels for Wind turbines? In class, pinwheels proved most

    In class, of all the shapes we tested, the pinwheel won in the total amount of current and voltage, power generated. (used a regular fan and blew a bunch of different blade designs) Question is, why don't we see pinwheels designs for turbines? Where else can I look for turbines designs? Thanks.
  22. G

    Understanding Wind Turbine Efficiency: Exploring Betz's Law and Other Factors

    I am trying to understand wind turbine efficiency and the phenomena of Betz's Law. I have a basic grasp of Betz Law which says the maximum efficiency of a wind turbine is 59 % energy capture of the wind swept turbine area (more or less in those words). I understand that when the wind hits the...
  23. Curiosity and a Cat

    Just a Thought About Tornadoes and Wind Turbines

    I was asked a question and since I have no solid answer I'm re-asking it here. The question was about wind turbines and tornadoes/hurricanes. All that raw energy and we've never tapped into it. Here's the question: Why? I understand the difficulties inherent with a project like this but the...
  24. I

    Do Wind Turbines Significantly Alter Weather Patterns?

    As more wind turbines are installed worldwide, I was wondering how much of an impact on weather they could/would have. (Full disclosure: I am not trained, merely an interested non-scientist) Collectively, wind turbines are collecting considerably more energy than Lorenz's butterfly, so could...
  25. Erika Brown

    Wind Turbines and Conic Sections

    I am working on a project for my precalculus class. They are going to study wind turbines and design a wind turbine blade. I am trying to understand the math behind wind turbines myself. Can I relate wind turbines to a study of conic sections?
  26. K

    Wind turbines turning in no wind?

    So last week I was returning from a holiday (by car) and on the way I saw a field with about 20 wind turbines on it. They were slowly turning, as usual. At first it seemed normal but I suddenly realized, by the open window of the car, that there was no wind at all. So I wondered if there was an...
  27. Zeynel

    Wind turbines with many small generators

    Hello, This is not a homework question. I'm not a student. In fact I'm retired. The other day, I was passing by a wind turbine. I thought "wouldn't it be better to have hundreds of small generators with small wings connected together instead of one huge generator with huge wings?" But I did...
  28. Basimalasi

    Do Steam-rockets follow the same calculations of turbines

    Hello, I'm working on a small steam rocket and I want to calculate how far up it can get by calculating the exhaust velocity of water after it's heated. I saw a similar exercise on my thermodynamics book but for turbines. Can I use the same calculations for the rocket.
  29. Hercuflea

    Lit recommendations for hor air turbines work

    I just wanted to ask if anyone could point me in the direction of a good, introductory to intermediate level resource which explains how air turbines work, and maybe to some design software I could play around with? I am coming from a plasma physics background so I have taken advanced fluid...
  30. R

    How does airfoil design affect wind turbines?

    I understand that when wind hits the blades straight on it spins for the same reason a pinwheel spins when you blow straight at it. But when wind is hitting the "cutting" parts of the blade how does air foil design help there? Wouldn't the lift generated by the air foil not matter since the...
  31. J

    Exploring Industrial Gas Turbines: Heat Loss and Energy Output

    Hey guys Don't know if this is posted in the right category. doing an technical report on industrial gas turbines. but i am kind of lost. Does anyone have any input to what we can write about? I'm thinking of any problems with the turbines that we can write about. What heat loss and how much...
  32. R

    Why aren't turbines used in water supply systems?

    I had an idea to put a rotating mill turbine into the pipes that supply water to home tap systems. So that as the water flows through, the turbine is spun and electricity is produced. But why isn't this actually done?
  33. F

    Could wind turbines be used as wind breaks in open farm land

    my question is would a line of wind turbines have a comparable effect to a wind break in reducing wind velocity
  34. BigWill

    Can this be solved without a knowledge of turbines?

    1) 10 Hydroturbines are in a line, fitted inside a 1m diameter vertical tube its height 1.2km. The top of the tube is 100m deep underwater in a high mountain saltwater lake. This 1200m long tube acts like an orthogonal drainpipe down the mountain. Hdyroturbine-A...
  35. D

    Why do Wind Turbines have such large blades

    This might sound like a ridiculous question and I am sure it is (they don't build them like that for fun) but why on Earth do they? I read an article that said the new PMG style turbines only require the shaft to be rotating at 16rpm to generate up to 8.6MW. Is there so much resistance that...
  36. M

    Where to Learn About Heat Exchangers and Turbines in Nuclear Reactors?

    Any good chapters/sources to learn about the design, fluid/thermodynamics etc of these systems pertaining to nuclear reactors? So far I've been jumping around wiki..
  37. J

    Some numbers with wind turbines

    http://en.wikipedia.org/wiki/GE_Wind_Energy The rotor swept area is 4657 m^2, and wind speed is 11.5 m/s. Produced power 1.5MW. I assumed that the air density is 1.2kg/m^3, and computed, that the theoretical upper limit for produced power would be 4.25MW. This was obtained by computing the...
  38. F

    [Thermodynamics] How big and heavy do steam turbines need to be?

    I'm curious how large(dimensions) and how heavy/massive a steam(or other gas) turbine needs to be to extract a given fraction and amount of the energy from the fluid. For example if a power plant is producing 1GW of thermal power, how much of that can realistically be converted to electrical...
  39. H

    How Do Impulse and Reaction Turbines Utilize Fluid Mechanics Principles?

    Hi all:I have a question regarding the fluid mechanics of turbine, both impulse and reaction turbines. I have searched many sites , including my fluid mechanic textbook, and yet I still don't quite understand the physics behind a turbine.Impulse turbine is a bit easier to understand as I can...
  40. M

    Inquiry on effects surface roughness on Tidal Turbines.

    Hi, I'm an intern in an energy research company and I'm asking if anyone has any links or channels to papers or studies conducted on the effects of barnacle growth or other causes of surface roughness on tidal turbines? I apologize in advance if I have posted under the wrong part of physics...
  41. S

    What about current de-icing technology used for wind turbines?

    I saw those giant wind turbines stopped working in winter, since winter has most wind in four seasons. so, what good comes out of that? while at least 1/4 of time in a year that the wind turbines don't generate power. and wind turbines are so expensive with limited life time around 20 years...
  42. T

    Small Steam Turbines: Impact on Efficiency

    Homework Statement Why are small steam turbine power plant more inefficient than larger ones? how does the size affect efficiency?Homework Equations - The Attempt at a Solution -
  43. L

    Thermodynamic cycles applied to gas turbines

    This is about the basic thermodynamic cycle of the gas turbine (i.e. Brayton or Joule cycle), consisting of adiabatic compression, heat addition at constant pressure, adiabatic expansion, and heat rejection at constant pressure, and the standard ways of analysing this through Pressure-Volume...
  44. B

    The affects of Lenz's Law on Wind Turbines

    Hi, If an electrical generator induces a current that opposes the shifting magnetic field that creates it then why don't the wind turbines on wind farms just stop turning after a while? Is it because they are not directly connected or drawn on by electrical devices? Thank you all in advance!
  45. U

    Differences between basic definitions for compressors and turbines

    While making a comparative study between turbines and compressors, I noticed some differences between the way they are studied...pleasehelp me understand why these differences exist... 1. Efficiency for a turbine = (actual work/ideal work) whereas for compressors, it is (ideal work/actual...
  46. P

    Power needed for turbines and pumps

    I have a friend who insists in an idea and I want to prove to him that it cannot work because it would violate basic physical laws. But somehow I don't find the right words. He says if he drilled a well of 2km (or any other depth) into the Earth and at the bottom there was a pump that...
  47. B

    Isentropic Effeciencies of steam turbines

    Hi, I'm have big problems calculating the Isentropic Effeciencies of steam turbines. There is a HP, IP and LP turbine in the system. I know the calculation is (h1 - h2)/(h1 - h2'), i have the temperatures and pressures in and out for the first two turbines so i can easily get h1 and h2 from the...
  48. K

    At what size do turbines stop becoming efficient?

    You never see them on small scales. Why not use small turbines with magnets on them to start a current?
  49. P

    Maximum flow rates through water turbines given power and head.

    Homework Statement Calculate the maximum flow rates through the Francis and the Samson turbines under the conditions specified: Table 1 Characteristics of some American water turbines, 1849–97, on the basis of 30-inch (760 mm) wheel and 12-inch (300 mm) head Type | Maximum power output...
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