Questions tagged [turbines]
106 questions
24
votes
5 answers
Why don't hydroelectric plants use cascades of turbines instead of single turbines?
In a gas turbine engine there're multiple sets of blades - one set after another and combustion products pass all the sets and each set of blades gets some of the power. This increases utilization of power from burning gas.
Meanwhile hydroelectric…
sharptooth
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12
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Why is using steam to rotate a turbine more efficient?
For example i have an exhaust pipe with very hot air from burning biofuel, and i have a turbine at the end of the exhaust that rotates and generates electricity.
Why is it more efficient to use the heat to boil water then use the steam produced to…
Mohdak
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8
votes
0 answers
Residuals of continuity not converging
I'm simulating a turbine.
The convergence of solution is monitored by checking the residuals of the numerically solved governing equations.
The "viscous-spalarat-almaras" model is used, and used air with constant density. Pressure-velocity coupled…
user19061
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8
votes
1 answer
To what degree are wind and water turbines exchangeable?
Assuming maximum efficiency is not the primary concern (but net positive efficiency is), to what extent could a wind turbine operate in water and vice versa?
How do the different turbine types fare in this respect? I.e., HAWT / VAWT (Savonius,…
Zubo
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8
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2 answers
Why do hydroelectric plants use turbines instead of an efficient 'water wheel' configuration?
I have been thinking about hydroelectric plants and I have been wondering why they are built the way they are. As in understand it, a stream of water is sprayed at a turbine, located at the bottom of a dam (Pelton Turbine.) This does not seem to…
Hoytman
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6
votes
1 answer
Streamlines at the boundary of rotating and stationary domains are malformed
I am simulating a turbine and have divided the mesh into domains: the piping before and after the blade and the turbine blades. The domain containing the blades rotates at 2000 rpm while the other domains are stationary.
The mesh is structure and…
user19061
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6
votes
2 answers
What is the Boussinesq approach?
I want to simulate a turbine in Fluent. For this reason, I studied some papers. In these papers, Turbulence is modeled using the realizable k–e model and Non-equilibrium wall functions are used in the near wall flow modeling. There are the following…
user19061
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6
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1 answer
efficiency and flow separation
I am studying about wind turbine and turbine.
I have some questions, but first, I explain some cases as follow:
Low velocity air over an airfoil at a zero-incidence angle does not initiate flow separation. If the air velocity slowly increases, the…
user19061
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5
votes
2 answers
Identifying category of wind turbine
I recently saw a wind turbine that I'm trying to identify the type or category of.
Basically, the turbine looks like two squirrel cage fans mounted side by side on a fairly tall ~40' pole.
The blades of the turbines rotate along the horizontal…
user16
5
votes
3 answers
Why not design a Wind Turbine like an Anemometer?
Anemometer measures wind speed. It's shaped with little cups---hollow half-spheres. That looks very logical as the cups grab the wind and the other side is rather streamligned to cut through the air as it spins.
So why are there no wind turbines…
DrZ214
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4
votes
1 answer
Why does my model of a wind turbine show high RPM with low power output?
I am designing a wind turbine to generate 1300 W.
I modeled the output voltage of an AC generator using the following specifics:
Number coil turns = 300.
Copper wire gauge = 1.02 mm.
Knowing the density of copper, I calculated the weight of the…
user510
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4
votes
1 answer
How many blades for a steam turbine?
I am building a very simple turbine that runs on steam. I want to make it as simple as possible, thus avoiding impulse and reaction turbines.
I want to design the turbine to fit in an exhaust pipe (about 15cm diameter) so that steam would rotate it,…
Mohdak
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4
votes
1 answer
What is the exact meaning of "dot product of the pressure and viscous force coefficients on each face with the specified force vector"?
I studied a thesis about a axial turbine and but i didn't understood the bold part of following sentences. What is the exact meaning of "dot product of the pressure and viscous force coefficients on each face with the specified force vector"? This…
user19061
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4
votes
1 answer
Fan Sensors (Tachometer vs Locked Rotor)
With regard to Fan Sensors, there are two very common methods for detecting whether the fan is doing what it's supposed to or not.
Locked Rotor- Detects when the fan is working, or when it has stopped.
(on or off voltage signal)
Tachometer- Detects…
Erathsmus
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4
votes
2 answers
Do 3 blade wind turbines generate more power than a 9 blade, all else being equal?
After doing some research, I have come to the realization that 3 blade design horizontal turbines have the greatest maximum coefficient of performance. Most sources seem to agree a Cp of ~0.45 at TSR=7 is optimal for 3 blade designs.
The power…
David_M16
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