Questions tagged [turbines]
The turbines tag has no usage guidance.
-1
votes
0answers
15 views
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 ...
1
vote
1answer
35 views
In horizontal axis wind turbines, why does axial component of absolute velocity stay constant (wake rotation theory)
I am having hard time understanding how does the axial component stay constant through the rotor. Every resource i look just says it is due to mass conservation but never gives the actual conservation ...
0
votes
1answer
26 views
Can turbine engines really run on “just about anything”?
I often read that turbine engines can run on almost any fuel source. I understand that turbine engines are less "picky" in terms of the fuel source that they can use, but surely there would still be ...
0
votes
2answers
26 views
How do turboshaft engines maintain a constant rpm regardless of load?
I understand that most turboshaft engines tend to run at (or close to) their most efficient rpm all of the time, and it is the load that is changed e.g. the pitch of the blade pitch on helicopters.
...
0
votes
2answers
34 views
How much power could a turbocharger generate?
I can find many figures online for the extra power generated when a turbo is fitted to an engine. However, I can't find any figures on how much energy the turbocharger turbine actually takes out of ...
1
vote
2answers
19 views
Gasturbine energy balance
I have a question regarding gasturbine energy balance,
the total energy that flows into the gasturbine is given 12 MW and the power needed for the compressor is 4.4 MW and the turbine power is 9.3 MW....
1
vote
1answer
55 views
Tesla's Turbine in Real Life
Internet search results don't give much results of real life examples of bladeless turbine. Has anyone ever seen a working real example of Tesla's bladeless turbine, in some industrial or other ...
3
votes
1answer
45 views
What is the difference between a diffuser and a duct in turbines?
I have been reading this paper, which addresses the advantages of diffusers in cross flow turbines.
The abstract says (emphasis is mine):
A CP’s extraordinary improving resulted when yaw increased ...
0
votes
2answers
63 views
If the turbine drives the compressor, then what limits the engine speed?
My understanding of a typical jet engine is that when running, the turbine extracts energy from the hot exhaust gases. This drives the turbine, which is coupled to the compressor at the front of the ...
1
vote
0answers
37 views
Would an afterburner on a turbine drastically improve acceleration lag?
A little bit of context. My friends and I were watching the "Dark Knight Rises" and a discussion about the Batmobiles ensued. I, being a former ME student, said it was stupid that batman has a turbine ...
1
vote
0answers
41 views
How is a Steam Power Plant designed?
I asked this question at physics but i think this suits it more. I'd like to know few things about how does one design a Thermal Power Plant? There is something fundamentally lacking in my knowledge ...
0
votes
2answers
46 views
Why aren't turbos/turbines controllable pitch?
I am wondering why turbines are not implemented with controllable pitch blades (on the rotor system)? I assume the reason is that the coupling between the stator and rotor systems posed by typical ...
2
votes
2answers
80 views
Is it possible to extract mechanical energy using Turbines behind PulseJet engine?
Pulsejet expels pulse of hot gas (unlike turbojet engine) which create some thrust(Not good enough for ). These gases are hot, fast and pulsed. Is it possible to convert kinetic energy of these gases ...
0
votes
3answers
49 views
What determines the cost of the wind turbines?
If there is an 11kW wind turbine, and a 15kW wind turbine. Why is the 15 kw wind turbine more expensive?
I know it seems like a basic question, but what exactly makes it more expensive? Is it only ...
1
vote
1answer
43 views
Is it possible to determine tip-speed ratio from rotor geometry?
Let's say I have the geometry of the rotor: the number of blades, the airfoils that make up each blade, their position, chord length and their twist angle. Would it be possible to use this information ...
2
votes
1answer
45 views
Generating practical power without an iron core, but with high RPM
Here's what I'm proposing - a small turbine directly coupled to a permanent magnet that's spinning at, say, 150k RPM. The magnet is enclosed one or several wire loops parallel to the axis of rotation.
...
0
votes
2answers
45 views
Thermal efficiency affected by hertz (Gas turbine)
Take the LMS100 gas turbine for example. Why does the efficiency change when generating power in 50 or 60hz waveform?
3
votes
2answers
79 views
Compressed air energy storage?
I'm wondering, if you put an air compressor pipe into a micro turbine, lets say something like that attached to a motor, does air that get out of the turbine have the same energy as when it gets in ?
...
0
votes
0answers
67 views
What is the exact meaning of “static and dynamic torque”?
I have the following parameters in my project.
enter link description here
I submitted a paper. Now, one of the Reviewer's comments is as follows:
Validation is not enough and convincing. The CFD ...
0
votes
1answer
24 views
When were airfoil cross-sections first used in turbine blades?
When were airfoil cross-sections first used in turbine blades? When did this become standard practice? Did people understand the connection to aircraft, or did heavier-than-air aircraft exist at all ...
2
votes
1answer
53 views
Estimating wind velocity behind a wind turbine
According to the Wikipedia page on the Betz Limit, the outgoing wind velocity behind a wind turbine can be as low as 33% of the incoming wind velocity. However, this figure assumes that the turbine is ...
3
votes
3answers
294 views
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 ...
1
vote
1answer
63 views
Does the turbine outlet affect the power generated by the turbine ?
In my text book , it is written
"Power generated by the turbine can be increased by using a gradual expansion at the turbine outlet"
The picture below explains the meaning of gradual expansion at ...
3
votes
1answer
130 views
Can combined cycle turbines be small enough for trains?
Combined Cycle Turbines are a gas turbine whose exhaust heat powers a second turbine running on steam. These can get thermal efficiencies greater than 50%, whereas a plain turbine would get 30 to 35%. ...
0
votes
1answer
67 views
turbojet axial compressor: blades of HP compressor
I noticed that blades of HP compressor are shorter in axial dimension next to its LP counterpart.
Why?
I understand why it is smaller in radial dimension (this is because compressed air has smaller ...
1
vote
1answer
116 views
In what order turbojet engine parameters are calculated?
As I see it, if you're going to calculate a twin-spool turbojet engine, you
Determine expected max aircraft speed, and engine thrust at that speed and when stationary.
Calculate peak mass of air flow
...
2
votes
4answers
788 views
Is it possible to use Ammonia vapor in steam turbine
I am currently designing a prototype. I have asked to use low boiling point liquid to run a steam turbine. So i am thinking of using liquid ammonia.
What are the complications involved when using ...
0
votes
0answers
305 views
Why is there negative static pressure in contour?
I studied a paper about turbine and i seen that there is negative static pressure in contour. Why does this happen?
Wave Energy Harvesting Turbine: Performance Enhancement
1
vote
2answers
280 views
What is reason of low axial velocity at tip and hub of an axial turbine?
I am analyzing results of my turbine simulation. I have created one line from hub to casing at downstream of the flow...please see the following figures. I want to investigate along this line how the ...
2
votes
1answer
132 views
Does this exist - Water flow control with energy recovery
Classically, if you have free flow (high level to low, no pump) between two vessels you want to control you use some restricting orifice, or flow over a variable height weir. Both dissipate energy.
...
2
votes
2answers
119 views
Why is more steam required to turn a steam turbine when electric power consumption is higher
I'm recently under industrial training at a plywood mill. My supervisor is from foreign country so there are some difficulties for me to understand what he is trying to say.
In the power plant, the ...
2
votes
4answers
1k views
What is the theoretical maximum energy efficiency of hydro turbines?
From what I've read it seems that hydro turbines can theoretically achieve 100% energy conversion from kinetic to electrical energy. However, I just wanted to double check if this was true.
-2
votes
1answer
271 views
What prevents the use of electric engines to assist with spacecraft launches? (Space Shuttle Booster Supplement)
Much power is used to get rocket off the platform on the initial launch? Could electric engines used like booster rockets work similar in the way they launch planes of an aircraft carrier? The ...
1
vote
0answers
52 views
Is it possible that entropy generation decreases with decreasing turbine efficiency(First Low efficiency )?
I simulated an axial turbine(Wells turbine). Now I have faced with strange problem.
Performance of any turbine can be improved if the losses are identified and minimized. Several losses can be ...
3
votes
2answers
90 views
Question about bounday layer thickness?
According to the following figure, boundary layer becomes progressively thicker with downstream distance x . Why?
I have an other question as follows:
When turbine blade thickness increases, what ...
1
vote
1answer
148 views
Why do thicker turbine blades delay flow separation? [closed]
I studied about the effect of turbine blade thickness on flow separation in following. The blade section is Naca 00 XX in this turbine.
The paper states that if blade thickness increases, separation ...
4
votes
1answer
222 views
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 ...
1
vote
0answers
51 views
How to design a fan that can be used to convert concentrated air to power [closed]
I am trying to design mechanism that is sort of like a wind turbine (uses wind as "fuel") but has a fan size that is in a pelton turbine. I was wondering if there is any math/equation that I can use ...
6
votes
1answer
131 views
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 ...
1
vote
0answers
35 views
How to set up the boundary between volumes in a simulated turbine
I am simulating a turbine and I have some doubts about the correctness of my approach.
In this turbine, there are three volumes:
The two volumes are the piping before and after the blade and the ...
2
votes
0answers
63 views
problem in the calculation of pressure drop for an axial turbine
I am simulating an axial turbine. In this turbine, there are two domains.
The first domain is the piping before and after the blade and the second domain contains the turbine blades. The domain ...
0
votes
2answers
528 views
Calculating water turbine mass based on head and flow [closed]
Is there a formula, which would allow to estimate water turbine rotor mass based on head and water flow, or based on the final energy output provided by the turbine? I am interested in rough estimate, ...
4
votes
1answer
598 views
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 (...
12
votes
5answers
2k views
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 ...
0
votes
1answer
4k views
Why is there reverse flow in Fluent?
I am simulating a axial turbine and number of cell are about 3000000.
Under relaxation factors are as follows:
Pressure: 0.1
momentum:0.1
Turbulent kinetic energy: 0.5
Turbulent dissipation rate: ...
2
votes
2answers
3k views
How do I set skewness correction in fluent?
I am simulating a turbine that has curves. Mesh is structure completely. But there is high skewness in tip clearance and some parts of around of the blade:
When I use SIMPLEC Method, one factor (...
1
vote
0answers
70 views
Boundary layer is not captured well in axial turbine blade simulation
I am simulating an axial turbine, I tried different mesh topologies and all give me almost the same number. In fact, Boundary layer is not captured well, Reynolds number is equal to $4.4 \times 10^5$ ...
2
votes
0answers
35 views
Is there correlation between friction of boundary layer and values of inlet and outlet pressure? [closed]
Is there correlation between friction of boundary layer(or inertia and viscous forces in boundary layer) and values of inlet and outlet pressure in an axial turbine? For example, when friction of ...
1
vote
0answers
252 views
Is the convergence of solution ok in Fluent?
I am simulating an axial turbine by using Fluent. The convergence of solution is monitored by checking the residuals of the numerically solved governing equations. Moreover, in order to judge the ...
4
votes
1answer
102 views
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 ...
