velocity profile at a ducted turbine intake

Cajamarca · September 29, 2015, 13:44

Hi Colleagues,

I’m just a beginner, learning through the tutorials and trying to duplicate the analysis I see in the research papers.

According to the theory, wind flows can be concentrated by duct, thus the wind velocity can be increased. This is proved in a study, by simulation. My simulation is completely different and I want to know the reason.
Here are the dimensions of duct: https://drive.google.com/file/d/0B6W...ew?usp=sharing
Here is the simulation result of the study (velocity profile): https://drive.google.com/file/d/0B6W...ew?usp=sharing
Here is the simulation result of the study (pressure profile): https://drive.google.com/file/d/0B6W...ew?usp=sharing

In my simulations, the projected air flow does not completely get into the duct; instead large amount of it flows around the duct. Since, only small amount of flow flows into the duct, the velocity at the ‘intake’ is much smaller than the actual wind velocity. I’m not really sure,
- if I define wrong boundary conditions or set wrong simulation settings
- if the simulation in the research paper is wrong (probably not :P)
The settings I used in simulation:
- Analysis Type: Steady state
- Material: Air Ideal Gas, Pressure: reference pressure 1 Atm
- Inlet domain-> Normal speed: 4m/s,
- Outlet domain-> static domain, relative pressure: 0 Pa
- Wall domain-> No slip wall, roughness: smooth wall
Here are my simulation results:
Pressure: https://drive.google.com/file/d/0B6W...ew?usp=sharing
Velocity:
https://drive.google.com/file/d/0B6W...ew?usp=sharing
https://drive.google.com/file/d/0B6W...ew?usp=sharing
https://drive.google.com/file/d/0B6W...ew?usp=sharing
https://drive.google.com/file/d/0B6W...ew?usp=sharing
https://drive.google.com/file/d/0B6W...ew?usp=sharing

Thank you for your dear comments,
Caja.

ghorrocks · September 29, 2015, 21:02

That is correct. The throat causes a high pressure region and the high pressure pushes air to the side so less air goes into the duct. This is all as expected. Your theory is going to have to account for this air which doe snot pass through the duct if you want your theory to be accurate.

September 29, 2015, 13:44	velocity profile at a ducted turbine intake	#1
Cajamarca New Member Join Date: Oct 2011 Posts: 1 Rep Power: 0	Hi Colleagues, I’m just a beginner, learning through the tutorials and trying to duplicate the analysis I see in the research papers. According to the theory, wind flows can be concentrated by duct, thus the wind velocity can be increased. This is proved in a study, by simulation. My simulation is completely different and I want to know the reason. Here are the dimensions of duct: https://drive.google.com/file/d/0B6W...ew?usp=sharing Here is the simulation result of the study (velocity profile): https://drive.google.com/file/d/0B6W...ew?usp=sharing Here is the simulation result of the study (pressure profile): https://drive.google.com/file/d/0B6W...ew?usp=sharing In my simulations, the projected air flow does not completely get into the duct; instead large amount of it flows around the duct. Since, only small amount of flow flows into the duct, the velocity at the ‘intake’ is much smaller than the actual wind velocity. I’m not really sure, - if I define wrong boundary conditions or set wrong simulation settings - if the simulation in the research paper is wrong (probably not :P) The settings I used in simulation: - Analysis Type: Steady state - Material: Air Ideal Gas, Pressure: reference pressure 1 Atm - Inlet domain-> Normal speed: 4m/s, - Outlet domain-> static domain, relative pressure: 0 Pa - Wall domain-> No slip wall, roughness: smooth wall Here are my simulation results: Pressure: https://drive.google.com/file/d/0B6W...ew?usp=sharing Velocity: https://drive.google.com/file/d/0B6W...ew?usp=sharing https://drive.google.com/file/d/0B6W...ew?usp=sharing https://drive.google.com/file/d/0B6W...ew?usp=sharing https://drive.google.com/file/d/0B6W...ew?usp=sharing https://drive.google.com/file/d/0B6W...ew?usp=sharing Thank you for your dear comments, Caja.

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September 29, 2015, 21:02		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,871 Rep Power: 144	That is correct. The throat causes a high pressure region and the high pressure pushes air to the side so less air goes into the duct. This is all as expected. Your theory is going to have to account for this air which doe snot pass through the duct if you want your theory to be accurate.