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April 30, 2013, 03:16 |
CFD analaysis of Pelton turbine
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#1 |
New Member
Amod Panthee
Join Date: Apr 2013
Location: Nepal
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Does any body have link for references to execute cfd analysis of Pelton turbine using ANSYS CFX? Any link for tangential flow turbines like turgo turbines might be beneficial.
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April 30, 2013, 09:26 |
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#2 |
Senior Member
OJ
Join Date: Apr 2012
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Have a look at the CFX tutorials, they provide ample information.
OJ |
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May 1, 2013, 07:59 |
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#3 |
New Member
Amod Panthee
Join Date: Apr 2013
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Is there any specific tutorial for tangential flow turbines?
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May 1, 2013, 08:41 |
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#4 |
Senior Member
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I think there is no specific tut on pelton turbine. For pelton turbine you have to model full wheel and place the jets at appropriate location. Placing GGI between jets and wheel may not be recommended but you can try.
Meshing definitely would be the most time consuming part. Make the CFD model (meshing, boundary conditions) and come back to further details. If you need help in meshing, you are also welcome. |
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May 1, 2013, 08:57 |
domain
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#5 |
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Amod Panthee
Join Date: Apr 2013
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[IMG]file:///C:/Users/RENP-PID-437-1/Desktop/domain.JPG[/IMG]
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May 1, 2013, 09:00 |
domain
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#6 |
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Amod Panthee
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I have set the domain as shown in the pic....Is it OK to simulate with it?
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May 1, 2013, 18:34 |
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#7 |
Super Moderator
Glenn Horrocks
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This will probably work, as long as you only want to model 5 blades.
It can probably be optimised somewhat by doing a few things: 1) Put a wall instead of your outlet, excpet for at the bottom. This will converge much easier and should not affect things too much. 2) You probably do not need to model the nozzle in too much detail. I would just make it an inlet with the necessary velocity - unless the small velocity distribution across the jet is important. |
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May 2, 2013, 07:39 |
trial simulation
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#8 |
New Member
Amod Panthee
Join Date: Apr 2013
Location: Nepal
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I am running a trial on the model. The boundary conditions are set as shown in the attachment. It gave an unexpected result. Why is the direction of jet changed when it passes from stationary domain to the rotating domain. I think I have some problem with rotating domain.
I have 22 buckets rotating at 600 rpm and 2 nozzles of which I took 5 buckets and lower nozzle. The nozzles are not in symmetric locations. How to choose pitch value in such cases? |
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May 2, 2013, 18:44 |
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#10 |
Super Moderator
Glenn Horrocks
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The jet is not straight because you are plotting velocity in the local frame of reference. To get a straight jet plot in CFD-Post using "Velocity in Stationary Frame of Reference".
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May 2, 2013, 23:45 |
velocity in stationary frame
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#11 |
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Amod Panthee
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The direction does not change when we see it in stationary frame too
Last edited by amodpanthee; May 3, 2013 at 00:36. |
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May 3, 2013, 01:58 |
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#12 |
Senior Member
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May 3, 2013, 02:55 |
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#13 |
New Member
Amod Panthee
Join Date: Apr 2013
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Yes of course..... Runner is rotating in anticlockwise direction. I have assigned value 600 rpm.
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May 5, 2013, 05:14 |
Flow Direction
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#14 |
New Member
Amod Panthee
Join Date: Apr 2013
Location: Nepal
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I have problem with the direction of jet at interference between rotating and stationary domain, attached picutre. I think I have problem with defining the flow direction at Inlet.
I was trying to simulate a complete runner and got an error on setting the cartesian co-ordinates 0,0,0, attached picture. So, I tried simulating taking normal to boundary which runs, attached picture.....I ran it although it does not give desired result. So, I think the flow direction is the reason for deflecting the jet. Is there any rule of thumb like right hand thumb rule or left hand thumb rule to define the flow direction? The two jets in my model are placed inclined at an angle 45 degree in second quadrant and third quadrant in XY plane. Changing the flow direction will probably help run the simulation correctly. Any suggestions would be highly appreciated. |
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May 5, 2013, 06:03 |
Pelton
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#15 | |
New Member
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Quote:
Sir, What I believe is : if you are working with Cartesian coordinates, you must specify each components of velocity!! cheers!!! |
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May 5, 2013, 07:36 |
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#16 |
Super Moderator
Glenn Horrocks
Join Date: Mar 2009
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Just use normal to the boundary for the inlet. No need to specify a direction.
Your jet is being deflected before it even gets to the pelton blades. This means something is fundamentally wrong with your setup to do this. What are streamlines of the air phase look like? If you have over-constrained the air phase it will deflect the water jet like this. I mean the air needs somewhere to go to get out of the way of the water jet. |
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May 5, 2013, 09:44 |
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#17 |
Senior Member
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Why are you using symmetry condition? if it strange to use symmetry condition for this type of flow where you don't know exactly where flow is going...
My suggestion : we did similar study on tip injection effect on stall margin enhancement of transonic axial compressor rotor ( to be specific, NASA rotor 37) http://arc.aiaa.org/doi/abs/10.2514/6.2012-329 http://www.researchgate.net/publicat...ow_Compressors The point which I want to discuss is that " we have divided tip clearance into two parts : one was with rotating domain of rotor and second was with stationary domain of tip injection. So instead of putting interface at the intersection of jet and casing of compressor we gave it some space into the rotating domain. I can locate that paper and send you if needed. |
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May 5, 2013, 23:36 |
paper
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#18 |
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Amod Panthee
Join Date: Apr 2013
Location: Nepal
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May 11, 2013, 02:46 |
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#20 |
New Member
Amod Panthee
Join Date: Apr 2013
Location: Nepal
Posts: 18
Rep Power: 13 |
Yes, I received the attachment. I am going through it.
Thank you |
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Tags |
cfd, pelton turbine, tangential flow turbines |
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