Hi,

I'm trying to model a turbine that is submerged in water and water is flowing with a speed to rotate the turbine. My objective is to find out the torque generated. My questions:

1) should I use global rotating reference frame or MRF? 2) should I take the torque when it's rotating or when it starts to rotate?

I did a CFD on wind turbine before, using global RF rotating the fluid (air) surrounding the wind turbine blade and calculated the lifting force on the airfoil. But I'm not sure if this is the correct approach for the water turbine.

Thanks for any help/reply

Peter

Dear Peter,

You can model the turbine.

You should be aware which turbine you are modelling. Radial, Axial or Mixed Flow.

In case of Francis Turbine, you can calculate the torque on the blades if you are simulating the system on Ansys CFX 11.

And in this case runner is always rotating with a stationary frame of reference.

I hope you get it

Regards,

Amit Roghs

Thanks for replying

Mine is axial turbine flow. Did you mean that I should apply rotational velocity to all the blade surfaces and also the fluid region surrounding it? I saw a centrifugal blower tutorial in Fluent manual, fluid and blades are rotating in the same direction inside the MRF. Is that what you meant?

Thanks again for helping

my promblem is desgin modeling in water turbine (pelton , frain kaplan etc turbin )which software is used

Hi Dushyanth,

What do you want model? can you send me pics so that i can suggest.

Sam

[ShaneStan]

hey peter, im modeling a 3d axial tidal turbine too-im only new to cfd so if you could give me a couple of steps to help get me started thated be brilliant?! i have my geometry made up and all!
cheers bro

[saini.yashwant]

Originally Posted by Amit Roghs
;55792

Dear Peter,

You can model the turbine.

You should be aware which turbine you are modelling. Radial, Axial or Mixed Flow.

In case of Francis Turbine, you can calculate the torque on the blades if you are simulating the system on Ansys CFX 11.

And in this case runner is always rotating with a stationary frame of reference.

I hope you get it

Regards,

Amit Roghs

sir i am student of M.tech at NIT surat. i am doing numerical simulation of wind turbine by fluent. so i am facing some problems with defining the boundary conditions. so wl u please help me regarding boundary conditions.sir i have modeled wind turbine in gambit and meshed it with two domain interior domain with .5d same as wind radius. and another one is off bigger domain of 4d in diameter. and 3d in front and 5d in back. i have defined the interface in between the surfaces of interior and outer domain. by giving the condition of rotor stationary and the near by domain air is rotating i am getting the axial velocity at the rotor plane more than inlet velocity. is this correct or not. and please help me out how to calculate the power output and coefficient of power.
thanks
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[morteza 1374]

Hi
I am a student of fluids and I like your site very much. I am researching on how to analyze Francis turbine. In visiting your site I noticed about the analysis of these turbines. I want to ask if you can, please help me about the procedures analysis of Francis turbine with full details.
Thank you so much