# Hydraulic turbine and buoyancy!

 Register Blogs Members List Search Today's Posts Mark Forums Read

 March 3, 2008, 04:16 Hydraulic turbine and buoyancy! #1 Nicola Guest   Posts: n/a Hi everyone! I want to simulate a hydraulic turbine (Francis). CFX resolves rho*g*z term in N. S. Equation automatically when I use water as material or do I need to set buoyancy? Why does CFX ask me to set a reference coordinates for buoyancy? I'm confuse. Can you explain me about buoyancy? Thanks a lot!

 March 3, 2008, 07:09 Re: Hydraulic turbine and buoyancy! #2 Rogerio Fernandes Brito Guest   Posts: n/a You choose where is the direction of your gravity!

 March 3, 2008, 11:35 Re: Hydraulic turbine and buoyancy! #3 Nicola Guest   Posts: n/a Thanks but I don't understand if I need to use buoyancy or not. I have two simulation with the same bc one is with buoyancy and other without. I don't find any real differences in pressure and total pressure. In buoyancy case I have an absolute pressure different from pressure because there is the rho*g term. Then what's the differences in two cases? If I don't use buoyancy does CFX solve correctly my flow? Thanks

 March 3, 2008, 12:02 Re: Hydraulic turbine and buoyancy! #4 Rogerio Fernandes Brito Guest   Posts: n/a when u consider buoyancy , you will perform a simulation more near from experimental!

 March 3, 2008, 12:52 Re: Hydraulic turbine and buoyancy! #5 Nicola Guest   Posts: n/a Ok Thank you very much! But how do I have to set the reference coordinates in buoyancy? Can I set it in automatic? Can reference coordinates modify the solution? I know it modifies the absolute pressure but are pressure and total pressure correct (near to experimental)independently the reference coordinates I choose? If I use buoyancy and I want to calculate energy between Inlet and Outlet, can I write Energy=(massflowAve(Total Pressure in Stn Frame)@Inlet-massflowAve(Total Pressure in Stn Frame)@Outlet)/rho ? Or I need to consider Energy=(massflowAve(Total Pressure in Stn Frame)@Inlet-massflowAve(Total Pressure in Stn Frame)@Outlet)/rho+g*(massflowAve(z)@Inlet-massflow(z)@Outlet) ? Thanks

 March 5, 2008, 03:59 Re: Hydraulic turbine and buoyancy! #7 Nicola Guest   Posts: n/a Dear Magnoli thank you very much for your walk-through.

 February 10, 2011, 02:05 francis turbine #8 New Member   fathe mohammad Join Date: Feb 2011 Location: banglore Posts: 1 Rep Power: 0 how can i get the details of francis turbine , i want to do cfd analysis of francis turbine

 Thread Tools Display Modes Linear Mode

 Posting Rules You may not post new threads You may not post replies You may not post attachments You may not edit your posts BB code is On Smilies are On [IMG] code is On HTML code is OffTrackbacks are On Pingbacks are On Refbacks are On Forum Rules

All times are GMT -4. The time now is 01:57.