Help Required on CFD for Turbine Blade Analysis

kkjj2008 · July 7, 2009, 21:37

Hi,
i m new here .. nd i m nt familiar with ANSYS flotran.. so can any one help me in doing a turbine blade analysis... i have the same divergent solution error each time ... the solution is not converging
i already use the MIR stability conditions...
i m not sure about the reference conditions will any body explain me how to specify them...
the temperature at the inlet is 900 K and pressure is 1.96 bar.

kindly some one help me ..
thanks in advance for any response......

atmcfd · July 9, 2009, 00:55

hi kkjj... i don tink der r many in dis forum who r interested in Flotran... i had a prob wit flotran too,but never got a reply.Since then i migrated to fluent.anyways it has almost become a thing of the past,since fluent,CFX and other commercial softs rule the roost.Even Ansys has put flotran in the backburner.any use of flotran today remains only to train new students of CFD,since it has all the components(prepro,solver and post) in the same interface.shift to some other popular code then u can find loads of help i guess....

kkjj2008 · July 9, 2009, 08:23

Thanks "Atmcfd" for ur reply but actually i m doing my MS project in flotran thats y i can not switch to fluent myself....

Ahmed · July 9, 2009, 11:42

Are you familiar with the concept of "artificial viscosity", this is how flotran stabilizes the solution. Simply, you start your iterations with a very high value (compared to the real coefficient) and reduce it as the solution proceeds, you need to search the online help system for a flow through a nozzle example, read it to get an idea of how this procedure is used. you need to experiment a little bit say you start with, for instance 1000 times the viscosity for 50 iterations, continue with less viscosity another 50 iterations reduce the viscosity and etc
Just remember to watch the residuals and how they oscillate until you reach a stable solution.
Of course, you need to remember, that was a long time ago and I am just using my memory
good luck

kkjj2008 · July 9, 2009, 12:45

Thanks ahmed for ur reply... i m using artificial viscosity... but kindly explain me how to use that may be i m using in a wrong way....

Ahmed · July 9, 2009, 15:41

as has been mentioned before, Flotran is old software and I am just trying to refresh my memory, perhaps you would get better response if you post your query on the right forum, the ansys forum
good luck

July 7, 2009, 21:37	Help Required on CFD for Turbine Blade Analysis	#1
kkjj2008 New Member Kami Join Date: Jul 2009 Posts: 6 Rep Power: 16	Hi, i m new here .. nd i m nt familiar with ANSYS flotran.. so can any one help me in doing a turbine blade analysis... i have the same divergent solution error each time ... the solution is not converging i already use the MIR stability conditions... i m not sure about the reference conditions will any body explain me how to specify them... the temperature at the inlet is 900 K and pressure is 1.96 bar. kindly some one help me .. thanks in advance for any response......

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July 9, 2009, 00:55		#2
atmcfd Senior Member ATM Join Date: May 2009 Location: United States Posts: 104 Rep Power: 16	hi kkjj... i don tink der r many in dis forum who r interested in Flotran... i had a prob wit flotran too,but never got a reply.Since then i migrated to fluent.anyways it has almost become a thing of the past,since fluent,CFX and other commercial softs rule the roost.Even Ansys has put flotran in the backburner.any use of flotran today remains only to train new students of CFD,since it has all the components(prepro,solver and post) in the same interface.shift to some other popular code then u can find loads of help i guess....

July 9, 2009, 08:23		#3
kkjj2008 New Member Kami Join Date: Jul 2009 Posts: 6 Rep Power: 16	Thanks "Atmcfd" for ur reply but actually i m doing my MS project in flotran thats y i can not switch to fluent myself....

July 9, 2009, 11:42		#4
Ahmed Senior Member Ahmed Join Date: Mar 2009 Location: NY Posts: 251 Rep Power: 18	Are you familiar with the concept of "artificial viscosity", this is how flotran stabilizes the solution. Simply, you start your iterations with a very high value (compared to the real coefficient) and reduce it as the solution proceeds, you need to search the online help system for a flow through a nozzle example, read it to get an idea of how this procedure is used. you need to experiment a little bit say you start with, for instance 1000 times the viscosity for 50 iterations, continue with less viscosity another 50 iterations reduce the viscosity and etc Just remember to watch the residuals and how they oscillate until you reach a stable solution. Of course, you need to remember, that was a long time ago and I am just using my memory good luck

July 9, 2009, 12:45		#5
kkjj2008 New Member Kami Join Date: Jul 2009 Posts: 6 Rep Power: 16	Thanks ahmed for ur reply... i m using artificial viscosity... but kindly explain me how to use that may be i m using in a wrong way....

July 9, 2009, 15:41		#6
Ahmed Senior Member Ahmed Join Date: Mar 2009 Location: NY Posts: 251 Rep Power: 18	as has been mentioned before, Flotran is old software and I am just trying to refresh my memory, perhaps you would get better response if you post your query on the right forum, the ansys forum good luck