Hi I am currently working on a third year project to design an optimised CPU FAN. I currently trying to run CFD analysis (characteristic graphs)on an existing design. to do so i have created the blade geometry and have imported it into Tubogrid. the mesh was created and refined such that all mesh statistic errors are below 1%

I then used CFX-Pre, and using the "turbomachinery" mode i chose machine type to be "FAN" and this way i managed to define all boundary conditions. I have assumed a shroud tip clearance of 0.4mm and an inlet pressure of 101300 pa and an exit pressure of 101350pa. the residual target i have set is 10^-5 but however i try the solver will not converge?! i have tried also using the energy methods (total energy/ isothermal) but have not got anywhere. my major problem is even when i stop the solver after it srarts fluctuating at about 4 X 10^-4 the result file gives a blade loading graph that does not make sense(invalid). i have got print screens of the blade loading and also the convergance history and i can also email them if they can explain anything?! i would dearly appreciate help as i am pretty behind on my third year project. many thanks Danyal.

would you please send me your file? Please send me the out file together. wuzhiyongspecial@gmail.com

http://www.cfd-online.com/Wiki/Ansys...gence_criteria

Hi

Try with inlet pressure boundary and outlet mass flowrate boundary. try with different mass flowrates.

BOL