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 December 11, 2016, 19:14 #21 New Member   Ahmad Hari Join Date: Dec 2016 Posts: 21 Rep Power: 9 Hi Brian, 1- the flow direction was based on Turbo comment. Since the axis of rotation is Z, I set x = - 1, y = tan (78.33) and Z= 0. I doubly I have a problem here 2- yes the efficiency was calculated by Rital (Comcept NREC). In Rital, I designed a turbine with volute and rotor ( no stator). So, the enthalpy drop should take place at the rotor.

 December 12, 2016, 07:20 #22 Senior Member   Join Date: Jun 2009 Posts: 174 Rep Power: 17 Why did you use the compressor template in performance? Post a 3d streamline view.

December 12, 2016, 08:03
#23
New Member

Join Date: Dec 2016
Posts: 21
Rep Power: 9
Hi Turbo,

I'm not using compressor template. I'm using turbine rotor template but I don't know why it appears as a compressor. Attached is the screenshot of the velocity streamlines
Attached Images
 velocity streamlines.jpg (74.6 KB, 28 views)

 December 12, 2016, 08:49 #24 Senior Member   Join Date: Jun 2009 Posts: 174 Rep Power: 17 Before trying any CFD, bear in mind that you need to study the basics of turbomachinery, especially the velocity triangle. Your geometry setting needs a negative rpm. There will be more to fix other than that. Just study setting aside the CFD job. This forum is not aiming for providing turbomachinery education, as I know.

 December 12, 2016, 10:08 #25 New Member   Ahmad Hari Join Date: Dec 2016 Posts: 21 Rep Power: 9 That's correct but I would be happy if you mentioned "the more things need to be fixed" though

 December 12, 2016, 17:42 #26 Member   turbo4life Join Date: Nov 2016 Posts: 41 Rep Power: 9 Based on the picture, rpm needs to be negative. Also, your inlet flow direction needs to be in the same direction as the rotation. Based on the axes you have, I think you need z=0, y=-1 and x = tan(78). I would strongly recommend reviewing this resource if you need a turbomachinery reference: https://www.google.com/url?sa=t&rct=...feI6rXhjuNutww Turbo is correct. You need to review the basics of turbomachinery so you can troubleshoot your CFD. Chapter 8 of this resource is for radial turbines, but there is a good general review in the first few chapters as well. Best of luck! Last edited by bparrelli; December 12, 2016 at 18:57.

 December 13, 2016, 10:17 #27 New Member   Ahmad Hari Join Date: Dec 2016 Posts: 21 Rep Power: 9 Dear Brian, Turbo and all, Thank you for your comments and advices. I'll keep working on that till it is fixed. Brian, Using the flow direction you mentioned (z=0, y=-1 and x = tan(78).), I got the following error: ERROR #002100024 has occurred in subroutine ASS_FLX_BDINIP. | | Message: | | The specified flow direction on boundaries must not be tangential | | to the boundary. However, on the boundary patch | | | | R1 Inlet | | | | a specified flow direction having an angle of 6.2 degrees | | was found, which the solver considers as being nearly tangential. | | Please do one of the following: | | (1) Check your direction specification on this boundary. | | (2) Set the 'Flow Direction Linearisation' to 'Velocity Magnitude' | | in your boundary specification. | | (3) Modify the solver tolerance by decreasing the expert parameter | | 'tangential vector tolerance' below its default of 10 degrees. I will try to follow the comments suggested by CFX Thanks again all of you

May 11, 2018, 01:44
#28
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SHUJAN
Join Date: Jun 2016
Posts: 17
Rep Power: 10
Quote:
 Originally Posted by Abo Anas Continue of the attached photos Just to let you, I'm using Cartesian coordinates based on comment by Turbo. I have a swirl angle (absolute flow angle) = 78.33 deg Many thanks in advance
Anas. Hi. Have you solved your issues. I need to do similar simulation and I only have 2 days to work on it. Please, can you reply.