CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > ANSYS

Supersonic TE tip in Centrifugal Comp.(Turbo)

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   November 9, 2019, 09:03
Post Supersonic TE tip in Centrifugal Comp.(Turbo)
  #1
New Member
 
Berk
Join Date: Nov 2019
Posts: 4
Rep Power: 5
mazdural is on a distinguished road
Hi,

I have been working on commercial turbo compressor wheel which is 3d scanned by me (for academic purposes). Despite there is a little deviation in the process of STL to CAD transformation, I could get nearly exact Pressure ratio for first speedline in performance map which is given by producer. But in the second speedline, flow at the trailing edge exceed speed of sound and this caused, decrease of pressure in the vaneless area and it doesn't suit with map. Are there any one who face with such problem?

My BC's:
Steady state analysis

Inlet: Stationary Total Pressure 101325Pa 300K Total temperature

Outlet: Exit corrected mass flow (Referances for sea level)

Air Ideal Gas

Total Energy Viscous term on

Physical timescale 0.5/w

Pressure ratio measured between outlet of volute to inlet.

In this conditions it converges without problem even under 1e-5 rms.

Meshed in Turbogrid +y is at the trailing edge around 58-60. This value is for highest cutoff refinement level possible in Turbogrid. I can't lower further. I quadrupled mesh even I got same solutions.


Volute is not original one, I drawed it. Area/Radius ratio is 0.65 original one is 0.5 but producer says A/r of compressor volute doesn't effect turbo performance significantly.

The performance map is on attachments. I also have doubts about the outlet BC, when I use mass flow outlet it diverges in the beginning. I want to know if exit corrected bc is same thing that mentioned as corrected mass flow in the map.Thanks for your help
Attached Images
File Type: png Domain.PNG (33.7 KB, 8 views)
File Type: jpg PerMap.jpg (71.7 KB, 10 views)
File Type: png Machnumber.PNG (46.5 KB, 10 views)
File Type: png Pressure.PNG (57.8 KB, 9 views)
File Type: png Pressure2.PNG (36.3 KB, 9 views)

Last edited by mazdural; November 9, 2019 at 13:59.
mazdural is offline   Reply With Quote

Old   November 11, 2019, 09:50
Default
  #2
New Member
 
Malte
Join Date: Nov 2017
Posts: 20
Rep Power: 7
stud-many is on a distinguished road
What is the MIN y+-Value, what is the MAX y+-Value? Did you do a mesh-study yet? Coarser grids tend to smooth out oscillations and stuff. So the residuals are may be low - but the solution is inaccurate

A volute can affect the compressor-stage very well. In the picture you posted here, i can see low mach-numbers in the volute (downstream, near outlet). This could be a boundary-layer detachment and this could be the reason for a low efficiency. You'll need to use the right geometry.

Are you using Mixing-Plane-Interfaces or FrozenRotor interfaces?

Last edited by stud-many; November 11, 2019 at 12:51.
stud-many is offline   Reply With Quote

Reply

Tags
supersonic, turbo chart, turbo machinery, turbo model, turbocharger

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

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 Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Out File does not show Imbalance in % Mmaragann CFX 5 January 20, 2017 11:20
Supersonic outlet working saisanthoshm88 CFX 1 November 15, 2015 19:43
[How to obtain supersonic flow inside a supersonic wind tunnel ?] yx213 Siemens 1 September 17, 2014 14:52
Probelm with supersonic exhaust to ambient newj CFX 2 August 9, 2012 19:01
How to model vortex of supersonic wing tip Bernard FLUENT 0 January 29, 2007 04:20


All times are GMT -4. The time now is 21:28.