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Eckardt Impeller (1980) test results.

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Old   September 26, 2007, 06:26
Default Eckardt Impeller (1980) test results.
  #1
Andrew de Wet
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Hi all!

I am simulating the Eckardt Impeller with NUMECA's FINE/Turbo with the aim of verifying the results. But I can't find any test results on the internet. Trust me, I have tried... I came onto the site (http://doc.adsabs.harvard.edu/abs_doc/site_map/) which have the 3 papers published by Diedrich Eckardt. The 3 papers are titled:

"D. Eckardt, Instantaneous Measurements in the Jet-Wake Discharge Flow of a Centrifugal Compressor Impeller. J. Eng. Power, 337, 1975."

"D. Eckardt, Detailed Flow Investigations Within a High-Speed Centrifugal Compressor Impeller. Trans. ASME, September, 1976."

"D. Eckardt, Flow Field Analysis of Radial and Backswept Centrifugal Compressor Impellers Part I: Flow Measurements using a Laser Velocimeter. In Performance Prediction of Centrifugal Pumps and Compressors, edited by S. Gopalakrishnan, P. Cooper, C. Grennan, and J. Switzer, ASME, 1980."

The only results I can get is a case study by Fluent (exactly what I am trying to do with FINE/Turbo) at http://www.fluent.com/about/news/new.../pdfs/nl34.pdf and also from the book by D. Japikse and N.C. Baines "Introduction to Turbomachinery"

Any help with experimental results will help. Thank you in advance! Andrew
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Old   October 3, 2007, 10:42
Default Re: Eckardt Impeller (1980) test results.
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Dothan
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Hi Andrew,

coincidently I am simulating the same thing and I'm desperately looking for the Eckardt's papers. Do you have find some information?

In the fluent paper there is a chart, but the impeller geometry isn't complete. In the paper are missing the axial length of the impeller, the tips thickness, betha angle (but maybe is possible to calculate this value from shroud to hub). furthermore, fluent paper refer to radial vanes impeller, but the first image is about a backsweept vanes impeller.

keep in touch

Dothan
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Old   October 4, 2007, 11:47
Default Re: Eckardt Impeller (1980) test results.
  #3
Andrew de Wet
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Hello Dothan! Good to hear someone else is also looking for the papers! I would like to know if you are also simulating the Eckardt impeller with NUMECA's FINE/Turbo? Or with Fluent? Just to know if we are on the same station and to what degree I can contribute.

My aim is to simulate the Eckardt radial impeller with FINE/Turbo (and no other CFD software) and then to compare the results with Eckardt's findings. This is to verify the accuracy of the results which FINE/Turbo gives for academic reasons. I have access to the previously mentioned book by Japikse and Baines and the compressor performance map supplied there is much more accurate than Fluent's. I have learned that our engineering library has a large collection of ASME journals (which are not listed on our web page) and I will be spending some time there tomorrow.

I would like to know what information you have gathered? I have since found an Concepts ETI NREC CCAD model of the Eckardt impeller which I then compiled in .geomTurbo format. The accuracy of the model is dependent on how well NREC modelled it as I found it under their examples folder. But the tip-clearance is unknown as CCAD says it is a closed impeller.

Hope to hear from you soon. Andrew.
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Old   October 8, 2007, 03:40
Default Re: Eckardt Impeller (1980) test results.
  #4
Dothan
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Hi Andrew, I'm very pleased to find you. I'll give you all my experience,insofar as I can.

I'm study a centrifugal compressor with Fluent (Mechanical engineering thesis ). Because I need to gain confidence with the results provided by CFD, my aim is to simulate Eckardt impeller before, verifying how close I'm, and after simulate my impeller. My university have an account at ASME digital library, but Eckardt's papers are too old.

I'm rebuild Eckardt impeller geometry with some assumption: -20 radially ending vanes -inner shroud diameter 280mm -inner hub diameter 90 mm -impeller tip@outlet diameter 400 mm -inlet domain upstream impeller 200 mm (is very much!imho) -outlet fluid domain diameter 700 mm -14000 rpm I'm calculating Angles @ leading edge with the basic theory. I think to model a impeller without tip clearance (naturally, errors expected ). unfortunately I have gambit without G/turbo, so I can't mesh with structured elements like hexaedra. I'meshing with tetrahedra elements.

At the moment I'm studing the influence of y+.

Do you have a impeller file? interesting! I'have scanned Nrec site and I didn't founded that...I'll run to control again.

keep in touch, Dothan
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Old   October 8, 2007, 05:31
Default Re: Eckardt Impeller (1980) test results.
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Andrew de Wet
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Hey Dothan, I'm glad to see that you are also busy with an academic exercise! I wrote a long reply but my Internet Explorer crashed as I was posting the message... I am also busy with my masters in mechanical engineering at Stellenbosch University and also have to gain confidence with the CFD software I am using, hence the Eckardt impeller. I am exclusively using FINE/Turbo by NUMECA for my studies and my thesis is on redesigning the General Electric 7S1408 A1 turbocharger's compressor.

Since our last correspondence I have found the first two papers by Eckardt; "Instantaneous Measurements..." and " Detailed Flow Investigations..." in our library records. If you'll give me your e-mail address I can send you the papers as PDFs. As a far as I know ASME do not have copyright policies and if you guys have an account at ASME, there shouldn't be a problem. My study coordinator also said it is fine.

The first paper does give more information such as the tip clearance which is 0.8mm. But unfortunately the beta angles are not available. What I can give you are the surface coordinates which I got from the NREC model (I also searched the internet in vain but later stumbled onto it in the examples folder of CCAD on my PC). I think it will also be of more help with Gambit as it skips you the trouble of generating the surface coordinates yourself.

Oh yes, from what university are you?

Till later, Andrew.
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Old   October 9, 2007, 06:56
Default Re: Eckardt Impeller (1980) test results.
  #6
Dothan
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Hi Andrew, I sent to you an e-mail by clicking your name in this forum.

Dothan
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