Thesis (MScEng)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: Stellenbosch University participated in a project to re-design the compressor
section of a diesel locomotive turbocharger. Tests conducted on the prototype
compressor showed possible rotating stall in the diffuser section before the
designed higher pressure ratio could be achieved. When approaching the higher
pressure ratio, the compressor inlet trunk started to rhythmically collapse (due
to suction), the engine shook and bellows of black smoke were exhausted by
the engine. It was decided to simulate the prototype compressor's operation
by using the 1-D theory of Aungier (2000) and to perform a 3-D CFD analysis
of the compressor using FINE/Turbo of NUMECA International.
A veri cation process was followed to show the accuracy of the 1-D and
3-D modelling methods using two well-known centrifugal compressor test cases
found in the literature, namely the O-Rotor by Eckardt (1975, 1976, 1980) and
the "Radiver" open CFD test case by Ziegler et al. (2003c). Results from the
models were compared to available experimental results and the accuracy was
found to be su cient to investigate the prototype compressor's impeller and
diffuser.
Both prediction methods con rmed separation in the vaned di user across
the entire operating ow range of the prototype compressor at the design impeller
speed. The 3-D method identi ed supersonic ow at the vaned diffuser
inlet at the operating point and also predicted a smaller operating range than
originally anticipated. Both the 1-D and 3-D methods also predicted impeller
blade stall over the entire operating ow range at the design impeller speed. A recommendation was made to redesign the impeller and diffuser of the prototype
compressor. / AFRIKAANSE OPSOMMING: Die Universiteit van Stellenbosch het deel geneem aan 'n projek om die kompressor
gedeelte van 'n diesel lokomotief se turbo-aanjaer te herontwerp. Toetse
uitgevoer op die prototipe kompressor het moontlike roterende wegbreking in
die diffuser seksie uitgewys voordat die ontwerpte hoër drukverhouding bereik
kon word. Toe die hoër drukverhouding genader is, het die kompressor inlaatpyp
begin ritmies inmekaar vou (as gevolg van die suig aksie), die enjin
het geskud en wolke swart rook is deur die enjin uitgeblaas. Die besluit is
geneem om die prototipe kompressor se werking te simuleer met behulp van
die 1-D teorie van Aungier (2000) en om ook 'n 3-D berekenings vloeimeganika
(BVM) analise op die kompressor uit te voer met behulp van FINE/Turbo
van NUMECA Internasionaal.
'n Veri kasieproses is gevolg om die akkuraatheid van die 1-D en 3-D modelle
te illustreer met behulp van twee welbekende sentrifugaal kompressor
toetsgevalle beskikbaar in die literatuur, naamlik die O-Rotor deur Eckardt
(1975, 1976, 1980) en die "Radiver" oop BVM toetsgeval deur Ziegler et al.
(2003c). Resultate van die modelle is vergelyk met beskikbare eksperimentele
resultate en die bevinding is gemaak dat die akkuraatheid genoegsaam is om
die prototipe kompressor se rotor en diffuser te ondersoek.
Beide voorspellingsmetodes het wegbreking bevestig in die gelemde diffuser
oor die hele werksbestek van die prototipe kompressor teen die ontwerp rotorspoed. Die 3-D metode het supersoniese vloei by die gelemde diffuser se inlaat
by die bedryfspunt geïdenti seer en het ook 'n kleiner werksbestek voorspel
as wat vroeër verwag is. Beide die 1-D en 3-D metodes het ook wegbreking
in die rotor oor die hele werksbestek teen die ontwerp rotorspoed voorspel. 'n
Voorstel is gemaak om die rotor en diffuser van die prototipe kompressor te
herontwerp.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/17784 |
| Date | 12 1900 |
| Creators | De Wet, Andrew Louis |
| Contributors | Von Backstrom, T. W., Van der Spuy, S. J., Stellenbosch University. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | English |
| Type | Thesis |
| Format | 136 p. : ill. |
| Rights | Stellenbosch University |
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