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Design procedure of a compact crossover diffuser for micro gas turbine application

Thesis (MEng)--Stellenbosch University, 2016.

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Main Author: Burger, Christiaan Johannes
Other Authors: Van der Spuy, S. J.
Format: Thesis
Language:en_ZA
Published: Stellenbosch : Stellenbosch University 2016
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access_status_str Open Access
author Burger, Christiaan Johannes
author2 Van der Spuy, S. J.
author_browse Burger, Christiaan Johannes
Van der Spuy, S. J.
author_facet Van der Spuy, S. J.
Burger, Christiaan Johannes
author_sort Burger, Christiaan Johannes
collection Thesis
dc_rights_str_mv Stellenbosch University
description Thesis (MEng)--Stellenbosch University, 2016.
format Thesis
id oai:scholar.sun.ac.za:10019.1/98634
institution Stellenbosch University (South Africa)
language en_ZA
last_indexed 2026-06-10T12:45:50.231Z
license_str Other — see source repository
provenance_str_mv Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository
publishDate 2016
publishDateRange 2016
publishDateSort 2016
publisher Stellenbosch : Stellenbosch University
publisherStr Stellenbosch : Stellenbosch University
record_format dspace
source_str SUNScholar — Stellenbosch University Repository
spelling oai:scholar.sun.ac.za:10019.1/98634 Design procedure of a compact crossover diffuser for micro gas turbine application Burger, Christiaan Johannes Van der Spuy, S. J. Von Backstrom, T. W. Stellenbosch University. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering. Compact crossover diffuser -- Design Micro gas turbine application UCTD Thesis (MEng)--Stellenbosch University, 2016. ENGLISH ABSTRACT: The design of a compact crossover diffuser to replace the size-limited radial diffuser and axial de-swirl cascade of the BMT120KS MGT is discussed. A crossover diffuser strives to combine the performance of a channel diffuser with the operating range and efficiency of a vaneless diffuser. Continuous aerodynamic vanes are designed to match the centrifugal impeller discharge flow and gradually diffuse the air towards the axial combustor inlet where the effect of swirling flow on combustor performance is experimentally investigated. Swirling combustor flow promotes combustion intensity, reduces combustion length, and enhances combustion stability. The study includes the development of a one-dimensional Mean-Line Code (MLC) which aids the designer in preliminary design and performance evaluation. A three-dimensional multiple operating point optimisation is conducted thereafter using Numeca FineTM/Turbo). The final design is manufactured using a five-axis CNC milling machine and experimentally tested by modifying the existing BMT120KS engine. The optimised crossover diffuser and modified impeller yielded a numerical increase in the total-to-static compressor stage pressure ratio from 2:93 to 3:83, increase in the static pressure recovery coefficient from 50:92% to 68:49%, and relaxed the compressor stage discharge flow angle from 84:14° to 34:28° (compared to the modified BMT120KS engine). Experimental results are recorded up to a rotational speed of 106 000RPM and extrapolated to the design speed of 120 000 RPM. The extrapolated results indicate a thrust increase from 107:3N to 220N and increase in total-to-static compressor stage pressure ratio from 2:62 to 3:65 at 120 000RPM (compared to the original BMT120KS engine). AFRIKAANSE OPSOMMING: Die ontwerp van n kompakte oorgangsdiffusor om die radiale lem diffusor en aksiale rig-lemme van die bestaande BMT120KS mikrogasturbine te vervang word bespreek. ‘n Kompakte oorgangsdiffusor beoog om die werksverigting van ‘n kanaaldiffusor met die bedryfsgebied van n lemlose diffusor te kombineer. Deurlopende aerodinamiese lemme is ontwerp om die sentrifigaalkompressor rotor uitlaatvloei geleidelik te diffundeer tot waar dit die verbrandingsruim binne gaan met ‘n beduidende tangensiale vloeikomponent. Die studie sluit in die ontwikkeling van ‘n een-dimensionele kode wat die ontwerper instaat stel om ‘n kompakte oorgangsdiffusor te ontwerp en te evalueer . Daarna is optimering gedoen in Numeca FineTM/Turbo (BVM sagteware) en die finale ontwerp is vervaardig met behulp van ‘n vyf-as numeries beheerde freesmasjien. Die geoptimeerde oorgangsdiffusor en rotor lewer ‘n numeriese toename in die totale-tot-statiese kompressor stadium drukverhouding vanaf 2:93 na 3:83, ‘n toename in die statiese druk herwinningskoëffisiënt vanaf 50:92% tot 68:49%, en verminder die uitlaat-vloeihoek vanaf 84:14°na 34:28° (vergeleke met die gewysigde BMT120KS enjin). Eksperimentele resultate is verkry tot by ‘n rotasie spoed van 106 000RPM en geëkstrapoleer tot die ontwerpspoed van 120 000 RPM. Die resultate dui op ‘n stukrag toename vanaf 107:3N na 220N en ‘n toename in die totale-tot-statiese kompressorstadium drukverhouding vanaf 2:62 na 3:65 (vergeleke met die oorspronklike BMT120KS enjin). 2016-03-09T14:42:43Z 2016-03-09T14:42:43Z 2016-03 Thesis http://hdl.handle.net/10019.1/98634 en_ZA Stellenbosch University 104 pages : illustrations application/pdf Stellenbosch : Stellenbosch University
spellingShingle Compact crossover diffuser -- Design
Micro gas turbine application
UCTD
Burger, Christiaan Johannes
Design procedure of a compact crossover diffuser for micro gas turbine application
title Design procedure of a compact crossover diffuser for micro gas turbine application
title_full Design procedure of a compact crossover diffuser for micro gas turbine application
title_fullStr Design procedure of a compact crossover diffuser for micro gas turbine application
title_full_unstemmed Design procedure of a compact crossover diffuser for micro gas turbine application
title_short Design procedure of a compact crossover diffuser for micro gas turbine application
title_sort design procedure of a compact crossover diffuser for micro gas turbine application
topic Compact crossover diffuser -- Design
Micro gas turbine application
UCTD
url http://hdl.handle.net/10019.1/98634
work_keys_str_mv AT burgerchristiaanjohannes designprocedureofacompactcrossoverdiffuserformicrogasturbineapplication