Pregled metode povezivanja rotorske i statorske mreže u proračunskoj mehanici fluida za simulacije turbostrojeva

Balatinec, Luka (2019) Pregled metode povezivanja rotorske i statorske mreže u proračunskoj mehanici fluida za simulacije turbostrojeva. = An overview of rotor-stator interfaces for computational fluid dynamics simulations in turbomachinery. Master's thesis (Bologna) , Sveučilište u Zagrebu, Fakultet strojarstva i brodogradnje, UNSPECIFIED. Mentor: Jasak, Hrvoje.

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Abstract (Croatian)

Ubrzan napredak računalne dinamike fluida (RDF) omogućio je nadilaženje jednostavnih zadataka te prelazak na složenije probleme poput turbostrojeva. Zbog složenosti turbostrojeva, često se uvode pojednostavljenja geometrije s ciljem smanjenja vremena trajanja simulacije. Pojednostavljenja je takoder moguće provesti primjenom adekvatnih stacionarnih simulacija za modeliranje gibanja unutar domene. Kako bi se omogućila komunikacija izmedu dijelova domene s različito definiranom rotacijom, nepovezanih ili djelomično povezanih dijelova domene te kružno ponavljajućih rubnih ploha, primjenjuju se različita sučelja. U sklopu ovog rada, izložena je teorijska pozadina pojedinih sučelja uz primjere primjene istih u računalnim simulacijama trubostrojeva s nestlačivim radnim fluidom. Simulacije su provedene u svrhu validacije različitih pristupa u korištenju sučelja za osnivanje komunikacije izmedu rotora i statora. Izvršen je niz simulacija na primjeru para kontra-rotirajućih brodskih propelera navedenih u nastavku: • Stacionarne simulacije s cjelovitom domenom propelera uz korištenje ggi sučelja. • Stacionarne simulacije s četvrtinom domene propelera uz korištenje cyclicGgi i overlapGgi sučelja te istovjetne simulacije s različitim medusobnim položajempropelera. • Stacionarne simulacije s četvrtinom domene propelera uz korištenje cyclicGgi i mixingPlane sučelja. • Tranzijentne simulacije s četvrtinom domene propelera uz korištenje cyclicGgi i overlapGgi sučelja. Provedena je analiza rezultata navedenih simulacija na temelju kojih su izračunati koeficijenti hidrodinamičkih performansi seta propelera. Pokazana je dobra usuglašenost rezultata simulacija s cjelovitom domenom te onih iz simulacije s četvrtinom domene. Usporedba rezultata stacionarnih simulacija pokazuje dobru usuglašenost s eksperimentalnim podacima za područja više efikasnosti propelera, dok je za radne točke u područjima niže efikasnosti potrebno provesti tranzijentne simulacije.

Abstract

Rapid progress of Computational Fluid Dynamics (CFD) allowed CFD to move past simple tasks and become a viable tool for the analysis of complex problems, such as turbo-machines. Nevertheless, due to the complexity of turbomachinery, some simplifications regarding interface and domain handling are sought in order to allow for reasonable simulation execution times. Most often, only a part of the whole turbomachine geometry is simulated, which decreases computational demands. To enable communication between domain regions wherein different rotation (or other movement) is modelled, between ill-connected or overlapping regions, or between cyclic patches bounding partial geometry domains, various interfaces are used. Moreover, steady-state ”frozen rotor” methods are frequently used to approximate transient problems but avoid computationally demanding transient simulations. This Thesis offers an overview of several rotor-stator interfaces available in foam-extend, with both theoretical background and numerical simulations. A series of numerical simulations is performed on a Contra-Rotating Propeller set (CRP), investigating different rotor-stator interface handling methods: • Steady-state simulations using the Multiple Reference Frame (MRF) approach and the whole CRP geometry with General Grid Interface (ggi). • Steady-state MRF simulations of a quarter CRP geometry using overlapGgi and cyclicGgi interfaces across periodic boundaries. Additional simulations are performed to investigate the effects of initial propeller position. • Quarter CRP geometry steady-state MRF simulations using cyclicGgi and mixingPlane interfaces. • Transient simulation of a quarter CRP geometry with the cyclicGgi and overlapGgi interfaces. The results were analysed in terms of hydrodynamic performance coefficients, showing good agreement between quarter and full CRP simulations and validating the interfaces used. Comparison to experimental data revealed good agreement with steady-state results for high-efficiency conditions and good agreement with transient simulations for lower-efficiency conditions.

Item Type: Thesis (Master's thesis (Bologna))
Uncontrolled Keywords: RDF, rotorska i statorska sučelja, kontra-rotirajući propeleri, ggi, overlapGgi, cyclicGgi, mixingPlane, foam-extend
Keywords (Croatian): CFD, rotor-stator interfaces, Contra-rotating propellers, ggi, overlapGgi, cyclicGgi, mixingPlane, foam-extend
Subjects: TECHNICAL SCIENCE > Mechanical Engineering
Divisions: 500 Department of Energy, Power Engineering and Environment > 530 Chair of Turbomachinery
Date Deposited: 20 Mar 2019 11:19
Last Modified: 31 Oct 2019 16:37
URI: http://repozitorij.fsb.hr/id/eprint/9252

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