Numerička simulacija strujanja u višestupanjskom aksijalnom kompresoru

master's thesis

• Title (english): Numerical simulation of the flow in a multi-stage axial compressor
• Author: Bruno Bartolec
• Mentor: Hrvoje Jasak (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2017-05-19, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering

Abstract

Konstrukcija i optimizacija različitih vrsta strojeva je značajno poboljšanja primjenom numeričkih simulacija. Područje istraživanja koje se bavi simuliranjem strujanja fluida naziva se računalna dinamika fluida. Jedna od najznačajnih primjena računalne mehanike fluida je numeričko modeliranje strujanja unutar turbostrojeva. Zbog važnosti uloge turbostrojeva u pretvorbi energije, njihov rad mora biti efikasan i fleksibilan. Kod simuliranja strujanja u turbostrojevima važno je obratiti pažnju na sučelje između rotora i statora. Strujanje u turbostroju se može smatrati periodičnim što omogućava provedbu simulacije samo na dijelu turbostroja, čime se smanjuju potrebni računalni resursi. Dodatno smanjenje računalnih resursa je moguće računanjem stacionarnog stanja unutar turbostroja umjesto tranzijentnog strujanja. U sklopu ovog rada, open source računalni paket OpenFOAM upotrebljen je za simulaciju stlačivog strujanja unutar trostupanjskog kompresora konstruiranog na sveučilištu Aachen. Za sučelje između rotora i statora upotrebljene su dvije različite metode, mixingPlane i overlapGGI. Metoda overlapGGI je izvedenica Generalized Grid Interface metode spajanja nekomfornih numeričkih mreža. Pod pretpostavkom periodičkog strujanja simuliran je samo jedan međulopatični prolaz. Na granicama međulopatičnog prostora kao periodični rubni uvjet primjenjen je cyclicGGI, također izvedenica Generalized Grid Interface metode. Numeričke simulacije provedene su za četiri radne točke, dvije za nominalnu brzine vrtnje te dvije za reduciranu brzinu vrtnje. Rezultati numeričkih simulacija prikazani su obliku polja značajnih fizikalnih veličina, ali također uspoređeni s eksperimentalnim podacima kao što su maseni tok, omjer totalnih tlakova i efikasnost.

Abstract (english)

Design and optimisation og various types of machinery has been significantly improved with the utilization of numerical simulations. Computational Fluid Dynamics (CFD) deals with numerical simulations of fluid flow in a wide variety of cases. One of the premier applications of CFD is simulating fluid flow inside turbomachines. Turbomachines play a vital role in energy conversion and as such it is important that turbomachines operate efficiently and flexibly. A key element that needs to be addressed when doing turbomachinery CFD simulations is the so called rotor-stator interface. The fluid flow inside a turbomachine is often assumed periodic which allows for only a part of the machine to be simulated thus, lowering the required computational resources. Computational resources can also be spared with approximating transient fluid flow with a quasi-steady state solution, the so called frozen rotor approach. In this thesis the fluid flow inside the IDAC is simulated using the open source CFD package OpenFOAM. The multi-stage axial turbo compressor was developed and extensively tested at RWTH Aachen University. In order to resolve the rotor-stator interaction two different types of interfaces are used: the mixing plane interface and the General Grid Interface (GGI). Since only a part of the compressor, a single passage is simulated a periodic boundary condition must be applied. For this purpose a variation of the GGI is employed. Numerical simulations are performed for four different operating points, two at the nominal design speed and two at 68% of the nominal design speed. The results of numerical simulations are presented as images of the flow field for different variables but also compared to avaliable experimental results in terms of mass flow rate, total pressure ratio, and efficiency.

• Keywords: Računalna mehanika fluida; OpenFOAM; višestupanjski turbokompresor
• Keywords (english): CFD; OpenFOAM; mixing plane; General Grid Interface; multi-stage turbomachinery
• Language: english
• URN:NBN: urn:nbn:hr:235:533577
• Study programme: Title: Mechanical Engineering; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka strojarstva (magistar/magistra inženjer/inženjerka strojarstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2019-05-22 19:33:23