Utjecaj parametara numeričkog modela u simulacijama strujanja uz transport topline

undergraduate thesis

• Title (english): Influence of the numerical model parameters in simulations of flow in presence of heat transfer
• Author: Filip Rukavina
• Mentor: Severino Krizmanić (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2025-02-25, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering

Abstract

Prilikom proračuna strujanja uz izmjenu topline, pravilan odabir parametara numeričkog postupka je od ključne važnosti. Pri tome, značajan utjecaj na rezultate proračuna imaju model turbulencije i njegove postavke, te primjena odgovarajućeg modela zidne turbulencije. Uvriježeni postupci pri izradi numeričkog modela obično dovode do dobrih rezultata u pogledu određivanja veličina vezanih uz mehaniku, dok se veličinama vezanim uz transport topline obično posvećuje manje pažnje.

U ovome radu ispitan je utjecaj parametara numeričkog modela na točnost rezultata pri računalnim simulacijama strujanja uz prisustvo transporta topline. U cilju izlučivanja graničnog sloja kao ključne pojave unutar svakog strujanja uz prisustvo transporta topline i kao onog koji najviše utječe na točnost rezultata, kao fizikalni model, odabran je proces prinudne konvekcije uz ravnu ploču.

Izrađen je jedan geometrijski model, koji pokriva cjelokupan raspon Reynoldsovih brojeva koji se susreću u inženjerskoj praksi, te je izrađeno više inačica prostorne diskretizacije. Za usporedbu rezultata s eksperimentalnim i analitičkim, odabrane su tri inačice prostorne diskretizacije koje se tipično koriste u praksi. U radu su opisani matematički i numerički model pojave, a računalne simulacije su provedene korištenjem OpenFOAM biblioteke računalnih rutina.

Temeljem usporedbe dobivenih rezultata s analitičkim i empirijskim dani su zaključci o ostvarenoj točnosti, kao i preporuke za osiguravanje ostvarive točnosti i u računalnim simulacijama dugih pojava u kojima se pojavljuje strujanje uz transport topline.

Abstract (english)

When calculating flow in presence of heat transfer, proper selection of numerical procedure parameters is of crucial importance. In this context, the turbulence model and its settings, as well as the application of an appropriate wall turbulence model, have a significant impact on calculation results. Conventional procedures in developing numerical models usually lead to good results regarding mechanical quantities, while less attention is typically paid to quantities related to heat transfer.

This work examines the influence of numerical model parameters on the accuracy of results in computer simulations of flow with heat transfer present. To isolate the boundary layer as a key phenomenon within every flow involving heat transfer and as the one that most affects result accuracy, forced convection along a flat plate was chosen as the physical model.

A single geometric model was created, covering the entire range of Reynolds numbers encountered in engineering practice, and multiple versions of spatial discretization were developed. For comparison of results with experimental and analytical data, three versions of spatial discretization typically used in practice were selected. The paper describes the mathematical and numerical model of the phenomenon, and computer simulations were conducted using the OpenFOAM library of computer routines.

Based on the comparison of obtained results with analytical and empirical data, conclusions about achieved accuracy are presented, as well as recommendations for ensuring achievable accuracy in computer simulations of other phenomena involving flow in presence of heat transfer.

• Keywords: računalna dinamika fluida; granični sloj; konvekcija; prijelaz topline; OpenFOAM
• Keywords (english): Computational Fluid Dynamics; boundary layer; convection; heat transfer; OpenFOAM
• Language: croatian
• URN:NBN: urn:nbn:hr:235:617748
• Study programme: Title: Mechanical Engineering; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka strojarstva (sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka strojarstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2025-02-24 11:00:28