Analiza nestlačivog strujanja fluida u blizini rotirajućeg diska

undergraduate thesis

• Title (english): Analysis of incompressible fluid flow near a rotating disk
• Author: Filip Pešorda
• Mentor: Ivo Džijan (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2017-03-02, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering

Abstract

U radu se analizira nestlačivo stacionarno strujanje fluida u blizini slobodno rotirajućeg diska u turbulentnom i laminarnom režimu strujanja. Za laminarno strujanje sustav Navier-Stokesovih parcijalnih diferencijalnih jednadžbi preveden je, uz određena pojednostavljenja i uvođenje bezdimenzijske udaljenosti od površine diska, u sustav običnih diferencijalnih jednadžbi. Kao rješenja sustava jednadžbi dobivaju se bezdimenzijski profili brzine i tlaka.
Na osnovu dobivenih rezultata za bezdimenzijske profile brzine i tlaka određen je koeficijent momenta trenja za laminarno strujanje. Zatim je pokazan način određivanja koeficijenta momenta trenja u turbulentnom režimu strujanja uvođenjem pretpostavki profila pojedinih komponenti brzine i integriranjem jednadžbi po debljini graničnog sloja.
Za turbulentno i laminarno strujanje dobivena analitička rješenja uspoređena su s eksperimentalnim rezultatima. Ova usporedba pokazuje dobro slaganje u oba analizirana režima strujanja.
Na kraju rada, rješenja dobivena za slobodno rotirajući disk uspoređena su s onima dobivenim za rotirajući disk smješten u kućištu. Iz te usporedbe se zaključuje kako je koeficijent momenta trenja veći u slučaju slobodno rotirajućeg diska nego u slučaju rotirajućeg diska smještenog u kućištu.

Abstract (english)

The paper analyzes the incompressible steady state fluid flow in the vicinity of the free rotating disk for turbulent and laminar flow regime. For laminar flow, system of Navier-Stokes partial differential equations was translated into a system of ordinary differential equations with some simplifications and introduction of the dimensionless distance from the surface of a disk. As a solutions of the equations, dimensionless profiles of speed and pressure was obtained.
Coefficient of friction torque for laminar flow was determined on the basis of the results for dimensionless velocity profile and pressure. The method for determining the coefficient of friction torque in a turbulent flow regime was then demonstrated with assumptions for velocity profiles and integration of the equations by the thickness of the boundary layer.
For turbulent and laminar flow, obtained analytical solutions were compared with experimental results. This comparison shows good agreement in both flow regimes.
At the end of the paper, the solutions obtained for free rotating disk were compared with those obtained on a rotating disk located in the housing. This comparison shows that in the case of free rotating disk, the coefficient of friction torque is higher than those obtained on a disk located in the housing.

• Keywords: slobodno rotirajući disk; laminarno strujanje; turbulentno strujanje; koeficijent momenta trenja
• Keywords (english): free rotating disk; laminar flow; turbulent flow; the coefficient of friction torque
• Language: croatian
• URN:NBN: urn:nbn:hr:235:293265
• 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: 2019-05-24 14:41:56