Računalna simulacija stacionarnog i nestacionarnog strujanja u složenoj cjevovodnoj mreži

undergraduate thesis

• Title (english): Numerical simulation of steady and unsteady flow in complex pipe network
• Author: Philipp Milović
• Mentor: Ivo Džijan (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2019-03-01, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering

Abstract

U ovom radu je analizirano stacionarno i nestacionarno strujanje kapljevine u složenim cijevnim mrežama proizvoljne konfiguracije pomoću računalnog koda HydNet razvijenog u okviru ovog rada te napisanog u programskom jeziku C++ . U radu je prikazan osnovni hidrodinamički model jednodimenzionalnog izotermnog strujanja slabo-stlačivog fluida u elastičnom cjevovodu. Osnovni model je zatim proširen diskretnim plinskim kavitacijskim modelom koji uzima u obzir prisutnost plina u kapljevini te pojavu kavitacije. Uz to, model je proširen tako da uzima u obzir utjecaj nestacionarnog trenja i utjecaj profila brzine preko faktora korekcije količine gibanja. Prezentirana je simultana Hardy-Cross metoda za proračun stacionarnog strujanja te metoda karakteristika i kompletna numerička shema korištena tokom simulacije nestacionarnog strujanja. Izvedeni su izrazi za unutarnje i jednostavne mrežne čvorove te za mrežne čvorove kojima se modeliraju spremnici, lokalni gubici i ventili. U radu je takoder opisan orginalno razvijeni računalni kod HydNet te je provedena validacija njegovog rada na jednostavnim cijevnim mrežama. Na kraju su prikazani rezultati simulacije na primjeru složene cijevne mreže. Prikazani rezultati pokazuju dobru aproksimaciju realnih strujanja u složenim cijevnim mrežama u usporedbi s dostupnim podacima.

Abstract (english)

The subject of this work is the analysis of steady and unsteady liquid flow in complex pipe networks of arbitrary configuration using the C++ computer code HydNet developed within it’s scope. A basic one-dimensional hydrodynamic model of isothermal flow of a weakly compressible fluid in an elastic pipeline is presented. The basic model is subsequently expanded with the discrete gas cavity model which takes into consideration the presence of gas within the liquid as well as the process of cavitation. Along with this the model is expanded to include the e↵ects of unsteady friction and the velocity profile through the momentum correction factor. The simultaneous Hardy-Cross method for steady flow computation is presented as well as the method of characteristics and the complete numerical scheme used for unsteady flow simulation. Expressions for internal and simple network nodes are derived along with expressions for nodes modelling reservoirs, local losses and valves. In this work the original computer code HydNet is described and validated on simple pipe networks while the results of flow simulation in a complex pipe network are shown at the end. The presented results are in good agreement with available data indicating good approximations of flow regimes in real pipe networks.

• Keywords: Računalna simulacija; stacionarno strujanje; nestacionarno strujanje; cjevovodna mreža
• Keywords (english): Numerical simulation; steady flow; unsteady flow; pipe network
• Language: croatian
• URN:NBN: urn:nbn:hr:235:049476
• 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: 2019-05-23 00:09:24