Zagrijavanje vode horizontalno odnosno vertikalno uronjenim grijačem

undergraduate thesis

• Title (english): Water heating using vertically or horizontally immersed heater
• Author: Frano Knezović
• Mentor: Antun Galović (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2018-09-26, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering; Process Energy Engineering

Abstract

U ovome radu primijenjen je analitički pristup za termodinamički proračun za slučaj zagrijavanja vode zadane mase te početne i konačne temperature. U tu svrhu korišten je program za tablično računanje – Excel. Na koncu je provedena i numerička analiza horizontalnog grijača s konstantnom površinskom temperaturom pomoću softverskog paketa FLUENT te su prikazana rješenja i za taj slučaj. Cilj je dobiti profil temperature vode tijekom zagrijavanja kao i vremensku promjenu trenutnog koeficijenta konvektivnog prijenosa topline te iznos trenutnog toplinskog toka. Također, želi se usporediti vrijednosti dobivene numeričkim i analitičkim putem kako bi se utvrdilo mogu li se analitičkim pristupom s kvazistacionarnim modelom dovoljno točno odrediti rješenja za ovaj slučaj. U analitičkom pristupu korištene su osnovne jednadžbe iz prijenosa topline te Churchillove korelacijske funkcije za računanje koeficijenta prijenosa topline. Numeričkom analizom rješavan je sustav parcijalnih diferencijalnih jednadžbi kojim se može opisati prirodna konvekcija u vodi.

Abstract (english)

In this paper, an analytical approach to the thermodynamic calculation was used for the heating water of the given mass and the initial and final temperature. For this purpose was used Excel spreadsheet. Finally, a numerical analysis of the horizontal heater with constant surface temperature was carried out using the FLUENT software package and the solutions and the case were also presented. The aim is to obtain the water temperature profile during the heating as well as the time change of the current convective heat transfer coefficient and the amount of current heat flow. It also seeks to compare numerically and analytically obtained values to ascertain whether an analytical approach to a quasi-model model can adequately determine the solutions to this case. In the analytical approach the basic heat transfer equations were used and Churchill correlation functions to calculate heat transfer coefficients. Numerical analysis solved the system of partial differential equations describing natural convection in water.

• Keywords: zagrijavanje vode; grijač; cilindar; prijenos topline; slobodna konvekcija
• Keywords (english): water heating; heater; cylinder; heat transfer; natural convection
• Language: croatian
• URN:NBN: urn:nbn:hr:235:302940
• 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: 2019-05-22 22:51:46