Numerična simulacija procesa hlajenja pri ekstruziji polietilenskih cevi

Močan, Blaž (author), Halilovič, Miroslav (mentor), Golobič, Iztok (co-mentor)

Delo obravnava problem procesa hlajenja pri ekstruziji polietilenskih cevi. Poznavanje procesa je ključno za proizvodnjo le-teh, saj proces vpliva na kvaliteto izdelka in strošek izdelave. V kolikor se cevi ohlajajo prehitro, postanejo krhke in med vgradnjo prej počijo. Poleg tega prekomerno ohlajanje ni ekonomično. V primeru nezadostnega hlajenja, pa se profil cevi ob navijanju v kolute stisne in postane ovalne oblike, kar prav tako povzroča probleme pri vgradnji. V nalogi je predstavljena dvodimenzionalna numerična simulacija procesa hlajenja preko več hladilnih korit. Slednja temelji na obstoječi proizvodni liniji in je nanjo skalibrirana. Predstavljena sta tudi enodimenzionalna modela v radialni in aksialni smeri. Slednji je rešen v Eulerjevem referenčnem oknu, ki omogoča obravnavo problema v stacionarnem stanju. V delu je osnovan tudi postopek zajemanja temperaturnih meritev na stenah cevi, meritev temperature vode na vstopu in izstopu iz hladilnih korit in njenega pretoka. S temi podatki je izračunan odvod toplote v posameznih koritih. Rezultati simulacij se skladajo z rezultati meritev, ki smo jih izvedli na stenah cevi.

• Language: Slovenian
• Keywords: metoda končnih elementov, polietilenske cevi, hlajenje, nestacionaren prevod toplote, ekstruzija, polimeri
• Work type: Master's thesis/paper
• Organization: FS - Faculty of Mechanical Engineering
• Year: 2017
• PID: 20.500.12556/RUL-98461
• Publication date in RUL: 02.12.2017

Secondary language

• Language: English
• Title: Numerical simulation of the cooling process of extruded polyethylene pipes

Abstract

The thesis addresses the issue of cooling extruded polyethylene pipes. Knowing the process is vital for the production of pipes, as it influences the quality of the product as well as the manufacturing costs. In case of rapid and excessive cooling, the pipes become brittle and tend to crack during installation. Furthermore, excessive cooling is wasteful. In case of insufficient cooling, the profile of the pipe is compressed and turns to an oval shape when coiled. This also causes problems during installation of the pipe. Presented is a two dimensional numerical simulation of the cooling process through several cooling troughs. It is based and calibrated to an existing production line. Presented are also the one dimensional models in the radial and axial dimension. The latter is solved in the Euler reference frame, which enables us to solve the problem in a stationary state. The thesis outlines a procedure for taking temperature measurements on the walls of the pipe, temperature measurements of water at the input and output of cooling throughs and also its mass flow measurements. These data are then used to calculate the energy drain from each through. The results from the simulations match the measurements taken from the walls of the pipe.

• Keywords: finite element method, polyethylene pipes, cooling, transient heat conduction, extrusion, polymers