ETD

Archivio digitale delle tesi discusse presso l'Università di Pisa

Tesi etd-02042014-110721


Tipo di tesi
Tesi di laurea magistrale
Autore
LANGELLA, GIOVANNI ELVIO
Indirizzo email
giov.langella@gmail.com
URN
etd-02042014-110721
Titolo
Single and two-phase flows of shear-thinning fluids: analytical and computational fluid dynamics modelling
Dipartimento
INGEGNERIA DELL'ENERGIA, DEI SISTEMI, DEL TERRITORIO E DELLE COSTRUZIONI
Corso di studi
INGEGNERIA ENERGETICA
Relatori
relatore Ing. Galletti, Chiara
Parole chiave
  • turbulent pipe flow
  • multiphase flow
  • gas-liquid flow
  • drag-reducing polymers
  • CFD
Data inizio appello
07/03/2014
Consultabilità
Completa
Riassunto
The injection of small amount of high molecular weight long-chain polymers into turbulent flows could decrease the pressure drop in the pipe flow and consequently decrease the required pumping power. This work is aimed to the modeling of viscoelastic fluid, specifically polymer, in single phase and 2-phase flows.
A literature review of drag-reduction by polymers in multiphase flow is firstly presented, then two different approaches are analyzed: one-dimensional analytical approach and CFD approach. Stratified gas-liquid flow and gas-liquid slug flow regimes are analyzed by means of analytical models developed by Taitel and Dukler (1976) and Taitel and Barnea (1990), respectively. The models are adapted for polymer solutions in order to estimate the pressure gradient and the holdup.
For single-phase flow, the modified k-ε model for power-law fluids developed by Ro and Ryou (2012) was implemented in Fluent through a User Defined Function (UDF) and validated for two polymer solutions CarboxyMethyl Cellulose (CMC) and Xanthan Gum (XG) in a turbulent pipe flow. The applicability and the effect on the structure of the flow of the modified k-ε model were studied for stratified and slug flow using the ANSYS Fluent software package.
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