Doctoral Thesis
DOI
https://doi.org/10.11606/T.18.2021.tde-12082021-185403
Document
Author
Full name
Matheus dos Santos Guzella
Institute/School/College
Knowledge Area
Date of Defense
Published
São Carlos, 2021
Supervisor
Committee
Gómez, Luben Cabezas (President)
Alvariño, Pablo Fariñas
Miranda, Caetano Rodrigues
Rabi, Jose Antonio
Ribatski, Gherhardt
Title in Portuguese
Simulação numérica da formação de bolhas em superfícies aquecidas utilizando o método de Lattice Boltzmann dos pseudopotenciais
Keywords in Portuguese
Ebulição
Método de Lattice Boltzmann
Modelo dos pseudopotenciais
Simulação numérica
Abstract in Portuguese
Title in English
Numerical simulation of the formation of bubbles on heated surfaces using the Pseudopotentials Lattice Boltzmann Method
Keywords in English
Boiling
Lattice Boltzmann method
Numerical simulation
Pseudopotential model
Abstract in English
In this work, two-dimensional numerical simulations of bubble formation on heated surfaces are performed using the Pseudopotential Lattice Boltzmann Method. The hydrodynamic equations are solved by the method and the energy equation is solved by 4th order Runge-Kutta method. A literature review of the numerical models based on the method is presented and a critical analysis of the models in the literature is performed. Based on the literature review, a numerical model based on the combination of two models from the literature is used, in order to guarantee thermodynamic consistency and surface tension adjustment independently of the density ratio. A model to obtain the parameters in lattice units based on parameters of the international system. Numerical results of the diameter and release period for the cycle of a bubble for a reduced temperature of Tr = 0.86 are obtained in order to evaluate the consistency of the model. These results are compared with empirical correlations and a reasonable agreement is observed. Subsequently, results of boiling curves are obtained for different reduced temperatures: Tr = 0.86 and Tr = 0.90. Finally, the model of obtaining parameters in lattice units is used for two reduced temperatures (Tr = 0.7604 and Tr = 0.7126) of the fluid HFE-7100. Numerical simulations with the referred parameters were prohibitive in terms of computational cost and, thus, simulations were performed with flexible lattice units parameters in order to evaluate the model for simulation in conditions different from those performed in the literature, in reduced temperature. A comparison of the results obtained for the reduced temperatures proved to be coherent, from a qualitative point of view.