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Numerical analysis of a bubble growth dynamics in boiling

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Mateus Faria de Andrade Paschoal
Total Authors: 1
Document type: Master's Dissertation
Press: Ilha Solteira. 2020-08-28.
Institution: Universidade Estadual Paulista (Unesp). Faculdade de Engenharia. Ilha Solteira
Defense date:
Advisor: Elaine Maria Cardoso; João Batista Campos Silva

The present work aims to present and develop a program able to simulate a single bubble growth in the pool boiling regime. Also, it presents some fluid mechanical, heat transfer, front tracking, and computational methods fundamentals. By using Fortran 90 programming language coupled with CodeBlocks IDE was developed a frame to simulate incompressible fluid flows in Cartesian coordinates with and without phase change. In order to discretize the governing equations were used Finite Element Method with Characteristic Based Split (CBS) scheme to stabilize the solution. The theoretical development of the Finite Element Method and CBS scheme are also presented. The code was tested in a driven-lit cavity and the cavity problem with natural convection which domain was discretized by a non-structured mesh of linear tetrahedrons and a structure mesh of hexahedral linear elements. It was observed that structured meshes are more stable to obtain the pressure field. Moreover, it was tested the pressure field by Poisson Equation and by Artificial Compressibility. It was evidenced both gives similar temperature field. Comparing the obtained results and benchmarking results can be concluded that the implemented code is capable to simulate fluid flow with heat exchange with low velocities. The code implemented for front capturing was tested and was verified that the Level Set Method is an easy method to implement and returned reasonable results compared with the reference simulation. The simulation of a single bubble growth under the pool boiling regime shows a growth radius coherent to the literature experimental data. (AU)

FAPESP's process: 18/12010-4 - Numerical analysis of the influence of surface tension and rougnhess on the vapor bubble growth mechanism
Grantee:Mateus Faria de Andrade Paschoal
Support Opportunities: Scholarships in Brazil - Master