@MastersThesis{Leal:2020:InExEs,
author = "Leal, Samuel Carvalho de Souza",
title = "Investiga{\c{c}}{\~a}o experimental de escoamento inerte
turbulento num banco de estudo de instabilidade de combust{\~a}o
usando PIV",
school = "Instituto Nacional de Pesquisas Espaciais (INPE)",
year = "2020",
address = "S{\~a}o Jos{\'e} dos Campos",
month = "2019-11-07",
keywords = "escoamento turbulento, instabilidade de combust{\~a}o,
velocimetria por imagem de part{\'{\i}}cula, combustion
instability, particle image velocimetry, turbulent flow.",
abstract = "No intuito de contribuir para o desenvolvimento nacional de
sistemas de combust{\~a}o adaptados a instabilidade
termo-ac{\'u}stica, o presente trabalho investigou as
caracter{\'{\i}}sticas do escoamento inerte turbulento, no caso,
o ar, em uma c{\^a}mara de combust{\~a}o usando Velocimetria por
Imagem de Part{\'{\i}}cula (PIV). A utilidade da
investiga{\c{c}}{\~a}o do escoamento inerte turbulento no estudo
da instabilidade termo-ac{\'u}stica, est{\'a} na
compara{\c{c}}{\~a}o das suas caracter{\'{\i}}sticas com as do
escoamento reativo. A partir desta compara{\c{c}}{\~a}o,
torna-se poss{\'{\i}}vel identificar os efeitos da
combust{\~a}o no escoamento turbulento e, consequentemente,
caracterizar a instabilidade de combust{\~a}o. Atualmente, este
fen{\^o}meno f{\'{\i}}sico {\'e} um dos principais problemas
dos sistemas de combust{\~a}o, tanto que diversas pesquisas
s{\~a}o realizadas para analisar e investigar meios de
control{\'a}-la. A instabilidade de combust{\~a}o, que se
comp{\~o}e de oscila{\c{c}}{\~o}es termo-ac{\'u}sticas de alta
amplitude, diminui o desempenho dos motores, prejudica o controle
das emiss{\~o}es de poluentes e danifica diversos componentes dos
motores. Para evitar estes efeitos indesej{\'a}veis, diversas
t{\'e}cnicas e adapta{\c{c}}{\~o}es foram desenvolvidas nos
combustores para minimizar ou eliminar a instabilidade
termo-ac{\'u}stica. A presente investiga{\c{c}}{\~a}o utilizou
um combustor de geometria retangular alimentado com ar em
condi{\c{c}}{\~o}es atmosf{\'e}ricas. Tr{\^e}s injetores
planos est{\~a}o instalados no combustor mas permaneceram
desligados durante as medi{\c{c}}{\~o}es. Dados de diversos
par{\^a}metros caracterizadores do escoamento turbulento foram
obtidos nas regi{\~o}es a montante e a jusante dos injetores. Nas
an{\'a}lises do presente trabalho, foi observado que o escoamento
turbulento {\'e} plenamente desenvolvido na regi{\~a}o a
montante dos injetores. Na regi{\~a}o a jusante dos injetores,
foi verificado zonas de recircula{\c{c}}{\~a}o e
produ{\c{c}}{\~a}o de v{\'o}rtices nas camadas de cisalhamento
localizadas nas bordas destes. Tamb{\'e}m foi constatado que as
estruturas coerentes de larga escala s{\~a}o disseminadas e
dissipadas ao longo da dire{\c{c}}{\~a}o longitudinal da
regi{\~a}o principal. Somado a isso, observou-se que, em diversos
aspectos, o escoamento turbulento foi afetado pelo cisalhamento
provocado pelas paredes em ambas as regi{\~o}es. Parte dos
resultados da investiga{\c{c}}{\~a}o, que utilizou Velocimetria
Laser de Efeito Doppler (LDV) no mesmo combustor, foi comparada
com os resultados desta investiga{\c{c}}{\~a}o. Nesta
compara{\c{c}}{\~a}o, foi constatado boa converg{\^e}ncia entre
os resultados dos dois trabalhos na regi{\~a}o de entrada e em
diversos aspectos na regi{\~a}o principal. ABSTRACT: In order to
contribute to the national development of combustion systems
adapted to thermo-acoustic instability, the present work
investigated the inert turbulent flow characteristics, in the
case, air, in a combustion chamber using Particle Image
Velocimetry (PIV). The usefulness of inert turbulence flow
investigation in the study of thermo-acoustic instability lies in
the comparison of its characteristics with reactive flow
characteristics. From this comparison, it becomes possible to
identify combustion effects in turbulent flows and, consequently,
characterize combustion instability. Nowadays, this physical
phenomenon is one of the main problems of combustion systems, and
a large number of investigations are performed to analyze and
investigate the means of controlling it. Combustion instability,
which results in high-amplitude thermo-acoustic oscillations,
decreases engine performance, impairs control of pollutant
emissions and damages various engine components. To avoid these
undesirable effects, various techniques and adaptations have been
used in combustors to reduce or eliminate thermo-acoustic
instability. The present investigation used a air-breathing
combustor with rectangular geometry in atmospheric conditions.
Three flat injectors are installed in the combustor but have
remained switched off during the measurements. Data from several
parameters characterized by turbulent flow were obtained in the
upstream and downstream regions of the injectors. In the present
work, it was observed that the turbulent flow is fully developed
in the upstream region of the injectors. In the downstream region
of the injectors, zones of recirculation and vortex production in
the shear layers located at the edges were detected. It has also
been found that coherent large scale structures are disseminated
and dissipated along the longitudinal direction of the main
region. Moreover, it was observed that, in many ways, the
turbulent flow was affected by the shear caused by the walls in
both regions. Part of the research results, which used the Doppler
Effect Laser Velocimetry (LDV) in the same combustor, was compared
with the results of this research. In this comparison, good
convergence was found between the results of the two studies in
the entrance region and in several aspects in the main region.",
committee = "Dourado, Wladimyr Mattos da Costa (presidente/orientador) and
Mendon{\c{c}}a, M{\'a}rcio Teixeira de and Savonov, Roman
Ivanovitch and Trevisan, Bruno Peruchi",
englishtitle = "Experimental investigation of turbulent inert flow in combustion
instability research beach using PIV",
language = "pt",
pages = "288",
ibi = "8JMKD3MGP3W34R/3UE5P7S",
url = "http://urlib.net/ibi/8JMKD3MGP3W34R/3UE5P7S",
targetfile = "publicacao.pdf",
urlaccessdate = "04 maio 2024"
}