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Atualização de sistema duplicador de pulsos para teste de proteses de valvulas cardiacas / Upgrade of a pulse duplicator system for cardiac valve prostheses evaluationCheade, Eduardo de Lima 08 August 2008 (has links)
Orientador: Eduardo Tavares Costa / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-12T13:09:13Z (GMT). No. of bitstreams: 1
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Previous issue date: 2008 / Resumo: A utilização de próteses de válvulas cardíacas tanto mecânicas quanto biológicas tem se tornado cada vez mais freqüente. Estas próteses devem ser avaliadas (testes in-vitro e in-vivo) para que sejam utilizadas clinicamente. Os testes de desempenho hidrodinâmico são realizados in vitro, e a análise dos resultados é importante para a classificação e caracterização de uma determinada prótese, sendo atualmente um dos requisitos obrigatórios exigido por órgãos reguladores para a aprovação de próteses a serem empregadas clinicamente. Os testes de desempenho hidrodinâmico são realizados por sistemas complexos, denominados duplicadores de pulso, cuja finalidade é reproduzir o comportamento hidrodinâmico do coração e simular as variáveis fisiológicas às quais as válvulas são normalmente submetidas em condições reais. Neste trabalho foi desenvolvido, para uso na empresa Braile Biomédica, utilizando a plataforma de programação LabVIEW®, um programa capaz de fazer a aquisição e interpretação dos sinais de fluxo e pressão provenientes de transdutores específicos, bem como a realização dos cálculos necessários e a geração de um relatório resultante do teste. Também foram desenvolvidos circuitos condicionadores de sinais para os transdutores de pressão e fluxo inerentes ao sistema duplicador de pulso existente na empresa. A partir das medidas e dos gráficos de pressão e fluxo é possível calcular os seguintes parâmetros: área específica do orifício, coeficiente de descarga, fração de regurgitação e índices de performance e eficiência da válvula. / Abstract: It has become very frequent the use of mechanic or biological cardiac valve prostheses. These prostheses must be evaluated (in vitro and in vivo tests) in order to be used clinically. The hydrodynamic performance tests are carried out in vitro. The analyses of the test results are very important for the characterizations and classification of a given prosthesis, being one of mandatory requirements of the regulatory organs in order to approve its clinical use. The hydrodynamic performance tests are carried out by complex systems often called pulse duplicators, which must reproduce the heart hydrodynamic behaviour and simulate the physiological variables that the cardiac valves are submitted in real conditions. In this work it has been developed a software program to be used at Braile Biomedica based on the LabVIEW® platform, capable of acquiring and processing flux and pressure signals from specific transducers, as well as all the necessary calculi and generation of the test results report. It has also been developed the signal conditioning circuits for the pressure and flux transducers inherent to the company pulse duplicator. The following parameters are calculated and reported with several graphics showing flux and pressure signals: orifice specific area, discharge coefficient, regurgitation fraction and valve performance and efficiency indices. / Mestrado / Engenharia Biomedica / Mestre em Engenharia Elétrica
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A Data Acquisition System Experiment for Gas Temperature and Pressure Measurements on a Liquid-Nitrogen-Powered VehicleLui, Samson Sze-Sang 05 1900 (has links)
A data acquisition system was set up to measure gas temperatures and pressures at various points on a liquid-nitrogen-powered vehicle. The experiment was attempted to develop a data acquisition method for applications on engines that use liquid air as the fuel. Two thermocouples and a pressure transducer were connected using data acquisition instruments interfaced to a laptop computer to acquire data.
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[en] DEVELOPMENT OF OPTICAL FIBER TRANSDUCERS FOR INTELLIGENT WELL COMPLETION / [pt] DESENVOLVIMENTO DE TRANSDUTORES A FIBRA ÓPTICA PARA COMPLETAÇÃO INTELIGENTE DE POÇOSROBERTH WALDO ANGULO LLERENA 30 December 2004 (has links)
[pt] O setor de petróleo e gás apresenta diversas oportunidades
de aplicação para os sensores a fibra óptica. Algumas
características inerentes às fibras ópticas, como baixo
peso, flexibilidade, longa distância de transmissão, baixa
reatividade do material, isolamento elétrico, imunidade
eletromagnética e alta capacidade de multiplexação, podem
ser determinantes em diversas situações, seja nos segmentos
de exploração, transporte, refino ou distribuição. As
principais operadoras internacionais do setor identificaram
a tecnologia de Sensores a Fibra Óptica como elemento chave
para viabilizar, com toda a funcionalidade esperada, a
instalação de sistemas de completação inteligente de poços
de petróleo (produção ou injeção). O sensoriamento do poço
permite obter, a qualquer momento, informações precisas
sobre diversas grandezas, entre outras a pressão,
temperatura, vazão, pH ou mesmo a posição de válvulas que
controlam o fluxo através do poço. A monitoração em tempo
real do poço é parte da estratégia de automação do processo
de produção do campo de petróleo. Esta é uma tendência que
no futuro próximo aponta para a exploração de campos de
petróleo inteligentes, onde a produção por vários poços de
um mesmo reservatório realizase de forma otimizada e
automatizada, reduzindo custos, e aumentando fatores de
recuperação das reservas de hidrocarbonetos fósseis. O
presente trabalho se insere neste contexto, e apresenta a
concepção, desenvolvimento e resultados de testes de dois
protótipos de transdutores de fundo do poço para integrar
um sistema de completação inteligente baseado na tecnologia
de sensoriamento utilizando redes de Bragg em fibras
ópticas. O primeiro deles destina-se à medida da pressão
diferencial num sensor de vazão do tipo Venturi. Resultados
de testes com protótipos do transdutor demonstraram que ele
pode operar numa faixa de mais ou menos 5 bar de pressão diferencial,
sob pressões médias de até 21 MPa e temperaturas de 90
graus Celsius com resolução de 0,06 por cento do fundo de escala. O segundo
transdutor desenvolvido, aplica-se à medida da posição de
abertura e fechamento de uma válvula controladora de fluxo
tipo camisa deslizante (sliding sleeves). Duas técnicas
foram investigadas. A primeira delas, para aplicações mais
gerais, baseia-se no uso de atuadores magnetoestrictivos. A
segunda procurou atender a um projeto específico para este
tipo de válvula, em cuja concepção utiliza-se uma mola
elástica para exercer a força de restituição contra um
atuador hidráulico. Neste caso, optou-se por desenvolver
uma célula de carga instrumentada com redes de Bragg. Nos
testes realizados foram obtidos resultados satisfatórios em
termos de sensibilidade e resolução, tendo-se chegado para
esta última a valores próximos de 0,03 mm num curso de 70
mm (0,04 por cento do fundo de escala). / [en] Optical fibers are finding a growing range of new
applications in the petroleum industry, which include, not
only those already well established in telecommunications,
but also in novel sensing technologies. Possibility of dense
multiplexing, continuous distributed measurements, long
distances between measurement points and electronic
circuits, and explosion risk free, are some of the
characteristics shared by different types of optical fiber
sensors. The major global oil and gas operators and service
companies have elected optical fiber sensing as one of the
key enablers to implement with all the expected
functionality and reliability the novel technology of
intelligent well completion. Continuous well monitoring
allows the operator to access, at any time during the well
life, important information regarding different process
variables, such as pressure, temperature, flow-rate, pH, or
even the position of sliding sleeves valves that control
the flow through the well. This is part of the automation
strategy to optimize production in the whole reservoir, a
technological trend that points towards the concept of an
intelligent oil field and that, in the near future, will be
applied to the integrated management of production from
several wells in the same reservoir, contributing to reduce
intervention costs, and increasing recovery factors of
fossil hydro-carbon reserves. The present work is inserted
in this context, and reports the conception, development
and results of tests conducted with prototypes of two
different optical fiber transducers to be integrated in an
intelligent well completion system. The first one is a
Bragg grating differential pressure transducer, which has
been developed to measure pressure drop across a Venturi
flow-meter inserted in the production tubing. Test results
with prototypes have demonstrated that the transducer may
be applied to measure differential pressures in the range
of more or less 5 bar, under static (average) pressures up to 21 MPa
and temperatures below 90 Celsius Degree, with 0.06 percent full-scale
resolution. The second development is a displacement
transducer applied to measure the opening position of
sliding sleeves valves. Two different measurement
principles were investigated. The first, intended to
general applications of displacement measurements, relied
on the use of magnetostrictive actuators and fiber Bragg
grating sensors. The second displacement transducer applies
to a specific type of valve, which employs a mechanical
spring to provide recovery forces to a hydraulic actuator.
The proposed solution was based on the use of a load cell
instrumented with fiber Bragg gratings. Tests results
demonstrated that the prototype transducer was capable of
resolving changes in displacement as lower as 0.03 mm in a
full-range of 70 mm, approximately 0.04 percent full-scale
resolution.
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Pressure loss associated with flow area change in micro-channelsChalfi, Toufik Yacine 06 July 2007 (has links)
Pressure drop across miniature-scale flow disturbances, including abrupt flow area changes, is an important source of error and confusion in the literature. Such pressure drops are frequently encountered in experiments, where they are often estimated using methods and correlations that have been developed based on experimental data obtained in conventional systems. However, physical arguments as well as the relatively few available experimental observations indicate that such pressure drops in microchannel systems are likely to be different than what is known about similar phenomena in conventional flow systems. Experimental data dealing with pressure drop associated with two-phase flow across abrupt flow area changes in microchannels are scarce, however, and the available data are insufficient for the development of reliable predictive methods.
In this investigation, experiments were conducted using a test section consisting of two capillaries, one with 0.84 mm, and the other with 1.6 mm inner diameters. A multitude of pressure transducer ports were installed along the two capillaries, and allowed for the measurement of the pressure gradients over the entire test section. The test section allowed for the measurement of frictional pressure gradients in the two straight channels, as well as pressure drops caused by the flow area expansion and contraction depending on the flow direction, for single-phase as well as two-phase flows. These measurements were performed over a wide range of parameters, using air as the gaseous phase, and room-temperature water as the liquid phase. The single-phase flow data were compared with existing conventional correlations, and with predictions of CFD simulations using the Fluent computer code.
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Coupled Dynamic Analysis of Flow in the Inlet Section of a Wave Rotor Constant Volume CombustorSmith, Keith Cameron 12 1900 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / A wave rotor constant volume combustor (WRCVC) was designed and built as a collaborative work of Rolls Royce LibertyWorks, Indiana University-Purdue University at Indianapolis (IUPUI), and Purdue University, and ran experimental tests at Purdue's Zucrow Laboratories in 2009.
Instrumentation of the WRCVC rig inlet flow included temperature and pressure transducers upstream of the venturi and at the fuel delivery plane. Other instrumentation included exhaust pressures and temperatures. In addition, ion sensors, dynamic pressure sensors, and accelerometers were used to instrument the rotating hardware. The rig hardware included inlet guide vanes directly in front of the rotating hardware, which together with concern for damage potential, prevented use of any pressure transducers at the entrance to the rotor. For this reason, a complete understanding of the conditions at the WRCVC inlet is unavailable, requiring simulations of the WRCVC to estimate the inlet pressure at a specific operating condition based on airflow.
The operation of a WRCVC rig test is a sequence of events over a short time span. These events include introduction of the main air flow followed by time-sequenced delivery of fuel, lighting of the ignition source, and the combustion sequence. The fast changing conditions in the rig inlet hardware make necessary a time-dependent computation of the rig inlet section in order to simulate the overall rig operation. The chosen method for computing inlet section temperature and pressure was a time-dependent lumped volume model of the inlet section hardware, using a finite difference modified Euler predictor-corrector method for computing the continuity and energy equations. This is coupled with perfect gas prediction of venturi air and fuel flow rates, pressure drag losses at the fuel nozzles, pressure losses by mass addition of the fuel or nitrogen purge, friction losses at the inlet guide vanes, and a correlation of the non-dimensional flow characteristics of the WRCVC. The flow characteristics of the WRCVC are computed by varying the non-dimensional inlet stagnation pressure and the WRCVC's operational conditions, assuming constant rotational speed and inlet stagnation temperature.
This thesis documents the creation of a computer simulation of the entire WRCVC rig, to understand the pressure losses in the inlet system and the dynamic coupling of the inlet section and the WRCVC, so that an accurate prediction of the WRCVC rotor inlet conditions can be computed. This includes the computational development of the WRCVC upstream rig dynamic model, the background behind supporting computations, and results for one test sequence. The computations provide a clear explanation of why the pressures at the rotor inlet differ so much from the upstream measured values. The pressure losses correlate very well with the computer predictions and the dynamic response tracks well with the estimation of measured airflow. A simple Fortran language computer program listing is included, which students can use to simulate charging or discharging of a container.
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