The two-phase gas/liquid flow phenomenon can be encountered over a range of gas and liquid flow rates in the chemical engineering industry, particularly in oil and gas production transportation pipelines. Monitoring and measurement of their characteristics, such as the gas void fraction, are necessary to minimise the disruption of downstream process facilities. Thus, over the last decade, the investigation, development and use of multiphase flow metering system have been a major focus for the industry worldwide. However, these meters suffer from several limitations in some flow conditions such as Slug flow regime. This research presents experimental results correlating Acoustic Emission measurements with Gas Void Fraction (GVF) in a two-phase air / water flow. A unique experimental facility was modified to accommodate an investigation into the applicability of the Acoustic Emission (AE) technology in monitoring two-phase gas\liquid flow. The testing facility allowed for investigations over a range of superficial liquid velocities (0.3 to 2.0 ms-1) and superficial gas velocities (0.2 to 1.4 ms-1). The influence of several variables such as temperature, viscosity and surface roughness were also investigated. Measurements of AE for varying gas void fractions were compared to conductive probe measurements and results showed a direct correlation between the AE energy and the gas void fraction. It is concluded that the GVF can be determined by measurement of Acoustic Emission and this forms the major contribution of this thesis.

Thesis (doctoral)--University of Oulu, 2007. / Includes bibliographical references. Also available on the World Wide Web.

Thesis (doctoral)--Lund University, 1997.

Thesis (doctoral)--Lund University, 1997.

The two-phase gas/liquid flow phenomenon can be encountered over a range of gas and liquid flow rates in the chemical engineering industry, particularly in oil and gas production transportation pipelines. Monitoring and measurement of their characteristics, such as the gas void fraction, are necessary to minimise the disruption of downstream process facilities. Thus, over the last decade, the investigation, development and use of multiphase flow metering system have been a major focus for the industry worldwide. However, these meters suffer from several limitations in some flow conditions such as Slug flow regime. This research presents experimental results correlating Acoustic Emission measurements with Gas Void Fraction (GVF) in a two-phase air / water flow. A unique experimental facility was modified to accommodate an investigation into the applicability of the Acoustic Emission (AE) technology in monitoring two-phase gas\liquid flow. The testing facility allowed for investigations over a range of superficial liquid velocities (0.3 to 2.0 ms-1) and superficial gas velocities (0.2 to 1.4 ms-1). The influence of several variables such as temperature, viscosity and surface roughness were also investigated. Measurements of AE for varying gas void fractions were compared to conductive probe measurements and results showed a direct correlation between the AE energy and the gas void fraction. It is concluded that the GVF can be determined by measurement of Acoustic Emission and this forms the major contribution of this thesis.

Orientador: Antonio Batocchio / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-05T20:37:36Z (GMT). No. of bitstreams: 1 Giusti_WyldsCarlos_D.pdf: 8566454 bytes, checksum: 33c2fa4e061a1ba0cf5b8c41db5aef96 (MD5) Previous issue date: 2005 / Resumo: Neste trabalho procurou-se desenvolver um sistema que tem por objetivo o controle de processos para viabilização de objetivos estratégicos. Para isto é necessário conhecer a missão da empresa, no cenário em que atua, detalhamento dos objetivos para cumprimento dessa missão, escolha dos processos mais ligados aos objetivos estratégicos estabelecidos, e a escolha de medidas adequadas como indicadores de desempenho dos processos selecionados. No processo de monitoramento, os conceitos de Desdobramento de Funções da Qualidade foram adaptados às necessidades do sistema, os conceitos de Manufatura Enxuta estão incluídos para estruturação do sistema proposto e foi utilizada a Simulação pelo processo Monte Carlo para projeção de resultados futuros. A análise do desempenho dos processos foi realizada através da constituição de índices para comparação de valores no tempo. Foi realizado um estudo de caso que ilustra a aplicação do sistema na prática / Abstract: This investigation describes a system which permits to control the processes to reach strategic objectives. To achieve this it is necessary to know the mission of the company in the work environment, the strategic objectives, selection of linked processes to the objectives and the determination of the measures to indicate the selected processes performance. In the monitoring process, the Quality Function Deployment was adapted to the system's needs. The concepts of lean manufacturing are included to develop the System structure and the Monte Carlo simulation was used to preview future results. The performance processes analysis was accomplished through the creation of rates to compare the obtained values through the time. A case study was included to illustrate a practical application to the proposed system / Doutorado / Processos de Fabricação / Doutor em Engenharia Mecânica

The aim of this study was to propose a nonlinear multiscale principal component analysis (NLMSPCA) methodology for process monitoring and fault detection based upon multilevel wavelet decomposition and nonlinear principal component analysis via an input-training neural network. Prior to assessing the capabilities of the monitoring scheme on a nonlinear industrial process, the data is first pre-processed to remove heavy noise and significant spikes through wavelet thresholding. The thresholded wavelet coefficients are used to reconstruct the thresholded details and approximations. The significant details and approximations are used as the inputs for the linear and nonlinear PCA algorithms in order to construct detail and approximation conformance models. At the same time non-thresholded details and approximations are reconstructed and combined which are used in a similar way as that of the thresholded details and approximations to construct a combined conformance model to take account of noise and outliers. Performance monitoring charts with non-parametric control limits are then applied to identify the occurrence of non-conforming operation prior to interrogating differential contribution plots to help identify the potential source of the fault. A novel summary display is used to present the information contained in bivariate graphs in order to facilitate global visualization. Positive results were achieved. / Dissertation (M Eng (Control Engineering))--University of Pretoria, 2007. / Chemical Engineering / unrestricted

Real-time quality monitoring continues to gain interest within the manufacturing domain as new and faster sensors are being developed. Unfortunately, most quality monitoring solutions are still based on collecting data from the end product. From a process improvement point of view, it is definitely more advantageous to proactively monitor quality directly in the process instead of the product, so that the consequences of a defective part can be minimized or even eliminated. In this dissertation, new methods for in-line process monitoring are explored using multiple sensors. In the first case, a new cutting force-based monitoring methodology was developed to detect out of control conditions in a broaching operation. The second part of this thesis focusses on the development of a test bed for monitoring the tool condition in a turning operation. The constructed test bed includes the combination of multiple sensors signals including, temperature, vibrations, and energy measurements. Here, the proposed SPC strategy integrates sensor data with engineering knowledge to produce quick, reliable results using proven profile monitoring techniques. While, the already existing methods are based on raw process data which requires more features to monitor without any loss of information. This technique is straight forward and able to monitor the process comprehensively with less number of features. Consequently, this also adds to the group of tools that are available for the practitioner. / Master of Science

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