Avaliação do desempenho de compósitos de PPA/Fibra de vidro para aplicação em bombas de óleo de motores de motocicletas

Pós-graduação em Ciência e Tecnologia de Materiais - FC

Estudo de causas de falhas em selos mecânicos de bombas centrífugas para circulação de óleo térmico

This study is about a heating line that uses thermal oil. It is located in a facility that produces interlayers used in cars windshields. A plastic resin is melted and is sent to a matrix called DIE where the interlayers are produced. The DIE needs to receive heat from the circulation of thermal oil in four different regions of its interior, to ensure the correct thickness of the interlayer. The thermal energy is provided by electric heaters and the flow of thermal oil is impelled by four mechanically sealed centrifugal pumps (one per region). The key point of this study is the fact that these four pumps of the system have reported successive failures in the mechanical seals. Apparently, a poorly designed project has burdened the system intermittently. The pumps operation condition is located in a region of low efficiency, according to the characteristic curves. This fact is the source of the noticeable reduced time between failures. Changes in the configuration of the facility and in the number of pumps will be proposed, aiming to achieve higher operational efficiency. The proposals will be mathematically analyzed according to the Hydraulic Institute criteria. At the same time, we will also keep focus on an in-depth study of a heating system structure, starting with a detailed approach for each component and discussion about its real need and economic viability. At the end of this paper it is shown that the gain in efficiency achieved with the new proposed configuration reflects not only in the reduction of maintenance costs, but also a potential improvement in energy efficiency. It is shown that these two aspects are closely related and together form the basis for the design of a reliable and efficient pumping system

Simulação computacional do escoamento em bombas de cavidades progressivas

The use of Progressing Cavity Pumps (PCPs) in artificial lift applications in low deep wells is becoming more common in the oil industry, mainly, due to its ability to pump heavy oils, produce oil with large concentrations of sand, besides present high efficiency when compared to other artificial lift methods. Although this system has been widely used as an oil lift method, few investigations about its hydrodynamic behavior are presented, either experimental or numeric. Therefore, in order to increase the knowledge about the BCP operational behavior, this work presents a novel computational model for the 3-D transient flow in progressing cavity pumps, which includes the relative motion between rotor and stator, using an element based finite volume method. The model developed is able to accurately predict the volumetric efficiency and viscous looses as well as to provide detailed information of pressure and velocity fields inside the pump. In order to predict PCP performance for low viscosity fluids, advanced turbulence models were used to treat, accurately, the turbulent effects on the flow, which allowed for obtaining results consistent with experimental values encountered in literature. In addition to the 3D computational model, a simplified model was developed, based on mass balance within cavities and on simplification on the momentum equations for fully developed flow along the seal region between cavities. This simplified model, based on previous approaches encountered in literature, has the ability to predict flow rate for a given differential pressure, presenting exactness and low CPU requirements, becoming an engineering tool for quick calculations and providing adequate results, almost real-time time. The results presented in this work consider a rigid stator PCP and the models developed were validated against experimental results from open literature. The results for the 3-D model showed to be sensitive to the mesh size, such that a numerical mesh refinement study is also presented. Regarding to the simplified model, some improvements were introduced in the calculation of the friction factor, allowing the application fo the model for low viscosity fluids, which was unsuccessful in models using similar approaches, presented in previous works

Desenvolvimento de um método para correção de curvas de desempenho em bombas centrífugas submersas operando com fluidos viscosos

Electrical Submersible Pump (ESP) is used as an artificial lift technique. However, pumping viscous oil is generally associated with low Reynolds number flows. This condition leads to a performance degradation respect to the performance expected from the regular operation with water that most of the centrifugal pumps are originally designed for. These issues are considered in this investigation through a numerical study of the flow in two different multistage, semi-axial type ESPs. This investigation is carried out numerically using a Computational Fluid Dynamics (CFD) package, where the transient RANS equations are solved numerically. The turbulence is modeled using the SST model. Head curves for several operating conditions are compared with manufacturer’s curves and experimental data for a three-stage ESP, showing good agreement for a wide range of fluid viscosities and rotational speeds. Dimensionless numbers (n, n, n e Re) are used to investigate performance degradation of the ESPs. In addition, flow phenomena through the impellers of the ESPs are investigated using flow field from numerical results. Results show that performance degradation is directly related to rotational Reynolds number, Re. In addition, it was verified that performance degradation occurs for constant normalized specific speedn, which shows that performance degradation occurs similarly for different centrifugal pumps. Moreover, experimental data and numerical results agreed with a correlation from literature between head and flow correction factors proposed by Stepanoff (1967). A definition of modified Reynolds number was proposed and relates the head correction factor to viscosity. A correlation between head correction factor and the modified Reynolds number was proposed, which agreed well with numerical and experimental data. Then, a method to predict performance degradation based on the previous correlations was proposed. This method was compared with others from literature. In general, results and conclusions from this work can also be useful to bring more information about the flow of highly viscous fluids in pumps, especially in semi-axial, multistage ESPs.

Professor Emeritus Leo G Carney Optometry's quiet achiever

Perhaps more than any other sub-discipline in optometry and vision science, the academic field of cornea and contact lenses is populated by an assortment of extroverted and flamboyant characters who constantly travel the world, entertaining clinicians with dazzling audiovisual presentations, informing them about the latest advances in the field and generally promoting their own scientific agendas. The antithesis of this is Leo Carney (Figure 1), a highly accomplished researcher, teacher, mentor and administrator, who has quietly and with great dignity carved out an impressive career in academic optometry. Indeed, Leo Carney is optometry's quintessential ‘quiet achiever’

Portrait of Leo Catzenstein with his mother-in-law Henriette Gottschalk holding a parasol Portraits Family

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Leo Catzenstein seated on an outdoor bench Portraits Men

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Portrait of Leo Catzenstein and his wife Aenny Catzenstein nee Gottschalk Portraits Couples

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Portrait of Leo Baeck as military chaplain Military; World War I; Portraits

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Leo Baeck with unidentified soldiers Military; World War I; Portraits Groups

Center May 2000

Seated portrait of Leo Baeck; Oppeln Portraits; Men

"Dr. Leo Baeck Im Jahre 1900 als junger Rabbiner in Oppeln O.S."

Rabbi Leo Baeck's arrival at La Guardia Airport, New York from London for the Union of American Hebrew Congregations American Jewish Cavalcade Portraits; Groups

Sitting l-r Leo Baeck, Maurice N. Eisendrath, Oscar M. Lazrus; Standing l-r Jane Evans, Henry W. Levy, Saul Elgart, Rabbi Daniel L. Davis, Louis Rittenberg and Leonard H. Spring

Leo Baeck with group; Boston Portraits; Groups; Men

Page 58 of the "American Jewish Cavalcade" scrapbook of Leo Baeck in New York found in ROS 10 Folder 3