CFD Simulation Of Erosion Rates In Electrical Submersible Pumps

Electrical Submersible Pump (ESP) is an efficient and useful artificial lift method for lifting fluids to the surface. In oil production, sand is an inevitable part which causes ESPs to fail regarding to erosion of the equipment. Therefore, erosion simulation in ESP pump would be a great help for maintenance and life span of the system. In the present work, a Computational Fluid Dynamics (CFD) simulation of erosion in an impeller is performed in order to give a better understanding. Meshing and CFD simulations are done using ANSYS Fluent software. Different scenarios are considered to find the effect of various parameters on the erosion rate. The pump is simulated at two frequencies as 50 and 60 Hertz. The model is based on Eulerian-Eulerian approach where the primary and secondary phases are oil and sand respectively. Also, CFD simulations of different boundary conditions, sand sizes and densities are presented to predict the erosion rate

Micro hydropower in water distribution systems

Considering various applications of Pump as Turbine (PAT) as an effective source of reducing the equipment cost in small hydropower plants as well as the selecting process of appropriate location and suitable machinery are the main concerns of this study. Vary range of PAT settings criteria has been propound by taking into account the State-of-the-Art researches. The purpose of this study is to establish the effectiveness of pump as turbine, considering all the possible obstacles such as producer’s market interests, accessibility of technical information and mechanical limitation. Cutting-edge scientific researches concerning PAT have been proposed by implementation of various approaches. The most challenging criteria of PAT, which is selecting the appropriate machinery, has been investigated subsequently. A comparative methodology to model the effectiveness of PATs, both numerical and experimental, has been developed based on the efficiency. The mechanical reliability of the hydropower devices in situ, prototype and numerical investigation have been reviewed. These results have been obtained through measurements and optimization of the simulated system by means of characteristic methods against the established PAT system in many different case studies. Water Distribution Networks (WDNs) allow to obtain a widespread and globally significant amount of produced energy by exploiting the head drop due to the network pressure control strategy for leak reductions. Replacing PAT in water distribution networks regarding to all the possible obstacles, will reduce the final cost and will improve the expected efficiencies, as much as the reduction of environmental impacts. This study definitively answers the question whether PAT is an effective alternative in WDNs. The comparative approach also aims for a better understanding of the impact of PAT on the transition to renewable energy systems

Investigation of transient interactions in centrifugal pumps

The quest for greater pump efficiency and improved reliability has focused research topics in the understanding of pump hydraulic and dynamic behaviours. On-Design pump performance has been optimised utilising modern design strategies incorporating Computational Fluid Dynamics technology to predict and simulate the fluid flow in a pump. The fluid conditions within the arrangement of an impeller and collector present a complex unsteady flow phenomenon, which give rise to fluid structure interaction. Periodic hydraulic excitation forces are generated as a consequence. The interaction forces increase as the flow recirculation grows; the flow becomes less uniform at the impeller periphery. Thus, the highest magnitude of forces is observed at low flow and high flow operating conditions. They are impacted onto the rotor and transmitted to the bearing housing, although the forces are not quantitatively known. Lateral analysis of a pump rotor can demonstrate the rotor will not traverse or operate within a region of a critical speed, however, bearing housing vibration can be excessive and outside acceptable limits when operating at part load. The rationale of the project was therefore to employ a numerical modelling technique to capture hydraulically induced vibration caused by the interaction of the rotor and stator. A series of transient numerical analyses were carried out to investigate the unsteady fluctuating pressure field within a single stage pump for five operating conditions. The hydraulic excitation forces were captured and incorporated into a rotordynamic model where the corresponding displacement vibration were evaluated. It was shown that the highest estimated displacement vibration was at the low flow operating condition and at the cutwater region. An experimental campaign of the single stage pump validated the unsteady pressure fluctuations within an acceptable margin of two percent for nominal flow and five percent for low flow operating point. Greater variations were found when comparing the numerical and experimental approximations to the displacement vibration

Smart Flow Control Processes in Micro Scale

In recent years, microfluidic devices with a large surface-to-volume ratio have witnessed rapid development, allowing them to be successfully utilized in many engineering applications. A smart control process has been proposed for many years, while many new innovations and enabling technologies have been developed for smart flow control, especially concerning “smart flow control” at the microscale. This Special Issue aims to highlight the current research trends related to this topic, presenting a collection of 33 papers from leading scholars in this field. Among these include studies and demonstrations of flow characteristics in pumps or valves as well as dynamic performance in roiling mill systems or jet systems to the optimal design of special components in smart control systems

Aerosol Filtration And Separation

ABSTRACT OF THE DISSERTATION Aerosol Filtration and Separation by Ta-Chih Hsiao Doctor of Philosophy in Energy, Environmental, & Chemical Engineering Washington University in St. Louis, 2009 Professor Da-Ren Chen, Advisor Particle control technologies are essential in many manufacturing industries: chemical, electronic, mineral, and food and beverages) as well as in pollution abatement and environmental control: for example, clean rooms and post processing of power plant emissions). A variety of particle control technologies using different physical forces and various collection substrates have been developed over the last 100 or so years. Among these technologies, filtration is known as the most economical means for submicron aerosol particles with low concentration, and cyclones are superior to other devices for supermicron particles with high concentration. The overall objective of this dissertation is to advance our current knowledge on these two particle control technologies. Accordingly, it has two major topics:: 1) Aerosol Filtration - Liquid-coated Particle Loading, and: 2) Inertial Separation - Axial Flow Cyclone. For the first part, Aerosol Filtration, a system which is able to generate stable liquid-coated particles is developed, and series of filter loading experiments are performed to study the behavior of filters loaded with liquid-coated particles, which exhibit transition behavior between those of solid and those of liquid particles. Different effects, including filter media, coated particle size, and coating liquid properties, on the transition behavior are explored. Moreover, an empirical model for predicting the loading curves for particles coated with liquids of different viscosity is proposed. For the second part, Inertial Separation, a cascade multistage axial cyclone which is capable of classifying particles from 10 μm to 40 nm is developed and evaluated. The characteristics of the axial flow cyclone are also investigated, and a semi-empirical model is established to predict the cyclone collection efficiency curve. These works do not only enhance researchers\u27 understanding of the specific particle control technologies, but also help engineers to develop better devices for solving current environmental problems or fulfilling industrial needs

Effect of Volute Collector on the Performance of Centrifugal Pump Based on Entropy Generation Analysis

A proper design of centrifugal pumps reduces power loss and improves efficiency. This study aims to investigate and analyze the effect of different volute collector configurations on centrifugal pump performance. Locations of losses are detected using the entropy production rate, whereas the number of losses is evaluated using user-defined codes. Three volute collectors are selected based on their connections with standard pipes. A steady flow numerical analysis is performed to determine the performance parameters of the centrifugal pump and select a modified volute collector design. Comparing the results of experiments on the base and modified volute collectors confirmed that the proper design of the volute collector can help reduce the secondary flow losses at subsequent locations, which reduces the entropy production and losses. As compared to the base pump, the modified volute collector improved the pump efficiency by 3% at the duty flow

Mathematical Modelling of Energy Systems and Fluid Machinery

The ongoing digitalization of the energy sector, which will make a large amount of data available, should not be viewed as a passive ICT application for energy technology or a threat to thermodynamics and fluid dynamics, in the light of the competition triggered by data mining and machine learning techniques. These new technologies must be posed on solid bases for the representation of energy systems and fluid machinery. Therefore, mathematical modelling is still relevant and its importance cannot be underestimated. The aim of this Special Issue was to collect contributions about mathematical modelling of energy systems and fluid machinery in order to build and consolidate the base of this knowledge

Estudo experimental de Bomba Centrífuga Submersa (BCS) operando com emulsão água/óleo

Orientadores: Marcelo Souza de Castro, Jorge Luiz BiazussiDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia MecânicaResumo: Dentre as metodologias de elevação artificial de petróleo, a Bomba Centrífuga Submersa (BCS) destaca-se por sua elevada produção e ampla aplicação em diversos cenários. Na extração de petróleo, a BCS pode operar com misturas gás-líquido, líquido-líquido ou gás-líquido-líquido, ou seja, misturas bifásicas (gás-óleo ou água-óleo) ou trifásicas (gás-óleo-água). No caso de operação com misturas gás-óleo, para altas vazões de líquido e baixas frações de gás, a bomba apresenta um desempenho similar ao observado em escoamentos monofásicos. Entretanto, o desempenho sofre uma severa degradação quando a bomba opera com elevadas frações de gás ou ainda com elevadas frações de água no escoamento. Para a operação com a mistura água-óleo, a presença de água causa a formação de emulsões no interior do rotor da BCS afetando consideravelmente sua capacidade de elevação. Isso ocorre principalmente, devido ao aumento da viscosidade da emulsão em relação às condições de projeto da bomba. Apesar da presença de água ser uma constante na produção de petróleo, apenas recentemente observa-se um esforço maior da comunidade científica em estudos da influência da presença de água nos fenômenos relacionados à produção de petróleo. Exemplos disso são os escoamentos líquido-líquido em tubulações e formação de emulsões em BCS. A emulsão é caracterizada pela presença de um fluido disperso (fase dispersa) em outro (fase contínua). Dependendo da fração de fase dispersa e das características físicas e químicas dos fluídos, há a ocorrência de um fenômeno denominado inversão de fase contínua. Esse fenômeno promove instabilidades operacionais na produção de campos produtores de petróleo. O objetivo deste trabalho é então investigar o fenômeno de inversão de fase e viscosidade efetiva da emulsão, ambos dentro da BCS. Para isso, inicialmente, foram comparados modelos de viscosidade efetiva em tubulação com as viscosidades efetivas obtidas experimentalmente em tubo, apresentando boa concordância. Para verificar a relação entre a viscosidade efetiva e o tamanho das gotas no escoamento, foi realizada uma análise de Distribuição de Tamanho de Gota (DTG) na saída da BCS e foi observado que a diminuição do tamanho de gota contribuía para o aumento da viscosidade efetiva tanto no tubo quanto dentro da BCS. Durante esses testes, o ponto de inversão de fase contínua foi detectado tanto no tubo, através da medida de diferencial de pressão, quanto na BCS, variação brusca de desempenho. Para determinar a viscosidade efetiva da emulsão dentro da BCS, curvas de desempenho monofásico viscoso foram obtidas experimentalmente. Esses dados foram usados para determinar os coeficientes geométricos de um modelo semi - empírico do adimensional de elevação para a BCS em questão. O modelo obtido foi utilizado para determinar a viscosidade efetiva na BCS. Então, foram comparadas as viscosidades efetivas obtidas com as viscosidades do óleo e da água, assim como, o desempenho da BCS operando com emulsão e com óleo, obtendo valores similares para baixas rotações. Com o aumento da rotação houve aumento da viscosidade efetiva dentro da BCS. Diferente comportamento da viscosidade efetiva entre o escoamento em tubo e dentro da BCS foi observado para emulsões do tipo água em óleo devido ao elevado campo centrífugo. E, finalmente, com o intuito de analisar o comportamento do fenômeno de inversão fase em uma situação mais fiel as condições reais, foram realizados testes trifásicos (gás/óleo/água) para analisar a influência do gás, detectando a inversão de fase para menor razão de água para elevadas rotações da BCSAbstract: Among the methodologies of oil artificial lift, one that stands out for its excellent production and wide application in several scenarios is the Electrical Submersible Pump (ESP). In oil extraction, ESPs can operate with gas-liquid, liquid-liquid or gas-liquid-liquid mixtures, i.e. two-phase (gas-oil or water-oil) or three-phase (gas-oil-water) mixtures. In the case of gas-oil operation, for high-liquid and low-gas flow rates, ESPs perform similarly to pumps observed in single-phase flows. Their performance deteriorates, however, when the ESP operates with high gas fractions or with high fractions of water. For an operation with a water-oil mixture, the water presence causes the formation of emulsions inside the ESP rotor, significantly impacting its lifting capacity. This happens due to the increase of emulsion viscosity relative to the pump design conditions. In petroleum production, the presence of water is a constant, yet it has been only recently that researchers have tried to fully grasp the influence of the water presence on oil production. Researchers have, for example, studied liquid-liquid flow in pipes and formation of emulsions within ESP. An emulsion is characterized by the presence of a dispersed fluid (dispersed phase) in another (continuous phase). Depending on the dispersed phase fraction and the physical and chemical characteristics of the fluids, there can occur what is known as continuous phase inversion. In oil production, continuous phase inversion promotes operational instabilities. The aim of this study then is to investigate phase inversion and emulsion viscosity, both within ESP. The work begins by comparing pipeline effective viscosity models with experimentally obtained viscosities, presenting good agreement. To verify the relationship between effective viscosity and droplet size, it was performed a Drop Size Distribution (DSD) analysis at the ESP outlet and it was observed that the decrease in droplet size contributed to the increase of the effective viscosity both in the tube and within ESP. During these tests, the continuous phase inversion was detected, at the same time in the pipeline by measuring the pressure and within the ESP by observing abrupt performance variation. To determine the emulsion-effective viscosity within the ESP, it were obtained¿via experiment¿viscous monophasic performance curves. These data were used to determine the geometric coefficients of an empirical model of the dimensionless head for the ESP tested. This model, in turn, is used to determine the effective viscosity on ESP. This is then compared with the effective viscosity obtained with oil and water viscosities, as well as the ESP performance operating with emulsion and oil, obtaining similar values for low rotations. Different behavior of the effective viscosity between the pipeline flow and within ESP was observed for water-in-oil emulsions due to the high centrifugal field in the ESP. Finally, to analyze the phase inversion phenomenon behavior, in more realistic conditions, it was analyzed the gas influence by carrying out three-phase tests (gas / oil / water), detecting the phase inversion for lower water ratio for high ESP rotational speedsMestradoTermica e FluidosMestre em Engenharia Mecânic