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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Effects of air dissolution dynamics on the behaviour of positive-displacement vane pumps: a simulation approach

Furno, Francesca, Blind, Vincent January 2016 (has links)
The aim of this paper is to evaluate the effects of the dissolution time – time for the liquid to absorb the gas till the saturation state - on the behaviour of positivedisplacement vane pumps, in terms of pressure peaks within internal chambers and forces applied to the stator ring. The chamber pressurization depends on the volume variation and fluid Bulk modulus in the pre-compression phase during which the volume is trapped between the suction and the delivery port rims. If the dissolution time is short, then the entrained air is quickly absorbed and the fluid Bulk modulus sharply increases just before opening the connection to the outlet; as a consequence, pressure peaks may appear thus degrading the NVH characteristics of the pump. Moreover the pressure within internal chambers generate i) a torque demand to the driver (the combustion engine or an electrical motor) and ii) a total force applied to the stator ring. In case of fixed displacement designs, the resultant pressure force simply represents a load for support bearings; while in case of variable designs, it contributes to the displacement regulation. Simulation results show that the pump behaviour is very sensitive to the dissolution time when it is quite close to the duration of the trapped period.
2

Snížení radiální síly odstředivých čerpadel / The centrifugal pump radial force reduction

Koutný, Luděk January 2009 (has links)
This diploma thesis deals with problematics of the radial force effect on the runner and possibilities of the force reduction. Some pump modifications were proposed and changes of radial force magnitude in reverse blocking state and optimal flow state were examined in consequence. Following investigation was focused on the new modifications regarding to the pump efficiency and its characteristics stability. All results were carried out using the Solidworks, the Fluent and the Microsoft Excel software.
3

Vyhodnocení provozu tlakové kanalizace obce Štěpánovice / Assessment of operation of the pressure sewerage system of the municipality Štěpánovice

Laksar, Luboš January 2012 (has links)
This thesis deals with the description of the pressure sewerage systems. Primarily focuses on the assessment of operation of the pressure sewerage system of the municipality Štěpánovice, where he was evaluated on the network pressure, flow of waste water, waste water quality and system silure rate.
4

A study into forces and moments acting on the swash plate of an axial piston pump using a novel approach to reduce pressure and flow pulsations.

Naik, Pratin J., Seeniraj, Ganesh K., Chandran, Ram S. 25 June 2020 (has links)
In hydraulic pumps, typically in axial piston pumps, reduction of pressure and flow ripples was attempted by providing relief grooves and pre-compression for noise reduction. Pre-compression is normally achieved by using the dead space between pump ports in the valve plate. Also valve plate profile modification is required, if system operating conditions such as pump output pressure and flowrate change, to maintain optimum operating conditions for reduced pressure/flow ripple. An earlier simulation study confirmed effectiveness of varying dead centre position to reduce pressure and flow ripples. A specifically designed mechanism, outlined in the earlier work, achieves this goal by varying the dead centre position of the pump swash plate. This study reports on the findings of the effect of varying dead centre position and groove configurations on forces and moments acting on the swash plate for various operating conditions. The simulation model cited in the earlier work was used in this study. This information is vital for the design of an actuating mechanism to vary dead centre position of a pump valve plate. These simulations were run using MATLAB/Simulink and S-functions. Results of this study are promising.
5

[en] A STUDY ON BLOWOUT CONTROL VIA RELIEF WELL: INCREASING DRILLSHIP CAPACITY / [pt] ESTUDO SOBRE AMORTECIMENTO DE POÇO EM BLOWOUT VIA POÇO DE ALÍVIO: AUMENTO DA CAPACIDADE DAS SONDAS

ELIZA GALVAO DA SILVA CARDOSO 02 September 2024 (has links)
[pt] A energia desempenha um papel estratégico global, com a indústria do petróleo sendo uma fonte crucial. No entanto, iniciativas visando reduzir a dependência do petróleo surgem, impulsionadas principalmente por preocupações ambientais, como as mudanças climáticas. A transição energética ganha destaque nas agendas nacionais, refletindo a interligação entre energia e meio ambiente. Apesar da redução na previsão de crescimento da demanda a indústria global de petróleo e gás, a indústria do petróleo permanece vital, sustentando fontes de energia, gerando receitas e empregos. Contudo, a indústria enfrenta pressões ambientais crescentes, destacando a necessidade de investir continuamente em segurança nas operações de exploração de poços. O blowout, apesar de ser evento com baixa probabilidade de ocorrência, representa uma ameaça grave, não apenas para a imagem da empresa, mas também para o meio ambiente e a vida das pessoas. O exemplo do blowout de Macondo, ocorrido no Golfo do Mexico, em operação da British Petroleum (BP) evidencia os impactos significativos. O combate ao blowout envolve mitigação de impacto e controle da fonte. Estratégias essenciais para mitigação de impactos e o controle da fonte incluem o fechamento do poço com equipamento de bloqueio (capping) e a construção de um poço de alívio. O primeiro é uma ação rápida para fechar o poço e cessar o vazamento de hidrocarboneto para o meio ambiente, enquanto o segundo visa construir um poço adicional para interceptar, amortecer e abandonar de forma definitiva o poço em blowout. O presente trabalho concentra-se em apresentar soluções para amortecimento do poço em blowout via poço de alívio em situações que exigem altas vazões e volumes. Simulações revelam desafios técnicos, como demandas de grandes volumes e altas vazões de amortecimento. Portanto, a pesquisa busca oferecer soluções diferenciadas para atender a essas demandas específicas e contribuir para a segurança e eficácia das operações. / [en] Energy plays a global strategic role, with the oil industry being a crucial source. However, initiatives aimed at reducing dependence on oil are emerging, mainly driven by environmental concerns such as climate change. Energy transition gains prominence in national agendas, reflecting the interconnectedness between energy and the environment. Despite the reduction in the demand growth forecast, the global oil and gas industry, the oil industry remains vital, sustaining energy sources, generating revenue, and jobs. However, the industry faces increasing environmental pressures, highlighting the need for continuous investment in safety in well drilling operations. Blowouts, although events with low probability of occurrence, represent a serious threat not only to the company s image but also to the environment and people s lives. The example of the Macondo blowout in the Gulf of Mexico, during British Petroleum (BP) operation, illustrates significant impacts. Combatting blowouts involves impact mitigation and source control. Essential strategies for impact mitigation and source control include well capping and the construction of a relief well. The former is a rapid action to close the well and stop hydrocarbon leakage into the environment, while the latter aims to build an additional well to intercept, killing, and permanently abandon the blowout well. This work focuses on presenting solutions for blowout well killing via relief well in situations requiring high flow rates and volumes. Simulations reveal technical challenges, such as demands for large volumes and high pump rates. Therefore, the research seeks to offer differentiated solutions to meet these specific demands and contribute to the safety and effectiveness of operations.
6

Využití odpadního tepla pro vytápění a ohřev TV / Utilization of waste heat for heating and hot water

Dvouletý, Tomáš January 2012 (has links)
The thesis aims to design a device for utilization of waste heat for heating and hot water in NETME Centre in area of FSI VUT in Brno. First of all there is summary of available sources of waste heat and evaluation of serviceability. Next there is design of a device for utilization of waste heat. Design incluades calculation of heat exchangers and selection of particular heat exchangers. It also incluades design of duct system which anables transportation of heated water from heat exchangers to machine room. In machine room is situated storage tank for accumulation of gained waste heat. This storage tank is conected to heating system and to consumption of hot water which anables utilization of waste heat. Finally there is economic evaluation based on amount of gained waste heat, consumption of heat and costs.

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