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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

Acoustic monitoring of hydraulic resistance in partially full pipes

Romanova, Anna January 2013 (has links)
Hydraulic losses in sewer pipes are caused by wall roughness, blockages and in-pipe sedimentation. Hydraulic resistance is a key parameter that is used to account for the hydraulic energy losses and predict the sewer system propensity to flood. Unfortunately, there are no objective methods to measure the hydraulic resistance in live sewers. A common method to estimate the hydraulic resistance of a sewer is to analyse collected CCTV images and then to compare them against a number of suggested hydraulic roughness values published in the Sewer Rehabilitation Manual. This thesis reports on the development of a novel, non-invasive acoustic method and instrumentation to measure the hydraulic roughness in partially filled pipes under various structural and operational conditions objectively. This research presents systematic laboratory and field studies of the hydraulic and surface water wave characteristics, of shallow water flows in a sewer pipes with the presence of local and distributed roughness, in order to relate them to some fundamental properties of the acoustic field measured in the vicinity of the flow surface. The results of this thesis indicate that for the local roughness the energy content of the reflected acoustic signal is an indicator of the pipe head loss and hydraulic roughness. In the case of the distributed roughness, the variation in the temporal and frequency characteristics of the propagated sound wave can be related empirically to the mean flow depth, mean velocity, wave standard deviation and hydraulic roughness.
2

Stanovení ztrát při nestacionárním proudění kapaliny v trubici / Hydraulic losses during unsteady flow of liquid in a pipe

Svoboda, Jakub January 2011 (has links)
This thesis is focused on solving hydraulic losses during unsteady flow of liquid in pipe for both laminar and turbulent flow in smooth pipes. Radial viscosity distribution is assumed to be the same as for steady flow. Viscosity distribution is derived from velocity profile, which is mathematically described with suitably chosen function. Laplace images of unsteady velocity profile and mean velocity in cross-section are derived depending on pressure difference. Loss coefficient is derived and on base of transfer matrix method, self-numbers are calculated. Self-numbers represent attenuation and own frequency. Self-numbers are compared to values from software called “F-ACHAR” and loss coefficient is compared to the one for quasi-steady method.
3

Acoustic monitoring of hydraulic resistance in partially full pipes.

Romanova, Anna January 2013 (has links)
Hydraulic losses in sewer pipes are caused by wall roughness, blockages and in-pipe sedimentation. Hydraulic resistance is a key parameter that is used to account for the hydraulic energy losses and predict the sewer system propensity to flood. Unfortunately, there are no objective methods to measure the hydraulic resistance in live sewers. A common method to estimate the hydraulic resistance of a sewer is to analyse collected CCTV images and then to compare them against a number of suggested hydraulic roughness values published in the Sewer Rehabilitation Manual. This thesis reports on the development of a novel, non-invasive acoustic method and instrumentation to measure the hydraulic roughness in partially filled pipes under various structural and operational conditions objectively. This research presents systematic laboratory and field studies of the hydraulic and surface water wave characteristics, of shallow water flows in a sewer pipes with the presence of local and distributed roughness, in order to relate them to some fundamental properties of the acoustic field measured in the vicinity of the flow surface. The results of this thesis indicate that for the local roughness the energy content of the reflected acoustic signal is an indicator of the pipe head loss and hydraulic roughness. In the case of the distributed roughness, the variation in the temporal and frequency characteristics of the propagated sound wave can be related empirically to the mean flow depth, mean velocity, wave standard deviation and hydraulic roughness.
4

Horkovodní roštový kotel / Hot Water Grate Boiler

Svoboda, Marek January 2019 (has links)
This thesis deals with design of hot water grate boiler, where the output is water with parameters 130 °C and pressure 16 bar. In the content of the whole thesis is gradually introduced a stoichiometric calculations, which is based on the specified fuel – wood chips. This is followed by the design of the individual heating surfaces according to the thermal calculations given in the thesis. Finally, the calculation is extended by hydraulic and aerodynamic losses. Dimensional design, as a basic scheme, is shown at thesis. More detailed drawing documentation is attached to this thesis.
5

Konstrukční studie axiálních bezucpávkových čerpadel / Design studies of axial sealing pumps

Dobrovolný, Martin January 2018 (has links)
Review of axial hydraulic machines and elementary procedures of design hydraulic machines are listed in the first part of thesis. Second part is dedicated axial pump with annular motor and measurement its characteristic curve. In the third part of thesis, procedure of design axial pump with tube motor is described, also there are listed CFD results and characteristic curve of axial pump with tube motor is predicted.
6

Hydrostatický pohon pojezdu multifunkčního nakladače DAPPER / Hydrostatic drive of multi-purpose loader DAPPER

Vydra, Tomáš January 2015 (has links)
This thesis deals with design of hydrostatic drive for multipurpose loader and tool carrier DAPPER. At the beginning is research of different basic concepts and modern solutions to the problem, aided by a detailed description of competitive machine in the same performance category. Extensive comparison with other producers is included in the annexes to this thesis. Furthermore, a theoretical driving characteristic and its appropriateness is examined further on the basis of two model situations. The calculations of the individual components of the hydraulic circuit precedes drive kinematics analysis of articulated machine frame, on it final conception of hydrostatic drive is chosen. Firstly hydromotors and hydogenerator are chosen on the grounds of calculations then hydraulic hoses, filters and flow divider. Next chapters are aimed to calculations of hydraulic losses and thermal calculation of hydraulic circuit. Final part deals with introduction the final characteristics of drive. The practical parts of the work are assembly drawings with main power components and hydraulic schematic of drive.

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