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Thin-plate rectangular weir with inlet shaft
Šváb, Jiří ; Šulc, Jan (referee) ; Zachoval, Zbyněk (advisor)
The thesis is divided into literary research and practical part (own measurement). The content of the literary research is a description of the flow over thin-plate rectangular weir. The practical part is focused on a description of the model, measuring equipment and measurement. The results are evaluation of lower and upper surface of nappe, determination of discharge coefficient, coefficient of relative length of shaft, limit value of relative length of shaft for uninfluenced shape of nappe.
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Discharge coefficients for nozzles of a low-NOx gas burner
Zifčáková, Barbora ; Bojanovský, Jiří (referee) ; Juřena, Tomáš (advisor)
Nozzles belong to the main parts of a low-NOx gas burner. Their purpose is to transport fuel into a combustion system. One way of judging a quality of a nozzle is to define its discharge coefficient. It expresses an efficiency of energy conversion – from pressure to kinetic energy. In this thesis the discharge coefficients of several nozzles were established, using Ansys Fluent software for computer simulation. A calculation was tuned to a reference geometry and then applied to other geometries of nozzles, which were both planar and spatial. Numerically obtained data were compared with experimental data. The benefits of this thesis are comparism of two main methods of flow modelling (Scalable Wall Function and Enhanced Wall Treatment) and formulation of a calculation methodology for this type of physical problem. The results provided by this thesis might be used for both another study and experimental research.
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Hollow cone valve capacity in the restricted outflow conditions
Nehudek, Adam ; Haluza,, Miloslav (referee) ; Šulc, Jan (advisor)
The thesis aims to determine the influence partial or complete submerge of hollow cone valve by outflow on its capacity without space restrictions, by outflow into discharge chamber and by outflow into water tunnel of circular cross section. The valve capacity is for mutual comparability purposes usually characterized by discharge coefficient. Research works have been performed on a spatial hydraulic model of the valve with inlet diameter D = 67 mm and an apex angle of a cone 90°. Values of the discharge coefficient obtained from measurements were statistically analyzed. The dependence of discharge coefficient, expressed by energy head, on submerged level was approximated by an exponential function. Exponent value of this function express the dependance rate of valve capacity on downstream water level. This procedure didn’t demonstrate signifiant dependance downstream water level on hollow cone valve capacity, only on tests at outflow to water tunel showed a low increase in the discharge coefficient partly due to the influence of kinetic energy of the stream flowing out of the tunnel on the energy head and also due to underpressure. Independence of discharge coefficient value on valve head has been prooved for head greather than 232 mm. Also was defined 3 stages of interaction outflow jet from valve and downstream water, some of them may cause on real waterworks structures unfavorable situations (may affect excessive load on valve by pressure pulsations). The presented results allow better evaluation of bottom outlets capacity at higher water levels, when the valves are flooded. Significant effect of sufficient aeration (especially in long water tunnels) on valve capacity was also confirmed. Taking into account on the specifics of hollow jet valves and cone valves, it is possible to generalize some of this resultos on them as well.
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Lateral recirculation zones of flow in approach channel of weir
Korálová, Nikola ; Pařílková, Jana (referee) ; Zachoval, Zbyněk (advisor)
The bachelor’s thesis is divided in to the literary research and practical part. The content of the literary research is the issue of side contracted weirs, where occurs side contracted flow. The sudden change of the channel width and formation of upstream wake have direct influence on value of discharge coefficient. There are described types of the weirs, ways of computing discharge and discharge coefficients which are influenced by contraction. In the practical part of thesis is described measurement of the velocity field of side contracted flow by UVP Monitor, follow up by assessment of boundary of the upstream wake, which is situated in the approach channel in front of the weir.
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Discharge coefficient of slit weirs
Havran, David ; Žoužela, Michal (referee) ; Zachoval, Zbyněk (advisor)
This work deals with experimental research, with outcomes of design and recommendation for determination of the discharge coefficient of the slit weir. At the same time states the possible effects on capacity. Then comparing the data with already existing ones. The thesis provides an overview and insight into the meaning of slit weirs as well. The goal is to recommend the determination of the discharge coefficient.
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Submergence of low rectangular sharp-edged broad-crested weirs
Major, Jakub ; PhD, Ján Rumann, (referee) ; Zachoval, Zbyněk (advisor)
This diploma thesis deals with submergence of low rectangular sharp-edged broad-crested weirs. From measurement of water levels in front of and behind of weir at different discharges and different weir heights, were determined values of submergence coefficient depending on relative height of submergence. From these values were determined the equation of submergence coefficient. Measured values were compared which results measurements, which are given in professional literature.
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Intake Ports for the Wankel Engine
Smělý, Jiří ; Beran, Martin (referee) ; Svída, David (advisor)
This master’s thesis deals with design of intake port for turbocharged Mazda 13B-T engine with Wankel-type rotating piston motion aiming for possible modifications leading to increase of performance parameters. The main objective of this thesis is to propose appropriate modifications in order to achieve increased torque in widest possible engine speed range.
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Full-width thin-plate rectangular weir influenced by channel width
Zmítko, Jakub ; Roušar,, Ladislav (referee) ; Zachoval, Zbyněk (advisor)
The diploma thesis deals with the propagation of a weir (channel) width on the weir capacity. The influence rate is analyzed by laboratory measurements on models with a weir (channel) width of 0,02 m to a width of 0,50 m. Different heads are analyzed and different discharges that calculate the discharge coefficient. The results are compared with previous works, especially with the work of Kindsvater and Carter (1957) and of Schoder and Turner (1929), where the same procedures are used to calculate discharge coefficients. The thesis contains a theoretical introduction to the problem of thin-plate weirs and the problem of the formation of the boundary layer in the flow of liquid, following with the analytical part. In the analytical part, the results of measurements, their comparison, and evaluation are published. The work is completed with evaluation and recommendations.
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