|
|
Thermodynamic Conditions in Quenching Chamber of Low Voltage Circuit Breaker
Urban, Ferdinand ; Hüttner,, Ľudovít (referee) ; Kapička, Vratislav (referee) ; Aubrecht, Vladimír (advisor)
Práce se zabývá studiem procesů probíhajících při zhášení silnoproudého oblouku ve zhášecí komoře jističe. Je zaměřena na výpočet dynamiky tekutin a teplotního pole v okolí elektrického oblouku. V práci je dále popsán vliv vzdálenosti plechů v komoře a vliv tvarů plechů z hlediska aerodynamických podmínek uvnitř komory. Dalším cílem dosaženým touto prací je poskytnutí informací o vlivu polohy elektrického oblouku na termodynamické vlastnosti uvnitř komory. Toto je důležité, zejména pokud je oblouk do komory vtahován jinými silami, např. elektromagnetickými a během tohoto vtahovacího procesu mění svůj tvar i polohu. Za účelem co nejjednoduššího, ale zároveň co nejefektivnějšího řešení úkolu, byl vyvinut software určen speciálně pro výpočet dynamiky tekutin numerickou metodou konečných objemů (FVM). Tato metoda je, v porovnání s rozšířenější metodou konečných prvků (FEM), vhodnější pro výpočet dynamiky tekutin (CFD) zejména proto, že režie na výpočet jedné iterace jsou menší v porovnání s ostatními numerickými metodami. Další výhodou tohoto softwarového řešení je jeho modularita a rozšiřitelnost. Cely koncept softwaru je postaven na tzv. zásuvných modulech. Díky tomuto řešení můžeme využít výpočtové jádro pro další numerické analýzy, např. strukturální, elektromagnetickou apod. Jediná potřeba pro úspěšné používání těchto analýz je napsáni solveru pro konečné prvky (FEM). Jelikož je software koncipován jako multi–thread aplikace, využívá výkon současných vícejádrových procesorů naplno. Tato vlastnost se ještě více projeví, pokud se výpočet přesune z CPU na GPU. Jelikož současné grafické karty vyšších tříd mají několik desítek až stovek výpočetních jader a pracují s mnohem rychlejšími pamětmi, než CPU, je výpočetní výkon několikanásobně vyšší.
|
|
|
The effectiveness of welding on furnace structures.
Rousová, Michaela ; Mrňa, Libor (referee) ; Kubíček, Jaroslav (advisor)
This diploma thesis is resolving all the possibilities of enhancing the efficiency of furnace structures welding. Small batch production does not offer many possibilities for implementing mechanization or automation. On the other hand, when using a big batch production, efficiency can be enhanced by means of a robotic workstation. When the production batch is big enough, we will see a costs save after a short time, mainly in labor costs. This means the return of investments will be in short time period. In the LAC company there are three types of products made. At laboratory furnaces the efficiency can be enhance by using fixtures. At other standard and atypical furnaces is very difficult to design fixtures or positioners because of their different sizes. Big complication can be also a company location on second floor. The most suitable product regarding to welding efficiency enhancement is big batch production of heaters. For this type the welding time can be shortened by means of a robotic workstation.
|
|
|
Idea design of experimental model for LV electric arc properties investigation
Fazekas, Tibor ; Valenta, Jiří (referee) ; Vávra, Zdeněk (advisor)
The aim of the work was a planing of an experimental model for the observation of the low voltage electric arc. The opening part observes the basics of the electric network switching and the electric arc in theory. The next point is definition about the behaviour of the electric arc in the low voltage switching devices, focusing on the movement of the arc along electrodes and in the extinguish chamber. The design of the experimental model, created in Autodesk Inventor 2008, is described in the last part of the work.
|
|
|
Visualisation and animation of charge carriers in electrical fields
Kachlík, Jan ; Aubrecht, Vladimír (referee) ; Bušov, Bohuslav (advisor)
This bachelor`s thesis deal with electromagnetic field. The aim of this thesis is acquaintance with physical regularity electric and magnetic field. Especially force effect to charge carriers traveling in these fields. In second part of this project is briefly describe switching arc behavior in high voltage circuit breaker. Principle function is animated in Autodesk 3ds Max 2009. Final point of assignment is create animated presentation about production nanofibres with help of unique technology NanospiderŽ
|
|
|
Simplified model of a axial cooled arc
Kasal, Ondřej ; Šenk, Josef (referee) ; Lázničková, Ilona (advisor)
Using of computer technology brings advantages of quick and well-arrange data. Computer technology offers change of transferring information the same way as that often using. Capacity and execution of computer technology is depending on kind and size of elaborated information. It is necessary to use to computer technology in application working with big data range and in application which needs many steps to finish calculation it means when we are using iterative methods. It is computer technology which creates main part of simulation, computation and visualization methods which are using in technical application. Plasma is using in many way of industry from technical manufacturing of materials to application in power electronics. Attention is paid to plasma. To description to fourth state of substance and for description to processes in plasma are used mathematic and physic equations. To solve to equations is hard and we need many steps to cover it. It is necessary to use computer technology to work up different method performs to describe electric arc.
|
|
|
Measurement of an Electric Arc Spectra
Šimek, D.
Article is focused on electric arc spectroscopy diagnostics related to electric low voltage apparatuses. The first attempts of spectroscopy measurements are dealt with. An example of radiation spectra of the electric arc burning between copper electrodes is presented. The problems connected with the measurements are discussed.
|
|
|
Větvení obloukového kanálu ve vnějším magnetickém poli
Mrázek, Josef ; Hlína, Jan
An electric arc burning in mercury vapours exposed to external magnetic field changes its discharge path into a helix according to the Thomson principle of energy minimization. The voltage between the adjacent turns of the helix curvature may result in the critical electric field strenght in the vicinity of the arc channel, that leads to the branching and formation of a new discharge path acting as a turn-to-turn short. We have been interested in the electric field profile and surrounding parameters at the moment of branching, the speed of a new channel warming, temporal evolution of the restoration of a regular spiral channel, development of the arc current and distribution of the voltage between the series resistor and arc channel during the breakdown.
|
|
|
Behavior of Electric Arc Inside a Quenching Chamber of High Voltage Circuit Breaker
Aubrecht, Vladimír ; Bušov, B.
A great influence on the switching process is exerted by aerodynamic relations in the quenching chamber, the direct measurement of which is hardly feasible using contemporary techniques. Therefore, the shape of the arc plasma burning between the circuit breaker contacts is scanned with a high-speed camera. The photographs from the high-speed camera represent a time analysis of the studied process, which allows through their digital processing the determination of the time changes of the arc plasma shape.
|
|
| |
|
|
Diagnostics of Breakdown in Electric Arc Exposed to External Magnetic Field
Hlína, Jan ; Šonský, Jiří
An arc in external magnetic field acquires a helical shape and when the magnetic field exceeds a critical value the arc starts to oscillate. The oscillations may lead to many types of shortenings (breakdowns) between the adjacent windings of the arc path. We have investigated experimentally the steepness of the voltage fall reflecting the breakdown and the influence of mean arc voltage and electrode polarity on this characteristic.
|
guest ::
