Recent designs of twin-fluid atomizers

Diplomová práce se zabývá konstrukcí dvoumédiových trysek. Hlavním úkolem je kategorizovat trysky, především setřídit a popsat současné typy dvoumédiových trysek s vnitřním směšováním. V této práci jsou popsány provozní výhody/nevýhody a složitost konstrukcí vybraných trysek. Práce také porovnává trysky s ohledem na kvalitu a způsob atomizace. Na základě získaných znalostí byla vytvořena výkresová dokumentace dvou vybraných trysek s vnitřním směšováním.This thesis deals with design of twin-fluid atomizers. The main task is to categorize atomizers, mainly to sort and describe recent types of twin-fluid atomizers. The thesis describes operating advantages/disadvantages, complexity of designs of selected nobles. The thesis compares nozzles with the quality and method of atomization. Based on the knowledge was created technical drawings of two selected nozzles with internal mixing.

ANALYTICAL METHODS FOR CALCULATING FAN AERODYNAMICS

This paper presents results obtained between 2010 and 2014 in the field of fan aerodynamics at the Department of Composite Technology at the VZLÚ aerospace research and experimental institute in Prague – Letnany. The need for rapid and accurate methods for the preliminary design of blade machinery led to the creation of a mathematical model based on the basic laws of turbomachine aerodynamics. The mathematical model, the derivation of which is briefly described below, has been encoded in a computer programme, which enables the theoretical characteristics of a fan of the designed geometry to be determined rapidly. The validity of the mathematical model is assessed continuously by measuring model fans in the measuring unit, which was developed and manufactured specifically for this purpose. The paper also presents a comparison between measured characteristics and characteristics determined by the mathematical model as the basis for a discussion on possible causes of measured deviations and calculation deviations

QUENCH FRONT PROPAGATION IN THE ANNULAR CHANNEL

Understanding the quench front propagation during bottom core reflooding is crucial for the effective cooling during the LOCA accident. The results presented in this paper were obtained on an experimental loop with an annular test section. The test section consists of a vertical electrically heated stainless steel tube with outer diameter 9 mm and length of 1.7 m. The heated tube is placed inside a glass tube with the inner diameter 14.5 mm. Water mass flux during the reflooding is in the range from 100 kg.m−2.s−1 up to 140 kg.m−2.s−1 and the initial wall temperature of the stainless steel tube is in the range from 250 °C up to 800 °C. The presented results show the influence of the initial conditions on the quench front propagation and the complexity of the phenomenon

Experimental study of radiative shocks at PALS facility

We report on the investigation of strong radiative shocks generated with the high energy, sub-nanosecond iodine laser at PALS. These shock waves are characterized by a developed radiative precursor and their dynamics is analyzed over long time scales (~50 ns), approaching a quasi-stationary limit. We present the first preliminary results on the rear side XUV spectroscopy. These studies are relevant to the understanding of the spectroscopic signatures of accretion shocks in Classical T Tauri Stars.Comment: 21 pages, 1 table, 7 figure

Numerisches Modellieren des ozeaninduzierten Magnetfeldes

This work is concerned with the forward modelling of ocean-induced magnetic fields on a global scale as the first step needed for the identification of the ocean-induced magnetic signals in the recently launched satellite mission Swarm and coastal-site magnetometers. The aim is at developing a numerical model for the estimation and evaluation of the magnetic field constituents generated by ocean flow dynamics. As an example of the input data, the strong semidiurnal M 2 tide with the period of 12 h 42 min is applied. Moreover, static main magnetic field of the Earth and a realistic distribution of the electrical conductivity in radial direction are considered. Three different solution methods for the Earth approximated by a spherically layered model are developed. For this purpose a magnetic induction equation in the form of the Helmholtz equation is derived. The analytical solution in the Fourier frequency domain in classical (strong) sense is found by using the spherical Bessel functions. The second method makes use of weak formulation of the induction equation where the spectral-finite element approach in Fourier frequency domain is later applied. The third method is used to solve for the toroidal magnetic field in time domain. The complex input ocean velocity field is discretized at individual time instants and the spectral-finite element approach is applied in time domain. The ocean-induced magnetic field in this work is split into toroidal and poloidal modes that are calculated separately. Additionally, the secondary poloidal magnetic field generated by the lateral conductivity contrast due to the ocean-continent boundary, the so-called coastal effect, is estimated. As the magnetic field is calculated for the identical input data sets and parametrization, the numerical results of the three methods are compared. Additionally, the behaviour of the calculated magnetic field is examined with respect to the variations of different input parameters. The results of the individual magnetic field constituents are compared in magnitude and spatial distribution.Diese Arbeit beschäftigt sich mit der Vorwärtsmodellierung ozeaninduzierter Magnetfelder auf globalen Skalen als eine Voraussetzung für die Identifizierung solcher Magnetfeldsignale in der vor Kurzem gestarteten Satellitenmission Swarm und küstennahen Magnetometern. Das Ziel ist die Entwicklung eines numerischen Modells für die Schätzung des Magnetfeldanteils, der durch die ozeanische Dynamik induziert wird. Als Eingangsdaten für die ozeanische Strömungen wird die stärkste halbtägliche M2 -Tide benutzt. Weitere Eingangsparameter der Modellierung bilden ein statisches Hintergrundmagnetfeld der Erde und eine realistische radiale Verteilung der elek- trischen Leitfähigkeit der Erde. In der Arbeit werden drei verschiedene Lösungsmethoden en- twickelt bei denen die Erde durch eine Kugel aproximiert ist. Um dieses Ziel zu erreichen wird eine Induktionsgleichung in Form der Helmholtzgleichung hergeleitet. Bei der ersten Methode wird die Induktionsgleichung mit einer analytischen Lösung in klassischer (starker) Formulierung im Fourier- Frequenzbereich mit Hilfe von spherischen Bessel-Funktionen gelöst. Bei dem zweiten Ansatz ist das Induktionsproblem in schwacher Formulierung, mit Hilfe der sogenannten Spektral- Finite-Element Methode, im Fourier-Frequenzbereich gelöst. Bei der dritten Methode wird die Lösung des toroidalen Magnetfeldanteils im Zeitbereich gesucht. In diesem Fall werden die kom- plexen Eingangsgrößen des periodischen Tidensignals in einzelne Zeitschritte diskretisiert und die Spektral-Finite-Element Methode ist im Zeitbereich angewandt. Das generierte Magnetfeld ist in einen toroidalen und einen poloidalen Anteil getrennt und diese werden separat berech- net. Neben dieser zwei primär induzierten Magnetfeldanteile wird zusätzlich der sogenannte Küsteneffekt, ein sekundär induzierter poloidaler Magnetfeldanteil, der aufgrund des lateralen elek- trischen Leitfähigkeitskontrastes zwischen Kontinent und Ozean induziert wird, geschätzt. Da die Berechnungen des Magnetfeldes bei allen drei Methoden mit identischen Eingangsgrößen und Parametrisierung durchgeführt werden, können die resultierenden Magnetfeldanteile untereinan- der verglichen werden. Zusätzlich wird die Sensitivität des induzierten Magnetfeldes bezüglich der wichtigsten Parameter untersucht und das magnetische Signal in Bezug auf seine Größe und räumliche Verteilung diskutiert

Prädiktion ozeanischer Tidensignale in Satellitenbeobachtungen des Erdmangnetfeldes

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Skol-orientalism : En religionsdidaktisk analys av hur läromedel framställer islam

This is a study that with critical eyes, studies schoolbooks that are meant for upper secondary school in the curriculum – Religion. I am studying how schoolbook authors portray Islam and its practitioners. Is there possibly any tendency towards orientalism to be found in them? Hopefully, none or very little. There are earlier studies that show how Muslims are portrayed as “the other”, the lesser, while Christians are portrayed as “we”, the normal. To be able to do this study I am using qualitative content analysis as a method. That way it is possible to systematically work through a larger text and cut it down to smaller themes. How are the authors portraying God? How is Islam´s view of man presented versus the Christian view of man? Finally, in what way has the representation of Islam changed over time?By using Edward Said’s theory of orientalism, I have been able to get the following result. It shows that the presentation of Islam and Christianity is still othering Islam and its practitioners, but differs on how easy you as a reader can see it. By using the theory of religious literacy, I have been able to identify how the author uses his/her language, if the author thought of conveying a deeper explanation and not just focus on small factual parts.

Skol-orientalism : En religionsdidaktisk analys av hur läromedel framställer islam

This is a study that with critical eyes, studies schoolbooks that are meant for upper secondary school in the curriculum – Religion. I am studying how schoolbook authors portray Islam and its practitioners. Is there possibly any tendency towards orientalism to be found in them? Hopefully, none or very little. There are earlier studies that show how Muslims are portrayed as “the other”, the lesser, while Christians are portrayed as “we”, the normal. To be able to do this study I am using qualitative content analysis as a method. That way it is possible to systematically work through a larger text and cut it down to smaller themes. How are the authors portraying God? How is Islam´s view of man presented versus the Christian view of man? Finally, in what way has the representation of Islam changed over time?By using Edward Said’s theory of orientalism, I have been able to get the following result. It shows that the presentation of Islam and Christianity is still othering Islam and its practitioners, but differs on how easy you as a reader can see it. By using the theory of religious literacy, I have been able to identify how the author uses his/her language, if the author thought of conveying a deeper explanation and not just focus on small factual parts.