Národní úložiště šedé literatury Nalezeno 10 záznamů.  Hledání trvalo 0.00 vteřin. 
Investigation of droplet nucleation in CCS relevant systems – design and testing of the expansion chamber
Čenský, Miroslav ; Hrubý, Jan ; Vinš, Václav ; Hykl, Jiří ; Šmíd, Bohuslav
A unique in-house designed experimental apparatus for investigation of nucleation of droplets in CCS relevant systems is being developed by the present team. The apparatus allows simulating various processes relevant to CCS technologies. Gaseous mixtures with CO2 are prepared in a Mixture Preparation\nDevice (MPD) based on accurate adjustment of flow rates of individual components [EPJ Web of Conferences 143, 02140 (2017)]. The mixture then flows into an expansion chamber, where it undergoes a rapid adiabatic expansion. As a consequence of adiabatic cooling, the mixture becomes supersaturated and nucleation and simultaneous growth of droplets occurs. In this study, we describe the design and testing of the expansion part of the experimental setup. The rapid expansion was realized using two valve systems, one for low pressures (up to 0.7 MPa) and the other for high pressures (up to 10 MPa). A challenge for a proper design of the expansion system is avoiding acoustic oscillations. These can occur either in the mode of Helmholtz resonator, where the compressible gas in the chamber acts as a spring and the rapidly moving\ngas in the valve system as a mass, or in the “flute” mode, where acoustic waves are generated in a long outlet tubing.\n
Surface tension of aqueous binary mixtures under the supercooled conditions – Development of the measuring technique and preliminary data for water + lower alcohols
Vinš, Václav ; Hykl, Jiří ; Nikl, Zbyněk ; Čenský, Miroslav ; Hrubý, Jan
An experimental apparatus originally developed for the measurement of surface tension of supercooled water was modified such that it allows for measurement of binary aqueous mixtures. The measuring principle based on the capillary rise technique is similar to that employed in the previous measurements with pure water [J. Hrubý et al., J. Phys. Chem. Lett. 5 (2014) 425 and V. Vinš et al., J. Phys. Chem. B 119 (2015) 5567]. The temperature dependence of the surface tension is determined from the\nmeasured height of the liquid column elevated in a vertical capillary tube with an inner diameter of 0.32 mm. The aqueous liquid rises to a height of 60 mm to 95 mm depending on the solute concentration and the temperature. Preliminary tests performed with the binary mixtures of water with methanol, ethanol, and n-propanol at various concentrations and temperatures down to –28 °C approved functionality of the measuring technique. Some difficulties, such as influence of impurities on the liquid column elevation or formation of bubbles in the liquid column, were observed. The experimental apparatus is further being modified in order to obtain more accurate data for various aqueous mixtures.
Měření tepelné vodivosti izolačních materiálů
Čenský, Miroslav
Cílem této práce bylo zjištění tepelných vodivostí dvou typů izolačních materiálů dodaných firmou Škoda Auto. Za pokojové teploty byly naměřeny tepelné vodivosti izolačních materiálů EKV/2 a EPA/1.
Investigation of droplet nucleation in CCS relevant systems – Design and testing of a CO2 branch of the mixture preparation device.
Vinš, Václav ; Čenský, Miroslav ; Hykl, Jiří ; Hrubý, Jan
A unique in-house designed experimental apparatus for investigation of nucleation of droplets in CCS relevant systems is being developed by our team. The nucleation is measured with the help of a rapid pressure drop within an expansion chamber. In this study, a CO2 branch representing an important part of the mixture preparation device (MPD) was designed, assembled and tested. MPD is intended for preparation of CO2-rich mixtures in a sense of accurate setting of flow rates of individual gaseous components through the experimental section with the expansion chamber. In the CO2 branch, the saturated liquid CO2 is pressurized by a supercritical pump to the pressures of up to 340 bar. The required mass flow of the supercritical CO2 is accurately tuned with a help of a set of stainless steel capillary tubes. Needed lengths of the capillary tubes were determined with a help of a one-dimensional numerical model allowing prediction of both isothermal and adiabatic flow conditions.
Studium plynných reakcí v chemickém kyslík-jódovém laseru
Jirásek, Vít ; Špalek, Otomar ; Čenský, Miroslav ; Kodymová, Jarmila ; Picková, Irena ; Jakubec, Ivo
Chemical methods of atomic iodine generation for a chemical oxygen-iodine laser (COIL) were studied using gaseous reactions of chlorine or fluorine atoms with hydrogen iodide. After optimization of reaction conditions, both methods provided high yields and concentrations of atomic iodine, which are sufficient for efficient laser generation in COIL. To get very high laser gain requires a prevention of the reaction of singlet oxygen with hydrogen iodide, which is a strong quencher of singlet oxygen in laser. A quasi-1D and CFD modeling was used for the experimental investigation support.
Produkce singletového kyslíku pro chemický kyslík-jodový laser
Čenský, Miroslav ; Jirásek, Vít ; Špalek, Otomar ; Kodymová, Jarmila ; Hrubý, Jan
Článek se týká výzkumu chemického sprejového generátoru singletového kyslíku pro chemický kyslík-jodový laser, který byl originálně navržen v FZÚ AV ve spolupráci s ÚT AV. Jsou uvedeny některé výsledky získané během studia parametrů tohoto generátoru.
Experimental results on chemical generation of atomic iodine
Špalek, Otomar ; Jirásek, Vít ; Čenský, Miroslav ; Kodymová, Jarmila ; Jakubec, Ivo
In this paper were presented experimental results on chemical generation of atomic iodine.
Generace atomárního jódu pro chemický kyslík-jodový laser
Jirásek, Vít ; Špalek, Otomar ; Kodymová, Jarmila ; Čenský, Miroslav
Byla navržena nová metoda produkce atomárního jódu pro kyslík-jódový laser, která je založena na rychlých chemických reakcích plynných reakčních složek přímo v proudu singletového kyslíku.
Výzkum a vývoj chemického kyslík-jodového laseru ve Fyzikálním ústavu AV ČR
Čenský, Miroslav ; Kodymová, Jarmila ; Špalek, Otomar ; Jirásek, Vít
Chemiský kyslík-jodový laser (dále COIL) je vedle laserového systému PALS (Prague Asterix Laser System) jedním ze dvou laserů, které jsou předmětem výzkumu ve Fyzikálním ústavu AV ČR. Oba tyto lasery září na elektronovém přechodu atomárního jódu v blízké IČ oblasti(1.315 ćm). Avšak princip čerpání horní laserové hladiny jódu je zcela odlišný.

Chcete být upozorněni, pokud se objeví nové záznamy odpovídající tomuto dotazu?
Přihlásit se k odběru RSS.