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Stability Analysis of Power Transfer in PF Supply System of Compass-U Tokamak.
Kokeš, Petr; Hauptmann, R.
2021 - Czech
Power transfer stability in supply circuits of PF (Poloidal Field) coils has been analysed. Proper energizing of these coils is necessary for COMPASS-U tokamak experiments. The analysis main method is linearization of a non-linear system in a steady-state working point. The steady state-points have been specified by the Institute of Plasma Physics ASCR so that the whole operating area of the tokamak would be involved. At first, a simplified numerical model has been set up and analysed, then the analysis of a complex model of the PF supply system has been carried out in several versions according to the requirements of the contractor. Byla řešena stabilita přenosu výkonu přes napájecí obvody vinutí PF (Poloidal Field). Správné vybuzení cívek PF je nezbytné při experimentech na tokamaku COMPASS-U. Hlavní metodou analýzy je linearizace nelineárního dynamického systému v ustáleném pracovním bodě. Ustálené pracovní body specifikoval Ústav fyziky plazmatu AVČR tak, aby byla co nejlépe reprezentována celá pracovní oblast tokamaku. Nejprve byla provedena analýza zjednodušeného modelu, poté došlo ke komplexnímu modelování celé napájecí soustavy v několika variantách podle požadavků zadavatele.
Keywords:
power transfer stability; poloidal field; tokamak; Compass-U
Available at various institutes of the ASCR
Stability Analysis of Power Transfer in PF Supply System of Compass-U Tokamak.
Power transfer stability in supply circuits of PF (Poloidal Field) coils has been analysed. Proper energizing of these coils is necessary for COMPASS-U tokamak experiments. The analysis main method is ...
Design of test section for experiments on prismatic cascades fo axial compressors
Fiala, Petr; Luxa, Martin; Šimurda, David
2021 - Czech
The report deals with description of the design of the test section intended for experiments on axial profile cascades. Zpráva obsahuje stručný popis návrhu měřicího prostoru pro měření axiálních profilových mříží.
Keywords:
test section; axial compressor; compressor cascade
Available at various institutes of the ASCR
Design of test section for experiments on prismatic cascades fo axial compressors
The report deals with description of the design of the test section intended for experiments on axial profile cascades.
Determination of mechanical properties of chocolate under impact loading
Buchar, Jaroslav; Trnka, Jan; Kober, Jan
2021 - Czech
The report based on the Economic Contract No. 5/2021 with the MU in Brno and contains the results of research of the deformation behavior of five types of chocolate when loaded with high strain rates of the order 103 s-1. Two methods were used in the research, the Split Hopkinson Pressure Bar method (SHPB) and the modified Hopkinson bar method, where higher deformation rates can be achieved. Attention is also focused to the fracture behavior of chocolate under dynamic tensile loading. This method of loading is based on the SHPB method using the arrangement of the so-called Brazilian test. In this research, high-speed cinematography was also used to study the formation and development of the fracture of the chocolate sample. The measurement results are processed in the time and frequency domains. Zpráva vznikla na základě Hospodářské smlouvy č. 5/2021 uzavřené s MU v Brně a obsahuje výsledky výzkumu deformačního chování pěti druhů čokolády při zatěžování vysokými rychlostmi deformace řádově 103 s-1. Při výzkumu byly použity především dvě metody, metoda Hopkinsonovy měrné dělené tyče (HMDT) a metoda modifikované Hopkinsonovy tyče, kdy lze dosáhnout vyšších rychlostí deformace. Pozornost je též věnována lomovému chování čokolády při dynamickém tahovém zatěžování. Tento způsob zatěžování vychází z metody HMDT pomocí uspořádání tzv. Brazilského testu. V tomto výzkumu byla použita též vysokorychlostní kinematografie umožňující studovat vznik a rozvoj lomu čokoládového vzorku. Výsledky měření jsou zpracovány v časové i frekvenční oblasti.
Keywords:
chocolate; split Hopkinson pressure bar method (SHPB); Brazilian test
Available at various institutes of the ASCR
Determination of mechanical properties of chocolate under impact loading
The report based on the Economic Contract No. 5/2021 with the MU in Brno and contains the results of research of the deformation behavior of five types of chocolate when loaded with high strain rates ...
Measurements on KR-D-4 Cascade
Šimurda, David; Radnic, Tomáš
2021 - English
This report contains results and evaluation of aerodynamic measurements conducted on a subsonic compressor blade cascade.
Keywords:
compressor blade cascade; experiment; subsonic flow; transonic flow; AVDR
Available at various institutes of the ASCR
Measurements on KR-D-4 Cascade
This report contains results and evaluation of aerodynamic measurements conducted on a subsonic compressor blade cascade.
Measurements on TR-W-4 Cascade
Luxa, Martin; Šimurda, David
2021 - English
The report contains results and evaluation of conducted optical /interferometry and schlieren technique) and pneumatic measurements on the transonic profile cascade intenden for root section of rotor turbine blade.
Keywords:
turbine cascade; transonic flow; hub section
Available at various institutes of the ASCR
Measurements on TR-W-4 Cascade
The report contains results and evaluation of conducted optical /interferometry and schlieren technique) and pneumatic measurements on the transonic profile cascade intenden for root section of rotor ...
Flutter methodology using reduced order aeroelastic model
Prasad, Chandra Shekhar; Pešek, Luděk; Šnábl, Pavel
2021 - English
The present research project is focused on development of fast and efficient numerical method based on reduced order aeroelastic method (ROAM) for modeling and analysis of \nclassical flutter in the low pressure (LP) stage steam turbine blade. Stability diagram such as aerodynamic damping (AD) of aeroelasticity of cascade of 3D turbine blades used as a prime \ncharacterization factor. In the calculation of the S-curve/AD, the problem of classical flutter formation associated with running waves is considered here. Running waves is simulated by \nthe inter-blade phase shift of the blades in the cascade. Panel method based boundary element flow solver is employed for calculation of unsteady aerodynamic forces. This method is good \ncompromise of speed and accuracy for the estimation of the stability of the blades on a classical flutter. One way loose coupling technique between PM based flow solver and the structural \nmodel. For the structural part modal model synthesis (MMS) method is adopted in the ROAM solver. MMS is adopted to further reduced the computational cost. The ROAM simulated AD \nand pressure distribution over blade is compared high fidelity CFD data on real blade geometry provided by Doosan Skoda Power s.r.o. Furthermore, the ROAM results are also compared \nwith experimentally obtained results on two different linear cascade. The ROAM model shows good agreement with linear cascade results, however, there is noticeable discrepancy with real blade CFD results.
Keywords:
reduced order model (ROM); classical flutter; steam turbine blade; panel method
Available at various institutes of the ASCR
Flutter methodology using reduced order aeroelastic model
The present research project is focused on development of fast and efficient numerical method based on reduced order aeroelastic method (ROAM) for modeling and analysis of \nclassical ...
Design of compressor cascade KOBRA
Fiala, Petr; Luxa, Martin; Šimurda, David
2021 - Czech
Prismatic profile cascade has static pressure taps on suction and pressure side of profiles, which form the interblade channel in the middle of the cascade. The sidewalls of the cascade are equipped with slots for boundary layer control. Prismatická profilová mříž má vyprojektovánu drenáž pro měření statických tlaků na profilech, které ohraničují její střední mezilopatkový kanál. Bočnice modelu jsou opatřeny sloty pro odsávání mezní vrstvy.
Keywords:
compressor cascade; axial compressor; aerodynamic experiments; AVDR
Available at various institutes of the ASCR
Design of compressor cascade KOBRA
Prismatic profile cascade has static pressure taps on suction and pressure side of profiles, which form the interblade channel in the middle of the cascade. The sidewalls of the cascade are equipped ...
Identification of material constants of new rubber damping segments from modal analysis of a railway rubber damped wheel
Šulc, Petr; Pešek, Luděk; Šnábl, Pavel; Bula, Vítězslav
2021 - Czech
The aim of the modal analysis was to compare and identify the material constants of two proposed mixtures of rubber damping segments of a railway wheel. The modal analysis was carried out in two stages, experimentally and then numerically. The experimental modal analysis was carried on a rubber-suspension wheel for the two proposed rubber types of segment , designated 42809 and 46809. From this dynamic analysis, the natural frequencies and eignemodes of the wheel oscillations were obtained in the frequency bandwidth up to 6.5kHz. The material constants of the rubber were obtained by tuning the material parameters of the rubber segments, i.e. elastic modulus and special proportional damping coefficient, of the 3D FEM model of the railway wheel to the values of natural frequencies and damping ratios of the selected wheel natural vibration modes. Cílem modální analýzy bylo porovnat a identifikovat materiálové konstanty dvou navržených směsí pryžových tlumících segmentů železničního kola. Modální analýza byla řešena ve dvou etapách, a to experimentálně a následně numericky. Experimentální modální analýza probíhala v laboratoři ÚT s použitím jednobodového buzení (SIMO) na gumo-odpruženém kole, a to pro obě navržené varianty pryžových segmentů s označením 42809 a 46809. Z této dynamické analýzy byly získány vlastní frekvence a tvary kmitání kola v pásmu do 6,5kHz. Materiálové konstanty pryže byly získány na základě ladění materiálových parametrů pryžových segmentů, tj. modulu pružnosti a koeficientu speciálního modelu proporcionální tlumení, 3D MKP modelu železničního kola na hodnoty vlastních frekvencí a poměrných útlumů vybraných tvarů vlastního kmitání kol.
Keywords:
material constants; rubber; railway wheels; damping
Available at various institutes of the ASCR
Identification of material constants of new rubber damping segments from modal analysis of a railway rubber damped wheel
The aim of the modal analysis was to compare and identify the material constants of two proposed mixtures of rubber damping segments of a railway wheel. The modal analysis was carried out in two ...
Shock waves in ducts
Luxa, Martin
2020 - Czech
The report deals with shock waves in ducts, which originate as a consequence of sudden closing of quick acting valve. Three methods of solving are described. Selected actual problems of czech power plants are solved. Zpráva se zabývá problematikou rázových vln potrubí, které vznikají při jeho náhlém uzavření. Jsou popsány tři možné teoretické přístupy k řešení a jsou uvedena i řešení praktických úloh.
Keywords:
water hammer; hydrodynamics; shock wave; aerodynamics
Available at various institutes of the ASCR
Shock waves in ducts
The report deals with shock waves in ducts, which originate as a consequence of sudden closing of quick acting valve. Three methods of solving are described. Selected actual problems of czech power ...
Software Implementation of Lowest Level Control for FB-MMC Converter
Kokeš, Petr
2020 - Czech
For FB-MMC converter (Full Bridge Cell, Modular Multilevel Converter), the software implementation of SA-PWM modulation (Sampled Average PWM) and SORT-BAL sorting type balancing of cell voltages have been designed. The report deals with the specifics of realizing control methods using the Beckhoff TwinCAT 3 system. The control structure was divided into explicitly defined function blocks for the Master controller as well as for the distributed EPX Slave units. Data transfer timing between the Master and the Slave units has been designed and the synchronization of EtherCAT link communication has been tested in practice. \n Pro měnič FB-MMC (Full Bridge Cell, Modular Multilevel Converter) byla rozpracována softwarová implementace pro modulaci SA-PWM (Sampled Average PWM) a pro balancování napětí buněk pomocí třídění SORT-BAL. Práce se zabývá specifikou realizace tohoto řízení se systémem Beckhoff TwinCAT 3. Řízení bylo rozděleno do jasně definovaných funkčních bloků pro hlavní počítač (Master) a pro distribuované jednotky EPX (Slave). Bylo navrženo časování přenosu dat mezi Master a Slave a byla prakticky testována synchronizace komunikace v síti EtherCat.
Keywords:
modular multilevel converter; full bridge cell; sampled average modulation; TwinCat
Available at various institutes of the ASCR
Software Implementation of Lowest Level Control for FB-MMC Converter
For FB-MMC converter (Full Bridge Cell, Modular Multilevel Converter), the software implementation of SA-PWM modulation (Sampled Average PWM) and SORT-BAL sorting type balancing of cell voltages have ...
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