National Repository of Grey Literature 35 records found  previous11 - 20nextend  jump to record: Search took 0.01 seconds. 
Study of unsteady phenomena in pump as turbine
Hliboký, Samuel ; Zemanová, Lucie (referee) ; Štefan, David (advisor)
This diploma thesis deals with centrifugal pump running as a turbine. Basic working principles of a pump are included, both in pump and turbine regime. Experimental data obtained from laboratory test bed are compared with CFD simulation on slightly simplified geometry. Obtained results are then processed using spectrogram. Influence of time step and mesh size on results is also researched.
Dynamic radial force on centrifugal pump impeller
Nováková, Naděžda ; Hudec, Martin (referee) ; Habán, Vladimír (advisor)
This thesis deals with the radial forces acting on the impeller of a centrifugal pump. It focuses on the centrifugal pump type BETA 26. It addresses forces acting on the pump shaft. These forces are converted into the impeller. The most extensive part of this thesis is devoted to the experimental measurement and evaluation. The results are summarized and processed graphically.
Influence of the impeller eye on the stability of Q -Y curve
Broža, Martin ; Dobšáková, Lenka (referee) ; Haluza, Miloslav (advisor)
The master thesis is focused on the examination of the influence of the impeller eye on the stability of Q-Y curves. It is the examination of the impact of a large inlet angle of the blade and the extension of the inlet part, which also supports good cavitation capabilities. Another consideration is the influence of the rotating fluid before the impeller, influence of the circumferential component of the absolute velocity at the inlet part. The proposed modification will be subject to simulation in ANSYS.
Stability of centrifugal pump characteristic curve
Kollár, Martin ; Haluza, Miloslav (referee) ; Pochylý, František (advisor)
This master's thesis includes theoretical analysis of characteristics of a centrifugal pump, conditions of stability of Y(Q) characteristic, calculation of characteristics ßč(ns), modifications leading to stabilization of a spiral body and a runner, a design of the spiral, the runner and follow-up computation in Fluent program.
The centrifugal pump radial force reduction
Koutný, Luděk ; Haluza, Miloslav (referee) ; Pochylý, František (advisor)
This diploma thesis deals with problematics of the radial force effect on the runner and possibilities of the force reduction. Some pump modifications were proposed and changes of radial force magnitude in reverse blocking state and optimal flow state were examined in consequence. Following investigation was focused on the new modifications regarding to the pump efficiency and its characteristics stability. All results were carried out using the Solidworks, the Fluent and the Microsoft Excel software.
Hydraulic design and CFD simulation of impeller with integrated inducer
Novosad, Pavel ; Kozák, Jiří (referee) ; Štefan, David (advisor)
Cílem této práce je hydraulický návrh oběžného kola čerpadla okysličovadla pro raketový motor. Úvodní část práce je věnována rešerši podstatných pojmů a jevů, které tento návrh ovlivňují. Následuje iterativní návrh radiálního čerpadla, které je ale náchylné na vznik kavitace. Poté je proveden návrh axiálního stupně čerpadla, který má navyšovat vstupní tlak do radiálního stupně. Návrh byl založen na analytickém výpočtu 2D proudění, který byl následně za pomoci CFD analýz modifikován pro zlepšení výkonu, účinnosti a kavitační stability čerpadla. Finálním krokem je tyto dvě oběžné kola spojit do jednoho, které díky kompaktnějším rozměrům dosahuje vyšší účinnosti a je méně náročné na výrobu. Pro toto kolo jsou provedeny kontroly vůči meznímu stavu pružnosti, výskytu rezonance a náchylnosti na výskyt kavitace při nízkém sacím tlaku.
Problematic of high speed and electrically-fed pumps utilized within the space applications
Kovář, Martin ; Machoň, Matěj (referee) ; Štefan, David (advisor)
The main aim of this research Bachelor thesis is to provide the reader with the simplest and clearest possible insight into the subject of electrically driven pumps in rocket engines and to lay a solid foundation for possible further study in this field. The work focuses on centrifugal pumps and their design elements, the current situation and direction of the space industry, and in particular details of the operating characteristics of electric-fed pumps.
Low specific speed pump working in turbine mode
Bezdíček, Jiří ; Moravec, Prokop (referee) ; Štefan, David (advisor)
The use of the pump in turbine mode is an evolving area. For this reason, research of less standard pumps from the edges of the specific speed spectrum is suitable for this purpose. This diploma thesis was focused on the influence of splitter blades on the exclusively turbine mode of a low specific speed pump. CFD calculations of the pump were performed, considering the sidewall gaps between the stator and the rotor. CFD served not only to obtain turbine characteristics but also to describe the flow and analysis of other phenomena, such as volumetric efficiency or hydraulic forces.
Computational modeling of cavitation characteristic curve of radial centrifugal pump
Leischner, Jakub ; Chabannes, Lilian (referee) ; Štefan, David (advisor)
Tato práce se zabývá jedním z nejčastějších problémů spojených s provozem radiální odstředivých čerpadel mimo optimální podmínky - kavitací. Její příčiny a vliv jsou vysvětleny a shrnuty společně s popisem hlavních částí čerpadel a simulačních metod výpočtového modelování proudění. K vyhodnocení vlivů kavitace na provozní parametry čerpadla jsou použita data z experimentálního měření a vytvořeného CFD modelu. Hlavní charakteristiky čerpadla, jako dopravní výška a účinnost, jsou srovnány ve 4 bodech zahrnujících rozmezí od návrhového bodu až po nevhodný provozní režim při poklesu dopravní výšky o více než 3 %. Jako doplněk je z výsledků CFD simulací vyhodnocen objem páry vznikající v oběžném kole a frekvence pulzací působících sil.
Study of unsteady phenomena in pump as turbine
Hliboký, Samuel ; Zemanová, Lucie (referee) ; Štefan, David (advisor)
This diploma thesis deals with centrifugal pump running as a turbine. Basic working principles of a pump are included, both in pump and turbine regime. Experimental data obtained from laboratory test bed are compared with CFD simulation on slightly simplified geometry. Obtained results are then processed using spectrogram. Influence of time step and mesh size on results is also researched.

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