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Cavitation in microfluidic orifice
Bohunský, Tomáš ; Burda, Radim (referee) ; Rudolf, Pavel (advisor)
This diploma thesis deals with cavitation flow in the microscale, which remains an area with a lack of sufficient description of this phenomenon. At the same time, microfluidics is a field experiencing a dramatic rise in numerous biochemical applications, which underlines the relevance of researches of this type. In theoretical part of the thesis, cavitation was described in detail. In the practical part, a microfluidic device with a cavitation orifice was designed and manufactured. The ANSYS program was used for this design. An experiment was performed with the designed microchip, the aim of which was to observe a cavitating flow on the orifice. This measurement took place at the microfluidic laboratory at Victor Kaplan Department of Fluid Engineering. Due to the failure of the experiment, a CFD model of two-phase cavitation flow was built. The conclusions of the thesis were compiled from the findings of measurement and the results of modeling.
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Cavitation onset by liquid acceleration
Mračko, Patrik ; Burda, Radim (referee) ; Rudolf, Pavel (advisor)
The main goal of bachelor’s thesis is description of complex phenomenon of cavitation caused by acceleration and design of experiment focusing on its observation. Thesis consist of two parts. Theoretic research focusing on basic information about cavitation, its formation and significance. Second part is design of experimental observation with help of high-speed camera, evaluation of possible complications which may occur and their solution. Conclusion proposes possible application for research in area of wastewater treatment.
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Digital twin concept for hydraulic machines
Klement, Jan ; Burda, Radim (referee) ; Rudolf, Pavel (advisor)
The term “Digital twin” is associated with Industry 4.0. It is a projection of an object into a virtual environment, which enables to predict behaviour and explore the existing behaviour. In engineering, such objects can be components, machines, or entire companies. Subsequently, Digital twin helps to determine the most suitable operation depending on the conditions. This thesis deals with the possibilities of digital twin. Subsequently, it describes the current state of turbomachinery, concentrating in particular on hydraulic machines in the field of Digital twin. The final part of the thesis describes the concept for creating a Digital twin for a centrifugal pump.
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Peristaltic pump
Burda, Radim ; Fialová, Simona (referee) ; Pochylý, František (advisor)
Cílem této diplomové práce je navrhnout peristaltické čerpadlo pro hemodialýzu s ohledem na minimalizaci tlakových pulzací. Pomocí analytické analýzy je navržen nový koncept redukce tlakových pulzací, který využívá zrychlení k navýšení tlaku v prostoru mezi válečky. Fungování peristaltického čerpadla je simulováno pomocí programu Ansys Fluent pro získání lepší představy o proudění v čerpadle. Souběžně s návrhem nového konceptu bylo navrženo více tradiční čerpadlo, které bylo následně vyrobeno a experimentálně odzkoušeno. Data získaná z experimentu mohou být dále použita pro nový koncept.
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Elimination of nanoplastics by cavitation and advanced oxidation processes
Kluknavská, Júlia ; Burda, Radim (referee) ; Rudolf, Pavel (advisor)
Táto práca sa zaoberá znečistením životného prostredia mikro a nanoplastami a ich možnou likvidáciou. Práca pozostáva z rešeršnej a experimentálnej časti. V rámci rešerše je opísaná problematika mikro a nanoplatov z hľadiska ich vzniku, disperzie do životného prostredia a živých organizmov. V závere rešeršnej časti sú opísané súčasné možnosti eliminácie mikro a nanoplastov pri čistení odpadových vôd. Súčasné riešenia sú založené prevažne na filtrácii, ktorá však zo svojej podstaty nemôže byť absolútna. Bol vyslovený predpoklad, že pomocou zariadenia CaviPlasma by bolo možné eliminovať mikro a nanoplasty z odpadových vôd. Cieľom práce bolo experimentálne overiť tento predpoklad. Skúšobnou vzorkou bola suspenzia vody a polyamidových častíc, ktorá bola následne vystavená pôsobeniu kavitácie a plazmového výboja. Pri experimente nedošlo ku zničeniu častíc a ani ich k viditeľnému porušeniu. Ukázalo sa však, že plazmový výboj môže iniciovať zhlukovanie sa častíc až do takej miery, že sú pozorovateľné kontinuálne štruktúry mikroplastov. Tento jav by mohol byť potenciálne prospešný pri zachytávaní mikročastíc filtráciou.
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Study of in-take vortices
Burda, Radim ; Štigler, Jaroslav (referee) ; Hudec, Martin (advisor)
This bachelor thesis deals with vortex flow, in particular intake-vortices formations with emphasis on intake-vortices with full air core which appear near vertical intakes. The thesis is divided into two parts. The first part contains theoretical research on the intake-vortices and maps development of this field during the last 60 years. The goal of the experimental part is to verify recommended dependence of the formation of intake-vortices with full air core on submerge of intake and volumetric flow rate. The experiment was conducted in the laboratory of the fluid engineering department of Viktor Kaplan.
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Multiphase CFD simulation of spiral vortex in vaneless swirl generator
Zatloukal, Filip ; Burda, Radim (referee) ; Štefan, David (advisor)
This thesis deals with multiphase CFD simulation of spiral vortex in bladeless swirl generator. Spiral vortex formed in the draft tube of hydraulic turbine is called “vortex rope”. Vortex rope is formed when the turbine is forced to operate in off-design conditions. Assessment of swirl generators used for the study of vortex ropes is presented. The multiphase CFD simulations are carried out for the bladeless swirl generator with use of Reynolds stress turbulence model in ANSYS Fluent software. The results from calculations are compared with available experimental data previously measured on this particular swirl generator. The main focus is on detailed analysis of velocity field in the diffusor part of the generator where the vortex appears. Experimentally estimated swirl number is compared with the one evaluated from simulation. The swirl number is also monitored along the length of diffuser and downstream. Finally, the synchronous and asynchronous pressure pulsations are studies by means of Fast Fourier Transformation.
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CFD simulation and analysis of hydrocyclone
Moravanský, Richard ; Burda, Radim (referee) ; Klas, Roman (advisor)
The main goal of the thesis is the design, analysis, CFD simulation and optimization of a hydrocyclone in order to increase the separation efficiency. The reason for this investigation is the lack of information about the design aspects of the hydrocyclone and their effect on the separation efficiency. An important part of the thesis is the teoretical knowledge, which mainly includes a description of the basic parts and a description of the flow. Furthermore, there are discussed the operation itself and the separation theory of the hydrocyclone, with the aim of deriving the basic assumptions and empirical equations. An important criterion for evaluating efficiency is the dependence of this parameter on the size of the particles dp and related phenomena leading to an increase the pressure loss in the device. The CFD simulation is performed by the ANSYS Fluent program, where the discrete phase model DPM was set. As part of the flow analysis, basic contours and a comparison criterion were defined, which describes the negative phenomena associated with the separation efficiency. During the subsequent evaluation, it was concluded that the most important parameter that fundamentally affects the efficiency is the internal dimension of the vortex finder, while the optimization of the geometry of the inlet part had only a minimal effect on the separation efficiency.
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Digital twin concept for hydraulic machines
Klement, Jan ; Burda, Radim (referee) ; Rudolf, Pavel (advisor)
The term “Digital twin” is associated with Industry 4.0. It is a projection of an object into a virtual environment, which enables to predict behaviour and explore the existing behaviour. In engineering, such objects can be components, machines, or entire companies. Subsequently, Digital twin helps to determine the most suitable operation depending on the conditions. This thesis deals with the possibilities of digital twin. Subsequently, it describes the current state of turbomachinery, concentrating in particular on hydraulic machines in the field of Digital twin. The final part of the thesis describes the concept for creating a Digital twin for a centrifugal pump.
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Multiphase CFD simulation of spiral vortex in vaneless swirl generator
Zatloukal, Filip ; Burda, Radim (referee) ; Štefan, David (advisor)
This thesis deals with multiphase CFD simulation of spiral vortex in bladeless swirl generator. Spiral vortex formed in the draft tube of hydraulic turbine is called “vortex rope”. Vortex rope is formed when the turbine is forced to operate in off-design conditions. Assessment of swirl generators used for the study of vortex ropes is presented. The multiphase CFD simulations are carried out for the bladeless swirl generator with use of Reynolds stress turbulence model in ANSYS Fluent software. The results from calculations are compared with available experimental data previously measured on this particular swirl generator. The main focus is on detailed analysis of velocity field in the diffusor part of the generator where the vortex appears. Experimentally estimated swirl number is compared with the one evaluated from simulation. The swirl number is also monitored along the length of diffuser and downstream. Finally, the synchronous and asynchronous pressure pulsations are studies by means of Fast Fourier Transformation.
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