|
|
Design of microfluidic mixer
Abrahám, Martin ; Fialová, Simona (referee) ; Rudolf, Pavel (advisor)
Microfluidic devices are more frequently being used in medicine as they operate with small amounts of test samples, such as blood or reagent chemicals. To work with such substances, effective mixing of the solution is usually required, which emerged as the most challenging problem in microfluidic systems. Due to the minor dimensions of the devices only laminar flow occurs, thus the turbulent eddies do not contribute to the mixing, but only the molecular diffusivity.
|
|
|
EFFECT OF FLOW PARAMETERS OF WATER AND AIR ATOMIZED SPRAYS ON COOLING INTENSITY OF HOT SURFACES
Boháček, Jan ; Střasák,, Pavel (referee) ; Rudolf, Pavel (referee) ; Horský, Jaroslav (advisor)
Práce komplexně popisuje vodní a vodovzdušné chlazení pomocí metod CFD (Computational Fluid Dynamics) konkrétně s využitím software ANSYS FLUENT. Skládá se ze dvou hlavních částí, z nichž první se zabývá numerickým popisem jediné vodní kapky a druhá popisem směsí kapek představující paprsek válcové a ploché trysky. Je založena převážně na vícefázových modelech proudění a vlastních uživatelsky definovaných funkcí (User Defined Functions, UDF) představujících stěžejní část práce. Uvedené výpočtové modely jsou ve většině případů verifikovány pomocí experimentálních dat nebo jiných numerických modelů. V první části práce jsou teoreticky postupně rozebrány všechny tři použité vícefázové modely proudění. První z nich, Volume Of Fluid model (VOF), byl použit pro modelování jediné kapky (mikromodel). Zatímco zbývající dva, Euler-Euler model a Euler-Lagrange model, byly aplikovány v modelu celého paprsku trysky (makromodel). Mikromodel popisuje dynamiku volného pádu vodní kapky. Pro malé průměry kapek (~100µm) standardní model povrchového napětí (Continuum Surface Force, CSF) způsoboval tzv. parazitní proudy. Z toho důvodu je v práci rozebrána problematika výpočtu normál, křivostí volných povrchů a povrchového napětí jako zdroje objemových sil v pohybových rovnicích. Makromodel se zabývá studiem dynamiky celého paprsku tj. oblastí od ústí trysky po dopad na horký povrch, bere v úvahu kompletní geometrii, tzn. např. podpůrné válečky, bramu, spodní část krystalizátoru apod. V práci je rozebrána 2D simulace dopadu paprsku válcové trysky pomocí VOF modelu Euler-Lagrange modelu na horký povrch. Pro případ s VOF modelem byl navržen model blánového varu. Euler-Euler model a Euler-Lagrange model byly využity pro simulaci paprsku ploché trysky horizontálně ostřikující horkou bramu přímo pod krystalizátorem nad první řadou válečků. Pro Euler-Euler model byl navržen model sekundárního rozpadu paprsku založený na teorii nejstabilnější vlnové délky (Blob jet model). Jelikož diskrétní Lagrangeovy částice tvořily v určitých místech spíše kontinuální fázi, byl navržen a otestován model pro konverzi těchto částic do VOF.
|
|
|
Aerodynamic analysis and shape optimization of ARES aircraft
Foltýn, Pavel ; Navrátil, Jan (referee) ; Popela, Robert (advisor)
This thesis deals with the aerodynamic analysis and shape modifications of the ARES aircraft. The analysis focuses on the evaluation lift, drag, and pitching moment coefficient, and further to identify the locations of stripping stream which is characterized by high drag. Before the analysis calibration of the CFD solver is done with the model, which has been measured in the wind tunnel. The aim of calibration is to verify the accuracy and veracity of the methodology used in mesh creation and calculated values. Calculated values are compared with measured data. The shape modifications of the aircraft are focused on conceptual design of the suction inlets for cooling radiators and engine aircraft. Aerodynamic analysis is performed with the modified model in order to determine the variation of lift, drag and pitching moment coefficient from its original configuration.
|
|
|
The design of screw pump
Hyriak, Maroš ; Klas, Roman (referee) ; Haluza, Miloslav (advisor)
This thesis is concerned with the topic of Pumps with crew centrifugal impeller. Thanks to the benefits such as free passage and efficiency there are many practical applications of these products. Despite this fact there is only few manufacturers dealing with them what results in lack of research and available information in the area. In order to fill the gap, this thesis aims to propose hydraulic of screw centrifugal impeller to the specified parameters. The impeller with a single moving blade will be designed for pumping heavily polluted water and hardly pumpable liquids. Blade will be balanced together with the rotor, while the emphasis will be placed on the highest free passage of impeller. The theoretical part of the thesis summarizes literature on the subject, practical part deals with the calculations and adjustments pointing to a concrete proposal. Parameters of designed hydraulics were verified using stationary calculations using MRF model in FLUENT. As a results, two possible solutions are offered.
|
|
| |
|
|
Aerodynamic analysis and optimization of TL-4000 aircraft
Trusík, Vojtěch ; Navrátil, Jan (referee) ; Popela, Robert (advisor)
This master´s thesis is focused on aerodynamic analysis of 3D configuration of aircraft TL – 4000 and designing shape modifications to improve flight performances. Modifications are focused on wing – fuselage junction and junction between tail units. In continuation are analyzed the shapes of air intakes to cooling engine. Based on aerodynamic analysis of aircraft TL – 4000 are chosen convenient positions for pitot-static tube and inlets for ventilation of cabin.
|
|
| |
|
|
Computation of vehicle aerodynamic characteristics
Čavoj, Ondřej ; Porteš, Petr (referee) ; Vančura, Jan (advisor)
This Diploma thesis deals with CFD simulations of flow around vehicles subjected to a crosswind with MIRA Reference Car in three body shapes with a diffuser serving as a vehicle. It contains tuning of computational grid and chosen solver settings in Fluent, mostly for v2f turbulence model. The main output of this thesis is a simulation of all body shapes in several crosswind angles in steady state and one chosen body shape with one chosen crosswind angle in unsteady state. All results are validated against measurements taken with full scale models in MIRA windtunnel.
|
|
|
The wide range impeller.
Wojnar, Pavel ; Žák, Radim (referee) ; Haluza, Miloslav (advisor)
The aim of the thesis was to propose a pump impeller with higher effectiveness and verify the proposal with the calculation using programs Gambit and Fluent. Three designed impellers were afterwards made using 3D printer and its characteristics were measured in a hydraulic laboratory in Kaplan Department of hydraulic machines. The proposal of a so called wideband impeller of the centrifugal pump was made with chaotic ordering of blade cascades, in one impeller occur blades with various input and output angles and different shapes of blades but all blades have got similar shape in a meridian sectional view of impeller. The thesis was divided into three parts. In the first part, a conforming transformation was theoretically described which was in the thesis used for the shape proposal of impeller blades. In the second part of the thesis final proposals and calculations of pump impellers were made. The third part of the thesis focused on the processing and evaluation of experimental measurement in the hydraulic laboratory and finally the results of the thesis were summarized in the conclusion.
|
|
| |
guest ::
