This diploma thesis deals with the design of a feedwater heater. The aim of the work is to perform thermal, hydraulic and stress analysis. A preliminary technical documentation is also part of this work. The first part contains a summary of basic types of heat exchangers and processes of heat transfer. The main part is focused on thermal analysis to determine the main parameters of the heat exchanger. Next part is followed up by hydraulic analysis to determine the pressure drop of the heating water. After that is created design of heat exchanger with stress analysis of the proposed wall thicknesses of the shell, water chambers and tubesheet. Achieved results are summarized and evaluated at the end of the diploma thesis.

This master’s thesis deals with the draft tube and its optimization for various operating conditions. The research investigates the theoretical description and function of the draft tube and explains known methods of suppressing pressure pulsation so far. In the computational part, the author proposes a new method and designs optimal geometry of adjustable installations (ribs) for the draft tube. Finally, the comparison with the default geometry without ribs is performed.

Study questions: Does the proportion of neural tube defects (NTDs) in which there are co-occurring anomalies of other systems vary by geographical area and time in Europe between 1980 and 2015? Which group of factors, e.g., sex, age, family history, condition at discovery, and prenatal screening during pregnancy that potentially affect ascertainment of isolated NTD cases and co-occurring anomalies, are associated with the presence of these anomalies? Methods: Data on fetuses or births with NTDs recorded in 28 European Surveillance of Congenital Anomalies (EUROCAT) registries operating throughout or during a part of the period 1980-2015, were obtained and analysed. Information on the corresponding denominators of total births for each registry were compiled, comprising approximately 15.7 million births. We developed algorithms to classify NTDs that occurred as part of certain recognized genetic and unknown etiology syndromes, isolated NTD cases (either with no other anomaly reported or only an anomaly considered to be secondary to the NTD), and NTDs not occurring as part of recognized syndromes but with one or more co-occurring anomalies. We assessed factors that could impact ascertainment of isolated NTD cases and NTD cases with co-occurring anomalies. We also conducted a sensitivity analysis to evaluate the effect of family history and consanguinity on NTD outcomes. Lastly, we reported on the prevalence of NTDs across Eastern, Western, Northern, and Southern Europe as defined by the World Bank. Results: A total of 14,703 fetuses or births with NTDs were recorded in the EUROCAT registries. The total number of births (live and stillbirths) that occurred during the periods when the EUROCAT registries were operating was 15.7 million. The overall prevalence at birth of NTDs in Eastern Europe was 11.6 per 10,000 births, in Western Europe 11.0 per 10,000 births, in Northern Europe 10.5 cases per 10,000 births and in Southern Europe 6.7 per 10,000 births. The most prevalent genetic syndromes were chromosomal anomalies, particularly trisomy 18. The most common secondary anomaly was Arnold-Chiari syndrome which occurred mostly with spina bifida. The most prevalent associated anomalies were limb defects, followed by congenital heart defects, abdominal wall, and urinary system defects. We found anencephaly to be most prevalent in isolated NTD cases without secondary anomalies and spina bifida in secondary anomalies and most of the co-occurring anomalies. For factors that could affect ascertainment, we found that birth type, birth weight, family history, maternal and paternal age (≥30 years) were risk factors for isolated NTD cases and for co-occurring anomalies. Lastly, approximately 48% of NTDs occurred in Northern Europe, followed 29% in Western Europe, 16% in Southern Europe, and 7.6% in Eastern Europe. Conclusion: In the absence of folate fortification, isolated NTD cases showed higher prevalence than NTDs with co-occurring anomalies over the past 35 years across Europe. This research suggests that Europe should develop and implement policies and guidelines for folate fortification to help prevent simpler NTD cases. Further research and data are needed for newer EUROCAT registries to predict trends and prevalence of NTDs. Contribution and involvement: This project was done in collaboration with the experts from the School of Epidemiology and Public Health (SEPH) and dysmorphologists that provided support with regards to NTD classification. AB spearheaded the development of the research protocol and thesis manuscript with funding and support from JL and TR. Evaluation of the output of cases from the algorithm was provided to AB by JL, TR, JE, FB, AN, EB, ML, and the EUROCAT Joint Research Centre.

The main goal of master’s thesis is a propsal of the heat exchanger. The heat exchanger is double way of water side with the integrated air-vapor mixture cooler. Another aims are heat computation, heat loss computation, solidity dimensioning and selection of a material for a major selection. The last task is about detection of a vapor pressure trought the tube bundle.

This master’s thesis deals with a design of Na-CO2 heat exchanger. There is a comparison of shell and tube heat exchanger with PCHE in the first part. Further the shell and tube heat exchanger with internally finned tubes was chosen as the basic conception. There was performed an optimization of construct and operations parameters for this concept. The optimization was performed on the basis of thermal and hydraulic calculations. Further there were performed calculations for ensuring of safe operation of the heat exchanger. The conclusion of the diploma thesis deals with comparison of the designed heat exchanger with similar projects.

This master's thesis deals with CFD simulation of vortex rope in the elbow draft tube for overload operation of Francis turbine. The main objective of the thesis is to compare results of the CFD simulations of the original elbow draft tube with a derived straight cone draft tube considering volume and the shape of the cavitation region and dynamic flow characteristic. Results of the 3D simulations are also compared with axi-symmetric simulations, which reduce demands for computing time and power.

This thesis deals with the design of water turbine enabling optimal utilization of hydro-energetic potential of given location (barrage on Úpa river) chosen by ČEZ a.s. company. Moreover, the option of multi-unit layout is discussed. Because of the low-head profile of given location, the technology of swirl turbine in siphon configuration was chosen. Technology of swirl turbine presents new modification of Kaplan turbine with no need of guide vane. Swirl turbine is characterized by its high discharge and high speed. The main part of this thesis is focused on hydraulic design of the turbine.

This thesis deals with the structural design of mass flowmeter based on the principle of the Coriolis force. The introduction explains how the Coriolis flowmeter operates, what types of flowmeters are currently being produced and what are the important parameters. There are appointed some of the principles that must be followed to the meter working correctly. It contains a proposal design of flowmeter for pipes DN80 and. Includes drawings for this design.

The Master thesis deals with the water-heater design for heat-exchange station with total power output 5,5 MW. The goal of the thesis is to make thermal and hydraulic calculation in the extent of the assignment and to develop a projection drawing of the heater along with a correct dimensioning of the shell and flanges. Thesis goals were met according to the assignment. The introductory part of the thesis briefly introduces to the heat-exchanger problematic and selected topics about heat-transfer. Following the basic mass and energy flows calculation inside the heater together with the thermal and hydraulic design determines the size of the heat transfer surface of pipes. After that the design calculations were made, whose results are used to determine the basic dimensions of selected parts and checking the accuracy of designed dimensions. In the last part of the work the design process is more described also with a more detailed description of selected parts.

This work deals with study of swirling flows where the spiral vortical structure appears. The main relation is to flow seen in the draft tube cone of hydraulic turbines operated out of the design point (i.e. best efficiency point). In this cases large coherent vortex structure (vortex rope) appears and consequently high pressure pulsations are propagated to the whole machine system leading to possible restriction of turbine operation. This flow features are consequence of flow instability called vortex breakdown in case of Francis turbine operated at part load (flow rate lower than optimal one). The present study is carried out using simplified device of swirl generator in order to access similar flow conditions as can be found in real hydraulic turbines. Both the dynamic and dissipation effect of spiral vortex breakdown are investigated. The first part of thesis deals with spiral form of vortex breakdown. The experimentally measured velocity profiles (LDA) and wall static pressures are correlated with numerical simulations carried out using open-source CFD package OpenFOAM 2.2.2. The high speed camera recording of cavitating vortex core is used to obtain image ensemble for further post-processing. The dissipation effect of spiral vortex structure is in detail discussed based on computed flow fields. The second part of thesis is dedicated to the application of POD decomposition to the study of spatio-temporal features of spiral vortex dynamics. Firstly the POD is applied to the both the experimentally obtained image ensemble of cavitating vortex and numerically computed static pressure fields. Secondly the comprehensive analysis of spiral vortex mitigation effect by the axial water jet is analyzed. The collaborative study employing the swirl generator apparatus designed by the researchers from Politehnica University of Timisoara in Romania is performed and changes in spatio-temporal vortex dynamic are studied. In this study the numerical data (in a form of three-dimensional pressure and velocity fields) are obtained using commercial CFD software ANSYS Fluent R14.