Orientador: Sandro Doninini Mancini / Banca: Nilson Cristino da Cruz / Banca: Helio Wiebeck / O Programa de Pós Graduação em Ciência e Tecnologia de Materiais, PosMat, tem carater institucional e integra as atividades de pesquisa em materiais de diversos campi da UNESP / Resumo: O processo de fabricação das pás que equipam as modernas turbinas eólicas e o seu descarte no fim da vida útil podem ter impacto negativo sobre o meio ambiente. O presente trabalho busca soluções para reciclagem de resíduos de compósitos fibra de vidro/resina epóxi utilizados na fabricação das pás eólicas, tanto de porções sólidas geradas na fabricação (posteriormente convertidas em pó por furação) quando do pó gerado no processo de acabamento das pás. A reciclagem química, através da pirólise à vácuo foi utilizada em escala laboratorial com o objetivo de reverter os resíduos em produtos químicos de interesse industrial e ainda recuperar a fibra para posterior utilização. Os experimentos mostraram que os resultados dependem da otimização das variáveis tempo e temperatura, tendo sido possível pirolisar e eliminar até 97% da matriz termofixa contida no compósito após 30 minutos de reação a 310ºC utilizando-se óleo de babaçu como líquido de pirólise. Outra possibilidade estudada foi a incorporação de resíduos de compósitos em resina epóxi. Os resultados mostram em princípio que há uma queda de até 30% na resistência à tração da matriz quando os resíduos são incorporados, embora o módulo de elasticidade tenha aumentado em 25% com a incorporação de 10% de resíduos de compósitos. Os resíduos também foram testados com relação a seu potencial calorífico, obtendo-se valores médios entre 9,9 e 18,6 KJ/kg, o que faz com que empreendimentos baseados na queima destes possam ser considerados arriscados, mas viáveis, para a geração de energia. De forma geral, o estudo consegue demonstrar a existência de soluções tecnicamente viáveis para a problemática dos resíduos da indústria de pás eólicas / Abstract: The manufacturing process of the blades that power the modern wind turbines and their disposal at the end of life may have negative impact on the environment. This work is aimed to solutions for recycling waste composite fiberglass /epoxy resin used in the manufacture of wind blades, both generated in the manufacture solid parts (later converted into powder by drilling) and the dust generated in the finishing process of the blades. Chemical recycling through the vacuum pyrolysis has been used in laboratory scale in order to reverse the wast in other industrial chemicals and recover the fiber for subsequent use. Experimental tests showed that the results depend on the optimization of the variables time and temperature, it was possible pyrolysis and eliminate up to 97% thermoset matrix contained in the composite after 30 min of reaction at 310ºC using babassu oil as pyrolysis liquid. Another possibility studied was to incorporate residues of epoxy composities. The results show that in principle there is a drop of up to 30% in tensile strength of the matrix when the waste is incorporated, although the modulus has increased by 25% with the addition of 10% waste composites. The residues were also tested in relation to their potential heat, resulting in average values between 9.9 and 18.6 KJ/Kg, which means that enterprises based in the burning of these can be considered risky, but feasible, for the generation energy. Overall, the study has demonstrated the existence of technically feasible solutions to the problem of residues in wind blade industry / Mestre

A typical approach to optimize wind turbine blades separates the airfoil shape design from the blade planform design. This approach is sequential, where the airfoils along the blade span are pre-selected or optimized and then held constant during the blade planform optimization. In contrast, integrated blade design optimizes the airfoils and the blade planform concurrently and thereby has the potential to reduce cost of energy (COE) more than sequential design. Nevertheless, sequential design is commonly performed because of the ease of precomputation, or the ability to compute the airfoil analyses prior to the blade optimization. This research investigates two integrated blade design approaches, the precomputational and free-form methods, that are compared to sequential blade design. The first approach is called the precomputational method because it maintains the ability to precompute, similar to sequential design, and allows for partially flexible airfoil shapes. This method compares three airfoil analysis methods: a panel method (XFOIL), a Reynolds-averaged Navier-Stokes computational fluid dynamics method (RANS CFD), and using wind tunnel data. For each airfoil analysis method, there are two airfoil parameterization methods: the airfoil thickness-to-chord ratio and blended airfoil family factor. The second approach is called the free-form method because it allows for fully flexible airfoil shapes, but no longer has the ease of precomputation as the airfoil analyses are performed during the blade optimization. This method compares XFOIL and RANS CFD using the class-shape-transformation (CST) method to parameterize the airfoil shapes. This study determines if the precomputational method can capture the majority of the benefit from integrated design or if there is a significant additional benefit from the free-form method. Optimizing the NREL 5-MW reference turbine shows that integrated design reduce COE significantly more than sequential design. The precomputational method improved COE more than sequential design by 1.6%, 2.8%, and 0.7% using the airfoil thickness-to-chord ratio, and by 2.2%, 3.3%, and 1.4% using the blended airfoil family factor when using XFOIL, RANS CFD, and wind tunnel data, respectively. The free-form method improved COE more than sequential design by 2.7% and 4.0% using the CST method with XFOIL and RANS CFD, respectively. The additional flexibility in airfoil shape reduced COE primarily through an increase in annual energy production. The precomputational method captures the majority of the benefit of integrated design (about 80%) for minimal additional computational cost and complexity, but the free-form method provides modest additional benefits if the extra effort is made in computational cost and development time.

No description available.

Content: The shaving process is one of the most important steps in leather production. However, the underlying principles and mechanisms are not yet fully understood. Generally, the successful performance of the shaving process is based on long-time experience, and the tanneries rather optimize the preceding process steps than change the shaving parameters. In a current research project the research partners (Heusch GmbH, TU Dresden and FILK gGmbH) have united their expertise in order to understand the interaction between the shaving blade and the semi-finished leather (wet-blue or wet-white). The objective of the project is to gain more insight into the physics of shaving and to create a background of knowledge, which will be the technical base for developing novel and more effective shaving blades. Heusch presents the advantages of a novel serrated shaving blade. In comparison with the standard design an serrated blade yields higher shaving accuracy and uniform thickness of the hides. Stretching forces along the dorsal line of the hides are reduced, which avoids structural damage. Marginal hide regions are less frayed, thus increasing the usable surface area. The small size and compact form of the shavings are advantageous for recycling and disposal. Exploiting these advantages combined with an optimized grinding process, the user can increase the lifetime of the serrated blades. Based on these experiences there is an urgent need to thoroughly understand the physical cutting processes which take place during the shaving step. In the current research project an experimental test station is designed which is intended to simulate the shaving process in a simplified setting as a cutting procedure of a blade into a leather surface. This test station will enable the variation of material, geometry and configuration of the blade as well as the measurement of forces emerging during cutting at the blade and the leather surface, which emerge during cutting. The registered data shall provide information on the question, how the cutting forces depend on technological parameters, like blade material, geometry, configuration, cutting speed, leather moisture or tanning method. Based on the knowledge of these relationships novel, even more effective shaving blades can be developed. In a second approach the cutting process of a single leather fibre will be simulated virtually on a microscale level. The goal is the understanding of the interaction of a moving metal blade with a flexible, unilaterally fixed leather fibre. The simulation is supposed to yield data on cutting speed and fibre behaviour under conditions which are experimentally difficult to access. Take-Away: The physical basics of the shaving process are not yet fully understood. The presented research project aims at the understanding of the interaction between shaving blade and leather fibres during the shaving process. The approach in the project is to model the cutting procedure in a simplified experimental test station and in a computational simulation model.

The submitted diploma thesis deals with wind machines in densely populated areas. The aim of the work is to design a appropriate wind machine for use on the roofs of buildings, including all the specifics that the air flow in the city may contain. At the beginning, the work focuses on the production of electricity in cities in general, which results in an ideal system of obtaining energy for households. Furthermore, the work deals with the wind in general, where all its specifics are taken over. A very important part of the work is the study of the specifics of air flow in the urban environment together with the numerical simulation of this flow, which results in certain regularities of the location of wind machines on the roofs of buildings. The work then passes to a search of used wind machines, from which the most suitable candidate for use in cities is subsequently selected. The last part of the work is the design of the machine itself for a specific location. In this chapter, the design wind speed is determined from the measured data, which is later followed by the calculation of the geometry of the blades, and finally its benefits and advantages are determined from the properties of the wind machine

This master‘s thesis deals with small water power plant Beneš. The first part of the thesis tries to find causes of low efficiency of this power plant. The second part contains suggestions of construction changes for increasing of efficiency – design of new runner blades and basic parameters of new distributor.

Diploma thesis deals with design and exploration of installation in the draft tube of the swirl turbine. Use of the draft tube is defined in the first part, with illustration of energetical gain and efficiency of draft tube. Further the suitable shape of draft tube is studied by CFD computing. Design, research and evaluation of installation in the draft tube are solved in the main part.

The main objective of the thesis is to verify the hydraulic inducer designs and to determine its effect on the cavitation characteristics of the pump. To increase the suction capability and cavitation resistance, the inducer is placed in front of the impeller centrifugal pump. Its role is to protect the impeller against the cavitation. The literary part of the thesis analyzes the issue of cavitation, its origin, development and termination of the cavitation bubble with so-called implosion. Special attention is devoted to describtion of cavitation effect occuring at the hydrodynamic pumps. In the theoretical part, the author is then dealing with the general principles and so far used approaches to the inducer design. The practical part of the thesis describes the process and the derivation of own designs of cylindrical inducer. The aim of the used, unconventional approaches to the inducer design is to achieve a constant pressure field and specific energy of the inducer design output. Partial variants of inducer blades design geometry are tested by the controlled calculation with CFD.

This master´s thesis will discuss the mechanical regulation of suction of ventilation turbines. There were designed and described three methods of mechanical regulation in this work. It is a regulation by half-valve, quarter-valve and so-called whirling turbine. Then the calculation of the auxiliary fan was included. The resulting mechanical regulation of this work permit, with high winds, restricting the flow of exhaust air without using electricity. Thanks to this there are saving overall cost of running ventilation turbines and reducing heat loss of industrial and commercial buildings.

The main goal of this master’s thesis is to investigate the drawn down of floating particles in mechanically stirred vessels. The first part of the thesis summarizes necessary theory to cope with defined objectives of the thesis. The literature review of mixing reactors with floating particles can be found in this part of the work as well. The second part of the master’s thesis includes the preparation of the stirred tanks CFD model, simulation and comparing of experimental data from literature, as well.