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PhD Thesis in Aeronautics and Mechanics Engineering, Physics and Chemistry in Aerospace Materials at the Technological Institute of Aeronautics, ITA, São José dos Campos, São Paulo State, Brazil, 2009.

Advisor: Prof. Dr. Mirabel Cerqueira Rezende

Keywords: Permittivity, Permeability, Microwave, Radar absorbing material.

Abstract: The main objective of this study is to contribute toward a comprehensive understanding the interaction of magnetic additives with the electromagnetic wave, in the microwave range (2-18 GHz) of radar absorbing materials (RAM).Thus, this work shows the electromagnetic behavior of different RAMs based on MnZn ferrite, carbonyl iron and their mixtures in a silicon rubber matrix. Emphasis is given to the complex permittivity and permeability parameters determination in the frequency range of 2 to 18 GHz and reflection loss measurements between 8-12 GHz. For the complex parameters determination a methodology based on coaxial transmission airline technique was established. The results show that the carbonyl iron interacts with the electric field of the incident wave through the storage component, since the electric field loss component is insignificant. The MnZn ferrite used shows variation of both storage and loss components with the increase of the additive concentration in the RAM and the frequency parameters. Considering the permeability, it is verified that the RAM sample based on carbonyl iron presents the highest values (1.0 to 2.2), in other words, this additive interacts more intensely with the wave magnetic field than with the ferrite (0.7 to 1.8). The measurements of the Reflection losses of RAM processed with the pure additives as well as with their mixtures present good results (70 - 99%). It is also observed that these samples behave as the resonant RAM type. The results also confirm that the microwave attenuation is dependent on the magnetic additive proportion, sample thickness and frequency. In the comparative studies of reflection losses, the experimental measurements and simulations show good agreement, suggesting that the simulation is an adequate support tool for optimizing these materials, diminishing costs and time of RAM processing.

Investigation of the distribution of the film cooling for the liquid rocket engine

  • LRE with 75 kN thrust

Luís Antonio Silva Institute of Aeronautics and Space silva@iae.cta.br


V. 1, n. 2, Jul. - Dec. 2009

Thesis Abstracts

Master’s Thesis in Engineering, defended at the Technological Institute of Aeronautics, ITA, São José dos Campos, São Paulo State, Brazil, 2009

Advisor: Prof. Dr. Amilcar Porto Pimenta

Keywords:. Investigation, Film cooling, Rocket engine, Liquid propulsion.

Abstract: This work presents a methodology for analyzing a liquid rocket engine cooling system and more specifically an investigation of the film cooling method applied to a 75 kN thrust, kerosene and liquid oxygen rocket engine. In the case study, the engine cooling film is created by the fuel injected by peripheral injectors. Two possibilities were analyzed: in the first it was assumed that 50 per cent of the fuel injected by the peripheral injectors became part of the cooling film; in the second, the cooling film is constituted by only the fuel that flows on the walls. The injection system of an engine under development in IAE (L15) was used in cold tests to validate theoretical and empirical design data obtained by experts from Moscow Aviation Institute (MAI) and to refine some design parameters used in engines under development in IAE.

Adjusting the vertical profile of wind data obtained from anemometric tower and radiossounding in the “Alcântara Launch Center”

Ricardo Costa Leão Institute of Aeronautics and Space leão@iae.cta.br

Master’s Thesis in Engineering, defended at the Technological Institute of Aeronautics, ITA, São José dos Campos, São Paulo State, Brazil, 2009

Advisors: Prof. Dr. Íria Fernandes Vendrame and Prof. Dr. Gilberto Fernando Fisch

Keywords: Matching, Vertical wind profiles, Cubic splines.

Abstract: This work aims to adjust (“match”) two different vertical wind profiles, one from an anemometric tower with 6 levels (6.0, 10.0, 16.3, 28.5, 43.0 and 70.0 m) obtained by measurements direct from the anemometer, and the other from radiosoundings with wind determination measured by GPS technique up to 500m, in vertical layers of 50m. The result was a single profile obtained using the cubic spline interpolation method, detection of average deviation

Journal of Aerospace Technology and Management

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