A espectroscopia de emissão foi utilizada na determinação da temperatura de chamas pré-misturadas de GLP. Investigou-se a emissão natural de radicais CH * em três diferentes condições de queima: razão estequiométrica de combustível/oxidante, excesso de combustível (chama rica) e excesso de oxidante (chama pobre). O valor médio obtido para a temperatura rotacional de CH * foi de 2845 70 K nas condições utilizadas nos experimentos. Esse valor não variou significativamente com os demais tipos de chama e é compatível com os cálculos de temperatura adiabática dos sistemas estudados. Essa temperatura também é concordante com resultados obtidos por via indireta, utilizando-se o método de linha reversa de sódio, que consiste em uma técnica bem estabelecida e independente da emissão natural. Temperaturas vibracionais de ca. 4600 K foram calculadas, indicando que o tempo de vida do CH * não é suficiente para que o equilíbrio entre os modos rotacionais e vibracionais seja estabelecido.Emission spectroscopy was used in the temperature determination of LPG (liquefied petroleum gas) premixed flames. Natural emission of CH * radicals was investigated in flames under three different burning conditions: fuel/oxydizer stoichiometric ratio, fuel excess (rich flame), and oxidizer excess (lean flame). An average value of 2845 70 K was obtained for CH * rotational temperature in the set up used in the experiments. This value did not show significant change with the type of flame analyzed and it is compatible with the calculated adiabatic flame temperatures of the investigated systems. This temperature value also agrees with that determined by an indirect measurement, using the sodium line reversal method, which is independent from the radical natural emission and well established in literature. Vibrational temperatures of ca. 4600 K were calculated, indicating that the CH * lifetime is insufficient for the establishment of an equilibrium state between the rotational and vibrational modes.

A laser-induced fluorescence (LIF)-based nitric-oxide flow-tagging technique was applied to measure both velocity and NO lifetime in a hypersonic shock tunnel from two experimental test runs. The results were supported by an analytical profile proposed in this paper that provides a way to correct velocity measurements under unknown systematic error sources. This procedure provided velocities with discrepancies lower than 3% for a total of five measurements, and lower than 2% when compared with that obtained from a linear fit. Additionally, the comparison between the proposed and experimental profiles allowed us to obtain the fluorescence NO lifetime from only one image.

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The Brazilian 14-X Hypersonic Aerospace Vehicle, a new generation of scientific aerospace vehicle, designed at Prof. Henry T. Nagamatsu Laboratory of Aerothermodynamics and Hypersonics, at Institute for Advanced Studies (IEAv), is part of the continuing effort of the Department of Aerospace Science and Technology (DCTA), to develop a technological demonstrator using: i) waverider technology to provide lift to the aerospace vehicle, and ii) scramjet technology to provide hypersonic airbreathing propulsion system based on supersonic combustion. In consequence of the nature of the supersonic combustion engines, they are unable to produce thrust while stationary, the static thrust is zero. Accordingly, they must be accelerated to a speed such that the shock waves produced by the air intake are able to compress the atmospheric air. This velocity, called initial operation speed, is approximately four times the speed of sound, Mach 4, considering scramjet. Two-stage, unguided, rail launched, solid rocket engines will be used to accelerate the 14-X Hypersonic Aerospace Vehicle to the pre-established conditions to operate the scramjet engine, i.e., position (altitude, latitude and longitude), speed (Mach number), dynamic pressure and angle of attack. The 14-X Hypersonic Aerospace Vehicle project consists of four atmospheric flights. The first flight is planned for 14-X captive (accelerator and 14-X vehicles coupled during the entire flight) unpowered scramjet Mach number 6; the second for 14-X free (accelerator and 14-X vehicles separated after burn of 2 nd stage of accelerator vehicle) unpowered scramjet Mach number 6 flight; and the two last are planned for free hydrogen-powered scramjet Mach number 6 and Mach number 10, respectively. Pure waverider aerodynamic, scramjet power off and power on as well as 14-X stage separation will be experimentally investigated using the three Hypersonic Shock Tunnels at Prof. Henry T. Nagamatsu Laboratory of Aerothermodynamics and Hypersonics. Pressure and temperature measurements at pure waverider external upper and lower surfaces and scramjet power off and power on internal surfaces will be obtain to provide wind-tunnel data to design the full 2-m. long atmospheric flight of 14-X Hypersonic waverider scramjet Aerospace Vehicle. Non-intrusive measurements using optical diagnostic techniques have been implemented at Hypersonic Shock Tunnels, as well as in-house computational fluid dynamics have been developed for waverider, scramjet and 14-X Hypersonic Aerospace Vehicle.