An experimental research programme on heterogeneous combustion processes under microgravity conditions. Preliminary results

In the present work preliminary results are given of an experimental programme on flame spreading over the surface of PMMA rods in NgO2 mixtures under microgravity conditions. Results were obtained in the NASA KC-135 aircraft laboratory. Six experiments were carried out in March of this year and 36 more experiments will be conducted in March 1987. These preliminary experiments allowed to determine the flame spreading velocities for three different mixture compositions, showing that they were smaller but of the same order of magnitude than downwards spreading velocities at one g and for the same mixture condition

An Experimental Programme on Flame Spreading at Reduced Gravity Conditions.

An experimental programme on flame spreading over the surface of polymethylmetacrylate (PMMA) samples has been conducted at reduced gravity conditions in the NASA KC-135 air craft laboratory. A total of 36 experiments were performed. From the results of these experiments the flame spreading velocities over PMMA samples have been obtained, as well as their laws of variation with pressure and mixture composition. Both cylindrical and flat samples have been investigated. These results were compared with those obtained for the same conditions of pressure and composition on the ground at 1 g. In this way it was shown how gravity does influence the spreading process and how this influence was affected by pressure and mixture composition

Optimization of actuation and cooling systems for advanced convergent-divergent nozzles of combat aircraft

The system or components of a convergent-divergent (CONDI) nozzle that offer better perspectives for improvement and optimization are the actuation and cooling systems. Performance offers little margin for a direct improvement, and the utilization of advanced materials in many components of the nozzle presents no specific problems as compared with those of other parts of the engine, with the exception of the petals, in which the introduction of ceramic materials has a direct influence on cooling and performance, and it will be included in the cooling optimization. The introduction of a thrust vectoring capability is a major improvement, though not the subjet of this paper. The problem of the optimization of the actuation system was preliminary discussed in ref. 1, mainly in connection with the utilization of one versus two parameters actuation system. Since that time, SENER and FTP have carried out many studies and tests on actuation systems and on cooling optimization. They have also accumulated experience by means of theoretical and experimental studies on the utilization of ceramic petals. Some results and the main conclusions of these studies and tests are presented in the present work

Programas de investigación sobre propagación de llamas en condiciones de gravedad reducida

Se presenta en este trabajo un resumen del programa experimental sobre propagación de llamas a gravedad reducida que se está llevando a cabo por la Escuela Técnica Superior de Ingenieros Aeronáuticos; programa en el que últimamente colabora la empresa SENER. La propagación de llamas sobre la superficie de un sólido en atmósfera reactante es un tipo de proceso fuertemente afectado por la convección libre, y por tanto, especialmente sensible al valor de la gravedad

Heterogeneous combustion processes under microgravity conditions

An experimental programme on flame spreading over the surface of PMMA (plexiglass) samples has been conducted under microgravity conditions in the NASA KC-135 aircraft laboratory. A few experiments (three) were conducted in 1986 under the preceding contract no. 6284/85/F/FL, but the largest part of the experimental programme has been carried out under the present contract in two parabolic flights campaigns. A total of 36 experiments were performed, most of them successful. From the results of these experiments the flame-spreading velocities over PMMA samples have been obtained, as well as their laws of variation with pressure and mixture composition. Both cylindrical (axial symmetry) and flat (bidimensional symmetry) samples have been investigated