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

Abstract

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.