Experimental study of strut insertion through divergent wall of a convergent divergent nozzle for thrust vector control

Abstract

In the present study, the experimental and the computational newlineinvestigations were carried out to evaluate the wall pressure distribution in a newlineconvergent-divergent nozzle with a strut inserted through the diverging wall. newlineThe insertion of a strut through the nozzle wall represented an active method newlinefor thrust vector control. Among the various aerospace vehicle steering newlinemethods, the secondary injection thrust vector control (SITVC) system is newlinewidely used in the space launch vehicles. Generally, in this type of thrust vector newlinecontrol, a fluid is injected as a secondary jet into a diverging portion of the newlinerocket nozzle through the nozzle wall. The consequential disturbed flow pattern newlineinduces a side force component that is used for thrust vector control. The earlier newlinestudies in the area of thrust vector control recommended for a replacement of a newlinesecondary jet with a solid strut to achieve the same effect for thrust vector newlinecontrol. Nevertheless, only a few studies attempted to explore its suitability and newlinepracticality as an alternative method. newlineThe design Mach number of the nozzle model used in the present newlinework was 1.84 with a corresponding area ratio of 1.48. A solid strut that was newlineinserted through the diverging wall of the nozzle had a square cross-section and newlinethe experiments were conducted at three different strut positions from the newlinenozzle throat, i.e. at Ld/3, Ld/2, and 2Ld/3, where, Ld was the length of the newlinediverging section of the nozzle. At each strut position, the strut height was newlinevaried and the maximum strut height corresponded to the radius of the local newlinecross-section where the strut was inserted. The investigation revealed that the newlinestrut with a square cross-section at 2Ld/3 from the throat produced larger newlinecoefficients of the axial force, the side force, and the pitching moment when newlinecompared to the other two positions. newline