Dual bell nozzle permits two different operating modes, which provide higher performance than conventional bell nozzles, when applied to rocket engines operating from sealevel. During the highly overexpanded mode the separation line is located near the geometrical discontinuity of the nozzle wall, in a region characterized by a negative value of the wall pressure gradient as in conventional nozzle and where side loads may occur. The characteristics of this region in hot full-scale applications are addressed by means of numerical simulations, and scaling laws are sought for cold sub-scale side loads experiments. In addition, because of the possible effect of wall cooling on the wall pressure gradient and thus on side loads, the relevant role of film cooling is discussed in detail.
Effect of Wall Shape and Real Gas Properties on Dual Bell Nozzle Flowfields / E., Martelli; Nasuti, Francesco; Onofri, Marcello. - (2005), pp. 1-14. (Intervento presentato al convegno 41st AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit tenutosi a Tucson, Arizona, USA nel 10-13 luglio 2005).
Effect of Wall Shape and Real Gas Properties on Dual Bell Nozzle Flowfields
NASUTI, Francesco;ONOFRI, Marcello
2005
Abstract
Dual bell nozzle permits two different operating modes, which provide higher performance than conventional bell nozzles, when applied to rocket engines operating from sealevel. During the highly overexpanded mode the separation line is located near the geometrical discontinuity of the nozzle wall, in a region characterized by a negative value of the wall pressure gradient as in conventional nozzle and where side loads may occur. The characteristics of this region in hot full-scale applications are addressed by means of numerical simulations, and scaling laws are sought for cold sub-scale side loads experiments. In addition, because of the possible effect of wall cooling on the wall pressure gradient and thus on side loads, the relevant role of film cooling is discussed in detail.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.