Dual-bell nozzles permit two different operating modes, which provide higher performance than conventional bell nozzles when applied to rocket engines operating from sea level. During the low-altitude mode, the flow is separated and the separation line is located near the inflection of the nozzle wall, in a region characterized by a negative value of the wall pressure gradient, as in conventional nozzles, and in which 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 subscale side-load experiments. Moreover, the flow behavior during the transition between the two operating modes is analyzed by time-accurate simulations.
Numerical parametric analysis of dual-bell nozzle flows / Emanuele, Martelli; Nasuti, Francesco; Onofri, Marcello. - In: AIAA JOURNAL. - ISSN 0001-1452. - STAMPA. - 45:3(2007), pp. 640-650. [10.2514/1.26690]
Numerical parametric analysis of dual-bell nozzle flows
NASUTI, Francesco;ONOFRI, Marcello
2007
Abstract
Dual-bell nozzles permit two different operating modes, which provide higher performance than conventional bell nozzles when applied to rocket engines operating from sea level. During the low-altitude mode, the flow is separated and the separation line is located near the inflection of the nozzle wall, in a region characterized by a negative value of the wall pressure gradient, as in conventional nozzles, and in which 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 subscale side-load experiments. Moreover, the flow behavior during the transition between the two operating modes is analyzed by time-accurate simulations.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
