Potential performance upgrade by the use of an extendible nozzle on ARIANE 5

Paper number

IAC-05-C4.2.04

Author

Mr. Alain Mercier, Snecma Propulsion Solide, France

Coauthor

Mr. Renaud Barreteau, Snecma Propulsion Solide, France

Coauthor

Mr. Alain Lacombe, Snecma Propulsion Solide, France

Coauthor

Mr. Thierry Pichon, Snecma Propulsion Solide, France

Year

2005

Abstract

The design of current nozzles of lower stages of launchers suffers the cruel dilemma of a compromise between the amplitude of side loads during the start-up transient and the maximum ISP during the vacuum phase of the flight. The highest the nozzle area ratio is, the highest the vacuum thrust is, as well as the highest are the ignition loads up to prohibitive loads for the nozzle itself or for the payload.

Several solutions are or have been investigated to push further this compromise up to an higher performance. For instance, dual bell nozzles are currently under study, and self adapting nozzles, like aerospike, have been investigated. Extendible nozzles can also be an interesting solution for this optimization, by allowing an increase of the nozzle area ratio as soon as possible during the flight. In addition, several extendible nozzles are currently in operation on missiles, although their existence is more induced by drastic constraints on the room available in the inter-stages. They prove that the use of this concept to improve performance is easy to reach.
	
This paper describes the concept study of an extendible nozzle mounted on the cryogenic lower stage of a launcher. The selected launcher is ARIANE5 and its engine is the VULCAIN 2. The concept proposed here takes the opportunity from the resistance of the Snecma Propulsion Solide thermal-structural composite material to high temperature, in order to use a simple non-cooled extendible part actuated by a simple deployment system.

This paper presents the nozzle predesign and its integration and deployment strategy, as well as the associated development logic. A lot of aerodynamic computations have been performed to assess the potential criticity of the deployment phase and the results of theses static analyses are shown here. A subscale test campaign have also been built in order to validate the concept and assess the potential risk of aerodynamic instabilities during the deployment.

Abstract document

IAC-05-C4.2.04.pdf

Manuscript document

IAC-05-C4.2.04.pdf (🔒 authorized access only).

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