Effect of the Plume of a Hybrid Propellant Rocket

Paper number

IAC-05-C4.P.08

Author

Mr. Claudio Lettieri, Second University of Naples, Italy

Year

2005

Abstract

The hybrid propulsion (chemical propulsion in which generally solid fuel grain burn with liquid Oxidiser)  has become in those days an interesting field of research. In this frame, unfortunately it is not already well understood, and it is still the state of art for the propulsion research (where other kinds of propulsion, like the electrical, cannot achieve the Thrust value necessary to lift off a launch vehicle) .

The main advantages of a hybrid rocket propulsion system are safety during fabrication, storage ,or operation (avoiding explosion) , stop-start-restart capabilities and higher potential reliability .For those reasons the hybrid could be a good (and cheaper) alternative to all the others propulsion systems.

In the other side, another interesting area is the study of the thermodynamic field of the exhaust plumes . Examples like the Space Shuttle and some particular Rocket configurations, show how this study is important to preserve the structural integrity of the components around the nozzle(like the tank or the boosters for the shuttle, or the rocket body itself for some propulsion systems which have the nozzle on the sides). In fact the thermal load could cause serious damages to all the system.

Matching those two research fields the work that is proposed is a complete study of an hybrid engine , with an overview on the basic fundamentals (grain regression , burn stability) ending with the exhaust gases and the interaction between  the plume and external surfaces.

A study on this phenomena was performed by the University of Neaples . A bench has been made in order to study an hybrid engine, in the military airfield of Grazianese, which was preventively designed for study basic hybrid propulsion .The work will be testing (with numerical and practical simulation)the best material configuration around the plumes for a particular hybrid booster. Part of this study will be done in ESA/ESTEC (Noordwijk, the Netherlands) where will be realised a bibliographic research, studied  a particular case of hybrid booster, and then developed a Fluent simulation  .Then a series of  tests will follow in order to validate the theoretical analysis.

In particular the work will concern also the design of the thruster  (once needed), and the understanding of the thermodynamic field  of the plume, for several Mach numbers and pressure values . Each step will be performed fixing fuel and oxidiser, grain configuration, feed system and nozzle, then studying the field around the plume and, if necessary, changing again fuel oxidiser , grain configuration, feed system  and nozzle.

In the conclusion the results will be used during the design of  particular rocket configuration(wireguided hybrid rockets).

Abstract document

IAC-05-C4.P.08.pdf

Manuscript document

IAC-05-C4.P.08.pdf (🔒 authorized access only).

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