Solid Rocket Propulsion Technology

619 Pages·1992·18.201 MB·English

by  A. Davenas (Eds.)

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SOLID ROCKET
PROPULSION TECHNOLOGY
Edited by
Alain D a v e n as
ancien eleve de I'Ecole Polytechnique
Technology and Research Director, SNPE, France
PERGAMON PRESS
OXFORD · NEW YORK · SEOUL · TOKYO
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JAPAN Pergamon Press Japan, Tsunashima Building Annex,
3-20-12 Yushima, Bunkyo-ku, Tokyo 113, Japan
English translation Copyright © 1993 Pergamon Press
Ltd.
Translation of: Technologie des propergols solides.
Copyright © Sociote Nationale des Poudres et Explo-
sifs, and Masson, Paris, 1988
All Rights Reserved. No part of this publication may be
reproduced, stored in a retrieval system or transmitted
in any form or by any means: electronic, electrostatic,
magnetic tape, mechanical, photocopying, recording
or otherwise, without permission in writing from the
copyright holders
First English edition 1993
Library of Congress Cataloging-in-Publication Data
Technologie des propergols solides. English.
Solid rocket propulsion technology/edited by Alain
Davenas.
p. cm.
Translation of: Technologie des propergols solides.
Includes bibliographical references.
1. Solid propellant rockets. I. Davenas, Alain. II. Title.
TL783.3.T4313 1991 662'.26—dc20 90-25612
British Library Cataloguing in Publication Data
Solid rocket propulsion technology.
1. Aerospace vehicles. Engines
I. Davenas, Alain
629.1
ISBN 0-08-040999-7
Printed in Great Britain by The Bath Press, Avon
Foreword
THIS book is a translation, with some slight adaptations, of Technologie des
propergols solides, published in French in 1989.
There are few books on solid propellants and their use in rocket propul
sion, and few of these present a comprehensive review of the field.
There are many reasons for this. For the most part, applications of this
technology, with the exception of fireworks displays, have been limited to the
fields of advanced armament and space activities. Therefore, most of it has
been protected by industrial or military security classifications. It was thus
necessary to wait for the moment when a significant quantity of data would
be disclosed through open literature or patents.
These restrictions on the free flow of information led to different designs
and methods in different countries. In France, for instance, there has been
intensive use of trimmed axisymmetric grain designs with high loading
fractions which have not been developed in any other countries, and for
which the design and production methods were protected by a "secret"
classification for a long time. In the USSR a very specific composite
propellant formulation has been used in a family of missiles, with a binder
that uses a derivative of a terpenic resin found only in the Ural forests of the
USSR.
The technology of propellants is, like other technology, subject to the
influence of fashionable trends. In France today, for example, Finocyl grain
designs are currently popular. The main reason for this is probably that
Finocyl geometries are very adaptable to various flow rate or thrust
requirements. There are, however, cases where a simple star-shaped design
would have satisfied the main requirements, and also offered some better
secondary characteristics.
While the original objective was to present, to the extent possible, a
universal body of knowledge, factors such as restricted information flow,
specific industrial developments in various countries and fashionable trends
have sometimes made this difficult. Readers may therefore find a French
flavor to some of the chapters.
As already stated, we tried to cover all aspects of the field, and consequently
this is a long book. We had to be as concise as possible on each subject;
therefore we often refer the reader to what we feel is essential material for
additional information. One original intention was that each chapter should
be readable independent of the others, implying a great amount of redun-
xi
xii Foreword
dancy. Because of space limitations we discovered that this could not be
done. Therefore, some chapters refer to other chapters. This practice was,
however, kept to a minimum, and we used a traditional approach: each
chapter uses concepts already developed in previous chapters.
After a first chapter reviewing the fundamentals of rocket propulsion, the
second chapter develops all the descriptive aspects. The second chapter is
recommended to anyone who is interested only in reading about one of the
more specialized subjects found in later chapters. The subsequent chapters
present the specific design methods and the theoretical physics underlying
them. These are chapters where, after the fundamental mechanisms involved
in the working of propulsion systems are presented, the rules of the art and
specialized engineering methods are then deduced.
The last part of the book deals with the industrial production of the most
important motor component: the propellant, and the inert materials, such as
thermal insulations and bonding materials.
Some subjects of common interest to different chapters are covered in only
one of them. Hence, processes used to manufacture composite propellants,
used for composite double-base propellants (Chapter 11), are covered in
Chapter 10. Non-destructive testing techniques used for every type of grain
are also found in Chapter 10. Some mechanisms for the transition from
deflagration to detonation are described in Chapter 11. The decomposition of
nitrate esters and critical dimensions for cracking by internal pressure are
discussed only in Chapter 9; vulnerability issues are discussed in Chapter 8,
etc.
All authors who contributed to this work belong to the same company:
Societe Nationale des Poudres et Explosifs — SNPE. The reason for this is
quite simple. SNPE originated from a famous official French governmental
organization: the "Service des Poudres". For several centuries this organiza
tion held the monopoly in France for the production of "explosive sub
stances" (substances that can deflagrate or detonate). During the 19th
century and the first part of the 20th century it was one of the great French
chemical groups where fundamental research in the field of physical chem
istry was most advanced. SNPE has kept the mandate, for reasons of national
interest, to develop all types of products for propulsion applications and for
all basic research programs in this area, differing from most other countries,
where companies often specialized in only one family of products.
Daniel Quentin had the original idea for this project, and stimulated the
first drafts. The requirements of his professional activities took him very far
away from France, making it impossible for him to participate directly in
later drafts. Even though there is now little left from the voluminous first
drafts, these had the great merit of resulting in internal documents on each
subject that are proving to be extremely valuable for our company.
I was assisted, for the French version of this book, by a very conscientious
editorial committee that included Claude Grosmaire, Roland Lucas and
Foreword xiii
Bernard Zeller, later replaced — again because of the press of other profes
sional duties — by Rene Couturier.
The French edition of this book was published by Masson, Paris, at the
beginning of 1989 with the usual high standards of this publisher. It found
quickly a significant audience (relatively speaking!) but its diffusion would
nowadays stay essentially limited to French-speaking countries.
The publication of an English version was considered at an early stage.
Pergamon Press, with its dynamic policy, agreed to publish it despite the
limited audience of this specialized subject. We asked Mrs Anne Baron,
Daniel Quentin's assistant, to make a first draft of translation. This draft was
then reviewed by the authors with the help of their knowledge of the
vocabulary of their technical field. Then we asked some English-speaking
colleagues, knowledgeable in the field, to check our translation. We wish to
express all our gratitude to Miss Carol Jones (Chapter 13), Professor Beddini
(4) and to Tom Boggs (9), John Consaga (11), Ron Derr (3), Geoffrey Evans
(9), Ray Feist (2), Joseph Hildreth (1), Frank Roberto (8,10,14), Bert Sobers
(12), Frank Tse (6) and Andy Victor (5).
Some of the problems we encountered during the translation were due to
the fact that some concepts that are represented by one word in one language
needed a long sentence for their translation — and this to my surprise is true
both ways (for instance "autoserrage" for "burning area to port area ratio"
or "indice structural" for "ratio of inert mass to propellant mass for a given
motor", etc.). Another difficulty was that terminology has sometimes still to
be standardized even if some progress is being made in this area (for example
in low visible signature propellants, hazards classification, etc.). This is
particularly true for propellant formulations. We have developed in French a
specific terminology to name propellants according to their main compo
nents, which is compact, efficient and (of course!) Cartesian. It was used for
the French version but there is no English equivalent so we had to decide, for
the English vocabulary, somewhat arbitrarily. Some traces of the French
names may be found in some chapters. In case of possible ambiguities we
have made a special presentation, in an addendum, of the decisions we have
taken to name propellants in English, and the rules of French terminology.
Since the French edition was published, at the beginning of 1989, there has
not been much important evolution in solid propulsion technology, so the
changes made are quite limited.
Some developments on program management were suppressed in Chapter
8 because they were very specific to the French organization. A small
addition was made in Chapter 12 on integral boosters that were briefly
mentioned in the French edition, and in Chapter 7 on XDT (delayed
detonation through shock). Some developments related to clean propellants
for future space boosters and continuous-mixing processes of composite
xiv Foreword
propellant, which may become important in the near future were added to
Chapter 14. Some "fresh" references were added to some chapters.
On behalf of myself and my co-authors I would like to record our gratitude
to our colleagues at SNPE, whose names do not always appear, for their
generous cooperation in the preparation of this book. We would also like to
thank all those who have provided illustrations.
Finally I would like to thank my wife Cathy for her patience and
understanding during the summers of 1987 and 1988 (French version) and
1989 (English version) while I was assuming my editorial duty, and to thank
my supervisor, Pierre Dumas, who encouraged me with this work, even when
business was brisk, also all our French, British and American colleagues and
friends who helped us in this task.
ALAIN DAVENAS
Note on International
Nomenclature for Solid
Propellant Compositions
TERMINOLOGY for propellants has still to be standardized. Many equivalent
names for the same propellant can be found in the literature (or in this book);
besides that the French have developed a specific terminology for composite
and high-energy propellants which is described in Chapter 2, Section 3.2.1.
This is probably due to the fact that authors sometimes refer to the chemical
composition, sometimes to the production process and sometimes to some
functional characteristics such as smoke or mechanical properties (e.g.
elastomeric modified double-base).
Homogeneous propellants are also called (surprisingly) double-base pro­
pellants (based on nitrocellulose and a nitric ester). The two main types are
extruded double-base or EDB (in French SD for "sans dissolvant", meaning
without solvent) and cast double-base or CDB (in French Epictete!). When
energetic solids are introduced into this propellant it becomes a CMDB, for
composite modified double-base. This name is used only for cast propellants
even if some EDBs can contain oxidizers or energetic solids. Elastomeric
modified cast double-base or EMCDB propellants have been developed.
They are cast double-base propellants in which an elastomeric binder has
been added to the double-base. They can involve the addition of energetic
solids. In French, since it is a composite propellant, the rules for nomencla­
ture apply: these propellants are nitrargols (generic term). If they contain AP
they will become nitralites. If they contain HMX they will be nitramites, etc.
These propellants will be minimum smoke propellants if their formula
contains only or mostly C, Η, Ο, N.
In English composite propellants are generally named according to their
binder, e.g. HTPB or polyurethane propellants, etc., which of course leaves
ambiguity except for the fact that most industrial composite propellants use
A Ρ for oxidizer, and this is generally implied. The presence of a solid fuel is
less clear, since more and more "reduced smoke" propellants, i.e. without
metallic fuel, are used in practical applications. In French the names will vary
according to the main ingredients of the composition. For instance a
composite propellant based on polybutadiene, AP, Al will be a butalane.
Without Al it will be a butalite, etc.
xv
xvi Nomenclature for Solid Propellant Compositions
So-called high-energy propellants are generally composite propellants with
an energetic binder. The most typical use a nitroglycerine plasticized binder
and are called XLDB for crosslinked double-base even if there is almost no
nitrocellulose in the binder. In French they are nitrargols (nitra for the
binder). Minimum smoke XLDB based on HMX, for instance, are nitramites.
The terms "minimum smoke" and "reduced smoke" are themselves not
sufficient to differentiate propellants clearly. A working group of AGARD is
now trying to define more clearly the level of smoke, in order to be able to
compare different propellants made in different countries or organizations.
The idea is to characterize the level of primary and the level of secondary
smoke of any propellant. In order to be independent of the method and
hardware used to measure optical transmission, the classification will be
made by reference to two given defined propellants, and the level of smoke
will be considered as higher than or lower than ...
C H A P T ER 1
Propulsion Elements for Solid
Rocket Motors
ROLAND LUCAS
1. Principles of Propulsion
1.1. INTRODUCTION
Rocket launches have become a familiar spectacle. Newspapers, movies
and television frequently show us the images of the first moments of lift-off.
Impressed by the large quantity of gases released at the lift-off* of the rocket, a
knowledgeable spectator will deduce the relationship between cause and
effect. As a perceptive observer he will have in fact discovered the principle of
propulsion, which links reaction force to the ejection of a mass.
Expressed by an equation and applied to rockets, this principle is:
F = q-Ve
where F is the reaction force which we call thrust, q is the gas mass flow rate
and Ve the exhaust velocity of the gases.
Following his logical line of reasoning, the observer will then wonder
about the origin of such a volume of gas ensuring for many seconds the
propulsion of the rocket. If his creative mind leads him to think of the
burning of a solid mass, on board the rocket, he will then have imagined the
concept of solid fuel rockets.
1.2. MAIN COMPONENTS OF A ROCKET MOTOR
The rocket motor (Fig. 1) is designed to ensure the combustion under
pressure of the propellant grain it contains. The resulting gases are expanded
through the nozzle, whose function is to convert this pressure into supersonic
exhaust.
As a rule, such a rocket motor has five major components.
1