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Chapter Title Survey of Solid Rocket Propulsion in Russia Copyright Year 2016 Copyright Holder Springer International Publishing Switzerland Author Family Name Lipanov Particle Given Name Alexey M. Suffix Division M.V. Keldysh Institute of Applied Mathematics Organization Russian Academy of Sciences Address Moscow 125047, Russia Email [email protected] Corresponding Author Family Name Zarko Particle Given Name Vladimir E. Suffix Division V.V. Voevodsky Institute of Chemical Kinetics and Combustion Organization Russian Academy of Sciences Address Novosibirsk 630090, Russia Organization National Research Tomsk State University Address Tomsk 634050, Russia Email [email protected] Abstract A short survey of development of solid propellants and solid rockets in Russia till the beginning of the twenty-first century is presented. The design solutions are considered which were used in development of ballistic missiles (field, tactical, mid-range, and intercontinental), as well as of other rockets like surface-to-air, air-to-air, sea, and antitank. The problems and accomplishments are considered concerning the justification of expediency and possibility of application of solid- propellant rockets. These works resulted in the creation of the theory of intra-chamber processes, including experimental and theoretical studies of processes of solid-propellant combustion and ablation of thermal protection coverings (insulating liners) of internal surfaces of solid motors and nozzles. Upon development of solid-propellant rockets, different automated systems have been employed: for design of elements of rocket as a whole, for processing experimental information, and for planning scientific and technological experiments. Development of novel design rockets was carried out in different Research and Development and Technological organizations of Russia. Practically all plants for production of solid propellants and manufacturing the motor cases and nozzles were established in the second half of the twentieth century. The exceptions are the plants which dealt with the volley fire rocket systems (Katyusha). Not everything could be discussed in this survey because design details of propellant charges and motors, as well as data on solid- propellant formulations, are not available in open literature. Keywords Russian propulsion history - Ballistic missiles - Solid propellant - (separated by “-”) Rocket motors - Internal ballistics - QSHOD flame models - ZN theory Survey of Solid Rocket Propulsion in Russia 1
Alexey M. Lipanov and Vladimir E. Zarko 2
Abstract A short survey of development of solid propellants and solid rockets 3 in Russia till the beginning of the twenty-first century is presented. The design 4 solutions are considered which were used in development of ballistic missiles (field, 5 tactical, mid-range, and intercontinental), as well as of other rockets like surface-to- 6 air, air-to-air, sea, and antitank. The problems and accomplishments are considered 7 concerning the justification of expediency and possibility of application of solid- 8 propellant rockets. These works resulted in the creation of the theory of intra- 9 chamber processes, including experimental and theoretical studies of processes of 10 solid-propellant combustion and ablation of thermal protection coverings (insulating 11 liners) of internal surfaces of solid motors and nozzles. Upon development of solid- 12 propellant rockets, different automated systems have been employed: for design of 13 elements of rocket as a whole, for processing experimental information, and for 14 planning scientific and technological experiments. Development of novel design 15 rockets was carried out in different Research and Development and Technological 16 organizations of Russia. Practically all plants for production of solid propellants and 17 manufacturing the motor cases and nozzles were established in the second half of 18 the twentieth century. The exceptions are the plants which dealt with the volley fire 19 rocket systems (Katyusha). Not everything could be discussed in this survey because 20 design details of propellant charges and motors, as well as data on solid-propellant 21 formulations, are not available in open literature. 22
A.M.UNCORRECTED Lipanov PROOF M.V. Keldysh Institute of Applied Mathematics, Russian Academy of Sciences, Moscow 125047, Russia V.E. Zarko () V.V. Voevodsky Institute of Chemical Kinetics and Combustion, Russian Academy of Sciences, Novosibirsk 630090, Russia National Research Tomsk State University, Tomsk 634050, Russia e-mail: [email protected]
© Springer International Publishing Switzerland 2016 L.T. DeLuca et al. (eds.), Chemical Rocket Propulsion, Springer Aerospace Technology, DOI 10.1007/978-3-319-27748-6_43 A.M. Lipanov and V.E. Zarko
Nomenclature 23
ADN Ammonium dinitramide 24 AP Ammonium perchlorate 25 AS Academy of Sciences 26 ASD Automatic systems of design 27 ASPEI Automatic systems of processing experimental information 28 ASSDD Automatic systems of service of design development 29 ASSSR Automatic systems of service of scientific research 30 CPSU Communist Party of the Soviet Union 31 CVEI Copolymer of vinyl ether of ethylene glycol mononitrate and isoprene 32 ICBM Intercontinental ballistic missile 33 ICP Institute of Chemical Physics 34 k ZN stability parameter 35 MAI Ministry of Aviation Industry 36 MDI Ministry of the Defense Industry 37 MGME Ministry of General Mechanical Engineering 38 MITT Moscow Institute of Thermal Technology 39 MMEI Ministry of Mechanical Engineering Industry 40 QSHOD Quasi-steady gas-phase homogeneous one-dimensional 41 r ZN stability parameter 42 SP Solid propellant 43 SRM Solid rocket motor 44 USSR Union of Soviet Socialist Republics 45 ’ Coefficient in Beer-Lambert-Bouguer law 46
1 Introduction 47
The authors present information on different samples of military equipment from 48 strategic rockets to antitank missiles, being at present on arms of the Russian Army. 49 For this reason the data on design details of propellant charges and rocket motors 50 are usually not available, as well as the data on formulation of solid propellants. 51 When speaking about solid-propellant rocket development in the beginning of the 52 twenty-first century, it must be kept in mind that all this was created and designed 53 at theUNCORRECTED turn of the twentieth century. In any case it is necessary PROOF to speak about the 54 link of times and a continuity of developing both the technological processes and 55 design solutions. In this regard it is necessary to make short historical excursus 56 in order to tell about expediency of creation of solid-propellant rockets of various 57 categories along with development liquid rocket motors, about work on ensuring 58 the minimum dispersion of interior ballistic parameters, and about development of 59 the theory of combustion and intra-chamber processes and development of various 60 automated systems to design and control the production of solid motors. 61 Survey of Solid Rocket Propulsion in Russia
To start with design and manufacture of solid-propellant rockets, the USSR 62 Government in the beginning of the 1960s was urged to establish the new industry 63 headed by the USSR Ministry of Mechanical Engineering Industry (MMEI), which 64 financed and controlled works on developing the formulations and charges of solid 65 propellants to various motors of all types of solid-propellant rockets. 66 The outstanding organizer of munition production, graduated from the Mechani- 67 cal Department of Lomonosov Moscow State University, V.V. Bakhirev, headed this 68 Ministry throughout nearly three decades [1]. Of course, MMEI performed only a 69 certain part of the work. Acted as the leading organizations for developing solid- 70 propellant rockets were the Ministry of the Defense Industry (MDI), the Ministry 71 of General Mechanical Engineering (MGME), as well as the Ministry of Aviation 72 Industry (MAI). 73 As a rule, the principal customer of solid motors was MDI, which also controlled 74 the systems of volley fire, production of the antitank shells, and all ballistic missiles 75 from tactical to intercontinental as well as all types of sea systems. MAI controlled 76 the antiaircraft missiles and also the rockets of “air-to-air” and “air-to-ground” 77 classes. 78 MGME generally directed works on development of liquid rockets. Solid- 79 propellant units were used there for the auxiliary purposes mainly. However, in 80 several cases, the MGME developed also solid-propellant rockets. As an example it 81 can be called the first USSR intercontinental ballistic missile (ICBM) RT-2 (Fig. 1) 82 launched from the underground silo (Chief designer Korolev S.P.). This three- 83 stage rocket (SS-13 mod.1 Savage by NATO classification) had a flight distance 84 of 9500 km and was exploited in the period of 1968Ð1994. It can be also mentioned 85
Fig. 1 The very first Russian ICBM RT-2 http://cannons.ru/ atombomb/nositeli/ussr/RT-2. htm
UNCORRECTED PROOF A.M. Lipanov and V.E. Zarko
Fig. 2 Submarine rocket RSM-52 “Typhoon” http://rbase.new-factoria.ru/sites/default/files/ missile/r39/r39.jpg
the sea ICBM “Typhoon” (Fig. 2) launched from submarines (Chief designer V.P. 86 Makeev). But these ones were only rare examples among the set of the liquid rockets 87 created by the MGME organizations. 88 In the second half of the twentieth century, work on new solid-propellant rockets 89 was strongly motivated by the fierce competition for supremacy in defense and space 90 applications between the world superpowers. 91
2 History of Solid Rocket Motor Design in Russia 92
After World War II, the USSR started creating liquid-guided missiles for which it 93 was clear how to create the guiding units. The relevant design solutions for solid- 94 propellant rockets were not known. 95 Besides,UNCORRECTED when speaking about launching on the long distances, PROOF charges of big 96 dimensions (calibers) are required as well as motors with the mass perfection 97 coefficient values (ratio of dry rocket mass to total propellant mass) equal to that 98 of liquid rocket engines. But at that time, the USSR had only systems of volley fire 99 (multiple rocket launchers) with charges of all-sides burning and with the coefficient 100
AQ1 of mass perfection exceeding unity. Consequently, the opinion existed that solid 101 rocket propulsion could exploited to realize only unguided short-range missiles. 102 Survey of Solid Rocket Propulsion in Russia
However, in 1960, under the guidance of Prof. R.E. Sorkin, at the Scientific 103 Research Institute 125,1 engineers A. Gorodetskaya and A. Lipanov executed 104 systematic calculations of the mass distribution on two-, three-, and four-stage 105 solid-propellant rockets. They took into account the values of the mass perfection 106 coefficient and propellant-specific impulse of a missile stage that would ensure 107 delivery of a given payload over a certain distance with the minimum launch weight. 108 Calculations showed that motors having a value of the mass perfection coefficient 109 close to 0.1 would allow developing intercontinental three-stage solid-propellant 110 rockets using USSR-produced ammonium perchlorate (AP)-based formulations. 111 These missiles would be capable to fly up to 10,000 distance km with a payload 112 of 1000 kg and a launch weight of 50Ð60 tons. 113 Sorkin informed about those findings the Director of the Institute B.P. Zhukov 114 who reported later to the Secretary of the CPSU Central Committee, D.F. Ustinov, 115 responsible for defensive issues. The latter understood the importance of this finding 116 and informed the staff of the USSR State Committee on defensive engineering. 117 As a result, in the same year, 1960, the rocket Chief designer S.P. Korolev 118 declared that it is possible to manufacture a three-stage intercontinental rocket which 119 he called RT-2, while another Chief designer A.D. Nadiradze declared that it is 120 possible to manufacture operational and tactical two-stage solid-propellant rockets 121 (1000 km flight distance) with mobile start. A.D. Nadiradze called it “Temp-S.” 122 As the Chief designers showed interest in developing solid rocket motors 123 (SRMs), it became necessary to build the production bases for manufacturing solid 124 rocket propellants and charges from them along with the production of the motor 125 cases, electronics elements, and devices for control systems of flight of rockets. 126 The first large-size motors had four nozzles. It allowed solving a problem of 127 executive units to guide the rocket flight on all three channels (tankage, snaking, and 128 maneuvering) in a simpler way. The four-nozzle design of solid motor, of course, 129 caused some overweighting but allowed to manufacture the rockets. 130 This was the start point to establish research and development organizations 131 and engineering capacities to manufacture solid propellants and charges, produce 132 motor cases, and build specialized facilities for testing rocket motors on ground 133 under simulated vacuum conditions. In parallel, groups of scientists, designers, and 134 technologists engaged in design of rocket flight control systems and element base 135 for the corresponding devices were formed. These works were controlled by the 136 Ministries of Electronic and Radio Industries of the USSR as well as the Ministry 137 of Communication Industry. 138 AtUNCORRECTED that time there was a need to solve the problems of PROOF stability of properties 139 of the used materials and minimization of dispersion of parameters both at 140 the received materials and in the manufactured motors. Sorkin in 1961 derived 141 expressions for variations of pressure, mass flow rate, and thrust of solid motor 142 induced by occasional deviations of construction, technology, and exploitation 143 parameters against their nominal values. The problem was solved for quasi-steady- 144
1The modern name is the Federal Center of Double Technologies “Soyuz (Union).” A.M. Lipanov and V.E. Zarko state motor performance and for volume-averaged parameters. Considering the 145 random deviations as independent values with zero mathematical expectation, he 146 obtained the formula for the maximum pressure deviations in the motor (with 147 a given probability). It became clear that for the mid-range SRMs, the pressure 148 exponent in the burning rate law of solid propellants has to be of low magnitude 149 (around 0.2Ð0.3), and scatter in the values of solid-propellant burning rates has to 150 come closer to the level of deviation for values of other parameters such as density 151 of solid-propellant or design parameters of the propellant charge [2]. 152 Serious work had to be conducted in order to elaborate the methods for uniform 153 distribution of heterogeneous components in a propellant slurry and then in a 154 propellant charge with the proper choice of components and their sizes. That was 155 necessary to provide suitable conditions to both pilot productions of the research 156 organizations and industrial serial conditions. Paying a great tribute to efforts of 157 scientists-chemists and engineers-technologists including those at serial plants, it 158 can be stated that this problem was successfully solved. 159
3 Studies on Solid-Propellant Combustion and Internal 160 Ballistics in Russia 161
To correctly design and test SRMs, it was necessary to investigate the internal 162 processes occurring in the motor. Therefore in the mid-1960s, A. Lipanov, at 163 that time a PhD student of Prof. R.E. Sorkin, investigated the 1D problem of 164 initial period of solid motor operations. The transient heating of the propellant 165 charge, the ignition of main charge by the combustion products of igniter, and 166 the gas flow pattern from the charge bore into the pre-nozzle space were studied. 167 The calculation results fitted well with the experimental data. At that time, one- 168 dimensional gas dynamic models of the combustion products motion in the channel 169 of the solid-propellant charge were elaborated for the initial stage of SRM operation 170 [3]. This allowed determining correctly the loads acting on the motor construction, 171 optimizing the case design, and choosing the mass of the igniter charge. To describe 172 the quasi-stationary period of SRM operation, an averaging hypothesis was made 173 along with the one-dimensional model of gas flow [4Ð6]. 174 Important fundamental works were performed to explore the combustion mech- 175 anism of solid propellants. For example, V.N. Vilyunov studied the mechanism of 176 erosiveUNCORRECTED (turbulent) burning of double-base solid propellants, PROOFincluding conditions of 177 its arising [7, 8]. Based on these results, the designers of charges and motors avoided 178 operating conditions which would make possible the rise of turbulent burning. Even 179 in the later works, the SRM designers preferred to choose the parameters of charge 180 and gas flow which mainly provided a nonturbulent gas flow in the combustion 181 chamber. 182 A similar theory of turbulent combustion was not created for composite solid 183 propellants. Therefore, in all concrete cases, the existence of turbulent combustion 184 Survey of Solid Rocket Propulsion in Russia was determined experimentally. Fortunately, the use of case-bonded charges of solid 185 propellant excluded the rise of turbulent burning owing to charge designs with 186 relatively large internal bore diameter. 187 Much attention was paid to research of nonstationary processes of solid- 188 propellant combustion, including ignition and extinction under abrupt changes of 189 external conditions. Here the ideas of Academicians N.N. Semenov and Ya.B. 190 Zel’dovich were fruitfully developed. Note that the well-known pioneering work by 191 Zel’dovich [9], published in 1942, appeared as a reply to urgent practical needs of 192 solid rocket motor development. The first Russian field missile M8 (further used in 193 a volley fire called “Katyusha” in 1940s) employed double-base propellants which 194 experienced pronounced unstable combustion. The Zel’dovich work promoted 195 further studies of solid-propellant combustion and for a long time served as a basis 196 for numerous combustion investigations in Russia. 197 It happened that Zel’dovich’s ideas became available in the West much later. 198 Nevertheless, they made an important impact on the development of the combustion 199 theory throughout the world. In 1942, the model of transient combustion of 200 homogeneous solid propellants proposed by Zel’dovich was based on the following 201 assumptions [9]: 202
1. The characteristic thermal relaxation time in the gas phase is much less than that 203 in the condensed phase (i.e., the gas-phase processes are quasi-steady). 204 2. The temperature at the burning surface is constant at a given pressure (Ts0 D 205 const). 206 3. There are no chemical reactions in the condensed phase and the burning rate is 207 totally determined by the reactions in the gas phase. 208
Later on, that model was improved by Novozhilov [10] assuming that the burning 209 surface temperature at a given pressure is a function of the surface temperature 210 gradient. This allowed performing more detailed and objective analysis of the 211 burning rate response to variations of environmental conditions. The improved 212 transient combustion model received abroad the title of ZN approach [11]. 213 There is a significant difference between the approaches developed in the 1960s 214 in Russia (then USSR) and the USA to understand SRM internal ballistics. The USA 215 approach put emphasis on acoustic combustion instabilities, whereas the Russian 216 approach seems to have been broader, applying the fundamental ZN transient 217 combustion approach to a wide variety of applications such as extinguishment, 218 ignition, spontaneous oscillatory combustion, etc. (remark made by Beckstead in 219 [12UNCORRECTED]). In the USA, different theories based on different flame PROOF models were applied 220 to each specific application. The basis for the US approach to evaluate combustion 221 instability was established by Denison and Baum [13]. An important generalization 222 of the theoretical knowledge available at that time in the Western literature was made 223 in 1968 by Culick [14], who reviewed and summarized the various combustion 224 models in terms of pressure-driven frequency response function. He concluded 225 that all QSHOD transient flame models (that assume a quasi-steady gas-phase, 226 homogeneous condensed-phase, and one-dimensional burning) lead to a common 227 A.M. Lipanov and V.E. Zarko numerical form of such a function. A critical review of QSHOD transient flame 228 models was presented in [15]. 229 Few years later, in 1971, Summerfield et al. [16] published the first work in the 230 USA based on the ZN approach. This started a debate about which approach is 231 better. Several papers were published by J. Osborn team and other investigators 232 comparing the results of the ZN approach and flame model methods in general [17]. 233 A straight comparison is not an easy task, because the results are very sensitive to the 234 influence of the initial temperature parameters. Direct comparisons between several 235 transient flame models and the ZN approach, in terms of predicted instantaneous 236 burning rate, show different trends not only between ZN and flame models approach 237 but also among the different transient QSHOD flame models tested. For example, 238 the ZN approach with respect to flame models predicts less sharp but protracted 239 excursions from quasi-steady behavior for the pressurization comparative tests 240 conducted in [18, 19]. 241 However, it was also established that, within the assumption of a quasi-steady 242 gas-phase flame (tc approximation in the Novozhilov’s terminology), the Denison 243 and Baum and the ZN approaches are exactly equivalent in terms of intrinsic 244 stability boundary. The first recognition of that was published by Novozhilov 245 in his 1973 monograph [20] and later discussed in detail in [21]. According to 246 D . /.@ =@ / D 247 Novozhilov, in terms of two parameters, k Ts0 Ta lnu Ta p and r .@ =@ / ; 248 Ts0 Ta p the conditions of unstable combustion are formulated as k >1 and 2 r <.k 1/ =.k C 1/.HereT is the temperature and u is the burning rate. Subscripts 249 s stand for surface, a for ambient, 0 for stationary conditions, and p for pressure. 250 Exactly the same expressions can be derived within the framework of the Denison 251 and Baum approach. The advantage of using the ZN approach is the potential 252 possibility of determining the parameters k and r under steady-state combustion 253 tests; however, initial temperature sensitivity data are not easy to collect and suffer 254 low accuracy. Later, Novozhilov developed also an extended stability analysis which 255 accounts for finite thermal inertia time in the gas phase in addition to the condensed- 256 phase lag time [20]. 257 Also for the problem of pressure-coupled response function of solid propellants, 258 the ZN approach can be shown to be numerically identical to the flame model 259 approach [12]. However, one must always remember that the ZN approach is 260 intended exclusively to treat homogeneous solid propellants and B.V. Novozhilov 261 never applied it for treating heterogeneous propellants combustion. An attempt to do 262 that was made by King [22], who concluded that further work is needed to include 263 theUNCORRECTED effects of surface heat release parameters and its dependency PROOF on combustion 264 environmental conditions. 265 The stability of combustion process under finite amplitude disturbances of 266 the combustion environment, such as time-dependent pressure, blowing gas flow, 267 radiant flux, etc., is important for several practical application problems which have 268 to be understood by the theory. The question arises, what are the critical values 269 of external parameters which could induce a catastrophic decrease in the burning 270 rate? The first estimate of the critical values was made by Zel’dovich [9, 11]. 271 Survey of Solid Rocket Propulsion in Russia
His analysis was based on the assumption of extremely high surface temperature 272 gradients (erroneously attributed to the very low initial temperatures), which could 273 cause the extinction of the propellant. 274 The Zel’dovich concept of extinction can be called “static,” as it predicts a 275 cessation of combustion immediately after reaching critical value of surface tem- 276 perature gradient. A static concept is very attractive due to its great simplicity and 277 was indeed used in several works [15, 16]. When combined with the Novozhilov’s 278 stability analysis, the concept meant that the combustion ceases at the boundary 279 of oscillatory combustion. However, this concept was later doubted by Frost and 280 Yumashev [23]. They discovered, through computer-aided simulation of propellant 281 combustion under fast depressurization, that no special hypotheses are needed 282 about critical conditions in order to characterize the extinction phenomenon. The 283 extinction occurs due to progressive cooling of the condensed-phase surface layer 284 and this manifests itself in the appearance of an inflection point on the temperature 285 profile in the bulk of the propellant. They also discovered that, in the course 286 of transient combustion, the parameters of the burning system may temporarily 287 correspond to an unstable combustion domain, but this is not a sufficient condition 288 for extinction. 289 These findings motivated the development of a “dynamic” extinction concept 290 based on examining the dynamic behavior of burning rate. According to this 291 concept, the extinction is determined not only by the instantaneous parameters 292 of the system at a given instant of time but also by the previous history of 293 heating and dynamic properties of the system (temperature sensitivity of the 294 burning rate). Further, a significant contribution in the development of the dynamic 295 concept was made by DeLuca [24]. Critical review and applicability limits of the 296 phenomenological models of transient combustion of solid propellants have been 297 presented in 2010 by Zarko and Gusachenko [25]. It is necessary to keep in mind 298 that the tc approximation fails for high oscillation frequencies in the gas phase or 299 for high pressures as well as for very low magnitude of the r parameter. Under 300 these extreme operating conditions, higher level analytical approaches or numerical 301 simulations with the support of detailed combustion models are required. 302 Another problem, which is also of great importance for practice, is ignition and 303 stability of transition to self-sustained combustion. The generalization of the results 304 of theoretical and experimental studies on condensed system ignition conducted 305 in Russia in 1960Ð1980s was made by Vilyunov and Zarko in a monograph [26]. 306 The available models of condensed- and gas-phase ignition were discussed in detail 307 andUNCORRECTED ignition criteria were formulated. It was experimentally PROOF established that, upon 308 action of a short impulse of powerful igniting radiant flux, the transition to self- 309 sustained burning does not occur. Recently, the problem was thoroughly examined 310 theoretically and it was shown that the transition process stability dramatically 311 depends on the steepness of the trailing edge of the energy pulse [27]. 312 Illustrative examples of the calculated response to the action of thermal radiation 313 pulses, for homogeneous energetic materials, are shown in Fig. 3. In the case 314 of a rectangular form of the radiation pulse, one can analyze the ignition-to- 315 combustion transition diagram qualitatively identical to that registered in pioneering 316 A.M. Lipanov and V.E. Zarko
th, s 0.3
q q0 0.2 1 t th 2 0.1 3
0 500 1000 1500 2000 2500 3000 q0, kW/m2
Fig. 3 Regions of the stability of ignition upon rectangular radiant flux action for propellants with ˛ D 100 000 (1), 11 500 (2), and 1500 m1 (3); dashed curves correspond to approximate calculation data experiments conducted in the 1980s both in USSR and the USA [28, 29]. The 317 diagram of Fig. 3 shows that, for heat flux qo acting during time th,thestable 318 transition to self-sustaining combustion proceeds only in the case when overheating 319 after reaching the ignition instant (low boundary of ignition domain) does not 320 exceed a critical value. The magnitude of admissible overheating time is very short 321 for low transparent propellant (˛ D 100,000 m 1) and is much larger for transparent 322 propellant (˛ D 1500 m 1). Here ’ is the coefficient in Beer-Lambert-Bouguer law 323 of radiation attenuation. 324 In the case of exponentially decreasing function q.t/ D q0 exp . t=te/,amuch 325 larger transition stability can be realized because the exponential decay of the energy 326 pulse, at the instant of the radiant flux cut off, only provides a small disturbance 327 of the heat balance to the burning system. In this case, a specific response of 328 the burning system is expected. Namely, when acting by small amplitude radiant 329 flux, the stable transition to combustion can be realized even for nontransparent 330 propellantUNCORRECTED (Fig. 4b). If the magnitude of radiant flux becomes PROOF higher than a certain 331 level, the unstable ignition at small characteristic time te can be changed to stable 332 one if te is increased. The physical reason for such behavior is rather simple. In the 333 case of short te, the burning system is disturbed to a larger extent that for longer te. 334 Thus, the recommended practice should be the following: design the ignition unit 335 in such a way that, at the end of the ignition stimuli operation, the disturbance of 336 temperature profile near the burning surface is reasonably small. 337 Some pioneering results were obtained by O. Leipunskii of the Semenov Institute 338 of Chemical Physics (Moscow) in the 1940s, when studying the solid-propellant 339 Survey of Solid Rocket Propulsion in Russia
bc te, s te, s
0.15
3 a 1 2 0.10 q0
q(t)=q0exp(-t/te)
0.05 t t e
0500 1000 1500 500 1000 1500 2000 2500 3000 3500 2 2 q0, kW/m q0, kW/m
Fig. 4 Regions of stable ignition upon action of exponentially decreasing (a) radiant flux for ˛ D 100,000 (b)and˛ D 11,500 m-1 (area 2 in c); dashed curves correspond to approximate calculation data combustion in conditions of intensive gas blowing over the burning surface [30]. 340 Much later, his discovery of the burning rate enhancement, after reaching a 341 threshold value of blowing gas velocity, was named erosive burning in the scientific 342 literature (Leipunskii called it “swelling effect”). The theoretical background of this 343 phenomenon was given by V.N. Vilyunov, who gave an analytical solution of the 344 problem and explained the burning rate enhancement by increased heat feedback 345 from the turbulent gas flow to the burning surface when the gas velocity exceeds a 346 certain limit value. 347 One may also mention the pioneering, and important for practice, results obtained 348 in studies about metal particles’ combustion performed under the leadership of A.F. 349 Belyaev and P.F. Pokhil. They successfully investigated combustion of aluminum 350 nanoparticles, incorporated in model solid propellants [31], well in advance of the 351 foreign investigators. 352
4 Automatic Processing Systems in Russia 353 UNCORRECTED PROOF Owing to severe requirements of high accuracy in processing experimental infor- 354 mation, and also because of the large volume of the processed information, in the 355 late 1960s of the last century, the development of Automatic Processing Systems 356 of Experimental Information (ASPEI) started. Such systems allowed partially 357 squeezing information if the corresponding experimental curve was in admissible 358 limits in relation to the average one. ASPEI allowed issuing all necessary graphic 359 information and provided release of the report. ASPEI surely allocated a point 360 and its vicinities where the deviation extended over admissible limits. It also 361 A.M. Lipanov and V.E. Zarko
indicated nonstandard fluctuations of the curves of pressure, thrust, or flow rate. In 362 certain cases, usually for research studies, other parameters (such as pressure drops, 363 acoustic fluctuations, temperature of gaseous substances, especially in stagnant 364 zones) were analyzed. 365 The necessity of an integrated approach to the SRM design process, including 366 that of solid-propellant charge, led to the creation of SRM Automatic Systems of 367 Design (ASD). These works had begun in the 1960sÐ1970s and the first options of 368 SRM ASD were put in operation in 1972. When using such approach, the specific 369 maximum distance for particular rocket was calculated with the use of parameter 370 values chosen close to the boundary or within the range of parameter variation. 371 The variation of the component magnitude allowed one to find an extremum of 372 the vector modulus. For example, if it was the flight range, reaching of its maximum 373 was the goal. If it was the production cost of the motor, its minimum was defined. 374
AQ2 There were optimally designed the SRMs, their constructive elements, processing 375 equipment, and other objects. 376 Along with the above systems, there were needs of creating the Automatic 377 Systems of Service of Scientific Research (ASSSR) and Automatic Systems of 378 Service of Design Development (ASSDD). Works in this direction began in the 379 1960s, but actually automatic systems were created in the 1980s [32, 33]and 380 allowed accelerating considerably the design process and elaboration of possible 381 searching options. 382 Of course, everything was carried out on the basis of computers and mathematical 383 models available at that time. In present times, these problems are solved in 384 more correct statements and on the basis of contemporary models of physical and 385 chemical processes, using the possibilities of modern computers with increased 386 computer speed by many orders of magnitude (up to 9) and huge random access 387 memory, with advanced and powerful mathematical software packages. 388
5 Guidelines for Solid Rocket Motor Development in Russia 389
The solid motors development became a sort of outcome of successful activity for 390 Russian chemists, technologists, and engineers and was based on accomplishments 391 of the scientists working in the field of processes of combustion and explosion.2 392 Some data regarding the history of development of solid rockets in Russia and 393 accomplishmentsUNCORRECTED achieved in the 1990s were summarized in PROOF the paper by Lipanov 394 [34]. Information on achievements of the Russian synthetic chemists engaged in 395 the search of perspective energetic materials was published in the work reported by 396 Prof. Z. Pak at the AIAA Joint Conference in 1993 [35]. It was announced there 397 that while searching the ways of decreasing the ecological damages from launch of 398
2See also chapter “The Russian Missile Saga: Personal Notes from a Direct Participant” by Manelis in this volume. Survey of Solid Rocket Propulsion in Russia
solid-propellant rockets, the Russian (Soviet) scientists developed solid propellants 399 containing new ingredients, for example, ammonium dinitramide (ADN) as oxidizer 400 and aluminum hydride as fuel. Thus, the theoretical specific impulse managed to 401 be raised up to the value of about 2850 Ns/kg (at the pressure ratio of 70/1). The 402 report [35] also contained new information on the main physical and chemical prop- 403 erties and kinetics of thermal decomposition of the prospective oxidizer. Unusual 404 dependency of the solid-propellant (SP) burning rate on the oxidizer dispersity was 405 for the first time noted. Contrary to what is known for AP-based formulations, 406 this dependency for SP based on ADN turned out to be rising for increasing size 407 of the oxidizer particles.3 It was also stressed that, for manufacturing the modern 408 composite SP, it is vital to use roundish particles of heterogeneous components. In 409 particular, when modifying the shape of ADN crystals, the possibility was realized 410 of increasing the SP loading with filler from 60 to 90 %. On the basis of the analysis 411 of dinitramide anion properties, the conclusion was drawn on advantages of using 412 nitrile oxide-based systems as the curing agents, since this provides the possibility 413 of carrying out curing with a relatively high rate at the room temperature. It can also 414 be mentioned that in this report, the specific proposals were made on optimization 415 of the processes of SP disposal from the motors removed from arms (Pershing-2 and 416 SS-20), in order to reduce the ecological damage. 417 More detailed discussions of the approaches to the SP design and manufacture 418 developed in Russia were presented by Sakovich [36]. In this review, the important 419 statement concerning the SP mass and energy characteristics was repeatedly 420 formulated and proved. On the basis of the analysis of Tsiolkovsky’s equation for 421 the vehicle maximum velocity increment, while keeping constant the motor volume, 422 the following expression is often used [37]: 423