Availableonlineatwww.sciencedirect.com SCIENGE DIRECT PROGRESS IN ENERGYAND COMBUSTION SCIENC ELSEVIER rogress in Energy and Combustion Science 30(2004)545-672 www.elsevier.com/locate/pecs Pulse detonation propulsion: challenges, current status and future perspective G.D. Roy. S.M. Frolov, A.A. Borisov, D W. Netzer Ofice of Naval Research, Ballston Centre Tower 1, Arlington, VA 22217, US N.N. Semenov Institute of Chemical Physics, Moscow, Russia Naval Postgraduate School, Monterey, CA, USA Received I April 2003: accepted 11 May 2004 Available online 27 September 2004 Abstract The paper is focused on recent accomplishments in basic and applied research on pulse detonation engines(PDE)and various PDE design concepts. Current understanding of gas and spray detonations, thermodynamic grounds for detonation-based propulsion, principles of practical implementation of the detonation-based thermodynamic cycle, and various operational constraints of PDEs are discussed c 2004 Published by Elsevier Ltd Keywords: Gaseous and heterogeneous detonation; Pulse detonation engine; Design concepts; Propulsion: Thrust performance Contents 2. Fundam 2.1. Historical review ...549 2.2. Gaseous detonations 552 2. 1. General propertie 2. 2. Detonability limits 559 2. 23. Direct initiation 2.2.5. Nonideal detonations 2.2.6. Transient deflagration and ddt 2.3. Heterogeneous detonations 2.3.1. General properties 2.3. 2. Detonability limits 2.3.3. Direct initiation 594 2.3. 4. Detonation transition 3.5. Nonideal detonations 2.3.6. Transient deflagration and dDt Abbreviations: Al, air inlet; BR, blockage ratio: CJ, Cha cross-section; DC, detonation chamber; dDt, deflagration to detonation transition; FAM, fuel-air mixture(-); HE, hi drogen peroxide; IPN, isopropyl nitrate: IR, infra red; NM Orescence: RFBR. Russian Foundation for Basic researc ean diameter: SwACER, shock wave amplification through coherent release: TEP, thermochemical equilibriu turbojet engine: TNT, trinitrotoluene: ZND, Zel'dovich- Neumann-Doering: 1D, one-dimensional: 2D, two-dimens 0360-1285/S- see front matter o 2004 Published by Elsevier Ltd. doi:10.1016 -pecs.2004.05001
Pulse detonation propulsion: challenges, current status, and future perspective G.D. Roya,*, S.M. Frolovb , A.A. Borisovb , D.W. Netzerc a Office of Naval Research, Ballston Centre Tower 1, Arlington, VA 22217, USA b N.N. Semenov Institute of Chemical Physics, Moscow, Russia c Naval Postgraduate School, Monterey, CA, USA Received 1 April 2003; accepted 11 May 2004 Available online 27 September 2004 Abstract The paper is focused on recent accomplishments in basic and applied research on pulse detonation engines (PDE) and various PDE design concepts. Current understanding of gas and sprary detonations, thermodynamic grounds for detonation-based propulsion, principles of practical implementation of the detonation-based thermodynamic cycle, and various operational constraints of PDEs are discussed. q 2004 Published by Elsevier Ltd. Keywords: Gaseous and heterogeneous detonation; Pulse detonation engine; Design concepts; Propulsion; Thrust performance Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 546 2. Fundamentals. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 549 2.1. Historical review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 549 2.2. Gaseous detonations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 552 2.2.1. General properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 552 2.2.2. Detonability limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 559 2.2.3. Direct initiation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 567 2.2.4. Detonation transition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 573 2.2.5. Nonideal detonations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 580 2.2.6. Transient deflagration and DDT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 584 2.3. Heterogeneous detonations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 588 2.3.1. General properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 588 2.3.2. Detonability limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 591 2.3.3. Direct initiation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 594 2.3.4. Detonation transition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 598 2.3.5. Nonideal detonations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 599 2.3.6. Transient deflagration and DDT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 600 0360-1285/$ - see front matter q 2004 Published by Elsevier Ltd. doi:10.1016/j.pecs.2004.05.001 Progress in Energy and Combustion Science 30 (2004) 545–672 www.elsevier.com/locate/pecs * Corresponding author. Tel.: þ1-703-696-4406. Abbreviations: AI, air inlet; BR, blockage ratio; CJ, Chapman-Jouguet; CS, cross-section; DC, detonation chamber; DDT, deflagration to detonation transition; FAM, fuel—air mixture (2); HE, high explosive; HP, hydrogen peroxide; IPN, isopropyl nitrate; IR, infra red; NM, nitromethane; ON, octane number; PDE, pulse detonation engine; PDRE, pulse detonation rocket engine; PLIF, particle laser induced fluorescence; RFBR, Russian Foundation for Basic Research; SMD, sauter mean diameter; SWACER, shock wave amplification through coherent energy release; TEP, thermochemical equilibrium program; TJE, turbojet engine; TNT, trinitrotoluene; ZND, Zel’dovich— Neumann—Doering; 1D, one-dimensional; 2D, two-dimensional; 3D, three-dimensional
546 G.D. Roy et al. Progress in Energy and Combustion Science 30(2004)545-672 2.4. Thermodynamic grounds for detonation cycle 2.5. Implementation of the detonation cycle 2.6. Detonation impulse 2.7. Operational constraints of pulse detonation e 3. 1. Preliminary remarks 3.2. Valved concepts 3.3. Valveless concepts 3. 4. Predetonator concept 3.5. Enchanced DDT concept 3.6. Stratified-charge concept 3.7. Dual-fuel concept 3.8. Shock-booster concept 3.9. Shock-implosion concept 3.10. Pulse-reinitiation concept 3. 11. Pulse-blasting concept 3. 12. Multitube schemes 3. 13. Resonator concept 3. 14. Inlets 3. 15. nozzles 16. Active control 3. 17. Rocket pulse detonation propulsic 4. Concluding remarks References the chamber resulting in a nearly constant-volume heat addition process that produces a high pressure in the The current focus in utilizing detonation for air -breathin combustor and provides the thrust. The operation of multitube propulsion has moved from the long-term studies of the PDE configurations at high detonation-initiation frequency possibility of fuel energy transformation in stabilized oblique(about 100 Hz and over)can produce a near-constant thrust. In detonation waves to investigations and practical development general, the near-constant-volume operational cycle of PDE of propulsion engines operating on propagating detonations in provides a higher thermodynamic efficiency as compared to a pulse mode. Contrary to the oblique-detonation concept that the conventional constant-pressure(Brayton) cycle used in gas is applicable to hypersonic flight at velocities comparable or turbines and ramjets. The advantages of PDE for air-breathing higher than the Chapman-Jouguet(C]) detonation velocity of propulsion are simplicity and easy scaling, reduced fuel the fuel-air mixture(FAM), the concept of pulse detonation consumption, and intrinsic capability of operation from zero engine(PDE) is attractive for both subsonic and supersonic approach stream velocity to high supersonic flight speeds flight with PDE as a main propulsion unit or as an afterburner The global interest in the development of PDE for in turbojet or turbofan propulsion system. In particular, PDE- propulsion has led to numerous studies on detonations, based propulsion is attractive for flight Mach number up to particularly pertaining to its control and confinement. This is about 3-4(see Section 2.4). Within this range of Mach evident from the formation of collaborative teams by number, solid rocket motors are known to be very efficient in iversities and industry worldwide. Dedicated technical terms of simplicity and high-speed capability, but they have a meetings and special minisymposia and sessions on PDE limited powered range. Turbojet and turbofan engines, due to in combustion-related conferences are becoming very popular their high specific impulse, provide longer range and heavie Several reviews have been already presented at various payloads, but at flight Mach number exceeding 2-3 they are meetings [1-10] and published in archival journals [11-13l getting too expensive. Ramjets and ducted rockets designed During the period from 1998 to 2002, the US Office of for flight Mach number up to 4 require solid rocket boosters to Naval Research(ONR)and the Russian Foundation for Basic accelerate them to the ramjet take over speed, which increases Research(rFBR) have jointly sponsored three International the complexity and volume of a propulsion system. Com olloquia on detonations, in particular, those aspects of bined-cycle engines, such as turborockets or turboramjet, are detonations that are directly relevant to the development of also very complex and expensive for similar applications. PDEs. In 1998, the International Colloquium on Advances in In a pde, detonation is initiated in a tube that serves as Experimentation and Computation of Detonations was held the combustor. The detonation wave rapidly traverses in St Petersburg with the participation of more than 60
2.4. Thermodynamic grounds for detonation cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 603 2.5. Implementation of the detonation cycle. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 609 2.6. Detonation impulse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 614 2.7. Operational constraints of pulse detonation engine. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 622 3. Design concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 625 3.1. Preliminary remarks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 625 3.2. Valved concepts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 625 3.3. Valveless concepts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 633 3.4. Predetonator concept . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 637 3.5. Enchanced DDT concept . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 639 3.6. Stratified-charge concept . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 643 3.7. Dual-fuel concept. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 644 3.8. Shock-booster concept . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 646 3.9. Shock-implosion concept . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 650 3.10. Pulse-reinitiation concept . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 651 3.11. Pulse-blasting concept . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 653 3.12. Multitube schemes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 655 3.13. Resonator concept . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 657 3.14. Inlets. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 658 3.15. Nozzles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 659 3.16. Active control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 661 3.17. Rocket pulse detonation propulsion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 661 4. Concluding remarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 663 References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 665 1. Introduction The current focus in utilizing detonation for air-breathing propulsion has moved from the long-term studies of the possibility of fuel energy transformation in stabilized oblique detonation waves to investigations and practical development of propulsion engines operating on propagating detonations in a pulse mode. Contrary to the oblique-detonation concept that is applicable to hypersonic flight at velocities comparable or higher than the Chapman-Jouguet (CJ) detonation velocity of the fuel–air mixture (FAM), the concept of pulse detonation engine (PDE) is attractive for both subsonic and supersonic flight with PDE as a main propulsion unit or as an afterburner in turbojet or turbofan propulsion system. In particular, PDEbased propulsion is attractive for flight Mach number up to about 3–4 (see Section 2.4). Within this range of Mach number, solid rocket motors are known to be very efficient in terms of simplicity and high-speed capability, but they have a limited powered range. Turbojet and turbofan engines, due to their high specific impulse, provide longer range and heavier payloads, but at flight Mach number exceeding 2–3 they are getting too expensive. Ramjets and ducted rockets designed for flight Mach number up to 4 require solid rocket boosters to accelerate them to the ramjet take over speed, which increases the complexity and volume of a propulsion system. Combined-cycle engines, such as turborockets or turboramjets, are also very complex and expensive for similar applications. In a PDE, detonation is initiated in a tube that serves as the combustor. The detonation wave rapidly traverses the chamber resulting in a nearly constant-volume heat addition process that produces a high pressure in the combustor and provides the thrust. The operation of multitube PDE configurations at high detonation-initiation frequency (about 100 Hz and over) can produce a near-constant thrust. In general, the near-constant-volume operational cycle of PDE provides a higher thermodynamic efficiency as compared to the conventional constant-pressure (Brayton) cycle used in gas turbines and ramjets. The advantages of PDE for air-breathing propulsion are simplicity and easy scaling, reduced fuel consumption, and intrinsic capability of operation from zero approach stream velocity to high supersonic flight speeds. The global interest in the development of PDE for propulsion has led to numerous studies on detonations, particularly pertaining to its control and confinement. This is evident from the formation of collaborative teams by universities and industry worldwide. Dedicated technical meetings and special minisymposia and sessions on PDE in combustion-related conferences are becoming very popular. Several reviews have been already presented at various meetings [1–10] and published in archival journals [11–13]. During the period from 1998 to 2002, the US Office of Naval Research (ONR) and the Russian Foundation for Basic Research (RFBR) have jointly sponsored three International colloquia on detonations, in particular, those aspects of detonations that are directly relevant to the development of PDEs. In 1998, the International Colloquium on Advances in Experimentation and Computation of Detonations was held in St Petersburg with the participation of more than 60 546 G.D. Roy et al. / Progress in Energy and Combustion Science 30 (2004) 545–672
G D. Roy et al. Progress in Energy and Combustion Science 30(2004)545-672 universal gas constant aaaA transverse detonation cell size Reynolds number ransverse size of primary detonation cell S entropy ansverse size of secondary detonation cell specific volume mplitude or coefficient tIme T Al, A2, A3 constants emperature b longitudinal detonation cell size U b, longitudinal size of secondary detonation cell voltage velocity speed of sound We Weber number specific heat at constant pressure specific heat at constant volume velocity fluctuation diamete coordinate shock wave, detonation, or flame front velocity P igh nonideal detonation velocity oordinate internal energy Es energy flux oxidizer-to-fuel ratio nergy or activation energy In explosive cross-section area B reaction progress variable specific heat ratio h formation enthalpy interval H flight altitude or total enthalpy function or width/height H mensionless fluctuation of enthalpy dimensionless velocity deficit acceleration of gravity parameter in detonation cell model coefficient momentum flux dimensionless energy loss cycle-averaged specific impulse temperature ratio function mpule at fully filled conditions ecific impulse at fully filled conditions rotation angle umber or dimensionless heat release coefficient of pressure loss in shock wave constants dimensionless distance k kinetic energy dissipation molecular weight dimensionless fluctuation of internal energy geometrical factor stoichiometric coefficient distance s number or nitrogen dilution coefficient nass or temperature exponent hE charge mas cycle-averaged specific thrust n density flow eo liquid density density ratio or normalized deficit of detonation mass flu M velocity Mach number time or dimensionless time reaction order shear stress t dimensionless duration of positive overpressure pressure equivalence ratio P function or cone/wedge angle mass flow rate X thermodynamic efficiency radius cone half-angle dynamic radius molar fraction 2 adius or gas constant transmissibility parameter R
Nomenclature a transverse detonation cell size a1 transverse size of primary detonation cell a2 transverse size of secondary detonation cell A amplitude or coefficient A1; A2; A3 constants b longitudinal detonation cell size b2 longitudinal size of secondary detonation cell B coefficient c speed of sound cp specific heat at constant pressure cv specific heat at constant volume C capacitance d diameter D shock wave, detonation, or flame front velocity D0 nonideal detonation velocity e internal energy Es energy flux E energy or activation energy f frequency F cross-section area h enthalpy h8 formation enthalpy H flight altitude or total enthalpy H0 dimensionless fluctuation of enthalpy g acceleration of gravity Is momentum flux I impulse ~Isp cycle-averaged specific impulse I 0 impulse at fully filled conditions ~I 0 sp specific impulse at fully filled conditions J number or dimensionless heat release k; K constants k0 kinetic energy dissipation K0 dimensionless fluctuation of internal energy L length l distance m mass or temperature exponent mc HE charge mass m_ mass flow ~m_ cycle-averaged mass flow Ms mass flux M Mach number n reaction order N power p pressure P thrust P~ cycle-averaged thrust q heat release Q mass flow rate r radius r dynamic radius R radius or gas constant R8 universal gas constant Re Reynolds number S entropy v specific volume t time T temperature u velocity U voltage w velocity W work We Weber number u0 velocity fluctuation X distance x coordinate Y height y coordinate Greek Symbols a oxidizer-to-fuel ratio an parameter in strong explosion theory b reaction progress variable g specific heat ratio D interval d function or width/height dD dimensionless velocity deficit 1 parameter in detonation cell model z coefficient h dimensionless energy loss q temperature ratio u function urot rotation angle k0 coefficient of pressure loss in shock wave l dimensionless distance m molecular weight n geometrical factor ni stoichiometric coefficient j number or nitrogen dilution coefficient p compression ratio P~ cycle-averaged specific thrust r density r0 l liquid density s density ratio or normalized deficit of detonation velocity t time or dimensionless time tw shear stress t þ dimensionless duration of positive overpressure F equivalence ratio w function or cone/wedge angle f dimensionless kinetic energy dissipation x thermodynamic efficiency y cone half-angle c molar fraction V transmissibility parameter G.D. Roy et al. / Progress in Energy and Combustion Science 30 (2004) 545–672 547
548 G.D. Roy et al. Progress in Energy and Combustion Science 30(2004)545-672 Inaxlmu b back N nitrogen without additive nozzle cell disappearance oxygen cl closed oD overdriven detonation combustion products plateau critical purging D detonation pressure recovery detonation chamber DDT deflagration-to-detonation transition reaction di diffuser inlet reinitiation diffuser exit shock wave stoichiometric nergy release traversing unit area measured wall flame or fuel along z-axis symmetry (1, 2, or 3) A fr fresh reactants turbed ignitin planar induction :98 standard temperature limit 3 spherical experts. In 2000, the International Colloquium on Control of the components in the detonation chamber (DC); (2)low- Detonation Processes was organized in Moscow with more energy source for detonation initiation to provide fast and than 100 participants. The International Colloquium on reliable detonation onset; (3)cooling technique for rapid, Advances in Confined Detonations was held in Moscow in preferably recuperative, heat removal from the walls of 2002 with more than 120 participants. As a result of these to ensure stable operation and avoid premature ignition of meetings, a number of books have been published containing FAM leading to detonation failure; (4) geometry of the extended abstracts of all presentations [14-16] and full combustion chamber to promote detonation initiation and f selected propagation at lowest possible pressure loss and to ensure colloquia [17-19]. The goal of this review paper is to high operation frequency; and (5)control methodology that provide, based primarily on the materials presented at the allows for adaptive, active control of the operation process eetings mentioned above, a text or reference for those who to ensure optimal performance at variable flight conditions, are interested in recent accomplishments in basic and applie while maintaining margin of stability. In addition to the research on PDE and numerous Pde design concepts fundamental issues dealing with the processes in the dC. ented in review meetings and discussed in the literature. there are other issues such as(6)efficient integration of pde In order to use propagating detonations for propulsion with inlets and nozzles to provide high performance; and and realize the pde advantages mentioned above. a number of challenging fundamental and engineering problems has configuration. Among the most challenging engineering yet to be solved. These problems deal basically with low- issues, is the problem of durability of the propulsion system. cost achievement and control of successive detonations in a As the structural components of PdE are subject to repeated propulsion device. To ensure rapid development of a high-frequency shock loading and thermal deformations, a detonation wave within a short cycle time, one needs to considerable wear and tear can be expected within a apply (1)efficient liquid fuel injection and air supply relatively short period of operation. The other problems ystems to provide fast and nearly homogeneous mixing of are noise and vibration
experts. In 2000, the International Colloquium on Control of Detonation Processes was organized in Moscow with more than 100 participants. The International Colloquium on Advances in Confined Detonations was held in Moscow in 2002 with more than 120 participants. As a result of these meetings, a number of books have been published containing extended abstracts of all presentations [14–16] and full edited manuscripts of selected papers presented at the colloquia [17–19]. The goal of this review paper is to provide, based primarily on the materials presented at the meetings mentioned above, a text or reference for those who are interested in recent accomplishments in basic and applied research on PDE and numerous PDE design concepts presented in review meetings and discussed in the literature. In order to use propagating detonations for propulsion and realize the PDE advantages mentioned above, a number of challenging fundamental and engineering problems has yet to be solved. These problems deal basically with lowcost achievement and control of successive detonations in a propulsion device. To ensure rapid development of a detonation wave within a short cycle time, one needs to apply (1) efficient liquid fuel injection and air supply systems to provide fast and nearly homogeneous mixing of the components in the detonation chamber (DC); (2) lowenergy source for detonation initiation to provide fast and reliable detonation onset; (3) cooling technique for rapid, preferably recuperative, heat removal from the walls of DC to ensure stable operation and avoid premature ignition of FAM leading to detonation failure; (4) geometry of the combustion chamber to promote detonation initiation and propagation at lowest possible pressure loss and to ensure high operation frequency; and (5) control methodology that allows for adaptive, active control of the operation process to ensure optimal performance at variable flight conditions, while maintaining margin of stability. In addition to the fundamental issues dealing with the processes in the DC, there are other issues such as (6) efficient integration of PDE with inlets and nozzles to provide high performance; and (7) efficient coupling of DCs in a multitube PDE configuration. Among the most challenging engineering issues, is the problem of durability of the propulsion system. As the structural components of PDE are subject to repeated high-frequency shock loading and thermal deformations, a considerable wear and tear can be expected within a relatively short period of operation. The other problems are noise and vibration. Indices A additive av average b back CJ Chapman-Jouguet c cycle cd cell disappearance cl closed cp combustion products cr critical D detonation DC detonation chamber DDT deflagration-to-detonation transition di diffuser inlet de diffuser exit d droplet e expansion eff effective er energy release ex exhaust exp measured f flame or fuel fd feed fl filling fr fresh reactants hs hot spot i ignition in initiation ind induction l limit m mechanical max maximum min minimum N2 nitrogen na without additive nz nozzle O2 oxygen OD overdriven detonation p plateau pg purging pr pressure recovery R ram r reaction ri reinitiation rz reaction zone s shock wave sp specific st stoichiometric tr traversing ua unit area w wall z along z-axis n symmetry (1, 2, or 3) S total 1 undisturbed 0 initial conditions 1 planar 2 cylindrical 298 standard temperature 3 spherical 548 G.D. Roy et al. / Progress in Energy and Combustion Science 30 (2004) 545–672
G D. Roy et al. / Progress in Energy and Combustion Science 30(2004)545-672 The paper is organized in such a way that the reader first th-explosive charge. Later on it was observed in long tubes gets acquainted with a brief history of detonation research even when gas was ignited by nonexplosive means(spark or Section 2. 1)and with the ci understanding of gas and open flame). In this case, flame acceleration along the tube, spray detonation properties and dynamics(Sections 2.2 and often accompanied with flame speed oscillations, was 2.3). Then, based on this material, thermodynamic grounds detected prior to onset of detonation. The most impressive detonation-based propulsion are discussed in Section findings of those times indicated that the detected detonation 2.4, followed by the principles of practical implementation velocity was independent of the ignition source and tub of the detonation-based thermodynamic cycle in Section 2.5. diameter and was primarily a function of the explosive As the main focus of this paper is the utilization of PDE for mixture composition. The main distinctive feature of propulsion, various performance parameters of PDEs(e.g. detonation was a severe mechanical effect implying the specific impulse, thrust, etc )are discussed in Section 2.6 development of a high pressure in the propagating wave. The Based on the analysis of detonation properties mechanism of detonation propagation has been identified as dynamics, and on the requirements for practical implemen- governed by adiabatic compression of the explosive mixture tation of the pulse-detonation cycle, various operational rather than by molecular diffusion of heat. During those constraints of PDEs are described in Section 2 times, the interest in detonation was basically associated Section 3 provides the reader with a detailed description with explosion prevention in coal mines of various PDe design concepts, including valved and a few years later, based on the shock wave theory of valveless approaches(Sections 3. 2 and 3.3), predetonator Rankine[28]and Hugoniot [29], Mikhelson in 1890[30, 311 concept(Section 3.4), design solutions utilizing enhanced Chapman in 1899[32], and Jouguet in 1904 [33, 34] provided deflagration-to-detonation transition (DDT)(Section 3.5), theoretical estimates for the detonation parameters based on concepts applying stratified fuel distribution in the PDe one-dimensional(ID)flow considerations and mass, momen- combustion chamber(Section 3.6), or using two fuels of tum and energy conservation laws. In their theory, the different detonability (Section 3.7), several novel PDE detonation wave was considered as a pressure discontinuity coupled with the reaction front (instantaneous reaction) (Sections 3.8-3. 10), and the pde concept applying stron ccording to the theory, the detonation products possess eactive shocks rather than detonations(Section 3.11). The density that is almost two-fold higher than the initial mixture PDE concepts described in Sections 3.2-3.10 imply the use density; temperature and pressure that are, respectively, of ducted combustors, either in single-tube or multitube 10-20% and two-fold higher than the corresponding values configuration. Some specific features of multitube PDE of constant-volume explosion; particle velocity that attains a design are discussed in Section 3. 12. Resonator concept of value close to one half of the detonation velocity. Comparison Section 3. 13 is somewhat different as it utilizes the cavity of the theoretical predictions with experimentally observed induced resonant flow oscillations in the combustion detonation velocities showed fairly good agreement. chamber. Problems of integrating inlets and nozzles to the Since the end of the 19uh-the beginning of the 20th century, PDE design are discussed in Sections 3 14 and 3. 15. Some significant progress has been made both in experimentation and ues dealing with control of repeated detonations in a PDE analysis of detonations. In addition to explosion safety issues in are considered in Section 3. 16. The last Section 3. 17 briefly coal mines and pits, other applications surfaced. in particular, describes application of PDEs for rocket propulsion those dealing with new technologies, balloon transportation d reciprocating intermal combustion engines. After the World War l, there was a considerable growth of interest to combustion 2. Fundamentals notive and aircraft engines worth mentioning are the early contributions of Dixon, Nernst, Crussard, Woodbury 2. Historical review Campbell, Bone, Frazer, Egerton, Payman, Laffite, Townsend, and lewis in understanding the mechanism of detonation onset Early attempts to utilize the power obtained from and propagation(see corresponding references in Refs. [35, 36D explosions for propulsion applications date back to late Two principal conditions required for detonation 17th-early 18th centuries and the contributions of Huygens ere observed, namely, (i)formation of a shock wave and Allen are noteworthy. In 1729, Allen proposed a jet tensity sufficient for explosive mixture to autoignite, and propelled ship [20]whose operation is owing to the (i)increase in the local rate of energy release up to the level explosion of gunpowder'in a proper engine placed within a sufficient for shock wave reproduction in the adjacent layer ship. Before this archival contribution, gunpowder was of the explosive mixture Mixture autoignition was often predominantly used in artillery for destructive purposes detected ahead of the accelerating flame giving rise to blast First exposure of gaseous detonations dates back to waves propagating downstream and upstream. The former 1870-1883 period when Berthelot and Vieille [21-251, and blast wave was attributed to detonation and the latter was Mallard and Le Chatelier [26, 27] discovered a combustion called retonation. Apart from gasdynamic models of mode propagating at a velocity ranging from 1. 5 to 2.5 km/s. detonation, there were attempts to develop models based This combustion mode arose when gas was ignited with on the molecular mechanism of energy transfer in
The paper is organized in such a way that the reader first gets acquainted with a brief history of detonation research (Section 2.1) and with the current understanding of gas and spray detonation properties and dynamics (Sections 2.2 and 2.3). Then, based on this material, thermodynamic grounds for detonation-based propulsion are discussed in Section 2.4, followed by the principles of practical implementation of the detonation-based thermodynamic cycle in Section 2.5. As the main focus of this paper is the utilization of PDE for propulsion, various performance parameters of PDEs (e.g. specific impulse, thrust, etc.) are discussed in Section 2.6. Based on the analysis of detonation properties and dynamics, and on the requirements for practical implementation of the pulse-detonation cycle, various operational constraints of PDEs are described in Section 2.7. Section 3 provides the reader with a detailed description of various PDE design concepts, including valved and valveless approaches (Sections 3.2 and 3.3), predetonator concept (Section 3.4), design solutions utilizing enhanced deflagration-to-detonation transition (DDT) (Section 3.5), concepts applying stratified fuel distribution in the PDE combustion chamber (Section 3.6), or using two fuels of different detonability (Section 3.7), several novel PDE concepts emphasizing on detonation initiation issues (Sections 3.8–3.10), and the PDE concept applying strong reactive shocks rather than detonations (Section 3.11). The PDE concepts described in Sections 3.2–3.10 imply the use of ducted combustors, either in single-tube or multitube configuration. Some specific features of multitube PDE design are discussed in Section 3.12. Resonator concept of Section 3.13 is somewhat different as it utilizes the cavityinduced resonant flow oscillations in the combustion chamber. Problems of integrating inlets and nozzles to the PDE design are discussed in Sections 3.14 and 3.15. Some issues dealing with control of repeated detonations in a PDE are considered in Section 3.16. The last Section 3.17 briefly describes application of PDEs for rocket propulsion. 2. Fundamentals 2.1. Historical review Early attempts to utilize the power obtained from explosions for propulsion applications date back to late 17th–early 18th centuries and the contributions of Huygens and Allen are noteworthy. In 1729, Allen proposed a jet propelled ship [20] ‘whose operation is owing to the explosion of gunpowder’ in a proper engine placed within a ship. Before this archival contribution, gunpowder was predominantly used in artillery for destructive purposes. First exposure of gaseous detonations dates back to 1870–1883 period when Berthelot and Vieille [21–25], and Mallard and Le Chatelier [26,27] discovered a combustion mode propagating at a velocity ranging from 1.5 to 2.5 km/s. This combustion mode arose when gas was ignited with a high-explosive charge. Later on it was observed in long tubes even when gas was ignited by nonexplosive means (spark or open flame). In this case, flame acceleration along the tube, often accompanied with flame speed oscillations, was detected prior to onset of detonation. The most impressive findings of those times indicated that the detected detonation velocity was independent of the ignition source and tube diameter and was primarily a function of the explosive mixture composition. The main distinctive feature of detonation was a severe mechanical effect implying the development of a high pressure in the propagating wave. The mechanism of detonation propagation has been identified as governed by adiabatic compression of the explosive mixture rather than by molecular diffusion of heat. During those times, the interest in detonation was basically associated with explosion prevention in coal mines. A few years later, based on the shock wave theory of Rankine [28] and Hugoniot [29], Mikhelson in 1890 [30,31], Chapman in 1899 [32], and Jouguet in 1904 [33,34] provided theoretical estimates for the detonation parameters based on one-dimensional (1D) flow considerations and mass, momentum and energy conservation laws. In their theory, the detonation wave was considered as a pressure discontinuity coupled with the reaction front (instantaneous reaction). According to the theory, the detonation products possess density that is almost two-fold higher than the initial mixture density; temperature and pressure that are, respectively, 10–20% and two-fold higher than the corresponding values of constant-volume explosion; particle velocity that attains a value close to one half of the detonation velocity. Comparison of the theoretical predictions with experimentally observed detonation velocities showed fairly good agreement. Since the end of the 19th–the beginning of the 20th century, significant progress has been made both in experimentation and analysis of detonations. In addition to explosion safety issues in coal mines and pits, other applications surfaced, in particular, those dealing with new technologies, balloon transportation, and reciprocating internal combustion engines. After the World War I, there was a considerable growth of interest to combustion in automotive and aircraft engines. Worth mentioning are the early contributions of Dixon, Nernst, Crussard, Woodbury, Campbell, Bone, Frazer, Egerton, Payman, Laffite, Townsend, and Lewis in understanding the mechanism of detonation onset and propagation (see corresponding references in Refs.[35,36]). Two principal conditions required for detonation onset were observed, namely, (i) formation of a shock wave of intensity sufficient for explosive mixture to autoignite, and (ii) increase in the local rate of energy release up to the level sufficient for shock wave reproduction in the adjacent layer of the explosive mixture. Mixture autoignition was often detected ahead of the accelerating flame giving rise to blast waves propagating downstream and upstream. The former blast wave was attributed to detonation and the latter was called retonation. Apart from gasdynamic models of detonation, there were attempts to develop models based on the molecular mechanism of energy transfer in G.D. Roy et al. / Progress in Energy and Combustion Science 30 (2004) 545–672 549