Multidisciplinary and Multi-objective Design Exploration Methodology for Conceptual Design of a Hybrid Rocket
Infotec@Aerospace 2011 I@A-89 Evolutionary Design of Intelligent Systems AIAA-2011-1634 Multidisciplinary and Multi-objective Design Exploration Methodology for Conceptual Design of a Hybrid Rocket Yukihiro Kosugi Tokyo Metropolitan University (TMU) Akira Oyama Japan Aerospace Exploration Agency Kozo Fujii Japan Aerospace Exploration Agency Masahiro Kanazaki Tokyo Metropolitan University (TMU)
Contents 2 Background Objectives Design method Evaluation procedure of LV with HRE Multi-objective Genetic Algorithm (MOGA) Scatter Matrix Plot (SPM) Design problem for LV with HRE Design variables Objective functions Results Design results Visualization of non-dominated solutions Design knowledge Conclusions
Background1 Rockets presently used for space transportation 3 Solid-propellant rocket engine Advantage：・Simple mechanism and construction ・Easy to maintain the propellant Disadvantage：・Low specific impulse (Isp) ・Inability to stop combustion after it is ignited ・Environment issues (caused by ammonium perchlorate (NH4ClO4), and aluminum oxide (Al2O3)) Liquid-propellant rocket engine Advantage ：・High specific impulse (Isp) ・Ability to stop/restart combustion Disadvantage：・Complex mechanism and construction ・Risk of explosion ・Difficulty to store low temperature propellant
Background2 What is hybrid rocket? 4Hybrid Rocket Engine(HRE) ： propellant stored in two kinds of phases It can adopt the beneficial features of both the liquid and solid rockets. Solid fuel + Liquid oxidizer : Advantage of HRE・Simple construction and mechanism・Higher specific impulse (ISP) than solid rocket engine・Ability to stop/restart combustion・Low environmental impact and low cost
Background4 Design of HRE 5 Solid rocket：Premixing type solid propellant Fuel rocket：Mass flow control of fluid propellant → Easy to maintain a constant oxidizer and mass - fuel ratio (O/F) and to get a stable thrust HRE：The mixture of fuel and oxidizer is initiated after ignition. Combustion occurs in the boundary layer diffusion flame. → Because O/F is decided in this part of combustion process, the solid fuel geometry and the supply control of the oxidizer have to be optimally combined. ⇔With excessive mass flow of oxidizer, the rocket achieves higher thrust, but structural weight should be heavier .Importance to find optimum fuel geometry and oxidizer supply ⇒Multi-disciplinary design which is considered propulsion, structure and trajectory
Background５ Meta-heuristics approach in aircraft design 6 Evolutionary Algorithm based Design Exploration Application of Mitsubishi Regional Jet (MRJ) Targets •Wing design •High-lift Airfoil design •Nacelle chine design Design Exploration •Genetic Algorithm •Surrogate model •Data mining・Chiba, K., Obayashi, S., Nakahashi, K., and Morino, H., "High-Fidelity Multidisciplinary Design Optimization of Aerostructural WingShape for Regional Jet," AIAA Paper 2005-5080, AIAA 23rd Applied Aerodynamics Conference, Toronto, Canada, June 2005.・Kanazaki, M., and Jeong, S., “High-lift Airfoil Design Using Kriging based MOGA and Data Mining,” The Korean Society forAeronautical & Space Sciences International Journal, Vol. 8, No. 2, pp. 28-36, November 2007.・Kanazaki, M., Yokokawa, Y., Murayama, M., Ito, T., Jeong, S., and Yamamoto, K., “Nacelle Chine Installation Based on Wind TunnelTest Using Efficient Design Exploration,” Transaction of Japan Society and Space Science, Vol.51, No. 173, pp. 146-150, November2008. … etc. Design Exploration is also expected in MDO for hybrid rocket.
Objectives of this study 7Development of the evaluation tool for concept of launch vehicle (LV) with HRE Evaluation based on the empirical modelDemonstration of multi-disciplinary design using genetic algorithm Conceptual design of single stage surrounding rocket which achieves low gross weight and high flight altitude Knowledge discovery using data mining
Design method1 evaluation1 8Overview of the evaluation procedure Input variable Output variable * Mass flow of oxidizer [kg/s] * Flight altitude [km] * Fuel length [m] * Gross weight [kg] * Port radius of fuel [m] * Total oxidizer weight [kg] * Combustion time [s] * Total fuel weight [kg] * Pressure of combustion chamber [MPa] * Nozzle length [m] * aperture ratio of nozzle [-] * Combustion chamber length [m] * Oxidizer tank length [m] * Rocket radius [m] * Rocket aspect ratio [-] * Nozzle throat area [m2] * Thrust at ignition [kN] * Initial oxidizer mass flux [kg/m2s] * History of flight, thrust, and combustion chamber pressure
Design method2 evaluation2 9 O/F and thrust power estimations Underlined variables are part of the design parameters. moxi t O F (t ) m fuel t rport (t ) a Goxi t nMass of vaporized fuel: m fuel t 2rport t L fuel fuel rport (t ) A NASA-CEA t rport (t ) rport (0) rport ( )d 0 T t T m propue Pe Pa Ae m prop (t ) moxi (t ) m fuel (t ) fuel tmoxi t = mass flow of oxidizer m prop t = mass flow of propellant rport (t ) rport (0) rport ( )d m fuel t = mass flow of fuel 0 Peh = pressure in the combustion chamberLfuel = length of fuel Pe = pressure at nozzle exitρfuel = density of fuel (constant) Pa = pressure of atmosphere at flight altituderport = radius of fuel port ue = velocity at nozzle exitT(t) = thrust ηT λ = momentum loss coefficient at nozzle exit by friction (<1) = total thrust loss coefficient by deflection of propellant at nozzle exit (<1)
Design method3 evaluation3 10 Weight and length estimations Mtot is estimated by the sum of the components’ weight moxi t dt tburn M tot M engine M pay M ex M oxi 0 m fuel t dt tburn M engine M oxi M fuel M res M ch M fuel 0 2 M ex M engine M res Vres 3 Ltot is one and a half times as long as HRE for including payload. M ch Vchtburn = combustion timeMoxi = mass of total oxidizerMfuel = mass of total fuelMres = mass of the oxidizer tankMch = mass of the combustion chamber The sketch of the oxidizer tanks. The sketch of the nozzles.Vres = integrated volume of material for the oxidizer tankVch = integrated volume of material for the combustion chamberMtot = gross weigh Ltot = total length of the rocketMengine = engine weight Lch = length of the combustion chamber (=Lfuel)Mpay = payload weight Lres = length of the oxidizer tankMex = weight of other equipments Lnozzle = length of the nozzle
Design method4 evaluation4 11 Trajectory prediction S-520: JAXA’s surrounding solid propellant rocket Equation of motion T t Dt at g M tot t D(t) = total drag at time tFriction drag coef. of outer surface of the rocket A(t) = acceleration at time t 0.455 C D f , Design (t ) g = gravitational acceleration log 10 Re2.58 1 0.144M 2 0.65 Dp, Design(t) Df, Design(t) = = pressure drag at time t friction drag at time tPressure drag coeff. based on S-520 flight data Re = Reynolds number S wet ,S 520 CDp, Design(t) = pressure drag coefficient at time t C D p , Design (t ) C D,S 520 (t ) C D f ,S 520 (t ) CDf, Design(t) = friction coefficient drag at time t S ref ,S 520 CDp, S-520(t) = pressure drag coefficient of the solid rocket S-520 D p , Design (t ) qS ref , DesignC D p ,S 520 CDf, S-520(t) = friction drag coefficient of the solid rocket S-520 a D q = dynamic pressure f , Design (t ) qS wet , DesignC D f , Design Sref, Design = area of cross section of the designed rocket Swet Design = wetted area of cylinder of the designed rocket D(t ) D p , Design (t ) D f , Design (t ) Sref, S-520 = area of cross section of the solid rocket S-520 Swet S-520 = wetted area of cylinder of the solid rocket S-520The aerodynamic effect of the rocket length and diameter can be evaluated.
Design method5 design method1 12 Heuristic search：Multi-objective genetic algorithm (MOGA) Inspired by evolution of life Selection, crossover, mutation Global search Pareto-ranking method Ranking of designs for multi-objective function Sub-population Individual Individual Island model Migration Sub-population (a) (b) Hiroyasu, T., Miki, M. and Watanabe, S., “The New Model of Parallel Genetic Algorithm in Multi-Objective Optimization Problems (Divided Range Multi-Objective Genetic Algorithm),” IEEE Proceedings of the Congress on Evolutionary Computation 2000, Vol. 1, pp. 333-340, 2000.
Design method6 design method2 13 Scatter Plot Matrix (SPM) →For the design problem investigation a Scatter plot of avs.b b Correlation of avs.b c dSPM arranges two-dimensional scatter plots among attribute values like a matrix ・The present SPM shows scatter plots on the upper triangular, and correlation coefficient on the lower triangular (Software R is used for statistical computing and graphics.)
Design problem for LV with HRE1 14 Swirling oxidizer type HRE Proposed by Yuasa, et al. Swirling oxidizer is supplied into the fuel. Polypropylene is employed as a fuel. rport t 0.0826Goxi This expression was 0.55 provided by Prof. Yuasa. regression rate against the mass flux of the oxidizerYuasa, S., et al, “Fuel Regression Rate Behavior in Swirling-Oxidizer-Flow-Type Hybrid Rocket Engines,” Proc 8th InternationalSymposium on Special Topics in Chemical Propulsion, No. 143, 2009.
Design problem for LV with HRE 15Design targetthe surrounding rocket with assuming that the 40kg payload is carriedDesign variables (6) Lower Upper Mass flow of oxidizer [kg/s](dv1) 1.0 30.0 Fuel length [m] (dv2) 1.0 10.0 Port radius of fuel [m] (dv3) 0.01 0.30 Combustion time [s] (dv4) 10.0 40.0 Pressure of combustion chamber [MPa] (dv5) 3.0 6.0 aperture ratio of nozzle [-](dv6) 5.0 8.0 Objective functions (2) Minimize Gross weight, Wgross Maximize Maximum flight altitude Hmax
Results1 Sampling results by MOGA 16 MOGA result colored by rocket’s aspect ratio (length/diameter) After 100 generation started with 64 individuals Non-dominated solutions The solutions for which Hmax is greater than 150 km have a larger Wgross than the solutions for which Hmax is less than 150 km. To achieve high flight altitude, the rocket’s aspect ratio becomes high. Optimum direction -There is trade-off between Wgross and Hmax. -Maximum Hmax is about 180km. - The rocket considered here is suitable for the sub-orbital flight around 100km altitude.
Results2 Comparison with JAXA’s S-210 17 S-210 Des1 Flight altitude [km](H) 110.0 108.2 Gross weight [kg](W) 260.0 334.0 Payload weight [kg] 40.0 40.0 Payload weight/gross weight 0.154 0.120 Fuel length [m] 5.2 8.5 Fuel diameter [mm] 210.0 210.0 Rocket’s aspect ratio [-] 24.8 40.5 -Comparison with sub-orbital solid rocket S-210 which flight about altitude 100km -Aspect ratio of the HRE rocket was larger than that of the S-210, because the oxidizer tank and the solid fuel are placed longitudinally in the rocket. -Wpey/Wgross of the designed rocket was less thanwww.isas,jaxa,jp that of the S-210. → Pch is supposed to be constant during the combustion process
Results3 Visualization of non-dominated solution by SPM 18 dv3(port diameter in the fuel) of non- dominated solutions becomes less. → better volumetric efficiency and slender chamber There are correlation among dv1(mass flow of oxidizer), dv2(fuel length), and two objective functions. The rockets’ aspect ratio and the Acc_max are correlative relation.
Results4 Design knowledge from non-dominated solution 19 There is a trade-off between the minimization of the gross weight and the maximization of the flight altitude. The designed rockets achieve a higher flight altitude by reducing the aerodynamic drag and by employing a higher aspect ratio. The rockets which is lower oxidizer mass flow, the diameter of the combustion chamber becomes smaller. As this result, the weight of the combustion chamber decreases. The rocket with HRE, which achieves a higher flight altitude and lower weight, tends to be long and narrow in the present MDO problem
Conclusions 20 Development of the design tool for concept of LV) with HRE Evaluation based on the empirical model Evaluation module (cygwin script) is open to the public, http://bit.ly/hmBYgB. English manual will be also uploaded in this April-May. This uploading will announced in twitter, (@tmu_craft_desig #hre). Knowledge discovery of multi-disciplinary design for a LV with HRE High aspect ratio rocket is better for the present design problem. With heavier mass of the oxidizer, the rocket’s gross weight becomes heavier. Future work: The sophisticate of the evaluation tool. Consideration of the pressure time variation of the combustion chamber. Structural type for realistic rocket. Conceptual design of orbital rocket for microsat launch
Acknowledgement 21We thank members of the hybrid rocket engine research working group in ISAS/JAXA for giving their experimental data and their valuable advices. This paper and presentation was supported by ISAS/JAXA. Thank you very much for your kind attention.