Design Optimization of Launch Vehicle Concept Using

Cluster Hybrid Rocket Engine for Future Space Transportation

Shoma Ito (Tokyo Metropolitan University)

Fumio Kanamori (Tokyo Metropolitan University)

Masaki Nakamiya (Kyoto University)

Koki Kitagawa (ISAS/JAXA)

Masahiro Kanazaki (Tokyo Metropolitan University)

Toru Shimada (ISAS/JAXA)

1OS8:Flow Dynamics and Combustion in Hybrid RocketsOS 8-9 2014 Eleventh International Conference on Flow Dynamics

October 8-10. Sendai, Japan

Contents

• Background

• Objectives

• Rocket Configuration and Structure

• Design and Evaluation Methods

• Problem Definition

• Results

• Conclusions

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BackgroundAdvantage of hybrid rocket engine(HRE)

Higher safety Lower cost Lower environmental

impact

Hybrid rocket has possibility to be next generation

efficient launch vehicle.

Space ship two※1

※1,VirginGalactic http://www.virgingalactic.com/※2, [1] Y. Kitagawa, K. Kitagawa, M. Nakamiya, M. Kanazaki, T. Shimada, T JSASS, 55(2012), R4

3

Our previous research※2

Development of multi-disciplinary design methodology

Optimization for single stage and three stage launch vehicle

Background

Cluster rocket

Installed several unit engines in a stage for sufficient thrust.

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Hybrid Launcher※3

Soyuz※2 (using liquid engine)

※2 Wikipedia http://ja.wikipedia.org/wiki/%E3%82%BD%E3%83%A6%E3%83%BC%E3%82%BA#mediaviewer/File:Soyuz_tma-3_transported_to_launch_pad.jpg※3 ANTARES Hybridtaken e.V. http://www.hybridraketen.de/Homepage/antares.html

Advantage of Cluster Rocket

Cluster rocket Advantage

High thrust without enhance the cost. Disadvantage

Increase the weight due to remain unburnt fuel. Difficulty of simulations control of unit engines.

Single engine rocket Limitation of total thrust.

5

Objectives

Design Optimization of Launch Vehicle (LV) Concept Using Three

Stage Clustered Hybrid Rocket (HRE)

6

Development design methodology for LV with clustered HRE

Investigation of the combination of the unit engine

Rocket Configuration and Structure

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Fuel Design

Regression rate rport is calculated by

n

tport Gatr ][)( )(0

8

.

.Radius of fuel is calculated by rport and tb

(tb is design variables) .

G0(t) Oxidizer mass flux

a Fixed number decided by kind of fuel

n

β Simulating fuel circling

.

Configuration of Engines on 1st Stage

In 1st stage, eight engines are installed.

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Configuration of Engines on 2nd Stage

In 2nd stage, two engines are installed.

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Cluster Rocket Design MethodEvaluation of rocket radius

Radius of 2nd and 3rd stage exterior wall is equal to radius of 2nd stage.Radius of 1st stage is calculated independently.

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Kind of fuel and oxidizer: Fuel…FT0070 Oxidizer…O2

FT0070spec

Chemical formula Density[kg/m3] Index n Coefficient a

C35H72 910.0 0.3905 0.1561

ntport Gatr ][)( )(0

Overview of Evaluation and Optimization Method

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Optimization Method• Multi-objective Genetic Algorithm(MOGA)

Search non-dominated solutions based on global explorations .

GA Flow

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Data Mining MethodParallel Coordinate Plot (PCP)

• One of the statistical visualization techniques from high-dimensional data into two dimensional graph.

• Normalized design variables and objective functions by upper bound and lower bound of design space.

• One design is expressed as a line in this graph.

0.0

0.2

0.4

0.6

0.8

1.0

dv1 dv2 dv3 dv4 dv5 H W L/D

Design variable or objective function name

No

rmal

ized

val

ues

ilowerboundiupperbound

ilowerboundi

xx

xxXi

,,

,

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Rocket Design Method 15

Problem Definition

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Problem DefinitionObjective functions

Maximize payload to gross weight ratio(Mpay/Mtot)Minimize gross weight(Mtot)

ConstraintsAfter 3rd stage combustion

• Height ≧ 250km• Angular momentum ≧ 52413.5km2/s• 0.5deg ≧ Flight path angle ≧-0.5deg

On 1st and 2nd stage • (Atmospheric pressure)×4 ≦ Pressure of nozzle exit

when start burning• Radius of nozzle exit ≦ Radius of engine

Rocket aspect ratio ≦ 20(Area of nozzle throat)×2 ≦ Area of grain portRadius of 3rd stage nozzle exit ≦ Radius of 2nd stage

exterior wall

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On the assumption that launch the super micro satellite

Design CasesDefinition of four design cases.

Shared engines have same chamber. Nozzle size and burning time are defined for each stages.

Case1: Employment of optimized engines for all stage Cluster rocket

Case2: Employment of shared engines for 1st and 2nd stage Cluster rocket

Case3: Employment of shared engines for all stage Cluster rocket

Non-clustered rocket(Non-clustered rocket)

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The shared engine is designed by 1st stage design variables.

Result

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Result of Design Optimization

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0 22.0 24.0 26.0 28.0 30.0

Mto

t/M

pay

[%]

Mtot[ton]

Case1 Case2 Case3 Non-clustered rocket

Trade off can be shown between two objective functions in each case. Case1 show similar result as non-clustered case. Case3 which employs same shared engine for each stage achieves

less than half performance compared with Case1. Unburnt fuel is appeared when one engine design is shared in

two or three stages.

OptimumDirection

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Des1 Des0

Des2

Des3

Mpay=100[kg]

Comparison from Pareto Solutions

Des1 has slender engines. Des1 and Des2 use small engine in 3rd stage. ↔ Des3 uses largest engine in 3rd stage.

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Length Radius

18.46[m] 0.60[m]

Length Radius

21.62[m] 0.59[m]

Length Radius(1st) Radius(2nd)

16.64[m] 1.42[m] 0.79[m]

Length Radius(1st) Radius(2nd)

14.83[m] 1.22[m] 0.68[m]

Des0

Des1

Des3

Des2

Comparison of Payload 100kg Rocket(PCP)

0.00.10.20.30.40.50.60.70.80.91.0

mo

1

O/F

1 a1

Go

1

tb1

Pc1

Pp

t1 ε1

Des1 Des2 Des3

0.00.10.20.30.40.50.60.70.80.91.0

mo

2

O/F

2 a2

Go

2

tb2

Pc2

Pp

t2 ε2

0.00.10.20.30.40.50.60.70.80.91.0

mo

3

O/F

3 a3

Go

3

tb3

Pc3

Pp

t3 ε3

For 1st stage, mo1 is small in each case.

For 2nd stage, O/F2 of Des3 is the highest. Sufficient thrust is small, so fuel become less.

For 3rd stage, tb3 of Des3 is small while mo3 is the highest. 1st Stage

2nd Stage 3rd Stage

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Comparison of time history of engine thrust per an engine

23Comparison of payload 100kg Rocket(Thrust)

Unit engine thrust = Total thrust by each stage/Number of engines in a stage

1st stage thrust is influenced by total mass and drag. Des3 has big total mass and drag, so it has the highest thrust.

Des0, Des1 and Des2 show similar result in 3rd stage, because these cases optimized engine only for 3rd stage.

Comparison of payload 100kg Rocket(Isp) 24

220

230

240

250

260

270

280

290

300

310

320

0 50 100 150 200 250 300 350 400 450

Isp[s

]

Time[s]

While Des3 achieves the highest thrust in all stage, Isp of 3rd stage is the lowest. Engines of Des3 are not only optimized for 3rd stage.

2nd stage of Des1 achieves the lowest Isp. The efficiency is limited because the radius of 1st stage is

small.

Comparison of Payload 100kg Rocket(Altitude) 25

Des3 achieves high acceleration at low altitude. Des3 achieves high

thrust in 1st and 2nd stage.

Des3 has the shortest flying time. Des3 become heavy by

using shared engines. Optimized to rise quickly.

Des0 and Des1 have long coasting time.

Comparison of Payload 100kg Rocket(Numerical Value)

Mtot

[ton]Mpay/Mtot

[%]

Des1 9.31 1.10

Des2 13.3 0.75

Des3 15.5 0.64

Payload ratio of Des3 is 0.5% less than Des1. Because of unburnt fuel, total mass of Des3 become heavy.

Fuel Filling Ratio

1st stage 2nd stage 3rd stageDes1 63[%] 80[%] 93[%]Des2 86[%] 86[%] 88[%]Des3 84[%] 84[%] 84[%]

Fuel filling ratio of Des1 is the smallest in 1st stage. Des1 has slender engines to reduce aerodynamic drag.

Fuel filling ratio of Des2 and Des3 are high. Because of the appearance of the unburnt fuel, payload

ratio of Des2 and 3 becomes lower than Des1. It is also required to reduce unburnt fuel. →(Future work)Addition of objective function objective function:

Minimize unburnt fuel

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Fuel Filling Ratio=Area of fuel/Area of chamber

ConclusionsOptimization of LV using clustered HRE was carried out.

Development of the clustered LV evaluation using HRE.

Investigate of the LV performance using shared endings. Three cases are compared.In case of design of shared engine for one stage,

the non-dominated front is the best among three cases.Because of the unburnt fuel is not appeared.

Installation of the shared engine for two or three stages, the unburnt fuel is appeared.

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Future Work To generate high payload ratio cluster rocket,

reconsider the design method of engine.

Thank you for listening

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