Hokkaido Univ. Since 1876

COSMOTORRE

Overview of 50m Drop Tower“ COSMOTORRE”
Further questions on this material could be addressed to:
Division of Mechanical and Space Engineering,
Hokkaido University Prof. Osamu Fujita
Email: ofujita@eng.hokudai.ac.jp

This info is as of March 26,2020

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Contents
１．Why Microgravity?
２．50m drop tower “COSMOTORRE”
３．Research projects on combustion
science2Why Microgravity? (1)-SimplificationNo buoyancy force→→

Elimination of convection
Simplification ofcombustion phenomena→・Simplification
・Elementary process→

Deep understanding ofelementary processes
composes of combustion
Numerical simulation forpractical purpose3

Example
Effect of external flow on jet diffusion flame*2.0ml/s O223%

2.0cc 23% 0cm/s

2.0cc 23% 2.5 cm/s

2.0cc 23% 3.75cm/s

2.0cc 23% 5cm/s

2.0cc 23% 6.25cm/s

B.H.Jeon, O.Fujita, Y.Nakamura,H.Ito, J. Thermal Science and Technology,
Vol.2, No.2, pp.281-290, (2007.12).

2.0cc 23% 7.25cm/s

4Why Microgravity? (2)-Place of New Findings-

１Ｇ to μＧ＝Paradime shift→ Place of new findings

Ito H., Fujita O., Ito K.,
Comb. Flame 1994, 1996
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Why Microgravity? (3)-Material ProductionCNT formation in 0G

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Why Microgravity? (4)-for Future Space ActivitiesμG Experiments→Preparation for
long-term manned
mission in space（Life support in space,
Food and energy, Safety,
Adaptation of human being
to space, Technology inspace, etc）
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Contents
１．Why Microgravity?
２．50m drop tower “COSMOTORRE”
３．Research projects on combustion
science8

Cascade of microgravity experiments
ISS, Flight tests on orbit- Cost of second floor or above is not small for broad researches- Attractive subjects affordable to higher cost are brought out fromtrials of many researchers.
- However, individual trial is not always affordable for each cost.
- Requirement of facility to take the role of first floor, which has notbeen covered previously, but essential.

9Construction of50M drop tower

Outer
CapsuleInnerCapsule3 sec DropFacility

Microgravity
Duration≒3seconds
Microgravity
Level ≦10-3G
Payload Volume
Φ500 x 800 m3
Payload Weight≒150kg2004.11北海道新聞

10HASTIC 50m Drop Tower

COSMOTORRE コスモトーレ

ItemsSpecifications

μG time

2.5 sec (45mdrop)G-quality>１０-3 G0Payload size

Φ50cm×105cm

Total weight

400 kgCapsule type

With inner capsule

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Structure of thedrop tower
Height ５０ｍ
Free fall length ４０ｍ

12Drop capsule and payload rack

Capsule with inner payload

Drop Capsulewith inner rack

Inner Rackφ50×105cm
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Example of inner capsule assembling

Available space of inner capsule is 50cm(diameter)×105cm (high), The space can be used
separately as in the above figure. Each equipment is set on a wooden base plate (see next page).

Base plate to be self-prepared by user
Please prepare the wooden
circular plate as blow and put
all of experimental set up onthe plate.
Rod hole, φ30×４

φ500455455

Wooden plate①Outer diameter φ500
②30mm thick wood plate③Four rod holes（φ30）, eightfixation holes (φ10) are needed.
Specific position of holes areshown in the next page.
④Experimental set up should bein outer circle of the plate.
Consider the interference withsuspension rods.

Specific position of holes①4 holes of 30mm for suspension rod at the position in the figure above.
400②8 holes of 10mm as M8 bolt clearance
holes as in the figure above.
③Consider interference with suspension rods and M8 bolt heads.

Capsule release system

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Breaking system

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Examples of experimental setup

19Capsule preparation（１）20Capsule preparation（２）21Capsule preparation（３）22Bottom View of Drop Tower

Gravity data

Microgravity data

Moment of break

Payload ：MAX 100kg（TBD）
Dimension of Payload：φ50cm×105cm highPower resource：User（TBD）
MicorG：10-3G or less
MicroG time：2.5-2.8 sec
Impact：20G or less24

Open for any researchers and educators
・To incubate future subject for higher level facilities
・To grow up next generation people

ResearchersDropTests

Application
Technical Info.

Technical Support
Maintenance

HASTIC Akabira
Test Field

HASTICTechnical Support Request

Uematsu Electric Co.Ltd
Technical Advise
Hokkaido Univ Analysis

http://www.hastic.jp/
email: office@hastic.jp25

Logo and Nickname

Nickname：from 533
Logo：from 81 proposals
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Contents
１．Why Microgravity?
２．50m drop tower “COSMOTORRE”
３．Research projects on combustion
science27

Research Area of Combustion ScienceSmall scale
High speed
High stretch

Diffusion flame
Flickering
Extinction

Premixed flameFlame ball
Oscillation
Comb velocity

Gravity Controlled
DropletLiquidPool firecombustion

Combustion
synthesis

Gr=L3gβ(T-To)/ν2
Fr=u2/gL

FireSolid
Coalcombustion
Ignition
Spreading

Large scale
Low speed
Low stretch
CNT
Fine particle
Synthesis

Less Gravity Effect

SootNOx
CO2

Pollutants
formation

Some research topics
are intensively studied,but many topics arestill remained.
In the remained part,subjects related tourgent important topics
on the ground areinvolved.
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Example of research projects(combustion research)・Fire safety
・Material synthesis
・Flame instability
・Properties on combustion(Flame speed, Flammable limit, etc)

・Secondary force (Thermophoresis,Electrophoresis, Magnetic effect, etc)

・Diffusion control process (Le effect)29

Acknowledgement
For the construction of drop tower, Hokkaido
University have supported from thecomponies, Hokkaido Electric Power,Co.,Inc.,
North Pacific Bank Ltd., IshikawajimaHarima Heavy Industies Co.,Ltd., ToshibaCo., The Hokkaido Bank Ltd., Japan SteelWorks Ltd., Toyo Engineering Co., Hokkaido
Gas Co., Ltd., Mitsubishi Heavy Industries
Ltd., IHI Aerospace Engineering Co.Ltd.

The researches introduced in the presentation are granted byAOs JSF ground based research, Grant-in-aid (Kiban (B) by JSPS.

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