Electrostatic Levitation Furnace (ELF)

This furnace can control the sample position with electrostatic force and heat it above 2000 degree Celsius using semiconductor laser from four different directions.

JAXA plans to measure the thermal properties(density, surface tension and visocity) of oxides in ISS, which are very difficult to measure on ground.

Electrostatic Levitator in JAXA :

Diagnostics

The position of the sample will be controlled at 1kHz(maximum). During the oscillation, the control speed will be lowered (less than resonant frequency) to get the precise surface tension and viscosity.

200-400(1600)nm

Engineering Requirements for ELF

3

Items Requirements

Sample Size φ1～5mm (main target ; φ2)

Accuracy of Positioning ±100μm

Heater

Laser (Wave

Length/Power) 970nm／40W x 4 directions

Target Temperature Melting Point of Zirconia (2710 degC)

Observation

Temperature

Measurements

IR thermometer (ORU)

Sampling Rate (100Hz)

Magnified Image higher than 140 pixel / diameter

Observation of Overview CCD camera

Measurements of

Thermo-physical

Properties

Density through Image Analysis

Surface Tension Oscillating Droplet Method

Viscosity Oscillating Droplet Method

Others Ambient

N2 (99.99% by volume ;ISS supply gas) ,

Ar Gas (JEM unique gas),

Vacuum with Evacuation Line

(maximum pchamber ressure 2atm)

Observation system of ELF

Pyrometer ・ Field of View:0.35mm diameter ・ sampling rate：100Hz ・ fixed emissivity ・detecting wavelength; InGaAs（1.45～1.8μm） ・ temperature range ;300～3000℃ Observation Camera 1 (High Temperature range observation, density

measurement) ・Field of view; 2.4×1.8mm - 19×14mm (with Zoom Lens) ・resolution;640×480 ・signal ; NTSC Observation Camera 2 (Solidification observation, wide dynamic range ) ・Field of View; 3.0×2.3mm - 24×18mm (with Zoom Lens) ・resolution ;640×480 ・signal ; NTSC

JEM-ELF 5

JEM-ELF (current design)

Ar Gas supply

ELF

MPSPR

UV Lamp

Sample

cartridge

Cross Section View with Sample Cartridge and ELF

Detailed design of the sample cartridge

Operation concept JAXA will lanuch the sample holder periodically by HTV, COTS vehicle, Proton or ATV. In case (such as cartridge windows become dirty), JAXA will prepare the sample cartridge as spare. After the experiment, the sample holder will ve retrieved by Soyuz or COTS vehicle.

Cartridge Set up

Sample Holder exchange

Select sample

Chamber Atomosphere set up

set sample position – (pre-heating) – start position control – start heating up – sample melt - thermal property measurement in various temperature – sample melt – solidification - sample retrieval into Sample Holder

evacuation (if needed)

ELF experiment flow

Measurement method: Density

M: mass V: volume (from image analysis) Uncertainty:±2%

Chung et al., Rev. Sci. Instrum. 67 (1996), 3517-

VM /

Oscillation excitation/ detection

of ELF

Bottom electrode

Slit

Power meter

sample

Sinusoidal

wave

Top electrode

He-Ne Laser

Uncertainty:

g ±３％

h ±10-15％

Surface tension and viscosity

measuermant

g 2

2r0

3

8

h r0

2

5

2: Freq. of mode 2 oscillation

: Decay constant

: density ｒ０:radius of sample g: surface tension h: viscosity

Rhim et al., Rev. Sci. Instrum. 70 (1999), 2796

Oscillating drop method

0

2

4

6

8

1 0

1 8 0 0 1 9 0 0 2 0 0 0 2 1 0 0 2 2 0 0 2 3 0 0 2 4 0 0

Vis

co

sit

y (

mP

a・

s)

Tm

Present work

Paradis

Agaev

Elijutin

5 4 0 0

5 6 0 0

5 8 0 0

6 0 0 0

6 2 0 0

6 4 0 0

1 2 0 0 1 4 0 0 1 6 0 0 1 8 0 0 2 0 0 0 2 2 0 0 2 4 0 0 2 6 0 0 2 8 0 0

Tm

Present work Paradis

Allen

Elijutin

Peterson

Maurakh

Temperature (K)

De

ns

ity (

kg

/m３）

1 3 5 0

1 4 0 0

1 4 5 0

1 5 0 0

1 5 5 0

1 6 0 0

1 6 5 0

1 8 0 0 1 9 0 0 2 0 0 0 2 1 0 0 2 2 0 0 2 3 0 0 2 4 0 0

Su

rfa

ce

Te

ns

ion

(m

N/m

)

Tm

Present work Paradis Allen

Flint Peterson Shunk Kostikov Frohberg

Paradis et al., Int. J. Thermophysics, 23 (2002), 825-

Example of Experimental Result: Zirconium (on Ground)

Density

Surface tension

Temperature (K)

Viscosity

)kJ/R8.31exp(76.0

)(11.01500

)(27.06120

T

TT

TT

m

m

h

g

Status of thermophysical property

measurements of Metals on ground

14

Targets of ELF are Oxides which are over 2000℃ melting temperature.