Ani So Tropic Thermal Behavior of Porous Carbonized Wood

  • View
    221

  • Download
    0

Embed Size (px)

Citation preview

  • 8/3/2019 Ani So Tropic Thermal Behavior of Porous Carbonized Wood

    1/24

    Anisotropic Thermal Behavior ofPorous Carbonized Wood

    Based Composites forThermal Management

    on the Space Solar Satellite

    1

  • 8/3/2019 Ani So Tropic Thermal Behavior of Porous Carbonized Wood

    2/24

    2

    Introduction

    Contents:

    Heat problem, the need of thermal management on the SPS

    Carbon based thermal conductive material: graphite and thenecessary improvement in the anisotropic thermal behavior

    Carbonized wood, a turbostratic carbon

    Composite with alternate layers of graphite and carbonized

    wood for anisotropic thermal behavior improvement

  • 8/3/2019 Ani So Tropic Thermal Behavior of Porous Carbonized Wood

    3/24

    Thermal Management in the SPS

    Heat problem in the SPS: when temperature increase exceed 100 C,the electric generation efficiency will be dropped.

    3

    Solar Power Satellite

    Heat distribution of the solar cell side(URSI white paper, 2007)

  • 8/3/2019 Ani So Tropic Thermal Behavior of Porous Carbonized Wood

    4/24

    Thermal Management in the SPS

    Solar Power Satellite

    Thermal management is necessary

    to keep the high efficiency of

    electric power generation of the

    SPS by keeping the temperaturebelow 100 C

    A thermal conductive material to

    discharge the heat to radiators ,

    retaining the increase in

    temperature

    4

  • 8/3/2019 Ani So Tropic Thermal Behavior of Porous Carbonized Wood

    5/24

    Thermal Conductive Materials

    A preferable material:High thermal conductivity, considerably strength, lightweight(low SG) and anisotropic behavior

    No Material KT(W/m.K)

    Modulus(GPa) SG(g/cm3)

    1 Aluminum 230 69 2.7

    2 Cooper 400 117 8.9

    3 Silicon 150 - 2.3

    4 Graphite* // 140 - 1.9

    225

    D.D.L. Chung and C. Zweben, 2001; *A.I. Lutcov et.al. 1970

    5

  • 8/3/2019 Ani So Tropic Thermal Behavior of Porous Carbonized Wood

    6/24

    Graphite

    Planar structure of ABA stacking sequence of hexagonal graphite (Klett et al., 2004)

    6

    Graphite consists of carbon layers (graphene layers) with covalent bonding withineach layer and are linked by van der Walls interactions.

    Graphite is anisotropic, good electrical and thermal conductor within the layersand a poor electrical and thermal conductor perpendicular to the layers.

  • 8/3/2019 Ani So Tropic Thermal Behavior of Porous Carbonized Wood

    7/247

    Graphite

    The High temperature treatment (HTT)

    improves the crystallites size (Taylor,2000) and increase the thermalconductivity.

    But the anisotropic behavior is notinfluenced

    (Oberlin et al., 1980)Crystallite orientation of Non-Graphitizable

    Carbon (Franklin,1951)

    Random orientation of the crystallites arepresent in non-graphitizable carbons.

    KH/KV or H/V ratio of natural and commercialgraphite = 1.15 3.2 (Slack, 1962)

  • 8/3/2019 Ani So Tropic Thermal Behavior of Porous Carbonized Wood

    8/248

    Carbonized Wood

    SEM images of cell wallof wood before andafter carbonization at700 C (Ishimaru et al., 2007)

    Dark field TEM image(Ishimaru et al., 2007)

    Turbostratic structure of carbonwith local molecular orientationlike crumpled paper(Oberlin et al., 1980)

  • 8/3/2019 Ani So Tropic Thermal Behavior of Porous Carbonized Wood

    9/249

    Carbonized Wood

    Relationship between carbonization temperaturewith electrical properties of carbonized wood(Ishihara, 1996)

    Carbonized wood becomes aconductor at around 700-800 C

    Thermal conductivity:- KH= 1.14 W/m.K- KV = 0.50 W/m.K

    H/V ratio: 2.31

  • 8/3/2019 Ani So Tropic Thermal Behavior of Porous Carbonized Wood

    10/2410

    Morphology of Carbonized WoodComposite

    Carbon foam produced by blowing

    process (Klett et al., 2004)Carbonized wood composite

    Carbonized wood composites possesses morphology with a porous structure

    Pores become important for thermal management application

  • 8/3/2019 Ani So Tropic Thermal Behavior of Porous Carbonized Wood

    11/2411

    Composites with Alternate Layers of CarbonsExhibiting Different Microstructures

    The alternating layers structure of graphitic and turbostratic carbons orientsgraphite in a macro-scale.

    Carbonized wood with a turbostratic structure are used to control heat flow inthe composite.

    Schematic structure of a three-layer laminated carbonizedwood-graphite (C/G) composite (Sulistyo et al., 2009)

  • 8/3/2019 Ani So Tropic Thermal Behavior of Porous Carbonized Wood

    12/2412

    Experimental

    CarbonizationAt 700 C, 4 C/min, 1 h

    Granulation25-32 and 63-90 m

    Alternate layering ofCarbonized Wood & graphite

    Heat treatmentAt 700 C, 71 C/min, 50 MPa,

    15 min, vacuum condition

    Effect of weight fraction ofcarbonized wood and particlesize: 0 100 wt% use 25-32

    and 63-90 m

    Effect interlayerinterface:

    2, 3,5, 7 and 9 layer

    Characterization:-Morphology

    - Microstructure- Thermal properties

    30 & 10 mm, d= 1 mm

    GraphiteCarbonizedwood

  • 8/3/2019 Ani So Tropic Thermal Behavior of Porous Carbonized Wood

    13/2413

    Thermal Conductivity

    Q: the absorbed quantity of heatd: the thickness: densityT0: the extrapolated temperature

    increase

    Thermal conductivity (k) (W/m K):a measure of the rate of heat flow through one unit thickness of a materialsubjected to a temperature gradient.

    Ck

    0Td

    QC

    : density (g/cm3)C: specific heat capacity (J/g/K)

    : thermal diffusivity (cm2/s)Specific heat capacity:

    the amount of energy needed to increase one unit of mass one unit in temperature.

    Thermal diffusivity: horizontal and vertical directiona measure of how quickly a material can absorb heat from its surrounding.

    2/1

    21388.0

    t

    d d: the thicknesst1/2: the time required for the temperature of

    the rear face to increase to a half of themaximum temperature

    Eff f W i h F i f

  • 8/3/2019 Ani So Tropic Thermal Behavior of Porous Carbonized Wood

    14/2414

    Effect of Weight Fraction ofCarbonized Wood

    C/G=10/90 C/G=20/80 C/G=33/67

    C/G=60/40 C/G=70/30 C/G=80/20

    Images by an optical microscope

  • 8/3/2019 Ani So Tropic Thermal Behavior of Porous Carbonized Wood

    15/2415

    0.0

    0.4

    0.8

    1.21.6

    0 20 40 60 80 100

    Weight fraction of carbonized

    wood (wt%)

    Sp

    ecificheatcapacity

    (J/g/K)

    measured

    calculated

    0.6

    0.8

    1.0

    1.2

    1.4

    1.6

    1.8

    0 20 40 60 80 100

    Weight fraction of carbonized

    wood (wt%)

    Specificheatcapacity

    (J/g/K)

    measured

    calculated

    25-32 m

    63-90 mGraphite

    Carbonizedwood

    A rough interlayerinterface

    Effect of Weight Fraction ofCarbonized Wood

    Specific Heat Capacity

    CCGG

    CCCGGG

    vv

    vCvCC

    Calculated C:

  • 8/3/2019 Ani So Tropic Thermal Behavior of Porous Carbonized Wood

    16/24

    Effect of Weight Fraction ofCarbonized Wood

    0

    5

    10

    15

    20

    25

    30

    35

    0 20 40 60 80 100

    Weight fraction of carbonized wood

    (wt%)

    k(

    W/mK)

    measured kHcalculated kHmeasured kVcalculated kV

    16

    25-32 m Thermal Conductivity

    Calculated kHand kV:

    HCtotalCHGtotalGHkddkddk

    VCtotalCVGtotalG

    V

    kddkddk

    11

    1

    0

    2

    4

    6

    8

    10

    12

    0 20 40 60 80 100

    Weight fraction of carbonized wood

    (wt%)

    H/Vratio

  • 8/3/2019 Ani So Tropic Thermal Behavior of Porous Carbonized Wood

    17/24

    Effect of Weight Fraction ofCarbonized Wood

    17

    Graphite

    Carbonizedwood

    Graphite

    3000

    3500

    4000

    4500

    1100 1200 1300 1400 1500 1600 1700 1800

    Raman shift (cm-1

    )

    Intensity(a.u.)

    D band

    G band

    500

    1000

    1500

    2000

    2500

    1100 1200 1300 1400 1500 1600 1700 1800

    Raman shift (cm-1

    )

    Intensity(a.u

    ) D bandG band

    Microstructure

    H/V ratio = 3.8

    H/V ratio = 1.9

  • 8/3/2019 Ani So Tropic Thermal Behavior of Porous Carbonized Wood

    18/24

    Effect of Weight Fraction ofCarbonized Wood

    18

    Optimum H/V

    ratio

    0

    5

    10

    15

    20

    2530

    35

    40

    0 20 40 60 80 100

    k(W/mK)

    0

    2

    4

    6

    8

    10

    12

    0 20 40 60 80 100

    H/Vratio

    0

    5

    10

    15

    20

    25

    30

    35

    0 20 40 60 80 100

    Weight fraction of

    carbonized wood (wt%)

    k(W/mK)

    25-32 mkH

    kV

    0

    2

    4

    6

    8

    10

    12

    0 20 40 60 80 100

    Weight fraction of

    carbonized wood (wt.%)

    H/Vr

    atio

    63-90 mkV

    kH

    Eff f W i h F i f

  • 8/3/2019 Ani So Tropic Thermal Behavior of Porous Carbonized Wood

    19/2419

    Effect of Weight Fraction ofCarbonized Wood

    C/G=10/90

    25-32 m

    C/G=10/90

    63-90 m

    Morpholologyby SEM

  • 8/3/2019 Ani So Tropic Thermal Behavior of Porous Carbonized Wood

    20/24

    20

    Effect of Interlayer Interfaces

    Graphite

    Graphite

    Carbonized wood

    Interlayer interfacePorous material withwood cellular structure

    The role of interlayer interface andparticle size on thermal propertiesbecome important to be known

  • 8/3/2019 Ani So Tropic Thermal Behavior of Porous Carbonized Wood

    21/24

    21

    Multilayer of C/G 10/90 images by an optical microscope

    Effect of Interlayer Interfaces

  • 8/3/2019 Ani So Tropic Thermal Behavior of Porous Carbonized Wood

    22/24

    22

    0.70

    0.75

    0.80

    0.85

    0 2 4 6 8 10

    No. of layer

    Specificheatcapacity

    (J/g/K)

    0

    5

    10

    15

    20

    25

    0 2 4 6 8 10

    No. of layer

    k(W/mK)

    Horizontal

    Vertical

    02

    4

    6

    8

    10

    0 2 4 6 8 10

    No. of layer

    H

    /Vratio

    Effect of Interlayer Interfaces

  • 8/3/2019 Ani So Tropic Thermal Behavior of Porous Carbonized Wood

    23/24

    23

    Conclusions

    1. Alternate layers of graphite and carbonized wood improvedthe anisotropic thermal conductivity2. The weight fraction of carbonized wood affected the

    thermal conductivity and the H/V ratio. The optimum H/Vratio of 10.17 was obtained at 10 wt% of carbonized wood

    3. Particle size affected the thermal conductivity and the H/Vratio in relationship with the morphology of carbonizedwood layer

    4. The interlayer interface of graphite and carbonized wood

    affected on the reduction of the thermal conductivity andthe H/V ratio

  • 8/3/2019 Ani So Tropic Thermal Behavior of Porous Carbonized Wood

    24/24

    Thank you very much