Material Properties and Regolith Layering
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Revision as of 16:10, 25 January 2019
Contents |
Regolith Layering
No Layering (Default)
IC2 = 999
No need to specify IC2 =999 (or thick, see below),
out = krc(lat = 0., lon = 0.) out = krc(lat = 0., lon = 0., IC2 = 999) out = krc(lat = 0., lon = 0., thick = 0.)
...give identical results.
Two Layers
The DaVinci Interface automatically determines the parameters to adjust from a thickness value (thick, in meters). The user can provide either an upper layer thickness (in m) or the layer index where the material properties change occurs.
out = krc(lat = 0., thick = 0.03)
Here, the property change occurs at a depth of 3 cm below the surface.
out = krc(lat=23., IC2 = 4)
Here, the property change occurs abetween the 3rd and the 4th mesh element.
H Parameter
A "H" parameter can describe the exponential variation of regolith properties with depth (density and conductivity). See Hayne et al. 2016. For this configuration, thick < 0, with abs(thick) = H
out = krc(lat = 0., lon = 0., thick = -0.3 )
In this case, H = 30 cm, and the material properties are taken from the default input file values.
out = krc(lat = 0., lon = 0., thick = -0.3, INERTIA = 200., INERTIA2 = 1200., LKofT = "F" )
In this case, H = 30 cm, and the material inertias are defined by the user.
Alternatively, all the parameters can be explicitely provided:
out = krc(lat = 0., lon = 0., thick = -0.3, COND = 0.1, DENSITY = 1800., SPEC_HEAT = 600., COND2 = 0.1, DENS2 = 1800., SpHeat2 = 600., LKofT = "F" )
out = krc(lat = 0., lon = 0., thick = -0.3, INERTIA = 200., INERTIA2 = 1200. )
In this case, H = 30 cm, and the material properties are defined by the user, with temperature dependence.
LIMITATION: Only top 2 elements have temperature-dependent properties
N Layers or Tables
Table Zone
Material Properties
Material properties are defined by (no temperature dependence):
INERTIA DENSITY SPEC_HEAT
INERTIA2 DENS2 SpHeat2
KRC doesn't explicitly require a conductivity, it derives it from INERTIA, DENSITY, and SPEC_HEAT. But the interface can ingest a conductivity, as well as a combo of other parameters.
COND
COND2
Density, conductivity, and specific heat can be calculated from standard materials behaviors ("basalt", and "H2O") assuming they form continuous media. To assign material properties, indicate Mat1 and and Mat2 if necessary.
Mat1 = "basalt"
...assigns bulk basalt properties to the upper material.
Mat2 = "H2O"
...assigns water ice properties to the lower material.
Density
Doesn't vary with temperature, and is defined by:
DENS
and
DENS2
Variations with depth can be defined with an H parameter, or a Table.
When TI < TI_CO, the interface assumes a density associated with a porosity of 0.4, and a bulk density associated with basalt. The porosity can be changed by setting:
Por1 = [0. - 1.]
And if needed:
Por2 = [0. - 1.]
Alternatively, the density can be set directly.
For water ice, the density is set to = 924.148 kg/m^3 (220 K). [Rottger et al. (2011): Lattice constants and thermal expansion of H2O and D2O Ice Ih between 10 and 265 K. Addendum], but depending on the temperature (body), this value might need to be changed. See plot below:
PLOT HERE DENSITY VS TEMPERATURE.
More details in the tab "Density(T) H2O" in this document for the derivation density versus temperature: File:Material KRC.xlsx
For basalt, the density is set to = 3100. kg/m^3. [J. MORE 2001, DENS. OF BASALT CORE FROM HILO DRILL HOLE, HAWAII]. For the absolute density value. For trend with temperature: [F.E. Heuze. High temperature mechanical, physical and thermal properties of granitic rocks: A review. Int. J. Rock Mech. Mining Sci., 20:3–10, 1983.].
PLOT HERE DENSITY VS TEMPERATURE.
More details in the tab "Density(T) Basalt" in this document for the derivation density versus temperature: File:Material KRC.xlsx
NOT IMPLEMENTED YET
For CO2, the density is set to = 1621. kg/m^3. [1], but depending on the temperature (body), this value might need to be changed. See plot below:
PLOT HERE DENSITY VS TEMPERATURE.
More details in the tab "Density(T) C2O" in this document for the derivation density versus temperature: File:Material KRC.xlsx
N2 Not formalized yet.
Specific Heat
SphUp0 = SPEC_HEAT = SpHeat2 SphUp1 SphUp2 SphUp3
Cp = SphUp0 + SphUp x + SphUp2 x^2 + SphUp3 x^3
where x = ( T - 220 ) * 0.01
See [REF VU] for trends and coefficients of a variety of materials.
Parameter | Basalt | H2O | CO2 | N2 | SO2 | CH4 |
SphUp0 | 609.906 | 1704.57 | 1399.88 | 6137.28 | 1132.09 | 18356.1 |
SphUp1 | 214.231 | 713.339 | 652.64 | 4082.15 | 364.914 | 29096.3 |
SphUp2 | -40.9437 | 110.694 | 432.015 | 789.538 | 127.915 | 18515.3 |
SphUp3 | 11.2575 | 75.7506 | 192.398 | -0.109612 | 77.4213 | 4143.07 |
Basalt: Hemingway, Robie, Wilson, http://adsbit.harvard.edu/cgi-bin/nph-iarticle_query?bibcode=1973LPSC....4.2481H&db_key=AST&page_ind=0&data_type=GIF&type=SCREEN_VIEW&classic=YES
H2O: W. F. Giauque and J. W. Stout (1936)]
CO2: REF HERE
N2: REF HERE
SO2: REF HERE
CH4: REF HERE
More details on the fits here: File:Material KRC.xlsx
Thermal Conductivity
For material properties temperature dependence:
ConUp0 = COND = COND2 ConUp1 ConUp2 ConUp3
k = ConUp0 + ConUp x + ConUp2 x^2 + ConUp3 x^3
where x = ( T - 220 ) * 0.01
Fines in Vacuum
In a vacuum, if INERTIA < TI_CO, the interface assumes a T^3 trend for the conductivity (INERTIA/COND set at T_user) from a polynomial fit between 10 and 500K yat follows the REF equation:
COND = INERTIA^2/(SPEC_HEAT*(1.-Por1)*Density_bulk)
k = COND*(1+2.7*((T-T_user)/350.)^3)
PLOT k HERE FOR A COUPLE OF EXAMPLES
Fines with an Atmosphere
With an atmosphere, if INERTIA < TI_CO, the interface assumes a sqrt(T) trend for the conductivity (INERTIA/COND set at T_user) from a polynomial fit between 10 and 500K yat follows the REF equation:
COND=INERTIA^2/(SPEC_HEAT*(1-Por1)*Density_bulk)
COND*sqrt(T/T_user)
HERE CHECK T_user vs 220 K in interface (interface seems to be stuck at 220k)
PLOT k HERE FOR A COUPLE OF EXAMPLES
Bulky Water Ice
If INERTIA > TI_CO, the conductivity trend is driven by bulk water ice properties [Slack, G.A. (1980), Thermal conductivity of ice. Physical Review , B22, 3065-71]:
ConUp0=INERTIA^2/(SPEC_HEAT*(1.-Por1)*Density_bulk) ConUp0=3.06 SI from Ref at 220K
ConUp1=-1.08693
ConUp2=-0.334381
ConUp3=-1.60453
More details in the tab "k(T) H2O bulk" in this document for the derivation density versus temperature: File:Material KRC.xlsx
PLOT HERE
Bulky Basalt
If INERTIA > TI_CO, the conductivity trend is driven by bulk water ice properties [REF UNKNOWN]:
ConUp0 = INERTIA^2/(SPEC_HEAT*(1-Por1)*Density_bulk) ConUp0 = 5.32202 SI from Ref at 220K.
ConUp1=-1.51737
ConUp2=0.587176
ConUp3=-0.126695
More details in the tab "basalt(T) H2O bulk" in this document for the derivation density versus temperature: File:Material KRC.xlsx
PLOT HERE
Bulky CO2 Ice
Text here
Bulky N2 Ice
tetx here
Parameter | Basalt | H2O | CO2 | N2 | SO2 | CH4 |
ConUp0 | 5.32202 | 3.06445 | 0.441346 | 0.07 | N/A | 0.0308666 |
ConUp1 | -1.51737 | -1.08693 | -0.0686357 | 0. | N/A | 0.071247 |
ConUp2 | 0.587176 | -0.334381 | 0.425127 | 0. | N/A | 0.289212 |
ConUp3 | -0.126695 | -1.60453 | 0.233004 | 0. | N/A | 0.0617607 |
define ice_prop(composition,T) {
if($ARGC == 0){
printf (" Returns a structure containing physical properties of ices: \n") printf (" density, specific heat, conductivity, vapor pressure \n") printf (" Source is Solar System Ices book \n") printf (" $1 = ice composition, between double quotes \n") printf (" Supported ices CO2, H2O, SO2, N2, CH4 \n") printf (" $2 = Temperature in K \n") }
if($ARGC !=0){
composition = $1 T = $2
ice=struct()
if (composition == "CO2") {
a_dens = 32.939*44.0095 b_dens = 0.06842*44.0095 c_dens = -0.0002847*44.0095 d_dens = 0.0 e_dens = 0.0
a_spht = -18282.0/44.0095 b_spht = 1360.3/44.0095 c_spht = -12.152/44.0095 d_spht = 0.05158/44.0095 e_spht = -0.00007699/44.0095
buffer = -5.39941 + 5.45894*log10(T) - 1.41326*(log10(T))^2 k = 10^buffer
a_p = 25.784 b_p = -3258.2 c_p = 0.77194 d_p = -0.0081188 e_p = 1 }
if (composition == "H2O") {
a_dens = 53.03*18.01528 b_dens = -0.0078409*18.01528 c_dens = 0 d_dens = 0 e_dens = 0
a_spht = -262.49/18.01528 b_spht = 140.52/18.01528 c_spht = 0 d_spht = 0 e_spht = 0
buffer = -8.98536+103.12814*log10(T)-413.60906*(log10(T))^2+909.93398*(log10(T))^3-1197.181581*(log10(T))^4 buffer = buffer+979.4272418*(log10(T))^5-502.5613545*(log10(T))^6+157.3223437*(log10(T))^7 buffer = buffer-27.46439969*(log10(T))^8+2.049301625*(log10(T))^9 k = 10^buffer
a_p = 28.766 b_p = -6109.19 c_p = 0.0 d_p = 0.0 e_p = 0.0 }
if (composition == "SO2") {
a_dens = 32.3811*64.0638 b_dens = -0.0204768*64.0638 c_dens = 0 d_dens = 0 e_dens = 0
a_spht = -22900/64.0638 b_spht = 1723.6/64.0638 c_spht = -16.519/64.0638 d_spht = 0.076593/64.0638 e_spht = -0.00012792/64.0638
k = 0.0
a_p = 95.972 b_p = -6426.94 c_p = -10.6005 d_p = 0.0 e_p = 0.0
}
if (composition == "N2") {
a_dens = 37.87*28.0134 b_dens = -0.060272*28.0134 c_dens = 0 d_dens = 0 e_dens = 0
a_spht = 27420/28.0134 b_spht = 170.1/28.0134 c_spht = 2.2125/28.0134 d_spht = 0 e_spht = 0
a_k = 1.3081 b_k = -0.085791 c_k = 0.0027961 d_k = -0.000044695 e_k = 0.00000027819
k = a_k+b_k*T+c_k*T^2+d_k*T^3+e_k*T^4
a_p = 28.766 b_p = -6109.19 c_p = 0.0 d_p = 0.0 e_p = 0.0
}
if (composition == "CH4") {
a_dens = 33.022*16.04246 b_dens = -0.01587*16.04246 c_dens = -0.000155*16.04246 d_dens = 0 e_dens = 0
a_spht = -2550/16.04246 b_spht = 1249.9/16.04246 c_spht = -14.17/16.04246 d_spht = 0.06648/16.04246 e_spht = 0
buffer = 5.679842 - 13.421524*log10(T) + 9.534462*(log10(T))^2 - 2.196201*(log10(T))^3 k = 10^buffer
a_p = 22.1398 b_p = -1159.3 c_p = 0.0 d_p = 0.0 e_p = 0.0
}
ice.dens = a_dens+b_dens*T+c_dens*T^2+d_dens*T^3+e_dens*T^4 ice.spht = a_spht+b_spht*T+c_spht*T^2+d_spht*T^3+e_spht*T^4 ice.k = k ice.TI = sqrt(ice.k*ice.dens*ice.spht) ice.pressure = exp(a_p+b_p/T+c_p*ln(T)+d_p*T^e_p)
return(ice)
} }
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