Contact thermal conductivity of a powder bed in selective laser sintering

Gusarov, A.V.; Laoui, Tahar; Froyen, Ludo; Титов, В. И.

doi:10.1016/s0017-9310(02)00370-8

Cited by 182 publications

(89 citation statements)

References 19 publications

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“…In the case of simple cubic packed and sintered "solid" particles, which is an extreme case of the present simulation, we can confirm that the present results are in considerably good agreement with the existing results (21)- (23) (see Fig. 5).…”

Section: Resultssupporting

confidence: 92%

Macroscopic Conductivity of Uniaxially Compacted, Sintered Balloon Aggregates

Taguchi

Kurashige

2007

JTST

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Balloon compacts attract a great attention as a new class of lightweight materials. In the present paper, macroscopic thermal conductivity of uniaxially compacted and sintered balloons is evaluated for various compaction degrees and balloon's inner-outer diameter ratios. The compaction is modeled by making the balloons overlapped without balloon flattening, and the sintering by adding some appropriate amount of mass around overlapping necks; the whole mass is conserved in both of the modelings. The macroscopic conductivities are estimated using Kirchhoff's current law. The results are expressed in terms of the two microgeometrical parameters. It is found that the uniaxial compaction complicatedly affects the macroscopic conductivities and strength of induced anisotropy of the compacts.

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Section: Resultssupporting

confidence: 92%

Macroscopic Conductivity of Uniaxially Compacted, Sintered Balloon Aggregates

Taguchi

Kurashige

2007

JTST

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“…Heat transfer in porous packed beds has been focusing huge efforts in many research fields in order to relate the effective thermal conductivity of the medium to porosity or grain size, either by the derivation of semiempirical relations from experiments or by analytical modeling via conductance networks, accounting for gas, contact or radiative conductivities (for nonexhaustive list see Rubiolo & Gatt 2002;Slavin et al 2002;Gusarov et al 2003;or Gundlach & Blum 2012). This yields numerous models, from most simple original to more complex ones, developed around numerical experiments and usually more parameter dependent.…”

Section: Effective Thermal Conductivity Of Porous Atmosphereless Surfmentioning

confidence: 99%

“…p = 0.26. The filling factor of the regolith D = 1−p can be calculated for face-centered-cubic to diamond classical pileups, from D = 0.74 (p = 0.26) to D = 0.34 (p = 0.66), with coordination number n C varying between 12 and 4 respectively (Gusarov et al 2003, for example). The upper limit of the porosity is limited to p = 0.84 for which the coordination number n C = 2, i.e., there is a minimum contact between spheres within the layer, at least two neighbors.…”

Section: Regolith Porosity and Grain Sizesmentioning

confidence: 99%

Low thermal inertias of icy planetary surfaces

Ferrari

Lucas

2016

A&A

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Context. Thermal inertias of atmosphereless icy planetary bodies happen to be very low. Aims. We relate the thermal inertia to the regolith properties such as porosity, grain size, ice form and heat transfer processes to understand why it is low. We interpret the dichotomy in thermal inertia of the surface of Mimas in terms of changes in regolith properties. We predict how the thermal inertia of these bodies may vary with heliocentric distance depending on these properties. Methods. We combine available models of conductivity by contact or radiation to understand what heat transfer process is predominant.Results. The magnitude of the thermal inertia of a porous icy regolith is mainly governed by the crystalline or amorphous ice forms, and the quality of contacts between grains. Beyond the orbit of Jupiter, thermal inertias as low as a few tens J/m 2 /K/s 1/2 are difficult to reproduce with plausible porosity and grains sizes made of crystalline ice unless contacts are loose. This is, on the contrary, straightforward for regoliths of sub-cm-sized grains made of amorphous water ice. This study points out the importance of including the temperature dependence of thermophysical properties of water ice forms and the radiative conduction in thermal models of these bodies. The relatively high thermal inertia of the leading face of Mimas can be explained by a regolith of crystalline ice grains in tight contacts, which are eventually sintered by the bombardment of high energy electrons. The low thermal inertia of its trailing face is easily reproduced by a regolith of moderate porosity with sub-mm-sized grains of amorphous ice. The characteristic decrease of thermal inertia with heliocentric distance of icy atmosphereless surfaces and the very low thermal inertia of relevant trans-Neptunian objects are easily explained if amorphous ice is present at cm depths below a thin layer of crystalline ice.

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“…Fig. 8 shows the curve of macroscopic conductivity against the nondimensional neck size denoted by , together with the three curves borrowed from the figure drawn by Gusarov et al [21]; they concluded that the three curves satisfactorily agree with each other at least in the case of smaller neck size. It can be seen from the figure that the present result is also in similar agreement with the existing three results; especially with that by Siu and Lee [22], although the present curve shows slightly stronger nonlinearity than theirs.…”

Section: Validity Of Network Modelmentioning

confidence: 68%

Microstructures and macroscopic conductivity of randomly packed and uniaxially pressed sphere compacts

Taguchi¹,

Kurashige²

2007

International Journal of Heat and Mass Transfer

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The present paper deals with simulation of microstructures and macroscopic conductivity of randomly packed, uniaxially pressed and sintered particles. Random packings of identical spheres are constructed by using a sequential deposition method and their microgeometry after the compaction in sintering is geometrically created by proportional reduction in distances between the sphere centers only in the vertical direction and by mass addition around overlapped necks. Some of microgeometrical characteristics of the created compacts are statistically examined. Using the data on the packings and geometrical models, macroscopic thermal conductivities of the compacts are estimated. It is found that the conductivities are greatly different from those of simple cubic packings, although both the packings have almost the same coordination number, and that anisotropy in the conductivity is induced by the compaction in addition to gravity. The conductivities are expressed as a function of the compaction and sintering degrees for practical purposes. Keywords

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Contact thermal conductivity of a powder bed in selective laser sintering

Cited by 182 publications

References 19 publications

Macroscopic Conductivity of Uniaxially Compacted, Sintered Balloon Aggregates

Macroscopic Conductivity of Uniaxially Compacted, Sintered Balloon Aggregates

Low thermal inertias of icy planetary surfaces

Microstructures and macroscopic conductivity of randomly packed and uniaxially pressed sphere compacts

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