Axial heat transfer in packed beds. Stagnant beds between 20 and 750°C

Beveridge, G.S.G.; Haughey, D. P.

doi:10.1016/0017-9310(71)90207-9

Cited by 40 publications

(8 citation statements)

References 44 publications

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“…Under such conditions, the effective thermal conductivity is primarily dependent on the thermal conductivities of the solid particle k,, the stagnant gas k,, and the bed properties. Several models have been published to determine the effective thermal conductivities of a packed bed of particles (Argo and Smith, 1953;Yagi et al, 1957;Beveridge and Haughey, 1971). In this study, the heat-conduction model of Deissler and Boegli (Beveridge and Haughey, 1971), which calculates the effective thermal conductivity of packed beds under low pressure yas used: where and where eA,, eA2, and eA3 are the area factors and n, is the number of contact points.…”

Section: Conduction Modelmentioning

confidence: 99%

“…Several models have been published to determine the effective thermal conductivities of a packed bed of particles (Argo and Smith, 1953;Yagi et al, 1957;Beveridge and Haughey, 1971). In this study, the heat-conduction model of Deissler and Boegli (Beveridge and Haughey, 1971), which calculates the effective thermal conductivity of packed beds under low pressure yas used: where and where eA,, eA2, and eA3 are the area factors and n, is the number of contact points. As shown in Figure 1, the unit cross-sectional area is divided into three parallel paths: eA1 is the path of gas conduction, eA2 the path of solid conduction, and the path of contact conduction.…”

Section: Conduction Modelmentioning

confidence: 99%

“…The value F,, = 0.576 has been computed by Wakao and Kato (1969). Quite often, the radiation heat transfer between the packed particles is expressed by a radiation thermal conductivity, k , (Beveridge and Haughey, 1971;Harris and Lenz, 1985;Kung, 1972), as Convection Heat-Transfer Coefficient. During tire pyrolysis, approximately 65% by weight of the rubber is decomposed and evaporated.…”

Section: Global-heat-transfer Modelmentioning

confidence: 99%

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Numerical model for the vacuum pyrolysis of scrap tires in batch reactors

1995

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Section: Conduction Modelmentioning

confidence: 99%

Section: Conduction Modelmentioning

confidence: 99%

Section: Global-heat-transfer Modelmentioning

confidence: 99%

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Numerical model for the vacuum pyrolysis of scrap tires in batch reactors

1995

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“…Topics such as radiation components in insulation systems, in chemical fixed bed reactors,inporousparticles, and theeffect of radiation on the wall heat transfer coefficient are mentioned only briefly. [9] sowie Zehner und Schliinder [lo] [8]. Vergleich mit (k:)c.…”

Section: Schlubbemerkungenmentioning

confidence: 99%

Wärmestrahlung in dispersen Feststoffsystemen

Vortmeyer

1979

Chemie Ingenieur Technik

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Heat radiation in packed solids. The term packed solids embraces fixed beds and all other, sometimes less rigidly fixed, arrangements of solids particles of any shape in a gaseous environment. Cell and quasihomogeneous models have been developed for determining heat radiation in such systems and their predictions compared with one another and especially with available experimental data. Since fixed beds of spherical particles have been considered most frequently so far, they receive the greatest attention in this article. Topics such as radiation components in insulation systems, in chemical fixed bed reactors, in porous particles, and the effect of radiation on the wall heat transfer coefficient are mentioned only briefly.

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“…Despite continuous efforts in the modeling of 𝑘 !"" of particle beds with varying materials, sizes, and packing structures since the 1960s [12][13][14][15][16][17][18] , an accurate and predictive model remains elusive due to the complexity of heat transfer in the particle bed. 𝑘 !""…”

Section: Introductionmentioning

confidence: 99%

Thermal conductivity modeling of monodispersed microspheres using discrete element method

Zeng

Chung

Zhang

et al. 2021

Journal of Applied Physics

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Particle beds are widely used in various systems and processes, such as particle heat exchangers, granular flow reactors, and additive manufacturing. Accurate modeling of thermal conductivity of particle beds and understanding of their heat transfer mechanisms are important. However, previous models were based on a simple cubic packing of particles which could not accurately represent the actual heat transfer processes under certain conditions. Here, we examine the effect of the packing structure on thermal conductivity of particle beds. We use monodispersed silica microspheres with average article sizes ranging from 23 to 330 µm as a model material. We employ a transient hot-wire technique to measure the thermal conductivity of the particle beds with packing density of 43 to 57% within a temperature range of room temperature to 500℃ and under N2 gaseous pressures of 20 to 760 Torr. We then use a discrete element method (DEM) to obtain the realistic packing structure of the particles, which is then fed into a finite-element model (FEM) to calculate the thermal conductivity, with the consideration of solid conduction, gas conduction, and radiation heat transfer. Our results show that the thermal conductivity model based on the more realistic random packing structure derived from the DEM shows better agreement with the experimental data compared to that based on the simple cubic packing structure. The combined DEM and FEM methodology can serve as a useful tool to predict effective thermal conductivity of particle beds and to quantify different heat transfer mechanisms under various conditions.

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Axial heat transfer in packed beds. Stagnant beds between 20 and 750°C

Cited by 40 publications

References 44 publications

Numerical model for the vacuum pyrolysis of scrap tires in batch reactors

Numerical model for the vacuum pyrolysis of scrap tires in batch reactors

Wärmestrahlung in dispersen Feststoffsystemen

Thermal conductivity modeling of monodispersed microspheres using discrete element method

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