Effect of particle shape on particle-surface thermal contact resistance.

Malhotra, Karun; Mujumdar, Arun S.

doi:10.1252/jcej.23.510

Cited by 12 publications

(6 citation statements)

References 5 publications

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“…It is shown later in this paper that the roughness parameter, s, , can greatly affect the dependency of the contact heat transfer coefficient on the particle size. In addition, Malhotra and Mujumdar (1990) have demonstrated the high sensitivity of the contact heat transfer coefficient to particle shape. This is examined in more detail later.…”

Section: Dry Solids Resultsmentioning

confidence: 99%

“…The specific heats of the particles were measured experimentally. Since the particles used in the experiments are angular and non-spherical, the expression derived by Malhotra and Mujumdar (1990), was used to calculate the contact heat transfer coefficient, h,:…”

Section: Input Data To the Modelmentioning

confidence: 99%

“…Schliinder (1982) proposes an expression for spherical particles: Malhotra and Mujumbar (1990) have presented analogous equations for ellipsoidal and slab-shaped particles. Table 2 compares the contact heat transfer coefficients calculated using the Schliinder (1982) equation for spherical particles, Equation (12), and those calculated using the Malhotra and Mujumdar (1990) equation for rectangular particles with one edge in contact with the wall, Equation (11). In addition, the corresponding values of the overall wall-to-bed heat transfer coefficient, h, , + are given.…”

Section: Sensitivities To Particle Size and Shapementioning

confidence: 99%

“…In addition to particle shape, Malhotra and Mujumdar (1991a) have identified the sum of the particle and surface roughness, s,, as an important parameter in calculating the contact heat transfer coefficient. Using the Malhotra and Mujumdar (1990) equation for a slab on its edge, the contact heat transfer coefficient was calculated as a function of particle size for several values of s, . The results are shown in Figure 14.…”

Section: Sensitivities To Particle Size and Shapementioning

confidence: 99%

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A comprehensive heat transfer model for rotary desorbers

et al. 1996

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A model that describes the heat transfer processes within a rotary desorber is presented. This model has several advantages over previous models. The method for calculating the wall-to-bed heat transfer rate includes the effects of moisture in the feed solids and allows for evaporation from the bed before the bulk bed temperature reaches the saturation temperature of the moisture. The method for calculating radiative heat transfer in the desorber accounts for the real nature of the participating gas and the amounts of CO, and H,O in the gas phase from both combustion and evaporation. Results from experiments performed using a pilot-scale desorber are discussed, and the model is validated by comparing the predicted bed temperature profiles and evaporation rates to those found experimentally. A preliminary attempt to account for the effects of a non-uniform bed on the evaporation rate from the bed is also presented along with several parametric studies.On prksente un modtle d&rivant les procedks de transfert de chaleur dans un dispositif de dksorbtion rotatif. Ce modtle prksente plusieurs avantages sur les modbles pr6ddents. La mkthode de calcul du taux de transfert de chaleur entre la paroi et le lit tient compte des effets de I'humiditk dans les solides d'alimentation et permet I'kvaporation 2 1 partir du lit avant que la temp6rature en masse du lit n'atteigne la temp6rature de saturation de I'humiditk. La mkthode pour calculer le transfert de chaleur radiatif dans le dksorbeur tient compte de la nature rklle du gaz participant et des quanties de CO, et H,O dans la phase gazeuse issue de la combustion et de 1'6vaporation. On analyse les rksultats des exp6riences menks ?i I'aide d'un dispositif de dtsorbtion ?i l'khelle pilote, et on valide rksultats en comparant la praiction des profils de temp6rature du lit et des taux d'kvaporation et Zt des donnks exphimentales. On prksente dgalement un travail prkliminaire pour tenir compte des effets d'un lit non uniforme sur la vitesse d'kvaporation Zt partir du lit ainsi que plusieurs ktudes paramktriques.

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Section: Dry Solids Resultsmentioning

confidence: 99%

Section: Input Data To the Modelmentioning

confidence: 99%

Section: Sensitivities To Particle Size and Shapementioning

confidence: 99%

Section: Sensitivities To Particle Size and Shapementioning

confidence: 99%

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A comprehensive heat transfer model for rotary desorbers

et al. 1996

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“…Shape factor (Hsu et al, 1994) Dimensionless radiative (Tsotsas and Martin, 1987) conductivity Dimensionless gas phase (Tsotsas and Martin, 1987) conductivity Effective particle diameter (Tsotsas and Martin, 1987) Effective scattering factor (Lund et al, 1999) Modified mean free path (Malhotra and Majumdar, 1990) where The parameters B, k R and k G are given in Table 1. While using Equations (13) to (16) to calculate the ETC of a packed bed, the bed porosity e must be known.…”

Section: Parameter Relationmentioning

confidence: 99%

Modelling the Effective Thermal Conductivity in Polydispersed Bed Systems: A Unified Approach using the Linear Packing Theory and Unit Cell Model

2002

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A comprehensive, unified approach, using the Linear Packing Theory and Unit Cell Model, is proposed for calculating of the effective thermal conductivity of polydispersed packed beds. In this new approach, the effect of packing density is incorporated by the use of (i) an initial porosity to take into account the packing of mono‐sized particles, and (ii) the packing size ratio as a measure of the particle‐particle interaction. The proposed approach was validated with the experimental measurements of binary and ternary beds. This new approach demonstrates that the effective thermal conductivity of beds composed of polydispersed particles can be simulated for any composition without the need to measure the in situ porosity.

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