Heat transfer behavior of melting polymers in laminar flow field

Sato, Sadao; Oka, Kenichiro; Murakami, Akihiko

doi:10.1002/pen.20038

Cited by 22 publications

(20 citation statements)

References 9 publications

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“…(a) and (b) depict the evolution in velocity and temperature characteristics with transverse coordinate, that is, normal to the plate surface for various Prandtl numbers, Pr . Relatively high values of Pr are considered since these physically correspond to industrial polymers . Prandtl number embodies the ratio of momentum diffusivity to thermal diffusivity in the boundary layer regime.…”

Section: Resultsmentioning

confidence: 99%

“…Relatively high values of Pr are considered since these physically correspond to industrial polymers. 53 Prandtl number embodies the ratio of momentum diffusivity to thermal diffusivity in the boundary layer regime. It also represents the ratio of the product of specific heat capacity and dynamic viscosity, to the fluid thermal conductivity.…”

Section: Validation Of Keller Box Solutionsmentioning

confidence: 99%

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Numerical exploration of thermal radiation and Biot number effects on the flow of a non‐Newtonian MHD Williamson fluid over a vertical convective surface

Amanulla¹,

Nagendra²,

Rao³

et al. 2017

Heat Trans. Asian Res.

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A theoretical and computational study of the magnetohydrodynamic flow and free convection heat transfer in an electroconductive polymer on the external surface of a vertical plate under radial magnetic field is presented. The Biot number effects are considered at the vertical plate surface via modified boundary conditions. The Williamson viscoelastic model is employed which is representative of certain industrial polymers. The nondimensional, transformed boundary layer equations for momentum and energy are solved with the second‐order accurate implicit Keller box finite difference method under appropriate boundary conditions. Validation of the numerical solutions is achieved via benchmarking with earlier published results. The influence of Weissenberg number (ratio of the relaxation time of the fluid and time scale of the flow), magnetic body force parameter, stream‐wise variable, and Prandtl number on thermo fluid characteristics are studied graphically and via tables. A weak elevation in temperature accompanies increasing Weissenberg number, whereas a significant acceleration in the flow is computed near the vertical plate surface with increasing Weissenberg number. Nusselt number is reduced with increasing Weissenberg number. Skin friction and Nusselt number are both reduced with increasing magnetic field effect. The model is relevant to the simulation of magnetic polymer materials processing.

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Section: Resultsmentioning

confidence: 99%

Section: Validation Of Keller Box Solutionsmentioning

confidence: 99%

Numerical exploration of thermal radiation and Biot number effects on the flow of a non‐Newtonian MHD Williamson fluid over a vertical convective surface

Amanulla¹,

Nagendra²,

Rao³

et al. 2017

Heat Trans. Asian Res.

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show abstract

“…In comparison, the tangential velocity in the present work, i.e., 520 mm/s, was much higher than 0.078 mm/s. Sato et al [28] noted that with this high tangential velocity, the convective heat transfer coefficient was predominant. [37].…”

Section: Comparison Of Temperatures Of Biomass Spheres and Pyrolysis mentioning

confidence: 95%

“…In co-pyrolysis conducted in a stirred tank reactor, heat transfer is driven by radiation and convection. In two extreme conditions, i.e., biomass pyrolysis and plastic pyrolysis, the former is more affected by heat radiation due to the presence of moderate emissivity of biomass and the later by heat convection because plastic melt induces high heat convection during its friction on the reactor hot wall [28]. Therefore, co-pyrolysis involves both heat radiation and heat convection with different proportions depending on the compositions of biomass-plastic feeds of the reactor.…”

Section: Introductionmentioning

confidence: 99%

Synergistic Effect on the Non-Oxygenated Fraction of Bio-Oil in Thermal Co-Pyrolysis of Biomass and Polypropylene at Low Heating Rate

2020

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Biomass pyrolysis and polypropylene (PP) pyrolysis in a stirred tank reactor exhibited different heat transfer phenomena whereby heat transfer in biomass pyrolysis was driven predominantly by heat radiation and PP pyrolysis by heat convection. Therefore, co-pyrolysis could exhibit be expected to display various heat transfer phenomena depending on the feed composition. The objective of the present work was to determine how heat transfer, which was affected by feed composition, affected the yield and composition of the non-polar fraction. Analysis of heat transfer phenomena was based on the existence of two regimes in the previous research in which in regime 1 (the range of PP composition in the feeds is 0–40%), mass ejection from biomass particles occurred without biomass particle swelling, while in regime 2 (the range of PP composition in the feeds is 40–100%), mass ejection was preceded by biomass particle swelling. The co-pyrolysis was carried out in a stirred tank reactor with heating rate of 5 °C/min until 500 °C and using N2 gas as carrier gas. Temperature measurement was applied to pyrolysis fluid at the lower part of the reactor and small biomass spheres of 6 mm diameter to simulate heat transfer to biomass particles. The results indicate that in regime 1 convective and radiative heat transfers sparingly occurred and synergistic effect on the yield of non-oxygenated phase increased with increasing convective heat transfer at increasing %PP in feed. On the other hand, in regime 2, convective heat transfer was predominant with decreasing synergistic effect at increasing %PP in feed. The optimum PP composition in feed to reach maximum synergistic effect was 50%. Non-oxygenated phase portion in the reactor leading to the wax formation acted as donor of methyl and hydrogen radicals in the removal of oxygen to improve synergistic effect. Non-oxygenated fraction of bio-oil contained mostly methyl comprising about 53% by mole fraction, while commercial diesel contained mostly methylene comprising about 59% by mole fraction

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“…Articles in this area discuss: heat transfer in a liquid-metal pool [JM18]; melting in metallurgical processes ; heat transport associated with simultaneous growth of solid-liquid melt layers [JM23]; melt flow in directionally solidified alloys [JM24,JM25]; polymer melt flow [JM26], melt furnace [JM27] and material interaction [JM28]; optical fiber manufacturing [JM29]; and food (cheese) processing [JM30]. A few studies were related to numerical modeling of the melting process .…”

Section: Melting and Melt Flowsmentioning

confidence: 99%