Heat Transfer inside Elliptic Cylindrical Reactor: Effect of Bed Porosity

The study of heat transfer phenomenon in porous media by fluids percolated in the axial direction has been of interest to many researchers in various branches of science and technology. Applications are directed to different process such as filtration, distillation, absorption and adsorption in columns, drying and catalytic reactions in fixed beds. The literature has presented several solutions of the heat diffusion / convection equation in fixed bed reactors, but these studies are limited to a cylindrical geometry. In this sense, this work aim to present a pseudo-homogeneous three-dimensional model to describe the steady-state heat transfer within a fixed bed reactor with elliptic cylindrical geometry by considering variable porosity. The energy equation written in elliptical cylindrical coordinates and applied to the porous medium (particulate system) is discretized numerically using the finite volume method. Results of the temperature distribution within the bed are presented analyzed. It was verified that with increased porosity heat transfer inside the reactor tends to be more intense and thus, lower temperature gradients are found in all cross section of the reactor.

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Heat Transfer in Packed Bed Elliptic-Cylindrical Reactor: The Geometry Effect

Defect and Diffusion Forum ◽

10.4028/www.scientific.net/ddf.391.54 ◽

2019 ◽

Vol 391 ◽

pp. 54-59 ◽

Cited By ~ 1

Author(s):

R. Moura da Silva ◽

A. Santos Pereira ◽

A.G. Barbosa de Lima ◽

Morgana Vasconcellos Araújo ◽

R.S. Santos

Keyword(s):

Heat Transfer ◽

Aspect Ratio ◽

Temperature Profile ◽

Fixed Bed ◽

Three Dimensional ◽

Packed Bed ◽

Dimensionless Temperature ◽

Variable Porosity ◽

Cylindrical Reactor ◽

Half Axis

This work aims to develop a transient three-dimensional mathematical model to predict the temperature distribution in a fixed-bed elliptical cylindrical reactor to different geometric aspect ratio (L2/L1=1.5, 2.0 and 3.0). The model considers variable thermo-physical properties, a flat temperature profile at the fluid inlet, as well as a variable porosity model. The governing equation is solved using the finite volume method, coupled with WUDS interpolation scheme and fully implicit method. Results of the temperature profile along the reactor are presented and discussed at different times. As results, it was found that the maximum rate of heat transfer within the reactor occurs near the minor half-axis region of the ellipse (cross-section area of the reactor) and it intensifies over time and that the dimensionless temperature profile is practically unchanged with the aspect ratio.

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THREE-DIMENSIONAL MODEL AND NUMERICAL SIMULATION OF HEAT TRANSFER IN AN ANISOTROPIC HELICAL SOLID-MASS WITH INNER HEAT SOURCE

High Temperature Material Processes An International Quarterly of High-Technology Plasma Processes ◽

10.1615/hightempmatproc.v10.i2.110 ◽

2006 ◽

Vol 10 (2) ◽

pp. 301-316

Author(s):

Xuefeng Wang ◽

David F. Chao ◽

Nengli Zhang

Keyword(s):

Heat Transfer ◽

Numerical Simulation ◽

Heat Source ◽

Three Dimensional ◽

Solid Mass ◽

Dimensional Model ◽

Three Dimensional Model

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CFD Study of Heat Transfer near and at the Wall of a Fixed Bed Reactor Tube: Effect of Wall Conduction

Industrial & Engineering Chemistry Research ◽

10.1021/ie049183e ◽

2005 ◽

Vol 44 (16) ◽

pp. 6342-6353 ◽

Cited By ~ 19

Author(s):

Anthony G. Dixon ◽

Michiel Nijemeisland ◽

E. Hugh Stitt

Keyword(s):

Heat Transfer ◽

Fixed Bed ◽

Fixed Bed Reactor

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Investigation of radial heat transfer in a fixed-bed reactor: CFD simulations and profile measurements

Chemical Engineering Journal ◽

10.1016/j.cej.2017.02.063 ◽

2017 ◽

Vol 317 ◽

pp. 204-214 ◽

Cited By ~ 40

Author(s):

Ying Dong ◽

Bahne Sosna ◽

Oliver Korup ◽

Frank Rosowski ◽

Raimund Horn

Keyword(s):

Heat Transfer ◽

Fixed Bed ◽

Fixed Bed Reactor ◽

Cfd Simulations ◽

Radial Heat

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AERODYNAMICS OF JETS INTERACTING WITH A FLAT SURFACE

Izvestiya Ferrous Metallurgy ◽

10.17073/0368-0797-2019-4-263-269 ◽

2019 ◽

Vol 62 (4) ◽

pp. 263-269

Author(s):

I. A. Pribytkov ◽

S. I. Kondrashenko

Keyword(s):

Heat Transfer ◽

Critical Point ◽

Flat Surface ◽

Stokes Equations ◽

Thermal State ◽

Exchange Process ◽

Three Dimensional ◽

Internal Diameter ◽

Three Dimensional Model ◽

Aerodynamic Properties

In this paper, the development features of a single free jet of hightemperature nitrogen interacting with a ﬂat surface were studied. Calculation of the heat exchange process during heating by the attacking jets is very difficult to implement analytically due to complexity of the gas-dynamic processes occurring both in a single jet and in a system of jets interacting with the metal. The computational difficulties are aggravated by the fact that when interacting with the surface the jet as such disappears. The ﬂat (fan) ﬂow interacts with the surface: form, aerodynamic properties and thermal state of the ﬂow strongly diﬀer from those of the original jet. The studies were conducted on the basis of numerical simulation in the FloEFD software and computing complex for multiphysical simulation based on solution of the equations of gas dynamics and heat transfer. The solved system of equations consisted of Navier-Stokes equations, equations of energy and continuity and was supplemented by k – ε turbulence model. A three-dimensional model was developed for simulation, the necessary properties, initial and boundary conditions were specified. In the study of aerodynamics of a single high-temperature jet interacting with the surface, the main defining values were: nitrogen ﬂow rate from the nozzle U0 , nitrogen temperature T, internal diameter of the nozzle d0 , distance from the nozzle section to the surface h, distance from the critical point (point of intersection of the jet axis with the surface) along the ﬂow radius r. Data on the gas velocity decrease as the jet develops due to the loss of initial energy to engage the motionless surrounding gas in motion, is presented. The studies have shown that increase in the initial velocity of gas outﬂow brings the area of higher velocities closer to the surface both in the jet itself and in the fan jet. This factor contributes to heat transfer intensification. In addition, high speeds increase the total thickness of the fan ﬂow and reduce the thickness of hydrodynamic boundary layer, which increases with distance from the critical point.

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Conjugate Flow and Heat Transfer Investigation of a Turbo Charger: Part I — Numerical Results

Volume 3: Turbo Expo 2003 ◽

10.1115/gt2003-38445 ◽

2003 ◽

Cited By ~ 18

Author(s):

Dieter Bohn ◽

Tom Heuer ◽

Karsten Kusterer

Keyword(s):

Heat Transfer ◽

Three Dimensional ◽

Heat Fluxes ◽

Inlet Temperature ◽

Three Dimensional Model ◽

Flow And Heat Transfer ◽

Turbine Inlet ◽

Turbo Charger ◽

Conjugate Calculation

In this paper a three-dimensional conjugate calculation has been performed for a passenger car turbo charger. The scope of this work is to investigate the heat fluxes in the radial compressor which can be strongly influenced by the hot turbine. As a result of this, the compressor efficiency may deteriorate. Consequently, the heat fluxes have to be taken into account for the determination of the efficiency. To overcome this problem a complex three-dimensional model has been developed. It contains the compressor, the oil cooled center housing, and the turbine. 12 operating points have been numerically simulated composed of three different turbine inlet temperatures and four different mass flows. The boundary conditions for the flow and for the outer casing were derived from experimental test data (part II of the paper). Resulting from these conjugate calculations various one-dimensional calculation specifications have been developed. They describe the heat transfer phenomena inside the compressor with the help of a Nusselt number which is a function of an artificial Reynolds number and the turbine inlet temperature.

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Numerical Study of Turbulent Flow and Convective Heat Transfer Characteristics in Helical Rectangular Ducts

Journal of Heat Transfer ◽

10.1115/1.4028583 ◽

2014 ◽

Vol 136 (12) ◽

Cited By ~ 3

Author(s):

Yunfei Xing ◽

Fengquan Zhong ◽

Xinyu Zhang

Keyword(s):

Heat Transfer ◽

Convective Heat Transfer ◽

Convective Heat ◽

Numerical Study ◽

Rectangular Cross Section ◽

Three Dimensional ◽

Flow Characteristics ◽

Axial Direction ◽

Outer Wall ◽

Centrifugal Effect

Three-dimensional turbulent forced convective heat transfer and its flow characteristics in helical rectangular ducts are simulated using SST k–ω turbulence model. The velocity field and temperature field at different axial locations along the axial direction are analyzed for different inlet Reynolds numbers, different curvatures, and torsions. The causes of heat transfer differences between the inner and outer wall of the helical rectangular ducts are discussed as well as the differences between helical and straight duct. A secondary flow is generated due to the centrifugal effect between the inner and outer walls. For the present study, the flow and thermal field become periodic after the first turn. It is found that Reynolds number can enhance the overall heat transfer. Instead, torsion and curvature change the overall heat transfer slightly. But the aspect ratio of the rectangular cross section can significantly affect heat transfer coefficient.

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