Equivalence of one- and two-phase models for heat transfer processes in packed beds: one dimensional theory

Vortmeyer, D.; Schaefer, R.J.

doi:10.1016/0009-2509(74)80059-x

Cited by 197 publications

(50 citation statements)

References 9 publications

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“…Investigations concerning the effects of the radial and axial dispersion in the bed were presented in [18,19]. How a single phase model can be derived from the continuous solid phase model was demonstrated in [20]. A storage unit of the fixed type using Schumann's model, including possible variations in the fluid inlet temperature, was modelled in [21].…”

Section: Introductionmentioning

confidence: 99%

Numerical investigation of sensible thermal energy storage in high temperature solar systems

Andreozzi¹,

Bianco²,

Manca³

et al. 2009

WIT Transactions on Modelling and Simulation

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A study on sensible thermal energy storage (TES) for high temperature solar systems is numerically accomplished. The high temperature TES is cylindrical, the fluid and the solid thermo-physical properties are temperature independent and the radiation heat transfer mechanism is neglected. A parametric analysis is carried out. The commercial CFD Fluent code is used to solve the governing equations in the transient regime. Numerical simulations are carried out at different mass velocity values of the heat-carrying fluid and porosity of the storage medium. The results show the effects of the porosity and of the working fluid mass velocity on the stored thermal energy and on the storage time.

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Section: Introductionmentioning

confidence: 99%

Numerical investigation of sensible thermal energy storage in high temperature solar systems

Andreozzi¹,

Bianco²,

Manca³

et al. 2009

WIT Transactions on Modelling and Simulation

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“…The set of equations (6) has an analytical solution when the conduction terms are negligible, which is usually accepted for high Reynolds numbers [Vortmeyer and Schaefer, 1974]. Then, the following expression is obtained.…”

Section: Analytical Solution Neglecting Solid Conductivitymentioning

confidence: 99%

Thermal Analysis and Optimization of a Heat Regenerator Composed of Two Coupled Moving Bed Heat Exchangers

Almendros-Ibáñez

Soria-Verdugo

Ruiz-Rivas

et al. 2008

International Symposium on Advances in Computational Heat Transfer

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This work presents a study to optimize the performance of a heat regenerator composed by two coupled moving bed heat exchangers (MBHE). A MBHE is used to recover heat, from a hot gas stream, and the other one is used to preheat an air stream. A direct application might be a gasifier. The heat exchangers performance was studied in two cases, considering or not the conduction heat transfer in the solid phase. When the solid conduction is taken into account, a numerical solution is obtained, while an analytical solution is possible when the conduction terms are neglected. In both cases, the optimum values of bed length (in the air flow direction) and particle diameter were obtained from an exergy point of view. Finally, an energy optimization of the heat regenerator was carried out, obtaining the optimal heat regenerator dimensions as a function of gas velocity and gas flow rate.

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“…The equation system (3) has also an analytical solution when the conduction terms are negligible, which is usually accepted for high Reynolds numbers [31]. Then, the equation system (3) becomes:…”

Section: 4mentioning

confidence: 99%

Solid conduction effects and design criteria in moving bed heat exchangers

Almendros-Ibáñez¹,

Soria-Verdugo²,

Ruiz-Rivas³

et al. 2011

Applied Thermal Engineering

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a b s t r a c tThis work presents a theoretical study of the energetic performance of a moving bed heat exchanger (MBHE), which consists of a flow of solid particles moving down that recovers heat from a gas flow percolating the solids in cross flow. In order to define the solid conduction effects, two solutions for the MBHE energy equations have been studied: an analytical solution considering only convection heat transfer (and neglecting solid conduction) and a numerical solution with the solid conductivity retained in the equations. In a second part, the power requirements of a MBHE (to pump the gas and to raise the down flowing particles) are confronted with the heat transferred considering the variation of design parameters, such as gas and solids' velocities, solids particle diameter or MBHE dimensions.The numerical results show that solid conductivity reduces the global efficiency of the heat exchanger. Therefore, a selection criterion for the solids can be established, in which their thermal conductivity should be minimized to avoid conduction through the solid phase, but to a limit in order to ensure that temperature differences inside an individual solid particle remain small. Regarding the other energy interactions involved in the system, these are at least one order of magnitude lower than the heat exchanged. Nevertheless, for a proper analysis of the system the efficiency of the devices used to pump the gas and to raise the particles and the relative costs of the different energy forms present in the system should be taken into account.

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Equivalence of one- and two-phase models for heat transfer processes in packed beds: one dimensional theory

Cited by 197 publications

References 9 publications

Numerical investigation of sensible thermal energy storage in high temperature solar systems

Numerical investigation of sensible thermal energy storage in high temperature solar systems

Thermal Analysis and Optimization of a Heat Regenerator Composed of Two Coupled Moving Bed Heat Exchangers

Solid conduction effects and design criteria in moving bed heat exchangers

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