Geschwindigkeitsverteilung in gasdurch‐strömten, isothermen Kugelschüttungen

Schuster, Joachim; Vortmeyer, D.

doi:10.1002/cite.330531012

Cited by 14 publications

(8 citation statements)

References 2 publications

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“…The long-recognized irregularities in the flow near the boundaries of fixed beds were newly investigated by Schuster and Vortmeyer in 1981. In 1982, Vortmeyer and Winter extended their model for the description of heat transfer and thus obtained a further improvement in the simulation of fixed bed reactions. The flow irregularities were attributed to the irregular distribution of the voidage at the boundary of a fixed bed.…”

Section: Bedmentioning

confidence: 99%

“…A local gas velocity distribution in the bed could be obtained from the above model by using a finite element method, recollecting that in the RFR the flow distribution is across the bank of tubes. Generally, according to Schuster and Vortmeyer (1981), it can be said that in a narrow zone along the walls the gas can flow considerably faster. For the AFR, the width of this zone is of the order of half a particle diameter (Martin, 1978).…”

Section: Bedmentioning

confidence: 99%

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Determination of the local voidage distribution in random packed beds of complex geometry

Schneider¹,

Rippin²

1988

Ind. Eng. Chem. Res.

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The voidage fraction distribution in packed beds is visually displayed and recorded by a newly developed optical method that is fast and can be easily demonstrated. It can be used on fixed beds of more complex form than a single packed tube and aids in the understanding of the behavior of new types of reactor configuration. Results are reported for the voidage distribution within a single tube, which are in close agreement with these obtained by other, much more expensive and timeconsuming methods. New results are presented for voidage distribution in radial flow configurations not accessible by other methods. The implications for heat transfer in a radial flow reactor are discussed.

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Section: Bedmentioning

confidence: 99%

Section: Bedmentioning

confidence: 99%

Determination of the local voidage distribution in random packed beds of complex geometry

Schneider¹,

Rippin²

1988

Ind. Eng. Chem. Res.

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“…Obviously the flow profile changes rapidly once it has left the fixed bed. That this is indeed true was demonstrated by solving the twodimensional NavierStokes-Equations for the empty tube taking the calcu lated fixed bed flow profile as the entrance profile [4].…”

Section: In Fixed Bed Chemical Reactor Analysis It Is Commonmentioning

confidence: 95%

“…We do not know about the success of other groups working in this field however, so far in literature solutions are published for conditions only setting the porosity at the wall to a value say of ε=0.5 or 0.6. Therefore, Schuster and Vortmeyer [4] re cently formulated the equivalent variational problem by minimizing the energy dissipation within the bed. For details we refer to [4].…”

Section: In Fixed Bed Chemical Reactor Analysis It Is Commonmentioning

confidence: 99%

“…Therefore, Schuster and Vortmeyer [4] re cently formulated the equivalent variational problem by minimizing the energy dissipation within the bed. For details we refer to [4]. The solution of the variation al problem was obtained without difficulties and Figure 2 shows a typical calculated flow profile.…”

Section: In Fixed Bed Chemical Reactor Analysis It Is Commonmentioning

confidence: 99%

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Impact of Porosity and Velocity Distribution on the Theoretical Prediction of Fixed-Bed Chemical Reactor Performance

Vortmeyer¹,

Winter²

1982

ACS Symposium Series

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Due to porosity changes and to the nonslip condition at the wall, the non uniform po rosity profiles in packed beds exhibit steep maxima close to the wall. The govern ing equations of energy and mass conserva tion were solved for fixed bed chemical reactors including these profiles. Under the assumption of non uniform flow the problems become two-dimensional also under adiabatic conditions. In all cases the agreement between available experimental data and theoretical predictions based on realistic flow conditions is improved. In particular measured and calculated moving speeds of migrating reaction zones fit to gether very well for adiabatic fixed bed reactors. Also considerable improvements concerning multiple steady states, temper ature profiles and conversion rates were obtained in situations when the reactor was wall cooled. In fixed bed chemical reactor analysis it is commonto assume uniform flow distribution within the bed. The reality however is different. Due to a change of the average porosity near the wall [ 1,2,3],(Figure 1.) -ε=1 at the wall -the flow velocity increases until close to the wall and is reduced again because of the non slip condition (Figure 2.) The artificial flow pro file is described by the Brinkman equation I =-150^ -L75 ρ »2 ψΙ.Α. Α. ( η iiL,àz a e 3 dp 2 9 £ 3 dp r dr 9 dr B.C. Ζ=0 : ρ=ρ 0 ;Γ=0: s 0 ; Γ « R : U = 0;

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Verbesserung der Analyse von Festbettreaktoren durch die Berücksichtigung von Porositäts‐ und Strömungsverteilung

Vortmeyer¹,

Winter²

1983

Chemie Ingenieur Technik

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Geschwindigkeitsverteilung in gasdurch‐strömten, isothermen Kugelschüttungen

Cited by 14 publications

References 2 publications

Determination of the local voidage distribution in random packed beds of complex geometry

Determination of the local voidage distribution in random packed beds of complex geometry

Impact of Porosity and Velocity Distribution on the Theoretical Prediction of Fixed-Bed Chemical Reactor Performance

Verbesserung der Analyse von Festbettreaktoren durch die Berücksichtigung von Porositäts‐ und Strömungsverteilung

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