Semi‐Empirical Equations for the Residence Time Distributions in Disperse Systems – Part 1: Continuous Phase

Ham, Jong-Ho; Platzer, Bernd

doi:10.1002/ceat.200407038

Cited by 46 publications

(30 citation statements)

References 10 publications

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“…This model was chosen because it is simple and correlates closely to the physical structure of the process. However, other models can also be used as reported by Ham and Platzer [15]. …”

Section: Comparison Between Dpf and Pf+2cstr Modelsmentioning

confidence: 94%

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Residence Time Distribution in Tubular Joule Effect Heaters with and without Geometric Modifications

André

Boissier

Fillaudeau³

2006

Chem Eng & Technol

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In the food industry, heat treatment of highly viscous fluids in continuous processes is becoming more and more common, and the process should perform as a homogenous thermal treatment, in order to ensure quality and safety of the final product. To improve treatment homogeneity, geometric modifications can be used even in the laminar regime, to induce flow perturbation and mixing. The objectives of this work include: (i) Investigation of the residence time distribution (RTD) for industrial indirect Joule effect heaters (JEH), with smooth (ST) and modified (MT) tubes, (ii) Demonstration and quantification of the efficiency of the geometrical modifications, and (iii) Proposition of a single semi-empirical model including the flow regime (10 < Re < 2000) and tube diameters (18 and 23 mm). The results obtained confirm that the simple Dispersed Plug Flow (DPF) model is not adaptable to small Reynolds numbers. Further analysis demonstrates that certain geometrical modifications improve the treatment homogeneity by increasing the plug flow contribution and reducing the value of the reduced variance. These beneficial effects increase when the Reynolds number is increased, the nominal diameter is reduced, and modified tubes are used. The proposed model enables the prediction of the RTD in JEH with an accurate degree of confidence.

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“…This model was chosen because it is simple and correlates closely to the physical structure of the process. However, other models can also be used as reported by Ham and Platzer [15]. …”

Section: Comparison Between Dpf and Pf+2cstr Modelsmentioning

confidence: 94%

“…Each distribution function can be characterized by a set of moments and centered moments of order j [11,15]. The function E(t) is characterized by the mean residence time, t S (see Eq.…”

Section: Residence Time Distributionmentioning

confidence: 99%

Residence Time Distribution in Tubular Joule Effect Heaters with and without Geometric Modifications

André

Boissier

Fillaudeau³

2006

Chem Eng & Technol

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“…4). The empirical model used in this work was first published by Ham and Platzer [41] and takes the form:…”

Section: Split-and-recombine (Sar) Reactormentioning

confidence: 99%

Residence Time Distribution Studies in Microfluidic Mixing Structures

et al. 2011

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The residence time distribution (RTD) characteristics of three microreactors containing different passive mixing structures, namely, a three dimensional serpentine structure, a split-and-recombine structure and a staggered herringbone structure, were investigated and compared. An experimental input-response technique was applied which required deconvolution of the measured data by modeling of the RTD. The proposed technique provides useful information on optimized application and operation of microfluidic devices. The serpentine reactor and the split-and-recombine reactor show improvement in RTD behaviour, i.e., narrowing of RTD curves, at Re-numbers > 30 due to effective transversal mixing and therefore reduced axial dispersion. In the case of the staggered herringbone structure, dead volumes could be observed which considerably affect the RTD.

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“…Adeosun and Lawal investigated laminar flow mixing behavior in a T-junction microchannel [21] and a MEMS-based mutilaminated/elongational flow micromixer using RTDs [22]. Mendez-Portillo et al performed a numerical investigation on the hydrodynamics of a split-and-recombination microreactor and multilamination microreactor [28].…”

Section: Introductionmentioning

confidence: 99%

“…There are many approaches to deconvolution such as linear, nonlinear, Fourier methods [25][26][27], and flow model fitting [20,21,28]. Deconvolution by solving a linear equation set was chosen for this work because obtaining the RTD is approached without preconceptions of the profile shape, unlike parameter fitting of a flow model.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Microchannel Hemodialyzers Using Residence Time Distribution Analysis

Coblyn¹,

Truszkowska²

2016

J Flow Chem

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Microchannel-based hemodialysis has a potential to improve survival rates and quality of life for end-stage renal disease patients compared to conventional hemodialysis technology. Characterization of hydrodynamic behavior in microchannel geometries is necessary for improving flow uniformity, a critical challenge in realizing a commercial device. A test loop was developed for measuring the impulse response of a tracer dye injected into a dialyzer test article for the purpose of developing residence time distributions (RTD) to characterize lamina design. RTD variance tended to lower for designs that are more dominated, volume-wise, by the microchannel array versus the headers. RTD results also emphasize how defect issues can significantly impact a microchannel device via discrepancies between conceptual and operational devices. A multisegmented CFD model, developed for pairing with the impulse response test loop and dialyzer, showed good agreement between visual observation of the tracer in simulations and experiments, and the shape and peak of the output profiles.

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Semi‐Empirical Equations for the Residence Time Distributions in Disperse Systems – Part 1: Continuous Phase

Cited by 46 publications

References 10 publications

Residence Time Distribution in Tubular Joule Effect Heaters with and without Geometric Modifications

Residence Time Distribution in Tubular Joule Effect Heaters with and without Geometric Modifications

Residence Time Distribution Studies in Microfluidic Mixing Structures

Characterization of Microchannel Hemodialyzers Using Residence Time Distribution Analysis

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