New Challenges in Thermal Processing

Klaus, Christian; Wegner, K. David; Rammelt, Thomas; Ommer, Matthias

doi:10.1007/s42411-021-0443-2

Cited by 4 publications

(3 citation statements)

References 4 publications

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“…The particular process conditions in the TP allow for a variety of continuous material treatment applications, e.g., drying, calcination, and annealing [2,3]. However, PRs are primarily recognized for the possibility of synthesizing ultra-fine powdery products with advantageous properties at an industrial scale [4][5][6]. For example, Heidinger et al [7] describe the synthesis of zirconia and silica nanoparticles in the PR.…”

Section: Pulsation Reactors For Materials Treatmentmentioning

confidence: 99%

Experimental Investigation of a Pulsation Reactor via Optical Methods

Zhang,

Dostál,

Heidinger

et al. 2024

Processes

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Material treatment in pulsation reactors (PRs) offers the potential to synthesize powdery products with desirable properties, such as nano-sized particles and high specific surface areas, on an industrial scale. These exceptional material characteristics arise from specific process parameters within PRs, characterized by the periodically varying conditions and the resulting enhanced heat and mass transfer between the medium and the particulate material. Understanding flame behavior and the re-ignition mechanism is crucial to controlling the efficiency and stability of the pulse combustion process. In order to accomplish this objective, an investigation was conducted into flame behavior within the combustion chamber of a Helmholtz-type pulsation reactor. The study was focused on primarily analyzing the flame propagation process and examining flame velocity throughout the operational cycle of the reactor. Two optical methods—natural flame luminosity (NFL) and particle image velocimetry (PIV)—were applied in related experiments. An analysis of the NFL measurement data revealed a correlation between the intensity of light emitted by the pulsed flame and the air-fuel equivalence ratio (range from 0.892.08 in this study). It is observed that a lower air-fuel equivalence ratio leads to higher flame luminosity in the PR. In addition, in order to study the parameters related to system stability and energy transfer efficiency, this study also focuses on the local velocity field measurement method and an example of a fluid flow result in a combustion chamber by using a phase-locked PIV measurement system upgraded from a classic PIV system. The presented results herein contribute to the characterization of flame propagation within a pulsation reactor, as well as in pulsatile flows over one working cycle in a broader context, with flow velocity in the center of the combustion chamber ranging from 1.55m/s. Furthermore, this study offers insights into the applicable experimental methodologies for investigating the intricate interplay between flames and flows within combustion processes.

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Section: Pulsation Reactors For Materials Treatmentmentioning

confidence: 99%

Experimental Investigation of a Pulsation Reactor via Optical Methods

Zhang,

Dostál,

Heidinger

et al. 2024

Processes

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show abstract

“…Pulsation reactors allow for various material treatment applications, e.g., drying, calcination, and annealing. However, they are primarily recognized as opening great opportunities for synthesizing (ultra-)fine powder products with advantageous properties, such as nanoparticle sizes and high specific surface areas, at an industrial scale [5][6][7]. For example, Heidinger et al [8] describe the upscaling of the synthesizing process of zirconia and silica from the laboratory-scale flame spray pyrolysis [9,10] to the PR.…”

Section: Introduction 1pulsation Reactors For Materials Treatmentmentioning

confidence: 99%

Effects of Fuel Input on Pulsation Reactor Behavior—An Experimental Study

Dostál

Heidinger

Klaus³

et al. 2023

Processes

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Material treatment in pulsation reactors (PR) brings the possibility of synthesizing powdery products with advantageous properties, such as nanoparticle sizes and high specific surface areas, at an industrial scale. The extraordinary material properties can be ascribed to special process parameters in a PR, primarily the periodically varying conditions and the consequently enhanced heat and mass transfer between the medium and the particles of the material. Understanding the connections between the PR operation parameters, such as fuel and air intake or PR geometry, and the resulting process parameters (temperature distribution, flow velocity and pressure field, and frequency of the pulsations) is essential to enabling a controllable treatment process. Despite the long history of pulsation reactor technology, many connections and dependencies remain unclear. Thus, the influence of the fuel (and air) supply on the pulsation reactor behavior is experimentally examined in this study. The investigated PR characteristics and process parameters are primarily those that have an impact on the heat and mass transfer, i.e., the temperature distribution, flow velocity, and pressure field, and frequency of the pulsations. In addition to these, the harmonic distortion of the oscillations and the heat losses are evaluated.

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“…A rigid, spherical particle suspended in a harmonically oscillating one-dimensional flow is considered. This configuration can be found, for example, with ultrasonic levitators [1,2] or pulsation reactors [3][4][5]. In case the particle is fixed in position (or the particle executes harmonic oscillations in a fluid at rest), the interaction between the fluid and the particle as well as the resulting flow state is defined by two dimensionless numbers: the particle Reynolds number Re and the amplitude parameter .…”

Section: Introductionmentioning

confidence: 99%

Simple Particle Relaxation Modeling in One-Dimensional Oscillating Flows

2022

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The relaxation of a rigid particle suspended in a one-dimensional oscillating flow is calculated according to different drag models and the results are compared. Conditions are derived under which relaxation can be neglected or drag models can be substituted by simpler ones. This investigation is conducted analytically and graphically via the plane defined by the Reynolds number and amplitude parameter. This work matches various, mostly analytic drag models together to consider simple particle relaxation with a few, broad range input parameters and cover large parts of the plane spanned by Reynolds number and amplitude parameter.

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New Challenges in Thermal Processing

Cited by 4 publications

References 4 publications

Experimental Investigation of a Pulsation Reactor via Optical Methods

Experimental Investigation of a Pulsation Reactor via Optical Methods

Effects of Fuel Input on Pulsation Reactor Behavior—An Experimental Study

Simple Particle Relaxation Modeling in One-Dimensional Oscillating Flows

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