---
_id: '63830'
abstract:
- lang: eng
  text: " This study investigates the effect of dispersion gas (DG) flow on the formation
    and properties of maghemite (γ-Fe2O3) nanoparticles using standardized SpraySyn
    burners (SS1 and SS2). Several diagnostics were employed to characterize the spray
    and nanoparticles. \r\nIncreasing DG flow (6 - 12 slm) results in smaller droplet
    sizes (DS), cooler flame temperatures, shorter high-temperature droplet/particle
    residence times, and smaller agglomerates in the size range of 5 - 12 nm with
    narrower primary particle size distribution, corresponding to higher mass fractal
    dimensions, as supported by TEM and SMPS analysis, resulting in more compact agglomerates.
    BET and TEM confirmed decreasing primary particle sizes with increasing DG flow.
    Raman and XRD analyses predominantly identified maghemite, which shows a bimodal
    distribution of crystallite sizes, while SS1 samples have a greater proportion
    of larger crystallites.\r\nThe self-preserving size distributions of agglomerates
    with a geometric standard deviation of 1.5 are reached faster with increasing
    DG flow. The barrier effect of DG observed in SS1 leads to slower droplet combustion
    kinetics, higher temperatures, and delayed precursor release, which, along with
    downstream flow recirculation, result in significantly higher agglomeration rates
    outside the visible flame. SS2 demonstrates improved atomization, more stable
    flames, and finer, uniform nanoparticles with less carbonaceous residues (CR).
    Conversely, SS1 showed broader DS distributions and higher CR levels on the γ-Fe2O3
    surface, especially at higher DG flow.\r\nThis work highlights the essential role
    of DG flow and nozzle geometry in controlling droplet evaporation, flame stability,
    and nanoparticle growth, offering insights for optimizing SFS and validating numerical
    models.\r\n"
article_number: '121992'
article_type: original
author:
- first_name: Orlando
  full_name: Massopo, Orlando
  last_name: Massopo
- first_name: Ricardo
  full_name: Tischendorf, Ricardo
  last_name: Tischendorf
- first_name: Munko
  full_name: Gonchikzhapov, Munko
  last_name: Gonchikzhapov
- first_name: Tina
  full_name: Kasper, Tina
  last_name: Kasper
- first_name: Peter
  full_name: Augustin, Peter
  last_name: Augustin
- first_name: Burak
  full_name: Özer, Burak
  last_name: Özer
- first_name: Manuel
  full_name: Reddemann, Manuel
  last_name: Reddemann
- first_name: Reinhold
  full_name: Kneer, Reinhold
  last_name: Kneer
- first_name: Mohammed-Ali
  full_name: Sheikh, Mohammed-Ali
  last_name: Sheikh
- first_name: Aydan Akyildiz
  full_name: Mert, Aydan Akyildiz
  last_name: Mert
- first_name: Hartmut
  full_name: Wiggers, Hartmut
  last_name: Wiggers
- first_name: Hans-Joachim
  full_name: Schmid, Hans-Joachim
  last_name: Schmid
citation:
  ama: Massopo O, Tischendorf R, Gonchikzhapov M, et al. Influence of dispersion gas
    flow on the spray characteristics and γ-Fe2O3 nanoparticles formation and properties
    in reference SpraySyn burners. <i>Powder Technology</i>. 2025;470. doi:<a href="https://doi.org/10.1016/j.powtec.2025.121992">10.1016/j.powtec.2025.121992</a>
  apa: Massopo, O., Tischendorf, R., Gonchikzhapov, M., Kasper, T., Augustin, P.,
    Özer, B., Reddemann, M., Kneer, R., Sheikh, M.-A., Mert, A. A., Wiggers, H., &#38;
    Schmid, H.-J. (2025). Influence of dispersion gas flow on the spray characteristics
    and γ-Fe2O3 nanoparticles formation and properties in reference SpraySyn burners.
    <i>Powder Technology</i>, <i>470</i>, Article 121992. <a href="https://doi.org/10.1016/j.powtec.2025.121992">https://doi.org/10.1016/j.powtec.2025.121992</a>
  bibtex: '@article{Massopo_Tischendorf_Gonchikzhapov_Kasper_Augustin_Özer_Reddemann_Kneer_Sheikh_Mert_et
    al._2025, title={Influence of dispersion gas flow on the spray characteristics
    and γ-Fe2O3 nanoparticles formation and properties in reference SpraySyn burners},
    volume={470}, DOI={<a href="https://doi.org/10.1016/j.powtec.2025.121992">10.1016/j.powtec.2025.121992</a>},
    number={121992}, journal={Powder Technology}, publisher={Elsevier BV}, author={Massopo,
    Orlando and Tischendorf, Ricardo and Gonchikzhapov, Munko and Kasper, Tina and
    Augustin, Peter and Özer, Burak and Reddemann, Manuel and Kneer, Reinhold and
    Sheikh, Mohammed-Ali and Mert, Aydan Akyildiz and et al.}, year={2025} }'
  chicago: Massopo, Orlando, Ricardo Tischendorf, Munko Gonchikzhapov, Tina Kasper,
    Peter Augustin, Burak Özer, Manuel Reddemann, et al. “Influence of Dispersion
    Gas Flow on the Spray Characteristics and γ-Fe2O3 Nanoparticles Formation and
    Properties in Reference SpraySyn Burners.” <i>Powder Technology</i> 470 (2025).
    <a href="https://doi.org/10.1016/j.powtec.2025.121992">https://doi.org/10.1016/j.powtec.2025.121992</a>.
  ieee: 'O. Massopo <i>et al.</i>, “Influence of dispersion gas flow on the spray
    characteristics and γ-Fe2O3 nanoparticles formation and properties in reference
    SpraySyn burners,” <i>Powder Technology</i>, vol. 470, Art. no. 121992, 2025,
    doi: <a href="https://doi.org/10.1016/j.powtec.2025.121992">10.1016/j.powtec.2025.121992</a>.'
  mla: Massopo, Orlando, et al. “Influence of Dispersion Gas Flow on the Spray Characteristics
    and γ-Fe2O3 Nanoparticles Formation and Properties in Reference SpraySyn Burners.”
    <i>Powder Technology</i>, vol. 470, 121992, Elsevier BV, 2025, doi:<a href="https://doi.org/10.1016/j.powtec.2025.121992">10.1016/j.powtec.2025.121992</a>.
  short: O. Massopo, R. Tischendorf, M. Gonchikzhapov, T. Kasper, P. Augustin, B.
    Özer, M. Reddemann, R. Kneer, M.-A. Sheikh, A.A. Mert, H. Wiggers, H.-J. Schmid,
    Powder Technology 470 (2025).
date_created: 2026-02-02T11:41:04Z
date_updated: 2026-02-25T07:45:44Z
doi: 10.1016/j.powtec.2025.121992
intvolume: '       470'
keyword:
- Spray flame synthesis
- iron oxide nanoparticle
- SpraySyn burner
- Dispersion gas
- Coaxial atomization
- HiaT-SMPS
language:
- iso: eng
main_file_link:
- open_access: '1'
oa: '1'
publication: Powder Technology
publication_identifier:
  issn:
  - 0032-5910
publication_status: published
publisher: Elsevier BV
status: public
title: Influence of dispersion gas flow on the spray characteristics and γ-Fe2O3 nanoparticles
  formation and properties in reference SpraySyn burners
type: journal_article
user_id: '98419'
volume: 470
year: '2025'
...
---
_id: '36983'
abstract:
- lang: eng
  text: "<jats:title>Abstract</jats:title><jats:p>The use of structured measuring
    systems to prevent wall slip is a common approach to obtain absolute rheological
    values. Typically, only the minimum distance between the measuring surfaces is
    used for further calculation, implying that no flow occurs between the structural
    elements. But this assumption is misleading, and a gap correction is necessary.
    To determine the radius correction <jats:inline-formula><jats:alternatives><jats:tex-math>$$\\Delta
    r$$</jats:tex-math><mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\">\r\n
    \               <mml:mrow>\r\n                  <mml:mi>Δ</mml:mi>\r\n                  <mml:mi>r</mml:mi>\r\n
    \               </mml:mrow>\r\n              </mml:math></jats:alternatives></jats:inline-formula>
    for specific geometries, we conducted investigations on three Newtonian fluids
    (two silicon oils and one suspension considered to be Newtonian in the relevant
    shear rate range). The results show that <jats:inline-formula><jats:alternatives><jats:tex-math>$$\\Delta
    r$$</jats:tex-math><mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\">\r\n
    \               <mml:mrow>\r\n                  <mml:mi>Δ</mml:mi>\r\n                  <mml:mi>r</mml:mi>\r\n
    \               </mml:mrow>\r\n              </mml:math></jats:alternatives></jats:inline-formula>
    is not only shear- and material-independent, but geometry-dependent, providing
    a Newtonian flow behaviour in a similar viscosity range. Therefore, a correction
    value can be determined with only minute deviations in different Newtonian fluids.
    As the conducted laboratory measurements are very time-consuming and expensive,
    a CFD-approach with only very small deviations was additionally developed and
    compared for validation purposes. Therefore, simulation is an effective and resource-efficient
    alternative to the presented laboratory measurements to determine <jats:inline-formula><jats:alternatives><jats:tex-math>$$\\Delta
    r$$</jats:tex-math><mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\">\r\n
    \               <mml:mrow>\r\n                  <mml:mi>Δ</mml:mi>\r\n                  <mml:mi>r</mml:mi>\r\n
    \               </mml:mrow>\r\n              </mml:math></jats:alternatives></jats:inline-formula>
    for the correction of structured coaxial geometries even for non-Newtonian fluids
    in the future.</jats:p>"
article_type: original
author:
- first_name: Sebastian
  full_name: Josch, Sebastian
  id: '38243'
  last_name: Josch
- first_name: Steffen
  full_name: Jesinghausen, Steffen
  id: '3959'
  last_name: Jesinghausen
  orcid: https://orcid.org/0000-0003-2611-5298
- first_name: Christopher
  full_name: Dechert, Christopher
  id: '69828'
  last_name: Dechert
- first_name: Hans-Joachim
  full_name: Schmid, Hans-Joachim
  id: '464'
  last_name: Schmid
  orcid: 000-0001-8590-1921
citation:
  ama: Josch S, Jesinghausen S, Dechert C, Schmid H-J. Experimental and simulative
    determination and correction of the effective gap extension in structured coaxial
    measuring systems. <i>Rheologica Acta</i>. Published online 2023. doi:<a href="https://doi.org/10.1007/s00397-023-01383-2">10.1007/s00397-023-01383-2</a>
  apa: Josch, S., Jesinghausen, S., Dechert, C., &#38; Schmid, H.-J. (2023). Experimental
    and simulative determination and correction of the effective gap extension in
    structured coaxial measuring systems. <i>Rheologica Acta</i>. <a href="https://doi.org/10.1007/s00397-023-01383-2">https://doi.org/10.1007/s00397-023-01383-2</a>
  bibtex: '@article{Josch_Jesinghausen_Dechert_Schmid_2023, title={Experimental and
    simulative determination and correction of the effective gap extension in structured
    coaxial measuring systems}, DOI={<a href="https://doi.org/10.1007/s00397-023-01383-2">10.1007/s00397-023-01383-2</a>},
    journal={Rheologica Acta}, publisher={Springer Science and Business Media LLC},
    author={Josch, Sebastian and Jesinghausen, Steffen and Dechert, Christopher and
    Schmid, Hans-Joachim}, year={2023} }'
  chicago: Josch, Sebastian, Steffen Jesinghausen, Christopher Dechert, and Hans-Joachim
    Schmid. “Experimental and Simulative Determination and Correction of the Effective
    Gap Extension in Structured Coaxial Measuring Systems.” <i>Rheologica Acta</i>,
    2023. <a href="https://doi.org/10.1007/s00397-023-01383-2">https://doi.org/10.1007/s00397-023-01383-2</a>.
  ieee: 'S. Josch, S. Jesinghausen, C. Dechert, and H.-J. Schmid, “Experimental and
    simulative determination and correction of the effective gap extension in structured
    coaxial measuring systems,” <i>Rheologica Acta</i>, 2023, doi: <a href="https://doi.org/10.1007/s00397-023-01383-2">10.1007/s00397-023-01383-2</a>.'
  mla: Josch, Sebastian, et al. “Experimental and Simulative Determination and Correction
    of the Effective Gap Extension in Structured Coaxial Measuring Systems.” <i>Rheologica
    Acta</i>, Springer Science and Business Media LLC, 2023, doi:<a href="https://doi.org/10.1007/s00397-023-01383-2">10.1007/s00397-023-01383-2</a>.
  short: S. Josch, S. Jesinghausen, C. Dechert, H.-J. Schmid, Rheologica Acta (2023).
date_created: 2023-01-17T08:04:24Z
date_updated: 2023-03-14T07:41:28Z
department:
- _id: '150'
doi: 10.1007/s00397-023-01383-2
keyword:
- rheology
- rheometry
- suspension
- coaxial
- correction
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://link.springer.com/article/10.1007/s00397-023-01383-2
oa: '1'
publication: Rheologica Acta
publication_identifier:
  issn:
  - 0035-4511
  - 1435-1528
publication_status: published
publisher: Springer Science and Business Media LLC
quality_controlled: '1'
status: public
title: Experimental and simulative determination and correction of the effective gap
  extension in structured coaxial measuring systems
type: journal_article
user_id: '3959'
year: '2023'
...