Experimental investigation of axisymmetric, turbulent, annular jets discharged through the nozzle of the SPP1980 SpraySyn burner under isothermal and reacting conditions

Martins, Fabio J. W. A.; Kirchmann, Jonas; Kronenburg, A.; Beyrau, Frank

doi:10.1016/j.expthermflusci.2020.110052

Cited by 29 publications

(15 citation statements)

References 46 publications

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“…As shown in Fig. 3 (b,c) predicted axial velocity of both simulation have a good agreement with the experiment [24], and (d,e) show that the peak location of temperature and mass fraction of major species are affected by the inclusion of the near the burner surface as computational domain. Figure 4 (a,b,c) shows contour plots of predicted particle number concentration N , aggregate particle diameter d, surface area concentration A in a burner cross-section.…”

Section: Resultssupporting

confidence: 72%

Large eddy simulations of nanoparticle synthesis in spray flames

Baik

Sellmann

Kempf

2021

ICLASS

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The "SpraySyn" burner [1] has been developed to investigate nanoparticle synthesis from spray flames by experiment and simulation. The spray is surrounded by a premixed pilot flame to stabilize combustion. Since the precursors are dissolved in the liquid fuel (ethanol) and evaporized by interaction with the hot (pilot) flame products, an accurate comprehension of the spray flame structure is necessary to study nanoparticle synthesis. In the present work, the in-house large eddy simulations (LES) code PsiPhi is applied to the SpraySyn burner to investigate the characteristics of spray flames and nanoparticle synthesis. The ethanol liquid droplets are described by Lagrangian particles, and gas-phase combustion is modeled by the flamelet generated manifold (FGM) approach combined with the artificial flame thickening (ATF) technique. The Iron(III) oxide nanoparticle formation and growth are modeled in terms of number-, surface-, and volume-concentration by a monodisperse model.

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Section: Resultssupporting

confidence: 72%

Large eddy simulations of nanoparticle synthesis in spray flames

Baik

Sellmann

Kempf

2021

ICLASS

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“…426 Meierhofer et al 32 applied PIV to characterize the radial spreading of non-reacting droplets produced by a large-scale FSP nozzle. Martins et al 427 recently measured high-speed PIV of a lab-scale FSP reactor and obtained maximum axial droplet velocities in the nozzle near field of about 50 and 80 m/s under non-burning and burning conditions, respectively. Hot-wire anemometry (HWA) is a method for gas velocity measurements that does not require tracer particles.…”

Section: Experimental Process and Nanoparticle Diagnosticsmentioning

confidence: 99%

“…However, it might be considered for the calibration of laser-based diagnostics, such as PIV, at roomtemperature conditions. 427 Laser diffraction spectrometry (LDS) is an ensemble method that uses the Fraunhofer diffraction theory to describe the population of a droplet size distribution. 429 The spray is based between a laser source and a ring detector unit that collects line-of-sight-averaged, time-integrated information.…”

Section: Experimental Process and Nanoparticle Diagnosticsmentioning

confidence: 99%

“…HWA is less suitable for the characterization of reactive multiphase flows because undefined ambient gas temperatures and particle deposition on the wire surface would affect the heat loss rate. However, it might be considered for the calibration of laser-based diagnostics, such as PIV, at room-temperature conditions …”

Section: Experimental Process and Nanoparticle Diagnosticsmentioning

confidence: 99%

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Synthesis of Metal Oxide Nanoparticles in Flame Sprays: Review on Process Technology, Modeling, and Diagnostics

Meierhofer

Fritsching

2021

Energy Fuels

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The gas synthesis of nanoparticles has gained major interest by different industries and research groups for the development of new materials and their subsequent implementation in numerous devices and applications. Actually, there are numerous research and application activities in flame-based nanoparticle production, mainly focusing on the process and its development, the in situ and ex situ analyses in experiments and simulations and new material and material combination developments. This review provides an overview on the flame synthesis of metal oxide nanoparticles and focuses in particular on the process design of flame spray pyrolysis (FSP). The first part of this review describes the historical background of flame-based particle production and further summarizes the emerging developments, achievements, and trends during the past 2 decades. The second part covers a general process overview of the flame aerosol-based manufacturing by explaining the key aspects of synthesis (chemical raw materials, metal precursors, solvents, and reactor configurations), in situ conditioning approaches, and powder and byproduct collection, along with additional post-processing steps (storage, handling, and modification). Applications of flame-made nanoparticles involve catalysts, gas sensors, energy storage materials, and nanotoxicity studies, among others, which will not be discussed in detail but are overviewed by listing the latest reviews of the respective field. The third part focuses on the growth mechanisms of solid particle products in liquid droplet/spray pyrolysis (liquid-to-particle and gas-to-particle conversion). The concept of characteristic process times is then exemplified for a lab-scaled FSP reactor, while afterward, particle dynamics and continuum models for reactor simulation are reviewed. The fourth part is a survey of more than 20 different diagnostic techniques that are commonly employed for characterization of reactive sprays and flame-made powders. We briefly explain the metrology basics of each method, indicate advantages and limitations, and present exemplary measurement results that have been acquired on flame reactor facilities for particle synthesis. Finally, we summarize the review and address some current challenges that might potentially shape the near future of nanoparticle synthesis in flame sprays.

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“…To define reasonable standard operation conditions and to understand the individual process steps in detail, a comprehensive database of boundary conditions and reproducible experiments is required. The investigations to fill the database are still in the early stages and require extensive studies to enable a characterization of the burner performance and to gain a deep understanding of the process (Abdelsamie and Thévenin, 2019;Aßmann et al, 2020;Bieber et al, 2019;Keller et al, 2020;Martins et al, 2020;Prenting et al, 2020;Stodt et al, 2019a,b), Stodt et al (2020). A detailed characterization of the primary and secondary atomization of the SpraySyn burner is necessary to assess the performance of this atomizer reference device from the very beginning of the process chain.…”

Section: Introductionmentioning

confidence: 99%

Drop Dynamics in Heterogeneous Spray Flames for Nanoparticle Synthesis

2020

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In flame spray pyrolysis (FSP), the understanding of the atomization and spray formation of the coaxial atomizer is a key step to control the mixing of reactants, and precursor release, as well as nanoparticle formation and growth mechanisms. The drop size and drop dynamics of fuel/precursor mixtures are relevant parameters to control the particle synthesis via gas-to-particle conversion for tailoring the nanoparticle. The investigation of the multiphase flow structures, especially in the dense spray region using sophisticated nonintrusive laser diagnostics, such as phase Doppler anemometry (PDA), enables a characterization of the burner with multiscale spatial and temporal resolution. In the present work, the evolution of drop size and velocity under varying iron nitrate (FNT) concentration of the precursor is investigated allowing for an estimation of precursor release and evaporation via detailed PDA measurements. The drop size distributions of pure ethanol, and ethanol + 2-ethylhexanoic acid, as well as for FNT-based spray flames, were studied in order to reveal the influence of metal precursors on the combustion. Drop size/velocity correlations were determined in order to resolve the size class averaged evolution of drop velocities. The evolution of the drop size distribution along the axial centerline revealed a variation of the evaporation rate in space and increased evaporation rates for FNT containing spray flames. Furthermore, bimodal drop size distributions were observed for heights above the burner larger than 40 mm in FNT precursor spray flames, indicating the occurrence of possible µ-explosions of drops, that have been reported in the literature for similar systems but only in single-droplet experiments so far.

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Experimental investigation of axisymmetric, turbulent, annular jets discharged through the nozzle of the SPP1980 SpraySyn burner under isothermal and reacting conditions

Cited by 29 publications

References 46 publications

Large eddy simulations of nanoparticle synthesis in spray flames

Large eddy simulations of nanoparticle synthesis in spray flames

Synthesis of Metal Oxide Nanoparticles in Flame Sprays: Review on Process Technology, Modeling, and Diagnostics

Drop Dynamics in Heterogeneous Spray Flames for Nanoparticle Synthesis

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