SpraySyn—A standardized burner configuration for nanoparticle synthesis in spray flames

Abstract

In many scientific communities, the definition of standardized experiments has enabled major progress in process understanding. The investigation of the spray-flame synthesis of nanoparticles at a well-defined standard burner by experiment and simulation makes it possible to produce a comprehensive data set with various established and novel measuring methods. In this work, we introduce the design of the SpraySyn burner as a new standard for a free-jet type burner that offers well-defined and simulation-friendly boundary conditions and geometries as well as accessibility for optical diagnostics. A combustible precursor solution is fed through a centrally located capillary and aerosolized with an oxygen dispersion gas flow. The spray flame is stabilized by a premixed flat methane/oxygen pilot flame fed via a porous bronze matrix surrounded by a stabilizing nitrogen coflow emanating through the same porous matrix, providing easy-to-calculate boundary conditions for simulations. This burner design enables the use of a wide choice of solvents, precursors, and precursor combinations. Best-practice operating instructions and parameters are given, and large-eddy simulations are performed demonstrating the suitability of the SpraySyn burner for computational fluid dynamics simulations. For ensuring reproducible operation across labs, we define a consumer-camera-based flame characterization scheme for the quantitative assessment of the flame geometry such as flame length, diameter, tilt angle, and photometric distribution of visible chemiluminescence along the center axis. These parameters can be used for benchmarking the pilot and spray flame by each user of the SpraySyn burner with the reference flames.

Numerical Study of Single Iron(III) Nitrate Nonahydrate/Ethanol Droplet Evaporation in Humid Air

“…The ambience is either dry or humid air where relative humidity up to 10 % is investigated. These conditions are chosen following the experimental conditions of a typical FSP burner [9]. For the present conditions, the Weber numbers stay well below the critical Weber number for which droplet breakup may occur and below thermal and mass Peclet numbers for which the distillation-limit model and the rapidmixing models are valid [12].…”

“…The experimental conditions are chosen following the experiment performed by Schneider et al [9]. The initial mass fraction of the INN in ethanol varies between 0.0125 and 0.025.…”

Multiscale Simulation of the Formation of Platinum-Particles on Alumina Nanoparticles in a Spray Flame Experiment

“…Figure 2 shows the experimental setup (left) and a close-up of the burner (right) in operation. For further details and sketches of the burner, the reader is referred to the work of Schneider et al [4].…”

“…The production of composite nanomaterials puts high demands on the flexibility and reliability of the synthesis, and the flame spray pyrolysis [1,2] has shown to be a very good option for such a process. The SpraySyn burner is used in the present study [3,4], which allows mixing priorly generated (and possibly pre-processed) carrier particles into the precursor solvent, which reduces the process complexity by removing the step of carrier particle formation. The simulation of the entire synthesis requires the properly coupled numerical solution of a series of processes taking place at different scales: spray evaporation and combustion, convective transport, combustion and decomposition of the particle precursor, particle formation and growth.…”

“…Rittler et al [10] showed an LES with tabulated chemistry approach, coupled with the monodisperse moment method model to predict the spray-flame synthesis of silica nanoparticles. This approach was also used for the assessment of the newly developed SpraySyn Burner [4]. Until now, these remained the only LES of the flame spray pyrolysis process.…”