Christoph Spijker
@unileoben.ac.at
Scopus Publications
- Effect of Particle Size Distribution on the Explosion Intensity of Hydrogen Direct-Reduced Iron Dust
Aleksandra Semenova, Christoph Spijker
Advances in Materials Science and Engineering, 2026
Steel production using direct‐reduced iron (DRI) in an electric arc furnace with natural gas has a lower carbon footprint compared to the blast furnace route (Bhaskar et al., 2019). When iron ore is reduced using hydrogen, the resulting product—H‐DRI—represents a key pathway to green steel and is increasingly used as a feedstock in industrial steelmaking processes. However, depending on the initial ore type and the reduction conditions, hydrogen direct‐reduced iron poses significant explosion hazards, particularly in a dust form. Therefore, understanding the parameters governing the explosibility of H‐DRI dust is essential for ensuring safe handling and processing. This study investigates the influence of particle size distribution on the explosion behavior of H‐DRI dust. Precise size classification revealed an explosibility threshold of 71 μm. Mixture experiments demonstrated that the explosibility of polydisperse H‐DRI dusts is determined by the mass fraction of fine, reactive particles, whereas the inerting effect of coarse particles depends on their mass fraction rather than their specific size range. During the investigations, the influence of the igniters on the explosion development was also identified as a critical factor, as the ignition source contributes substantially to the measured rate of pressure rise. It was found that the second pressure peak correlates more reliably with the actual combustion dynamics of H‐DRI dust and therefore provides a more representative evaluation parameter for low‐reactivity materials, such as H‐DRI dust. These findings suggest that the current European test standard, EN 14034‐2, should be revised to account for igniter‐induced effects when characterizing dust explosion severity. Incorporating such improvements would enhance the assessment of low‐reactivity dusts and support the development of safer operational guidelines and risk mitigation strategies in H‐DRI‐related industries. - Transient thermo-mechanical modeling of real-scale metallurgical converter preheating
Zlatko Raonic, Christoph Spijker, Harald Raupenstrauch
Thermal Science and Engineering Progress, 2025
Modelling the thermal dynamics occurring during the converter preheat treatment step of a metallurgical process on a real-time processing scale is numerically complex and challenging for detailed time-resolved analysis. Physical phenomena within the fluid phase with turbulent combustion in the systems with gaseous fuel, are numerically expensive due to prevailing time scales. Arbitrary real-scale geometries consisting, in addition to the fluid zone, of multiple solid regions with different physical properties and the interaction between them, are another influential factor for the geometry size and its modeling complexity. Furthermore, high temperatures lead to thermal stress in the material, as the result of thermal expansion, which in the last consequence can cause material failure affecting the reliability of the entire system. This paper describes the implemented computationally efficient formulation of the transient multi-region solver with turbulent combustion based on the flamelet approach and the evaluation of the thermal and mechanical stresses in an industrial application within the finite volume method. - A Numerical Study of Flow Structures and Flame Shape Transition in Swirl-Stabilized Turbulent Premixed Flames Subject to Local Extinction
Stefanie Tomasch, Nedunchezhian Swaminathan, Christoph Spijker, Ivar S. Ertesvåg
Combustion Science and Technology, 2025
Large Eddy Simulations (LES) of turbulent lean-premixed flames of V- and M-shape are presented. A simple algebraic closure with the ability to capture finite-rate chemistry effects is used for subgrid reaction rate modeling. The V-shaped flame is stabilized in the inner shear layer between a swirling annular jet and a central recirculating bubble in a sudden expansion duct. The M-shaped flame is stabilized in the inner and outer shear layer, adjoining the corner recirculation zone induced by the vertical step. The focus of the study is on the flow fields and shapes of the flames, which distinguish themselves through different heat load and sensitivity to local extinction. Good agreement with measurements is observed for the cold and the reacting flow cases. The numerical results suggest that the entrainment of hot gases into the outer recirculation zone occurs close to the impingement point of the swirling annular jet on the wall and this process is strongly dependent on intense vortical structures in the outer shear layer. The results further suggest that local extinction influences the position of the flame in the inner shear layer and, thereby, also the intensity of the local entrainment process. - Numerical study of an industrial burner to optimise NOx emissions and to evaluate the feasibility of hydrogen-enriched fuel
Senthilathiban Swaminathan, Christoph Spijker, Zlatko Raonic, Michael Koller, Irmela Kofler, Harald Raupenstrauch
International Journal of Hydrogen Energy, 2024 - Numerical Simulation and Performance Evaluation of Hydrogen-Enriched Natural Gas for an Industrial Burner in a Testing Chamber
Senthilathiban Swaminathan, Christoph Spijker, Markus Gruber, Irmela Kofler, Harald Raupenstrauch
Energies, 2023
A two-step numerical concept was developed for modelling combustion and predicting nitrogen oxide emissions. The model was validated by the Sandia flame D experiment and with measurement data from burners on industrial furnaces. In this paper, the developed model was implemented to evaluate the influence of hydrogen blending with natural gas up to 40 vol.% on an industrial burner with oxidizer temperatures at 300 K and 813 K to assess the performance of the burner without altering the power output of the burner. An experimental test facility is under construction, and the feasibility of using this industrial burner on the test facility with different fuel mixtures was analyzed. Temperature, flow field, and emission characteristics were investigated. Using 40 vol.% hydrogen with natural gas resulted in a decrease of 14.82% in CO2 emissions and an increase of in 16.1% NO emissions when combusted with air at 300 K. The temperature profile indicated that the burner produces a symmetrical flame profile with preheated air and an asymmetrical flame profile with ambient air. - TGA-FTIR for kinetic and evolved gas analysis of the coal particles in dust deflagration
Yangyue Pan, Christoph Spijker, Harald Raupenstrauch
Applied Thermal Engineering, 2023
The common approach in the dust deflagration simulations ignores the temperature gradient inside of the particles. Therefore, the reaction rate of the particle at one temperature remains constant. In order to explore the mass loss and evolve gas characters during the coal particle decomposition procedures, a single-particle model was created using OpenFOAM tool kit. In this study, the pyrolysis characteristics and gas properties of the coal sample were determined by TGA-FTIR. The evolution of gases in real-time was investigated and implemented as kinetic models in the dust deflagration. To solve the heat and mass transfer of the single-particle, a two-phase solver based on the Eulerian method was developed based on reactingFoam. The porosity of the coal particle was included with respect to the coal mass. The result of the heat and mass transfer of the single-particle model agrees well with the experiment. In order to simulate the particle behavior in the dust explosion, new boundary conditions extracted from dust explosion simulations will be implemented. The final goal of the single-particle model is to implement the new particle decomposition behavior into the full scale of dust explosion simulations. - CFD-DEM Modeling of Shaft Furnaces Using the Volume Fraction Smoother Approach
Christoph Spijker, Werner Pollhammer, Harald Raupenstrauch
Chemical Engineering and Technology, 2023
Abstract Shaft furnaces are widely used in high‐temperature processes for granular materials due to their high energy efficiency. The modeling of these furnaces is challenging because of large domains and long process times. Small geometric details like the natural gas burner nozzles demand a fine grid on the computational fluid dynamics (CFD) side, resulting in a grid size smaller than the particle size. Resolving a discrete element particle over several cells is computationally expensive. Interpolation methods on non‐structured grids are complex. In order to provide a fast and simple solution, the volume fraction smoother was developed, and to shorten the calculation time, the time scale splitting method, which separates the time steps for CFD and the discrete‐element method (DEM), was introduced. - Dust cloud evolution and flame propagation of organic dust deflagration under low wall influence
Stefan Puttinger, Christoph Spijker, Simon Schneiderbauer, Stefan Pirker, Georg Meyer, Christoph Buchner, Andreas Kerbl
Journal of Loss Prevention in the Process Industries, 2023
The present study discusses experiments on organic dust explosions in a setup with low wall influence. The proposed apparatus decouples the dust dispersion and the deflagration event in two separate compartments. The use of a continuous-wave laser to illuminate the centre plane of the observation chamber allows capturing both, the dust cloud and the flame during the same experiment and eliminates typical problems caused by the limited dynamic range of high-speed cameras. A k-means clustering method is used for image segmentation to obtain the spatial extent and the propagation velocities of the unreacted particle cloud and the flame zone. Spatially resolved velocities are calculated by the additional use of an optical flow method. The main goal of the presented setup and image processing method is to provide high quality validation data for the development of numerical models on dust deflagration. - CFD modeling of particle dispersion behavior in the MIKE 3 apparatus
Yangyue Pan, Christoph Spijker, Harald Raupenstrauch
Alexandria Engineering Journal, 2022
A simulation investigation on the flow domain and particle movement pattern in the dispersion stage of dust explosion experiment were conducted using CFD simulation based on Euler–Lagrange approach. A new solver that couples two phases was developed based on the default solver rhoPimpleFoam from the OpenFOAM tool kit. Three sizes of particles 25 μm, 125 μm and 250 μm were simulated and studied. The simulation results of dust front propagation were evaluated by the experiment data. Particles with smaller diameters tended to move slower. Due to the high turbulence, flow vortices in the lower part of the dispersion domain were identified. These vortices gradually became larger with time and the decrease of inflow velocity. Uneven distribution of particles along with the equipment and high concentration of particles between the discharge electrodes were found in the simulation. Furthermore, particles with higher velocity favored the middle position in the tube. These facts suggested that the ignition delay time for particles larger than 125 μm should be higher than 60 ms. - Development of a turbulence dissipation based reaction rate model for progress variable in turbulent premixed flames
Stefanie Tomasch, Nedunchezhian Swaminathan, Christoph Spijker, Ivar S. Ertesvåg
Combustion Theory and Modelling, 2022
This study presents an algebraic combustion closure for Large eddy simulation (LES) exhibiting attributes of simplicity and simultaneous accuracy under realistic combustion conditions. The model makes use of the interlink between the reaction and dissipation rates in premixed turbulent combustion but relaxes the thin flame assumption by considering finite-rate chemistry effects in the small-scale turbulence structure. The core idea of the approach is to approximate the reaction progress in the unresolved spectrum of wave lengths and to use it within a filtered reaction rate expression. The model is implemented in OpenFOAM 4.0 and is tested on a turbulent, premixed flame behind a bluff-body, applying an LES approach for turbulence modelling. The cross comparison of velocity, temperature and composition data with experiments and a well-investigated combustion model in literature reveals competitive performance of the new model. Especially in the near-field of the bluff body flame, corresponding to thin and moderately thickened flame regions, its ability to capture the flame structure is highly promising. The chosen, partly explicit approach to recover the temperature from the transported sensible enthalpy, involving a strong coupling between filtered reaction and heat release rate, also shows advantages over obtaining the temperature from presumed probability density functions. - A Numerically Efficient Method for the Prediction of Nitrogen Oxide Emissions in Industrial Furnaces
Christoph Spijker, Senthilathiban Swaminathan, Harald Raupenstrauch
Steel Research International, 2020 - New developments to the post-processor in determining nitrogen oxide emissions with an computationally efficient approach
Senthilathiban Swaminathan, Christoph Spijker, Harald Raupenstrauch, Irmela Kofler, Michael Koller
Carbon Resources Conversion, 2020 - The Atmosphere Particle Kinetic Model for Particle Reactions in a Combustion Dust Reactor Using CFD Methods
Franz Edler, Bernhard Geier, Wolfgang Reiter, Johannes Rieger, Christoph Spijker, Harald Raupenstrauch
Chemie Ingenieur Technik, 2018 - Numerical investigation on inner particle effects in Lycopodium/Air dust deflagrations
Christoph Spijker, Harald Raupenstrauch
Journal of Loss Prevention in the Process Industries, 2017 - Numerical investigations of the inner processes for lycopodium particles during a dust deflagration
VDI Berichte, 2017 - Modelling the jet cooler for hot-DIP galvanization of steel strips
VDI Berichte, 2017 - Mathematical burner modeling for the reduction of nitrogen oxide emissions using flamelet - NOx post-processor in OpenFOAM
VDI Berichte, 2017 - Numerical modelling of industrial burners for reduction of NOx emissions using flamelet methods in combination with a newly developed postprocessor for fast and accurate emission prediction
International Congress on Energy 2017 Topical Conference at the 2017 Aiche Annual Meeting, 2017 - Numerical modelling of industrial burners for reduction of NOx emissions using flamelet methods in combination with a newly developed postprocessor for fast and accurate emission prediction
Environmental Division 2017 Core Programming Area at the 2017 Aiche Annual Meeting, 2017 - Numerical modelling of industrial burners for reduction of NOx emissions using flamelet methods in combination with a newly developed postprocessor for fast and accurate emission prediction
Catalysis and Reaction Engineering Division 2017 Core Programming Area at the 2017 Aiche Annual Meeting, 2017 - Numerical modelling of industrial burners for reduction of NOx emissions using flamelet methods in combination with a newly developed postprocessor for fast and accurate emission prediction
Advances in Fossil Energy R and D 2017 Topical Conference at the 2017 Aiche Annual Meeting, 2017 - Modeling of a walking beam furnace using CFD-methods
Werner Pollhammer, Christoph Spijker, Jakob Six, Daniel Zoglauer, Harald Raupenstrauch
Energy Procedia, 2017 - Development of an atmosphere particle kinetic model for particle reactions in a combustion Flash-Reactor using CFD- methods
Franz Edler, Bernhard Geier, Wolfgang Reiter, Johannes Rieger, Christoph Spijker, Harald Raupenstrauch
Energy Procedia, 2017 - Development of a computational fluid dynamic modelling concept for the recodust-process
Process Development Division 2017 Core Programming Area at the 2017 Aiche Annual Meeting, 2017 - Inclusion of simulation in the development of a dust-laden combustion reactor with regard to burner and reactor design
VDI Berichte, 2017 - Development of a computational fluid dynamic modelling concept for the RecoDust-Process
Computing and Systems Technology Division 2017 Core Programming Area at the 2017 Aiche Annual Meeting, 2017 - CFD-simulation of an indstrial furnace in the hot-dip galvanization process
Computing and Systems Technology Division 2014 Core Programming Area at the 2014 Aiche Annual Meeting, 2014 - Investigations on the self heating potential of garage waste as basis for the hazard evaluation of bulk storage facilities
28th Center for Chemical Process Safety International Conference 2013 Ccps Topical Conference at the 2013 Aiche Spring Meeting and 9th Global Congress on Process Safety, 2013 - Investigations on the self heating potential of garage waste as basis for the hazard evaluation of bulk storage facilities
Aiche 2013 2013 Aiche Spring Meeting and 9th Global Congress on Process Safety Conference Proceedings, 2013 - Investigations on the self heating potential of garage waste as basis for the hazard evaluation of bulk storage facilities
Aiche Annual Meeting Conference Proceedings, 2013 - Modeling dust explosions
Particle Technology Forum 2013 Core Programming Area at the 2013 Aiche Annual Meeting Global Challenges for Engineering A Sustainable Future, 2013 - Optimization of turbulence and radiation models for an improved prediction of non-premixed turbulent flames
International Review of Mechanical Engineering, 2011
RECENT SCHOLAR PUBLICATIONS
- Thermal Processing Technology-From high-temperature processes to safe, efficient industry–science powering sustainable transformation
K Doschek-Held, R Renner, C Spijker, Z Raonic
Science 4 Technology@ MUL 2026-Poster Exhibition , 2026
2026 - Flame size analysis in premixed starch/suppressant powders as a reference case for CFD model validation
S Puttinger, C Spijker, S Schneiderbauer, A Kerbl
2026 - CFD-DEM Coarse-Graining for modelling self-heating of direct reduced iron
C Spijker
2026 - Effect of Particle Size Distribution on the Explosion Intensity of Hydrogen Direct‐Reduced Iron Dust
A Semenova, C Spijker
Advances in Materials Science and Engineering 2026 (1), 8840500 , 2026
2026 - Computational analysis of carbon-neutral biofuels co-firing in a rotary kiln
S Saberi, C Spijker, M Gruber, I Kofler
2025 - Transient thermo-mechanical modeling of real-scale metallurgical converter preheating
Z Raonic, C Spijker, H Raupenstrauch
Thermal Science and Engineering Progress 63, 103691 , 2025
2025 - Computational analysis of carbon-neutral biofuels pyrolysis and combustion
S Saberi, C Spijker, Z Raonic, M Gruber
2025 - A numerical study of flow structures and flame shape transition in swirl-stabilized turbulent premixed flames subject to local extinction
S Tomasch, N Swaminathan, C Spijker, IS Ertesvåg
Combustion Science and Technology 197 (2), 338-370 , 2025
2025
Citations: 2 - Numerische Abbildung von reaktiven Strömungen und Partikel
C Spijker
2025 - Numerical development of a thermal Pre-processing step for the recycling of Lithium-Ion batteries
EE Barros de Souza, C Spijker
BHM Berg-Und Hüttenmännische Monatshefte 169 (8), 453-457 , 2024
2024
Citations: 1 - A Coupled CFD-DEM Approach to Model Reactive Granular Beds
C Spijker, W Pollhammer
BHM Berg-und Hüttenmännische Monatshefte 169 (8), 437-443 , 2024
2024 - NOx Postprocessing for industrial combustion processes
C Spijker, S Swaminathan, Z Raonic, H Raupenstrauch
Proceedings of the 14th european conference on industrial furnaces and boilers , 2024
2024 - Numerical study of an industrial burner to optimise NOx emissions and to evaluate the feasibility of hydrogen-enriched fuel
S Swaminathan, C Spijker, Z Raonic, M Koller, I Kofler, H Raupenstrauch
International Journal of Hydrogen Energy 49, 1210-1220 , 2024
2024
Citations: 16 - Numerical Development of a Thermal Pre-processing Step for the Recycling of Lithium-Ion Batteries
EEB de Souza, C Spijker
2024 - Numerical Simulation and Performance Evaluation of Hydrogen-Enriched Natural Gas for an Industrial Burner in a Testing Chamber
S Swaminathan, C Spijker, M Gruber, I Kofler, H Raupenstrauch
Energies 16 (17), 6380 , 2023
2023
Citations: 6 - TGA-FTIR for kinetic and evolved gas analysis of the coal particles in dust deflagration
Y Pan, C Spijker, H Raupenstrauch
Applied Thermal Engineering 231, 120881 , 2023
2023
Citations: 11 - CFD‐DEM Modeling of Shaft Furnaces Using the Volume Fraction Smoother Approach
C Spijker, W Pollhammer, H Raupenstrauch
Chemical Engineering & Technology 46 (7), 1333-1339 , 2023
2023
Citations: 4 - Dust cloud evolution and flame propagation of organic dust deflagration under low wall influence
S Puttinger, C Spijker, S Schneiderbauer, S Pirker, G Meyer, C Buchner, ...
Journal of Loss Prevention in the Process Industries 83, 105042 , 2023
2023
Citations: 4 - Numerical investigation of carbon and nitrogen emissions by enriching natural gas with hydrogen on a low-NOx burner
S Swaminathan, C Spijker, H Raupenstrauch
2023 - NOx postprocessing for the steady laminar flamelet mode
C Spijker, S Swaminathan, H Raupenstrauch
2023
MOST CITED SCHOLAR PUBLICATIONS
- CFD modeling of particle dispersion behavior in the MIKE 3 apparatus
Y Pan, C Spijker, H Raupenstrauch
Alexandria engineering journal 61 (12), 9305-9313 , 2022
2022
Citations: 22 - Numerical study of an industrial burner to optimise NOx emissions and to evaluate the feasibility of hydrogen-enriched fuel
S Swaminathan, C Spijker, Z Raonic, M Koller, I Kofler, H Raupenstrauch
International Journal of Hydrogen Energy 49, 1210-1220 , 2024
2024
Citations: 16 - Modeling of a walking beam furnace using CFD–methods
W Pollhammer, C Spijker, J Six, D Zoglauer, H Raupenstrauch
Energy Procedia 120, 477-483 , 2017
2017
Citations: 12 - TGA-FTIR for kinetic and evolved gas analysis of the coal particles in dust deflagration
Y Pan, C Spijker, H Raupenstrauch
Applied Thermal Engineering 231, 120881 , 2023
2023
Citations: 11 - Numerical investigation on inner particle effects in Lycopodium/Air dust deflagrations
C Spijker, H Raupenstrauch
Journal of Loss Prevention in the Process Industries 49, 870-879 , 2017
2017
Citations: 11 - Numerical Simulation and Performance Evaluation of Hydrogen-Enriched Natural Gas for an Industrial Burner in a Testing Chamber
S Swaminathan, C Spijker, M Gruber, I Kofler, H Raupenstrauch
Energies 16 (17), 6380 , 2023
2023
Citations: 6 - CFD als Werkzeug in der Industrieofentechnik
C Pfeiler, CJ Spijker, H Raupenstrauch
BHM Berg-und Hüttenmännische Monatshefte 156 (9), 347-352 , 2011
2011
Citations: 5 - CFD‐DEM Modeling of Shaft Furnaces Using the Volume Fraction Smoother Approach
C Spijker, W Pollhammer, H Raupenstrauch
Chemical Engineering & Technology 46 (7), 1333-1339 , 2023
2023
Citations: 4 - Dust cloud evolution and flame propagation of organic dust deflagration under low wall influence
S Puttinger, C Spijker, S Schneiderbauer, S Pirker, G Meyer, C Buchner, ...
Journal of Loss Prevention in the Process Industries 83, 105042 , 2023
2023
Citations: 4 - Development of an atmosphere particle kinetic model for particle reactions in a combustion Flash-Reactor using CFD-methods
F Edler, B Geier, W Reiter, J Rieger, C Spijker, H Raupenstrauch
Energy Procedia 120, 540-547 , 2017
2017
Citations: 4 - Modeling Dust Explosions: AIChE annual meeting 2013 Conference Proceedings
C Spijker, H Raupenstrauch, H Kern, K Held
AIChE annual meeting 2013 , 2013
2013
Citations: 4 - Vergleich des EDC und SLF Verbrennungsmodells anhand der Sandia Flamme D und deren Anwendbarkeit für Industrieofensimulationen
C Pfeiler, CJ Spijker, H Raupenstrauch
BHM Berg-und Hüttenmännische Monatshefte 156 (11), 457-462 , 2011
2011
Citations: 4 - Unsteady Laminar Flamelet Modellierung zur Beschreibung von Mündungsmischbrennern
C Spijker
2010
Citations: 4 - Investigations on the effect of particle size on dust dispersion in MIKE 3 apparatus
Y Pan, C Spijker, H Raupenstrauch
13th International Symposium on Hazards, Prevention, and Mitigation of … , 2020
2020
Citations: 3 - Development of a twostep simulation concept for fast and accurate prediction of NOX using flamelet model and detailed chemistry in OpenFOAM
WR Pollhammer, C Spijker, H Raupenstrauch, M Koller
Minisymposium Proceedings 2018 , 2018
2018
Citations: 3 - Numerische Untersuchung der Wechselwirkung zwischen explosionsfähigen Lykopodium/Luft-Gemischen und inerten partikulären Additiven mittels Euler-Lagrange Ansatz in OpenFOAM
S Tomasch, W Pollhammer, C Spijker, H Kern, H Raupenstrauch
5. Magdeburger Brand-und Explosionsschutztage , 2017
2017
Citations: 3 - Development of a dust dispersion system for investigations on reduced pressure conditions in the 20 liter SIWEK apparatus using OpenFOAM
W Pollhammer, C Spijker, H Kern, H Raupenstrauch
Graz, March 30th and 31st, 2016, 167 , 2015
2015
Citations: 3 - CFD-Simulation eines direkt befeuerten Ofens zur Vorbehandlung feuerverzinkter Stahlbänder
C Triebl, C Spijker, H Raupenstrauch, A Jarosik, G Angeli
BHM Berg-und Hüttenmännische Monatshefte 159 (7), 310-311 , 2014
2014
Citations: 3 - Optimization of turbulence and radiation models for an improved prediction of non-premixed turbulent flames
C Pfeiler, CJ Spijker, H Raupenstrauch
International review of mechanical engineering 5 (2), 218-225 , 2011
2011
Citations: 3 - A numerical study of flow structures and flame shape transition in swirl-stabilized turbulent premixed flames subject to local extinction
S Tomasch, N Swaminathan, C Spijker, IS Ertesvåg
Combustion Science and Technology 197 (2), 338-370 , 2025
2025
Citations: 2
