Browsing NTNU Open by Author "Haugen, Nils Erland L"
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A comprehensive model for char particle conversion in environments containing O2 and CO2
Haugen, Nils Erland L; Mitchell, Reginald E.; Tilghman, Matthew B. (Journal article; Peer reviewed, 2015)In this work, conversion of char is studied in a simulation code that includes a simplified heterogeneous adsorption–desorption reaction mechanism for char chemical reactivity and uses GRI-Mech 3.0 as the chemical kinetic ... -
A Two-Dimensional Study on the Effect of Anisotropy on the Devolatilization of a Large Wood Log
Haugen, Nils Erland L; Skreiberg, Øyvind (Journal article; Peer reviewed, 2019)In this work, a two-dimensional (2D) model for wood particle drying, devolatilization, and char conversion is presented and validated against experimental studies of devolatilization of a large, dry, cylindrical birch wood ... -
Assessment of Transient NOx Reduction Potential in Wood Stoves
Skreiberg, Øyvind; Li, Tian; Bugge, Mette; Haugen, Nils Erland L (Journal article; Peer reviewed, 2020)NOx emissions from wood stoves remain a significant concern, even though modern wood stoves are continuously improved regarding emissions due to incomplete combustion, e.g. particulates of organic origin. Today, state of ... -
Bed Model for Grate-Fired Furnaces: Computational Fluid Dynamics Modeling and Comparison to Experiments
Haugen, Nils Erland L; Bugge, Mette; Mack, Alexander; Li, Tian; Skreiberg, Øyvind (Peer reviewed; Journal article, 2022)A detailed but still central processing unit (CPU)-efficient bed model for grate-fired combustion of biomass and waste is developed. Simulations of wood chip combustion are performed, and the results are compared to ... -
Cloud-droplet growth due to supersaturation fluctuations in stratiform clouds
Li, Xiangyu; Svensson, Gunilla; Brandenburg, Axel; Haugen, Nils Erland L (Journal article; Peer reviewed, 2019)Condensational growth of cloud droplets due to supersaturation fluctuations is investigated by solving the hydrodynamic and thermodynamic equations using direct numerical simulations (DNS) with droplets being modeled as ... -
Combustion of Thermally Thick Wood Particles: A Study on the Influence of Wood Particle Size on the Combustion Behavior
Haberle, Inge; Haugen, Nils Erland L; Skreiberg, Øyvind (Journal article; Peer reviewed, 2018)A one-dimensional (1D) comprehensive combustion model for thermally thick wet wood particles, which is also applicable for studying large wood logs, is developed. The model describes drying, devolatilization, and char ... -
Comparison of numerical efficiency of the thermal and the kinetic rate drying model applied to a thermally thick wood particle
Haberle, Inge; Haugen, Nils Erland L; Skreiberg, Øyvind (Journal article; Peer reviewed, 2017)In this work, the drying and devolatilization of a thermally thick wood particle were modeled. The work was validated against experiments and good agreement was found. The work compared the numerical efficiency and accuracy ... -
Condensational and Collisional Growth of Cloud Droplets in a Turbulent Environment
Li, Xiang-Yu; Brandenburg, Axel; Svensson, Gunilla; Haugen, Nils Erland L; Mehlig, Bernhard; Rogachevskii, Igor (Peer reviewed; Journal article, 2020)We investigate the effect of turbulence on the combined condensational and collisional growth of cloud droplets by means of high-resolution direct numerical simulations of turbulence and a superparticle approximation for ... -
Conversion of solid reacting particles in a non-premixed double shear layer
Zareba, Patrycja Dominika (Master thesis, 2018)As the increasing the efficiency of the combustion processes is crucial nowadays, a fundamental understanding of this process is required. This thesis is focusing on the effect of turbulence on the conversion rate of solid ... -
Correlation effects between turbulence and the conversion rate of pulverized char particles
Krüger, Jonas; Haugen, Nils Erland L; Løvås, Terese (Journal article; Peer reviewed, 2017)The effect of turbulence on heterogeneous reactions on the surface of char particles embedded in a turbulent oxidizer, consisting of oxygen and carbon-dioxide, is in this work studied numerically. It is shown that for a ... -
Drag force for a burning particle
Zhang, Hancong; Luo, Kun; Haugen, Nils Erland L; Mao, Chaoli; Fan, Jianren (Peer reviewed; Journal article, 2020)Fully-resolved simulations of a burning char particle are performed to understand the effects of chemical reastions on the drag force by using the ghost cell immersed boundary method. The momentum, heat and mass transfers ... -
Drying of Thermally Thick Wood Particles: A Study of the Numerical Efficiency, Accuracy, and Stability of Common Drying Models
Haberle, Inge; Haugen, Nils Erland L; Skreiberg, Øyvind (Journal article; Peer reviewed, 2017)The primary focus of this paper is on studying different numerical models for drying of wet wood particles. More specifically, the advantages and disadvantages of the models, with respect to numerical efficiency, stability, ... -
The effect of Stefan flow on Nusselt number and drag coefficient of spherical particles in non-isothermal gas flow
Jayawickrama, Thamali R.; Haugen, Nils Erland L; Bäbler, Matthâus Ulrich; Chishty, Muhammad Aqib; Umeki, Kentaro (Peer reviewed; Journal article, 2021)A Stefan flow can be generated during a phase change or reactions of a particle immersed in a fluid. This study investigates the effect of Stefan flow on the exchange of momentum (drag coefficient (CD)) and heat transfer ... -
Effect of Turbulence on Collisional Growth of Cloud Droplets
Li, Xiangyu; Brandenburg, Axel; Svensson, Gunilla; Haugen, Nils Erland L; Mehlig, Bernhard; Rogachevskii, Igor (Journal article; Peer reviewed, 2018)Weinvestigate the effect of turbulence on the collisional growth of micrometer-sized droplets through highresolution numerical simulations with well-resolved Kolmogorov scales, assuming a collision and coalescence efficiency ... -
The effect of turbulence on mass transfer in solid fuel combustion: RANS model
Karchniwy, Ewa Malgorzata; Haugen, Nils Erland L; Klimanek, Adam F.; Langørgen, Øyvind; Sladek, Slawomir (Peer reviewed; Journal article, 2021)In this paper, a kinetic-diffusion surface combustion model is examined. The model is modified such that two effects of turbulence are included: 1) enhancement of the mass transfer due to relative velocity between particles ... -
The effect of turbulence on the conversion of coal under blast furnace raceway conditions
Wartha, Eva-Maria; Haugen, Nils Erland L; Karchniwy, Ewa Malgorzata; Bösenhofer, Markus; Harasek, Michael; Løvås, Terese (Peer reviewed; Journal article, 2022)dynamics (CFD) can be used to analyze the process virtually and thus improve its performance. Different reducing agents can be used to (partially) substitute the coke and consequently reduce overall emissions. To analyze ... -
Eulerian and Lagrangian approaches to multidimensional condensation and collection
Li, Xiang-Yu; Brandenburg, A.; Haugen, Nils Erland L; Svensson, Gunilla (Journal article; Peer reviewed, 2017)Turbulence is argued to play a crucial role in cloud droplet growth. The combined problem of turbulence and cloud droplet growth is numerically challenging. Here an Eulerian scheme based on the Smoluchowski equation is ... -
Experimental and numerical kinetic study on charged and excited species in oxyfuel combustion for CO2 capture
Grabinski, Krzysztof Adam (Master thesis, 2016)Within the scope of the work, selected chemical kinetics and combustion issues were investigated. The first part contains a study of high temperature plasma and its po- tential usage as a working fluid in the magnetohydrodynamic ... -
Fully resolved simulations of single char particle combustion using a ghost-cell immersed boundary method
Luo, Kun; Mao, Chaoli; Fan, Jianren; Zhuang, Zhenya; Haugen, Nils Erland L (Journal article; Peer reviewed, 2018)A novel ghost‐cell immersed boundary method for fully resolved simulation of char particle combustion has been developed. The boundary conditions at the solid particle surface, such as velocity, temperature, density, and ... -
High-order overset grid method for detecting particle impaction on a cylinder in a cross flow
Aarnes, Jørgen Røysland; Haugen, Nils Erland L; Andersson, Helge Ingolf (Journal article; Peer reviewed, 2019)An overset grid method was developed to investigate the interaction between a particle-laden flow and a circular cylinder. The method is implemented in the Pencil Code, a high-order finite-difference code for compressible ...