| 1. |
- Astaneh, Majid, 1990, et al.
(författare)
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Calibration Optimization Methodology for Lithium-Ion Battery Pack Model for Electric Vehicles in Mining Applications
- 2020
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Ingår i: Energies. - : MDPI AG. - 1996-1073 .- 1996-1073. ; 13:14
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Tidskriftsartikel (refereegranskat)abstract
- Large-scale introduction of electric vehicles (EVs) to the market sets outstanding requirements for battery performance to extend vehicle driving range, prolong battery service life, and reduce battery costs. There is a growing need to accurately and robustly model the performance of both individual cells and their aggregated behavior when integrated into battery packs. This paper presents a novel methodology for Lithium-ion (Li-ion) battery pack simulations under actual operating conditions of an electric mining vehicle. The validated electrochemical-thermal models of Li-ion battery cells are scaled up into battery modules to emulate cell-to-cell variations within the battery pack while considering the random variability of battery cells, as well as electrical topology and thermal management of the pack. The performance of the battery pack model is evaluated using transient experimental data for the pack operating conditions within the mining environment. The simulation results show that the relative root mean square error for the voltage prediction is 0.7–1.7% and for the battery pack temperature 2–12%. The proposed methodology is general and it can be applied to other battery chemistries and electric vehicle types to perform multi-objective optimization to predict the performance of large battery packs.
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| 2. |
- Astaneh, Majid, 1990, et al.
(författare)
-
Finite-size effects on heat and mass transfer in porous electrodes
- 2022
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Ingår i: International Journal of Thermal Sciences. - : Elsevier BV. - 1290-0729. ; 179
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Tidskriftsartikel (refereegranskat)abstract
- In thin electrode applications, as the ratio of the obstacle size with respect to the system size increases, issues such as finite-size effects become more influential in the transport of heat and mass within a porous structure. This study presents a numerical approach to evaluate the finite-size effects on the heat and mass transfer in porous electrodes. In particular, numerical simulations based on the lattice Boltzmann method (LBM) are employed to analyze the pore-scale transport phenomena. Analyzing the results at both the electrode level and the pore level shows that the mass transfer performance is more influenced by the finite-size effects compared to the transfer of heat. The numerical simulations show that as the parameter m being the ratio of the electrode thickness to the particle diameter is halved, the effective diffusivity increases by 20% while the effective conductivity remains unchanged. We propose a novel analytical tortuosity–porosity (τ−ϕ) correlation as τ=[1−(1−ϕ)m+1]/ϕ where the finite-size effects are taken into account via the parameter m. Besides, particles of small size provide more uniform distributions of temperature and concentration within the porous structure with standard deviations of approximately half of the values obtained from the case made up of large particles. Our findings at the electrode level are compared with the commonly used macroscopic porosity-dependent correlations found in the literature. At the end, by performing a systematic assessment, we provide guidelines for efficient design of porous electrodes.
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| 3. |
- Astaneh, Majid, 1990, et al.
(författare)
-
Lithium-Ion Battery Pack Modelling for Electric Vehicles in Mining Applications Using GT-AutoLion
- 2020
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Large traction battery packs play a pivotal role in electric vehicles (EVs) to fulfill the system demand for high voltage and capacity. Therefore, accurate and robust modeling of both individual battery cells and their aggregated behavior in battery packs is of crucial importance. This presentation proposes a novel approach to integrate the validated electrochemical-thermal models of the Lithium-ion (Li-ion) cells into battery pack simulations for electric vehicle applications. The approach employs the calibration optimization methodology that utilizes experimental measurements for battery cells and for the battery pack under realistic operating conditions in mining applications. The random variability of battery cells, as well as electrical topology and thermal management of the pack have been considered in the present study to mimic the actual behavior of the battery pack under consideration. The simulations were carried out in GT-AutoLion and the optimizations were performed using GT-SUITE direct optimizer. The experimental data were provided by Northvolt AB, a leading European manufacturer of the next-generation Li-ion battery cells and complete battery systems. The proposed methodology is general and can be applied to other battery chemistries and electric vehicle types to perform multi-objective optimization to predict the performance of large battery packs.
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| 4. |
- Baricci, Andrea, et al.
(författare)
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Modeling of Polymer Electrolyte Membrane Fuel Cells
- 2023
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Ingår i: Electrocatalysis for Membrane Fuel Cells: Methods, Modeling, and Applications. - 9783527830572 ; , s. 473-510
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- This chapter outlines analytical and numerical methods for modeling proton exchange membrane fuel cells. To provide the fundamentals of fuel cell simulation, a monodimensional analytical (steady-state isothermal) model for reconstructing the cell polarization curve is presented and then applied to a case of practical interest. The monodimensional model is perfectioned by considering multiphase water transport affecting electrical conductivity properties of cell membrane. As an example, the impact of catalyst layer thickness is simulated under dry and humid conditions. A detailed mass transport model, based on the volume-averaging technique for the Darcy equation, is provided for an accurate simulation of fuel cell diffusion layers. The last part of this chapter concerns the analytical modeling of fuel cell dynamics. A physical-based approach, allowing for a fast and reliable quantitative interpretation of electrochemical impedance spectroscopy experimental data, is eventually provided.
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| 5. |
- Farzaneh Kaloorazi, Meisam, 1982, et al.
(författare)
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Pore-Scale Transport and Two-Phase Fluid Structures in Fibrous Porous Layers: Application to Fuel Cells and Beyond
- 2021
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Ingår i: Transport in Porous Media. - : Springer Science and Business Media LLC. - 1573-1634 .- 0169-3913. ; 136:1, s. 245-270
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Tidskriftsartikel (refereegranskat)abstract
- We present pore-scale simulations of two-phase flows in a reconstructed fibrous porous layer. The three-dimensional microstructure of the material, a fuel cell gas diffusion layer, is acquired via X-ray computed tomography and used as input for lattice Boltzmann simulations. We perform a quantitative analysis of the multiphase pore-scale dynamics, and we identify the dominant fluid structures governing mass transport. The results show the existence of three different regimes of transport: a fast inertial dynamics at short times, characterised by a compact uniform front, a viscous-capillary regime at intermediate times, where liquid is transported along a gradually increasing number of preferential flow paths of the size of one–two pores, and a third regime at longer times, where liquid, after having reached the outlet, is exclusively flowing along such flow paths and the two-phase fluid structures are stabilised. We observe that the fibrous layer presents significant variations in its microscopic morphology, which have an important effect on the pore invasion dynamics, and counteract the stabilising viscous force. Liquid transport is indeed affected by the presence of microstructure-induced capillary pressures acting adversely to the flow, leading to capillary fingering transport mechanism and unstable front displacement, even in the absence of hydrophobic treatments of the porous material. We propose a macroscopic model based on an effective contact angle that mimics the effects of the such a dynamic capillary pressure. Finally, we underline the significance of the results for the optimal design of face masks in an effort to mitigate the current COVID-19 pandemic.
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| 6. |
- Hidman, Niklas, 1989, et al.
(författare)
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Laser-induced vapour bubble as a means for crystal nucleation in supersaturated solutions - Formulation of a numerical framework
- 2019
-
Ingår i: Experimental and Computational Multiphase Flow. - : Springer Science and Business Media LLC. - 2661-8877 .- 2661-8869. ; 1:4
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Tidskriftsartikel (refereegranskat)abstract
- We use in this work numerical simulations to investigate the evolution of a laser-induced vapour bubble with a special focus on the resolution of a thin layer of liquid around the bubble. The application of interest is laser-induced crystallization, where the bubble acts as a nucleation site for crystals. Experimental results indicate the extreme dynamics of these bubbles where the interface during the period of 200 us, from nucleation to collapse, reaches a maximum radius of roughly 700 µm and attains a velocity of well above 20 m/s. To fully resolve the dynamics of the bubble, the volume of fluid (VOF) numerical framework is used. Inertia, thermal effects, and phase-change phenomena are identified as the governing phenomena for the bubble dynamics. We develop and implement into our numerical framework an interface phase-change model that takes into account both evaporation and condensation. The performed simulations produce qualitatively promising results that are in fair agreement with both experiments and analytical solutions from the literature. The reasons behind the observed differences are discussed and suggestions are made for future improvements of the framework.
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| 7. |
- Hidman, Niklas, 1989, et al.
(författare)
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Numerical Frameworks for Laser-Induced Cavitation: Is Interface Supersaturation a Plausible Primary Nucleation Mechanism?
- 2020
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Ingår i: Crystal Growth & Design. - : American Chemical Society (ACS). - 1528-7505 .- 1528-7483. ; 20:11, s. 7276-7290
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Tidskriftsartikel (refereegranskat)abstract
- Crystallization has been observed in laser-induced cavities in saturated solutions, but the mechanisms behind nucleation of crystals are not entirely clear. A hypothesis is that high solution supersaturation during the bubble growth period triggers the nucleation. Because of small spatiotemporal scales of the cavitation event, the supersaturation is very difficult to measure experimentally. To test the nucleation hypothesis, we perform a two-dimensional axisymmetric direct numerical simulation of an experimentally observed laser-induced cavitation event with crystallization. We demonstrate a significant degree of supersaturation and argue that the nucleation hypothesis is indeed plausible. To analyze factors that lead to a high supersaturation, we develop a comprehensive one-dimensional model for spherical laser-induced cavities. We conduct an extensive investigation on how the solute solubility, solute diffusivity, laser pulse energy, and superheated liquid volume affect the supersaturation. We show that high supersaturation is possible under a range of relevant conditions but not readily obtained for all solutions and laser setups. Guidelines are provided to identify if a specific solution or laser setup may attain high supersaturation. The insights obtained and the numerical methods formulated in this work can be applied to assess and design new laser-induced cavitation setups that allow for precise control of the duration and degree of the supersaturation
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| 8. |
- Hidman, Niklas, 1989, et al.
(författare)
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Numerical simulation of a laser-induced vapour bubble for crystal nucleation at low supersaturation levels
- 2019
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- We use in this work numerical simulations to investigate the dynamics of a laser-induced vapour bubble. The application of interest is laser-induced crystallization, where the bubble acts as a nucleation site for crystals. To fully resolve growth and collapse of the bubble, the Volume of Fluid (VOF) numerical framework is used. Inertia, thermal effects and phase-change phenomena are identified as the governing phenomena for the bubble dynamics. We develop and implement into our numerical framework an interface phase-change model that takes into account both evaporation and condensation. Performed simulations produce qualitatively promising results that are in fair agreement with both experiments and analytical solutions from the literature. The reasons behind the observed differences are discussed and suggestions for future improvements of the framework are described.
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| 9. |
- Jareteg, Adam, 1989, et al.
(författare)
-
Detailed simulations of heterogeneous reactions in porous media using the Lattice Boltzmann Method
- 2018
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Flows though porous media are commonly found in many systems, both natural and manmade. A few examples from nature include petroleum reservoirs, soil and solid biomass where industrial applications include fuel cells, foams and packed beds. Most of these areas are still subject to both scientific and engineering challenges ranging from basic understanding to detailed optimization. A non-trivial part of the remaining challenges includes the interaction between macro-scale performance and micro-scale characteristics. For some systems, it is possible to control and tune micro-scale properties to optimize the overall performance of the application. This scenario typically manifests in the design of packed beds, especially when reactions occur within the bed. In such situations, particle shape and size distribution will affect not only the pressure drop (and hence the preferential flow paths), but also local reaction rates and thereby efficiency and selectivity. This work aims to understand and identify key design parameters that influences reactions within a packed bed, and ultimately, the overall performance of the pack- ing. Representative microstructures of packed beds are generated with a Discrete Element Method. Flow, temperature and concentration fields (cf. Figure 1) are then fully resolved using the Lattice Boltzmann Method with a first order reaction scheme at the boundaries. Residence time, flow structures and permeability of the systems are correlated to conversion and selectivity of the chemical reactions in the system. Comparisons between packings of different particle shapes and spacing serve to eluci- date phenomena involved in the process and implies design directions for macro-scale optimization.
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| 10. |
- Jareteg, Adam, 1989, et al.
(författare)
-
Effects of bed aging on temperature signals from fixed-bed adsorbers during industrial operation
- 2020
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Ingår i: Results in Engineering. - : Elsevier BV. - 2590-1230. ; 8
-
Tidskriftsartikel (refereegranskat)abstract
- The capacity of adsorber beds used in industrial-scale temperature-swing adsorption diminishes over time due to bed aging. Here, we present industrial data on the temperature signals from fixed-bed adsorbers using activated carbon designed to remove benzene and other impurities from the gas produced in biomass gasification. The aging of the adsorber beds proceeds due to irreversible adsorption of trace species and manifests itself via two simultaneous effects: a decrease in the availability of active adsorption sites over time and an increase in the overall thermal mass of the bed. Both effects tend to dampen the temperature response of the beds during operation, implying that they are easily confounded. Model descriptions of bed aging should account for both effects.
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