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Publikasjoner (10 av 28) Visa alla publikasjoner
Zhang, J., Schulze-Netzer, C., Li, T. & Løvås, T. (2024). A novel model for solid fuel combustion with particle migration. Proceedings of the Combustion Institute, 40(1-4), Article ID 105575.
Åpne denne publikasjonen i ny fane eller vindu >>A novel model for solid fuel combustion with particle migration
2024 (engelsk)Inngår i: Proceedings of the Combustion Institute, ISSN 1540-7489, E-ISSN 1873-2704, Vol. 40, nr 1-4, artikkel-id 105575Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Solid fuel conversion in a fixed-bed is a challenging modelling task due to different time and length scales and the importance of heat transfer mechanisms. The current study aims to propose a novel model that can capture all the main features of the conversion of fuel bed while maintaining a moderate computational cost. The model is based on the commonly applied porous media approach, which describes the solid phase using an Eulerian framework. A layered particle submodel with four types of solids, wet wood, dry wood, char, and ash, is implemented to account for different conversion stages. At each computational cell, a matrix is used to record the information on all the properties of the four types of solids, including the number and volume of particles. The model allows the exchange of particles between cells, thus capable of simulating the motion of the fuel bed during conversion, such as bed collapsing. In addition, the new model can efficiently calculate heat transfer between particles and particles and fluid in each computational cell. The proposed model is validated against a series of experiments on biomass conversion in a rectangular fixed-bed combustor operated in a counter-current mode with various air supply rates. Good agreement with experiments was found even at the limited combustion regime. With the overall low computational cost generated by the bed model, the proposed model framework has the potential to efficiently simulate a wide range of solid fuel conversion processes at a large scale, not only in fixed-beds but also in moving beds and rotary kilns. 

sted, utgiver, år, opplag, sider
Elsevier Ltd, 2024
Emneord
Bioconversion; Brickmaking; Combustion; Computational fluid dynamics; Heat transfer; Bed collapsing; Computational cell; Computational costs; Fixed bed; Modeling task; Particle migration; Porous medium; Solid fuel conversion; Solid fuels; Solid fuels combustion; Porous materials
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-74837 (URN)10.1016/j.proci.2024.105575 (DOI)2-s2.0-85199264833 (Scopus ID)
Merknad

The authors acknowledge support from the Research Council of Norway and a number of industrial partners through the BioCarbUp project (294679) and BioSynGas project (319723).

Tilgjengelig fra: 2024-08-27 Laget: 2024-08-27 Sist oppdatert: 2024-08-27bibliografisk kontrollert
Zhao, Z., Qin, H., Li, T., Hua, B., Hou, Y., Chen, T. & Ström, H. (2024). CFD simulation of soot generation during biomass gasification in a cyclone gasifier. Fuel, 364, Article ID 131103.
Åpne denne publikasjonen i ny fane eller vindu >>CFD simulation of soot generation during biomass gasification in a cyclone gasifier
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2024 (engelsk)Inngår i: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 364, artikkel-id 131103Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Soot generation is a challenging issue in high-temperature biomass gasification, which reduces the biomass conversion rate and leads to contamination of the reactor. To provide new means and insights to optimize gasification processes, the soot generation during biomass gasification in a cyclone reactor is studied here by establishing a novel biomass gasification and soot formation model to improve the accuracy attainable in numerical predictions of spatio-temporal soot evolution. The new method is validated by comparing it with gasification experiments in two reactor configurations. A good performance in capturing the overall soot generation and light gas yield of the current model is obtained in the simulations of an entrained flow reactor compared with experimental data. Besides, the biomass gasification behavior in this entrained flow reactor is systematically studied by reviewing the tar, precursor, and soot mass fraction evolution in the reactor under different steam/carbon ratios, gasification temperatures, and air excess ratios with the new model. Furthermore, the influence of varying air equivalence ratios, the operation temperature and the fuel moisture on the soot generation in a cyclone gasifier, as well as the ability of the proposed model to reflect such influences, are also discussed. Numerical simulations demonstrate the existence of an optimal operation condition for the cyclone gasifier in terms of the soot generation. The current work thus provides a useful tool for analyzing the mechanism of soot formation at the reactor scale. 

sted, utgiver, år, opplag, sider
Elsevier Ltd, 2024
Emneord
Biomass gasification, Entrained flow reactor, High-temperature, Soot formation
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-71938 (URN)10.1016/j.fuel.2024.131103 (DOI)2-s2.0-85184030547 (Scopus ID)
Forskningsfinansiär
Swedish Research Council Formas, 2017-00677Swedish Energy Agency, 46439-1The Research Council of Norway, 319723
Merknad

This work is financially supported by the National Natural Science Foundation of China (No. 52206206 and No. 52276160), the Swedish Energy Agency (No. 46439-1), the Swedish Research Council Formas (No. Dnr 2017-00677), and the Research Council of Norway (BioSynGas - Next generation Biogas production through the Synergetic Integration of Gasification, 319723). 

Tilgjengelig fra: 2024-02-27 Laget: 2024-02-27 Sist oppdatert: 2024-02-27bibliografisk kontrollert
Sæter Bøe, A., Jiang, L. & Li, T. (2024). Facade exposures in cross-laminated timber compartments affected by wind. In: : . Paper presented at Fire Safety of Facades (FSF). Lund, Sweden. 10. juni 2024 - 12. juni 2024.
Åpne denne publikasjonen i ny fane eller vindu >>Facade exposures in cross-laminated timber compartments affected by wind
2024 (svensk)Konferansepaper, Publicerat paper (Fagfellevurdert)
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-76983 (URN)
Konferanse
Fire Safety of Facades (FSF). Lund, Sweden. 10. juni 2024 - 12. juni 2024
Merknad

Norges forskningsråd 294649

Tilgjengelig fra: 2025-01-30 Laget: 2025-01-30 Sist oppdatert: 2025-01-30
Stølen, R., Li, T., Wingdahl, T. & Steen-Hansen, A. (2024). Large- and small-scale fire test of a building integrated photovoltaic (BIPV) facade system. Fire safety journal, 144, Article ID 104083.
Åpne denne publikasjonen i ny fane eller vindu >>Large- and small-scale fire test of a building integrated photovoltaic (BIPV) facade system
2024 (engelsk)Inngår i: Fire safety journal, ISSN 0379-7112, E-ISSN 1873-7226, Vol. 144, artikkel-id 104083Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

The number of installed photovoltaic (PV) modules has increased significantly over the last years, and using available building surfaces to generate electricity by integrating PV modules in the construction is an attractive option. Building integrated photovoltaics (BIPV) or other vented claddings can spread fires rapidly to large parts of a building if the fire is allowed to propagate. To investigate this hazard, a large-scale SP FIRE 105 façade fire test was conducted. A façade measuring 4000 mm × 6000 mm covered with BIPV modules was exposed to flames that represent the fire plume from a window in a room at flashover. The results from the test show that critical failures, like falling objects and vertical flame propagation, can be expected in such constructions. These results highlight the importance of details in mounting of BIPV-façades and to require proper documentation from relevant fire tests of such systems. Small-scale cone calorimeter tests were conducted on the studied BIPV module to provide material properties of the combustible parts of the installation. These aspects should be considered when planning new or when retrofitting façades, to prevent escalation of fires. The results presented are, however, only valid for the configuration that was tested. Other BIPV-façades should also be investigated to study how these constructions can be built safely in the future with regard to critical details.

Emneord
Facade, BIPV, Full-scale fire test, Reaction to fire, Cavity, Cone calorimeter
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-69351 (URN)10.1016/j.firesaf.2023.104083 (DOI)
Forskningsfinansiär
The Research Council of Norway, 294649
Merknad

This research is supported by the Fire Research and Innovation Centre (FRIC), funded by the Research Council of Norway (Project no. 294649) and project partners. The authors would also thank the C40 Urban Village project led by OBOS with support from Multiconsult, Hunton and Innovation Norway for initiating, planning and financing the test and sharing data. 

Tilgjengelig fra: 2024-01-10 Laget: 2024-01-10 Sist oppdatert: 2024-07-28bibliografisk kontrollert
Jiang, L., Sæter Bøe, A. & Li, T. (2024). Numerical simulation of fire spread in a large-scale open CLT compartment. Fire safety journal, 150, Article ID 104289.
Åpne denne publikasjonen i ny fane eller vindu >>Numerical simulation of fire spread in a large-scale open CLT compartment
2024 (engelsk)Inngår i: Fire safety journal, ISSN 0379-7112, E-ISSN 1873-7226, Vol. 150, artikkel-id 104289Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Recent experiments have shown that exposed cross-laminated timber (CLT) can have a significant effect on the fire dynamics of large compartments. A simulation with the Fire Dynamic Simulator has been conducted to better understand the fire behaviour of open-plan compartments with exposed CLT. The simulation was set up to replicate a large-scale experiment, FRIC-02, with exposed CLT on the back wall and ceiling. The compartment was 95 m2 (18.8 m × 5.0 m × 2.5 m), with one long wall open (opening factor 0.18 m1/2). A continuous wood crib was used as the variable fuel load. The characteristic results of FRIC-02 with a rapid fire development and non-symmetrical external flames were successfully reproduced. With the wind coming diagonally from behind, as in FRIC-02, the external flames emerged mainly out of one window. The flames covered the entire window height, which effectively inhibited the inflow of air through that window. The imbalance in air supply also created large temperature differences throughout the compartment. With no implementation of wind, external flames and temperatures were more symmetrical. Despite a good match to FRIC-02, the method still has several limitations, including the adaption of the burning rate to the feedback from surroundings.

sted, utgiver, år, opplag, sider
Elsevier Ltd, 2024
Emneord
Fireclay; Fires; Timber; Cross laminated; Cross-laminated timber compartment; Exposed timber; External flame; External wind; FDS; Fire dynamics; Fire spread; Laminated timber; Large-scales; Premixed flames
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-76445 (URN)10.1016/j.firesaf.2024.104289 (DOI)2-s2.0-85209133411 (Scopus ID)
Merknad

The authors gratefully acknowledge the financial support by the Research Council of Norway through the program BRANNSIKKERHET, project number 294649. 

Tilgjengelig fra: 2025-01-29 Laget: 2025-01-29 Sist oppdatert: 2025-01-29bibliografisk kontrollert
Luu, T. D., Zhang, J., Gärtner, J. W., Meng, S., Kronenburg, A., Li, T., . . . Stein, O. T. (2024). Single particle conversion of woody biomass using fully-resolved and Euler–Lagrange coarse-graining approaches. Fuel, 368, Article ID 131600.
Åpne denne publikasjonen i ny fane eller vindu >>Single particle conversion of woody biomass using fully-resolved and Euler–Lagrange coarse-graining approaches
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2024 (engelsk)Inngår i: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 368, artikkel-id 131600Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

The conversion of woody biomass is studied by means of a layer-based model for thermally-thick biomass particles (Thunman et al. 2002, Ström et al. 2013). The model implementation is successfully validated against experiments that study particle conversion in a drop tube reactor. After this validation step, this work focuses on the well-known problem of grid dependence of two-phase numerical simulations using the standard Euler–Lagrange (EL) framework. This issue is addressed and quantified by comparing EL data that models the particle boundary layers to corresponding simulations which fully resolve these boundary layers (fully-resolved, FR, simulations). A comparison methodology for the conceptually different FR and EL approaches by extracting the heat transfer coefficient from the detailed FR simulations is proposed and confirms that the EL results are strongly grid-dependent. This issue is overcome by applying a set of coarse-graining methods for the EL framework. Two coarse-graining methods are evaluated, a previously suggested diffusion-based method (DBM) and a new approach based on moving averages referred to as MAM. It is shown that both DBM and MAM can successfully recover the detailed FR data for pure particle heating for a case where the grid size is half the particle diameter, i.e. when the standard EL method fails. Both coarse-graining methods also give improved results for an EL simulation that considers the more complex combined physics of particle heating, drying and devolatilisation, given that the CG model parameters that scale the corresponding CG interaction volumes are sufficiently large. Based on the available FR data, recommended model parameter ranges for DBM and MAM are provided as a function of normalised boundary layer thickness. The novel MAM approach is shown to be significantly more efficient than the DBM and therefore suitable for future EL simulations with multiple particles. 

sted, utgiver, år, opplag, sider
Elsevier Ltd, 2024
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-72945 (URN)10.1016/j.fuel.2024.131600 (DOI)2-s2.0-85189673301 (Scopus ID)
Merknad

The authors acknowledge the financial support by the DeutscheForschungsgemeinschaft, Germany for project number 450158108 andthe Chinese Scholarship Council (no. 201906420087, S. Meng). The authors gratefully acknowledge the financial support by the Helmholtz Association of German Research Centres (HGF), within the research fieldEnergy, program Materials and Technologies for the Energy Transition(MTET), topic Resource and Energy Efficiency.

Tilgjengelig fra: 2024-04-25 Laget: 2024-04-25 Sist oppdatert: 2024-04-25bibliografisk kontrollert
Zhu, G., Xu, L., Wang, S., Niu, F., Li, T., Hui, S. & Niu, Y. (2024). Synergistic reduction on PM and NO source emissions during preheating-combustion of pulverized coal. Fuel, 361, Article ID 130699.
Åpne denne publikasjonen i ny fane eller vindu >>Synergistic reduction on PM and NO source emissions during preheating-combustion of pulverized coal
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2024 (engelsk)Inngår i: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 361, artikkel-id 130699Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

The present research focuses on the synergistic source control of particulate matter (PM) and NOx formation from pulverized coal combustion. Comparative experiments of preheating-combustion and conventional combustion were conducted in a lab-scale high-temperature preheating-combustion furnace, and PM10 and NO were measured by an electrical low pressure impactor and a flue gas analyzer, respectively. The results of the experiment indicate that preheating-combustion has a significant reduction in PM10 (especially PM0.3 up to 37.51 %) and NO, which can achieve the synergistic control of PM10 and NO source emissions during the combustion process. The fragmentation in preheating-combustion was weaker compared to the conventional combustion. Meanwhile, the relatively weak preheating-combustion coal char oxidation reaction leads to a decrease in ultrafine mode PM yielded due to the inhibition on vaporization of mineral inclusions. The PM0.3/PM1 mass ratio of the preheating-combustion has a decreasing trend, implying an elevated yield of PM0.3-1 and a shift of the average PM1 particle size toward a larger particle size. Higher preheating temperature (Tp) presented the potential to further reduce NO formation, and the NO reduction efficiency increased from 46.59 % to 56.60 % when the Tp was increased from 1200 K to 1600 K. All our preliminary results throw light on the nature of synergistic source control of preheating-combustion PM and NO formation. 

sted, utgiver, år, opplag, sider
Elsevier Ltd, 2024
Emneord
Char, Minerals, NO, Particulate matters, Preheating-combustion, Coal, Coal combustion, Particle size, Particles (particulate matter), Pulverized fuel, Reduction, % reductions, Conventional combustions, NO formation, Particulate Matter, Particulate matter 10, Pulverized coals, Source control, Preheating
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-71983 (URN)10.1016/j.fuel.2023.130699 (DOI)2-s2.0-85180415026 (Scopus ID)
Forskningsfinansiär
The Research Council of Norway, 267957
Merknad

he present work was supported by Central University Basic Research Fund of China (No. xzd012022079). Tian Li would like to acknowledge the financial support by the Knowledge-Building Project Grate CFD (267957) funded by the Research Council of Norway and industry partners.

Tilgjengelig fra: 2024-02-22 Laget: 2024-02-22 Sist oppdatert: 2024-02-22bibliografisk kontrollert
Zhang, J., Li, T., Ström, H., Wang, B. & Løvås, T. (2023). A novel coupling method for unresolved CFD-DEM modeling. International Journal of Heat and Mass Transfer, 203, Article ID 123817.
Åpne denne publikasjonen i ny fane eller vindu >>A novel coupling method for unresolved CFD-DEM modeling
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2023 (engelsk)Inngår i: International Journal of Heat and Mass Transfer, ISSN 0017-9310, E-ISSN 1879-2189, Vol. 203, artikkel-id 123817Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

In CFD-DEM (computational fluid dynamics-discrete element method) simulations particles are considered Lagrangian point particles. The details of the flow near the particle surface are therefore not fully resolved. When the particle scale is larger than the resolved flow scale, the coupling between the CFD model and the DEM model is critical. An effective coupling scheme should minimize the risk of artificial influences on the results from choices of numerical parameters in implementations and consider efficiency and robustness. In this work, a novel coupling method is developed. The method includes both the smoothing of the particle data and the sampling of the gas phase quantities. The smoothing employs the diffusion-based method. The gas sampling method can reconstruct the filtered fluid quantities at the particle center. The sampling method is developed based on the diffusion-based method with higher efficiency. The new method avoids mesh searching and it can be easily implemented in parallel computing. The developed method is validated by the simulation of a forced convection experiment for a fixed bed with steel spheres. With the well-posed grid-independent coupling scheme, the simulation results are in good agreement with the experimental measurements. The coupling effects and the computational cost are discussed in detail. 

sted, utgiver, år, opplag, sider
Elsevier Ltd, 2023
Emneord
CFD, Coupling, DEM, Fixed bed, Forced convection, Diffusion in liquids, Efficiency, Coupling methods, Coupling scheme, Discrete element method simulations, Discrete elements method, Lagrangian points, Method model, Point-particles, Sampling method, Computational fluid dynamics
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-65504 (URN)10.1016/j.ijheatmasstransfer.2022.123817 (DOI)2-s2.0-85146016750 (Scopus ID)
Merknad

Funding details: Norges Forskningsråd, 267957, 294679; Funding details: Centre for Combustion Science and Technology, Faculty of Engineering, LTH, CECOST; Funding text 1: The authors acknowledge support from the Research Council of Norway and a number of industrial partners through the project BioCarbUp (294679) and Project GrateCFD (267957). NTNU IDUN/EPIC computing cluster provided high-performance computational resources for CFD simulations. Henrik Ström gratefully acknowledges co-financing from the Centre for Combustion Science and Technology (CECOST) and the Swedish Gasification Centre (SFC).

Tilgjengelig fra: 2023-06-13 Laget: 2023-06-13 Sist oppdatert: 2023-06-13bibliografisk kontrollert
Skilbred, E. S., Holmvaag, O. A., Stenstad, V., Fjærestad, J. S. & Li, T. (2023). Fire safety in semi-automatic parking facilities. In: Proceedings of Seventh International Conference on Fires in Vehicles: . Paper presented at Seventh International Conference on Fires in Vehicles, Stavanger, Norway, April 24-25, 2023 (pp. 201). RISE Research Institutes of Sweden
Åpne denne publikasjonen i ny fane eller vindu >>Fire safety in semi-automatic parking facilities
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2023 (engelsk)Inngår i: Proceedings of Seventh International Conference on Fires in Vehicles, RISE Research Institutes of Sweden , 2023, s. 201-Konferansepaper, Publicerat paper (Fagfellevurdert)
Abstract [en]

This paper investigates fire safety in semi-automatic parking facilities (garages). A semi-automatic parking facility is a parking facility where larger or smaller areas have a system for automatic car stacking or close parking of cars on the same level. The paper is based on a project initiated to increase the knowledge about semi-automatic parking facilities and fire safety in these facilities. Information about semi-automatic parking facilities in Norway and abroad was collected through surveys, interviews, and literature studies.

sted, utgiver, år, opplag, sider
RISE Research Institutes of Sweden, 2023
Emneord
parking facilities, car stacking, fire safety, interviews, regulations.
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-71493 (URN)
Konferanse
Seventh International Conference on Fires in Vehicles, Stavanger, Norway, April 24-25, 2023
Merknad

The project is funded by The Norwegian Directorate for Civil Protection (DSB) and The NorwegianBuilding Authority (DiBK). 

Tilgjengelig fra: 2024-01-26 Laget: 2024-01-26 Sist oppdatert: 2024-02-06bibliografisk kontrollert
Boddaert, S., Bonomo, P., Eder, G., Fjellgaard Mikalsen, R., Ishii, H., Kim, J.-T., . . . Zang, Y. (2023). Fire safety of BIPV: International mapping of accredited and R&D facilities in the context of codes and standards 2023. International Energy Agency (IEA)
Åpne denne publikasjonen i ny fane eller vindu >>Fire safety of BIPV: International mapping of accredited and R&D facilities in the context of codes and standards 2023
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2023 (engelsk)Rapport (Annet vitenskapelig)
Abstract [en]

The objective of Task 15 of the IEA Photovoltaic Power Systems Programme is to create an enabling framework to accelerate the penetration of BIPV products in the global market of renewables, resulting in an equal playing field for BIPV products, BAPV products and regular building envelope components, respecting mandatory issues, aesthetic issues, reliability issues, and financial issues.

Subtask E of Task 15 is focused on pre-normative international research on BIPV characterisation methods and activity E.3 is dedicated to fire safety of BIPV modules and installations.

sted, utgiver, år, opplag, sider
International Energy Agency (IEA), 2023
Serie
IEA-PVPS ; T15-15:2023
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-65661 (URN)978-3-907281-39-0 (ISBN)
Tilgjengelig fra: 2023-07-12 Laget: 2023-07-12 Sist oppdatert: 2024-01-26bibliografisk kontrollert
Organisasjoner
Identifikatorer
ORCID-id: ORCID iD iconorcid.org/0000-0002-4248-8396
v. 2.45.0