Particle-fluid interactions under heterogeneous reactions
Document identifier: oai:DiVA.org:ltu-77326
Keyword: Engineering and Technology,
Mechanical Engineering,
Energy Engineering,
Teknik och teknologier,
Maskinteknik,
Energiteknik,
Stefan flow,
Drag coefficient,
Particle-laden flow,
Reacting flowPublication year: 2020Relevant Sustainable Development Goals (SDGs):
The SDG label(s) above have been assigned by OSDG.aiAbstract: Particle-laden flows involve in many energy and industrial processes within a wide scale range. Solid fuel combustion and gasication, drying and catalytic cracking are some of the examples. It is vital to have a better understanding of the phenomena inside the reactors involving in particle-laden flows for process improvements and design. Computational fluid dynamics (CFD) can be a robust tool for these studies with its advantage over experimental methods. The large variation of length scales (101- 10-9 m) and time scales (days-microseconds) is a barrier to execute detailed simulations for large scale reactors. Current state-of-the-art is to use models to bridge the gap between small scales and large scales. Therefore, the accuracy of the models is key to better predictions in large scale simulations.
Particle-laden flows have complexities due to many reasons. One of the main challenge is to describe how the particle-fluid interaction varies when the particles are reacting. Particle and the fluid interact through mass, momentum and heat exchange. Mass, momentum and heat exchange is presented by the Sherwood number (Sh), drag coefficient (CD) and Nusselt number (Nu) in fluid dynamics. Currently available models do not take into account for the effects of net gas flow generated by heterogeneous chemical reactions. Therefore, the aim of this research is to propose new models for CD and Nu based on the flow and temperature fields estimated by particle-resolved direct numerical simulations (PR-DNS). Models have been developed based on physical interpretation with only one fitting parameter, which is related to the relationship between Reynolds number and the boundary layer thickness. The developed models were compared with the simulation results solving intra-particle flow under char gasification. The drawbacks of models were identied and improvements were proposed.
The models developed in this work can be used for the better prediction of flow dynamics in large scale simulations in contrast to the classical models which do not consider the effect of heterogeneous reactions. Better predictions will assist the design of industrial processes involving reactive particle-laden flows and make them highly effcient and low energy-intensive.
Authors
Thamali Rajika Jayawickrama
Luleå tekniska universitet; Energivetenskap
Other publications
>>
Kentaro Umeki
Luleå tekniska universitet; Energivetenskap
Other publications
>>
Henrik Ström
Chalmers University
Other publications
>>
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header:
identifier: oai:DiVA.org:ltu-77326
datestamp: 2021-04-19T12:40:56Z
setSpec: SwePub-ltu
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recordInfo:
recordContentSource: ltu
recordCreationDate: 2020-01-09
identifier:
978-91-7790-517-2
978-91-7790-518-9
http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-77326
titleInfo:
@attributes:
lang: eng
title: Particle-fluid interactions under heterogeneous reactions
abstract: Particle-laden flows involve in many energy and industrial processes within a wide scale range. Solid fuel combustion and gasication drying and catalytic cracking are some of the examples. It is vital to have a better understanding of the phenomena inside the reactors involving in particle-laden flows for process improvements and design. Computational fluid dynamics (CFD) can be a robust tool for these studies with its advantage over experimental methods. The large variation of length scales (101- 10-9 m) and time scales (days-microseconds) is a barrier to execute detailed simulations for large scale reactors. Current state-of-the-art is to use models to bridge the gap between small scales and large scales. Therefore the accuracy of the models is key to better predictions in large scale simulations.
Particle-laden flows have complexities due to many reasons. One of the main challenge is to describe how the particle-fluid interaction varies when the particles are reacting. Particle and the fluid interact through mass momentum and heat exchange. Mass momentum and heat exchange is presented by the Sherwood number (Sh) drag coefficient (CD) and Nusselt number (Nu) in fluid dynamics. Currently available models do not take into account for the effects of net gas flow generated by heterogeneous chemical reactions. Therefore the aim of this research is to propose new models for CD and Nu based on the flow and temperature fields estimated by particle-resolved direct numerical simulations (PR-DNS). Models have been developed based on physical interpretation with only one fitting parameter which is related to the relationship between Reynolds number and the boundary layer thickness. The developed models were compared with the simulation results solving intra-particle flow under char gasification. The drawbacks of models were identied and improvements were proposed.
The models developed in this work can be used for the better prediction of flow dynamics in large scale simulations in contrast to the classical models which do not consider the effect of heterogeneous reactions. Better predictions will assist the design of industrial processes involving reactive particle-laden flows and make them highly effcient and low energy-intensive.
subject:
@attributes:
lang: eng
authority: uka.se
topic:
Engineering and Technology
Mechanical Engineering
Energy Engineering
@attributes:
lang: swe
authority: uka.se
topic:
Teknik och teknologier
Maskinteknik
Energiteknik
@attributes:
lang: eng
topic: Stefan flow
@attributes:
lang: eng
topic: drag coefficient
@attributes:
lang: eng
topic: particle-laden flow
@attributes:
lang: eng
topic: reacting flow
@attributes:
lang: swe
authority: ltu
topic: Energiteknik
genre: Research subject
@attributes:
lang: eng
authority: ltu
topic: Energy Engineering
genre: Research subject
language:
languageTerm: eng
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publication/licentiate-thesis
vet
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Published
1
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authority: ltu
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Jayawickrama
Thamali Rajika
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Luleå tekniska universitet
Energivetenskap
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Umeki
Kentaro
Professor
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affiliation:
Luleå tekniska universitet
Energivetenskap
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Ström
Henrik
Senior Researcher
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affiliation: Chalmers University
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genre: grantAgreement
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namePart: Vetenskapsrådet
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identifier: 2015-05588
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titleInfo:
title: Licentiate thesis / Luleå University of Technology
identifier: 1402-1757
originInfo:
dateIssued: 2020
publisher: Luleå University of Technology
location:
url: http://ltu.diva-portal.org/smash/get/diva2:1384219/FULLTEXT04.pdf
accessCondition: gratis
physicalDescription:
form: electronic
typeOfResource: text