Effect of momentum flow ratio on entrainment of a confined coaxial jet in a co-flow

Iron ore pellet production processes produce large amounts of CO2 emissions when burning fossil fuels. One example is the grate-kiln process, where normally a coal flame is used to indurate pellets. To mitigate the emissions, coal used in rotary kilns can be replaced with for example hydrogen. Howev...

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Main Authors: N. Martin Östman, I. A. Sofia Larsson, T. Staffan Lundström, Daniel Marjavaara, Fredrik Normann
Format: Article
Language:English
Published: Taylor & Francis Group 2024-12-01
Series:Engineering Applications of Computational Fluid Mechanics
Subjects:
Online Access:https://www.tandfonline.com/doi/10.1080/19942060.2024.2374977
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author N. Martin Östman
I. A. Sofia Larsson
T. Staffan Lundström
Daniel Marjavaara
Fredrik Normann
author_facet N. Martin Östman
I. A. Sofia Larsson
T. Staffan Lundström
Daniel Marjavaara
Fredrik Normann
author_sort N. Martin Östman
collection DOAJ
description Iron ore pellet production processes produce large amounts of CO2 emissions when burning fossil fuels. One example is the grate-kiln process, where normally a coal flame is used to indurate pellets. To mitigate the emissions, coal used in rotary kilns can be replaced with for example hydrogen. However, the fuel is mixed with secondary process air, and replacing a solid fuel with a gaseous one changes the mixing characteristics. This demands different means of injecting the fuel. A coaxial jet can be used to control the mixing of fuel and secondary air, as well as the flow field. The aim is to control the mixing of hydrogen and secondary air to achieve a hydrogen flame that is similar to the reference coal flame. This study numerically investigates different coaxial jet configurations. Steady-state simulations of a simplified model of the real kiln are performed using a Reynolds Stress turbulence model. Results show that decreasing the momentum flow ratio between the outer and inner jet, [Formula: see text], to a certain value delays the spread of the hydrogen jet and thus gives a longer jet. Further decreasing this ratio gives an even longer jet, but has the side effect of producing recirculation of hydrogen.
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spelling doaj-art-60b8db854cde4520a3933e62b7f185722024-12-09T09:43:46ZengTaylor & Francis GroupEngineering Applications of Computational Fluid Mechanics1994-20601997-003X2024-12-0118110.1080/19942060.2024.2374977Effect of momentum flow ratio on entrainment of a confined coaxial jet in a co-flowN. Martin Östman0I. A. Sofia Larsson1T. Staffan Lundström2Daniel Marjavaara3Fredrik Normann4Division of Fluid and Experimental Mechanics, Luleå University of Technology, Luleå, SwedenDivision of Fluid and Experimental Mechanics, Luleå University of Technology, Luleå, SwedenDivision of Fluid and Experimental Mechanics, Luleå University of Technology, Luleå, SwedenLKAB, Kiruna, SwedenLKAB, Kiruna, SwedenIron ore pellet production processes produce large amounts of CO2 emissions when burning fossil fuels. One example is the grate-kiln process, where normally a coal flame is used to indurate pellets. To mitigate the emissions, coal used in rotary kilns can be replaced with for example hydrogen. However, the fuel is mixed with secondary process air, and replacing a solid fuel with a gaseous one changes the mixing characteristics. This demands different means of injecting the fuel. A coaxial jet can be used to control the mixing of fuel and secondary air, as well as the flow field. The aim is to control the mixing of hydrogen and secondary air to achieve a hydrogen flame that is similar to the reference coal flame. This study numerically investigates different coaxial jet configurations. Steady-state simulations of a simplified model of the real kiln are performed using a Reynolds Stress turbulence model. Results show that decreasing the momentum flow ratio between the outer and inner jet, [Formula: see text], to a certain value delays the spread of the hydrogen jet and thus gives a longer jet. Further decreasing this ratio gives an even longer jet, but has the side effect of producing recirculation of hydrogen.https://www.tandfonline.com/doi/10.1080/19942060.2024.2374977CFDCoaxial jetHydrogen jetMixing
spellingShingle N. Martin Östman
I. A. Sofia Larsson
T. Staffan Lundström
Daniel Marjavaara
Fredrik Normann
Effect of momentum flow ratio on entrainment of a confined coaxial jet in a co-flow
Engineering Applications of Computational Fluid Mechanics
CFD
Coaxial jet
Hydrogen jet
Mixing
title Effect of momentum flow ratio on entrainment of a confined coaxial jet in a co-flow
title_full Effect of momentum flow ratio on entrainment of a confined coaxial jet in a co-flow
title_fullStr Effect of momentum flow ratio on entrainment of a confined coaxial jet in a co-flow
title_full_unstemmed Effect of momentum flow ratio on entrainment of a confined coaxial jet in a co-flow
title_short Effect of momentum flow ratio on entrainment of a confined coaxial jet in a co-flow
title_sort effect of momentum flow ratio on entrainment of a confined coaxial jet in a co flow
topic CFD
Coaxial jet
Hydrogen jet
Mixing
url https://www.tandfonline.com/doi/10.1080/19942060.2024.2374977
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