Numerical analysis of the unsteady transition of multiple laminar methanol/air spray flame structures in the counterflow configuration
The counterflow configuration is a well-established setting to study the structure of laminar spray flames. Typically, the similarity transformation is introduced to transfer the two-dimensional gas-phase equations into one-dimensional governing equations. The equations which describe droplet motion...
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Elsevier
2025-09-01
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| Series: | Applications in Energy and Combustion Science |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2666352X25000445 |
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| author | Jiawei Wan Eva Gutheil |
| author_facet | Jiawei Wan Eva Gutheil |
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| collection | DOAJ |
| description | The counterflow configuration is a well-established setting to study the structure of laminar spray flames. Typically, the similarity transformation is introduced to transfer the two-dimensional gas-phase equations into one-dimensional governing equations. The equations which describe droplet motion are two-dimensional. For spray flames in the counterflow configuration, Continillo and Sirignano suggested that more than one numerical solution of these equations may exist, which meanwhile was confirmed by several studies. Up to three different structures were found for the same boundary conditions for the combustion of fuel sprays carried by air directed against an air stream. The first structure shows two chemical reaction zones one of which resides on the fuel side and the other one on the air side of the configuration. The other two spray flame structures show single chemical reaction zones that reside on one but different side of the stagnation plane. The present paper investigates the unsteady transition mechanisms between multiple methanol/air spray flame structures in the counterflow configuration. Perturbations are introduced to key parameters including gas strain rate, initial droplet size, and the equivalence ratio, to systematically analyze the physicochemical mechanisms that underlie the transitions between the different flame structures. The transitions, in general, result from the complex interplay between the spray vaporization and motion, which includes droplet reversal and oscillation, and the chemical reactions. The timescales of the transitions between the three different spray flame structures are analyzed in detail in the present paper. |
| format | Article |
| id | doaj-art-d32d9aeb8ac84829b3228cd6beeb2742 |
| institution | Kabale University |
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| language | English |
| publishDate | 2025-09-01 |
| publisher | Elsevier |
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| series | Applications in Energy and Combustion Science |
| spelling | doaj-art-d32d9aeb8ac84829b3228cd6beeb27422025-08-20T05:07:54ZengElsevierApplications in Energy and Combustion Science2666-352X2025-09-012310036310.1016/j.jaecs.2025.100363Numerical analysis of the unsteady transition of multiple laminar methanol/air spray flame structures in the counterflow configurationJiawei Wan0Eva Gutheil1Interdisciplinary Center for Scientific Computing, Heidelberg University, Im Neuenheimer Feld 205, 69120 Heidelberg, GermanyCorresponding author.; Interdisciplinary Center for Scientific Computing, Heidelberg University, Im Neuenheimer Feld 205, 69120 Heidelberg, GermanyThe counterflow configuration is a well-established setting to study the structure of laminar spray flames. Typically, the similarity transformation is introduced to transfer the two-dimensional gas-phase equations into one-dimensional governing equations. The equations which describe droplet motion are two-dimensional. For spray flames in the counterflow configuration, Continillo and Sirignano suggested that more than one numerical solution of these equations may exist, which meanwhile was confirmed by several studies. Up to three different structures were found for the same boundary conditions for the combustion of fuel sprays carried by air directed against an air stream. The first structure shows two chemical reaction zones one of which resides on the fuel side and the other one on the air side of the configuration. The other two spray flame structures show single chemical reaction zones that reside on one but different side of the stagnation plane. The present paper investigates the unsteady transition mechanisms between multiple methanol/air spray flame structures in the counterflow configuration. Perturbations are introduced to key parameters including gas strain rate, initial droplet size, and the equivalence ratio, to systematically analyze the physicochemical mechanisms that underlie the transitions between the different flame structures. The transitions, in general, result from the complex interplay between the spray vaporization and motion, which includes droplet reversal and oscillation, and the chemical reactions. The timescales of the transitions between the three different spray flame structures are analyzed in detail in the present paper.http://www.sciencedirect.com/science/article/pii/S2666352X25000445Methanol/air spray flamesCounterflow configurationTransition of flame structures |
| spellingShingle | Jiawei Wan Eva Gutheil Numerical analysis of the unsteady transition of multiple laminar methanol/air spray flame structures in the counterflow configuration Applications in Energy and Combustion Science Methanol/air spray flames Counterflow configuration Transition of flame structures |
| title | Numerical analysis of the unsteady transition of multiple laminar methanol/air spray flame structures in the counterflow configuration |
| title_full | Numerical analysis of the unsteady transition of multiple laminar methanol/air spray flame structures in the counterflow configuration |
| title_fullStr | Numerical analysis of the unsteady transition of multiple laminar methanol/air spray flame structures in the counterflow configuration |
| title_full_unstemmed | Numerical analysis of the unsteady transition of multiple laminar methanol/air spray flame structures in the counterflow configuration |
| title_short | Numerical analysis of the unsteady transition of multiple laminar methanol/air spray flame structures in the counterflow configuration |
| title_sort | numerical analysis of the unsteady transition of multiple laminar methanol air spray flame structures in the counterflow configuration |
| topic | Methanol/air spray flames Counterflow configuration Transition of flame structures |
| url | http://www.sciencedirect.com/science/article/pii/S2666352X25000445 |
| work_keys_str_mv | AT jiaweiwan numericalanalysisoftheunsteadytransitionofmultiplelaminarmethanolairsprayflamestructuresinthecounterflowconfiguration AT evagutheil numericalanalysisoftheunsteadytransitionofmultiplelaminarmethanolairsprayflamestructuresinthecounterflowconfiguration |