Methane flames in a jet impinging onto a wall

Wei Dong Hsieh, Shuhn Shyurng Hou, Ta-Hui Lin

Research output: Contribution to journalConference article

6 Citations (Scopus)

Abstract

Traditionally, research has focused on positive stretch in the stagnation flow and negative stretch along the Bunsen flame. Only a very limited amount of research has been devoted to studying the behavior of a conical Bunsen flame established in a stagnation flow, which is significantly affected by the combined effects of the curvature stretch and the aerodynamic straining. This investigation is aimed at studying the characteristics of laminar conical premixed flames in an impinging jet flow experimentally and theoretically. First, we analyze the transport processes of a nonreactive impinging jet flow numerically. For lower burner-toplate distance, the potential core becomes concave at the top. Hence, a conical Bunsen flame established in such a flow field may suffer positive flow stretch. The predicted flame shapes using a simple model incorporated with the numerical results agree well with the experimental observations. Flame shapes exhibit double-solution characteristics in a certain range of methane concentrations. Experimentally, by following different paths of adjusting methane concentration (decreasing from rich to lean or increasing from lean to rich), two different flame configurations (planar or conical flame) may exist at the same flow conditions, namely burner-to-plate distance, inlet velocity, and methane concentration. At the higher (or lower) critical methane concentration, the transition from a flat flame to a conical flame (or from a conical flame to a flat flame) occurs. The calculation of stretch and measurement of flame temperature for the low inlet velocity, 0.8 m/s, show that the stretch of a conical flame established in a stagnation flow is negative (dominated by the flame curvature). However, it is important to emphasize that at high velocity, e.g., Uin = 1.6 m/s, a negatively stretched flame tip can suffer positive flow stretch. This significant finding has been verified in the experiment since the conical flame tip is higher than the positively stretched flat flame.

Original languageEnglish
Pages (from-to)267-275
Number of pages9
JournalProceedings of the Combustion Institute
Volume30
Issue number1
DOIs
Publication statusPublished - 2005 Jan 1
Event30th International Symposium on Combustion - Chicago, IL, United States
Duration: 2004 Jul 252004 Jul 30

Fingerprint

Methane
flames
methane
Fuel burners
stagnation flow
Flow fields
Aerodynamics
jet flow
burners
Experiments
curvature
Temperature
flame temperature
premixed flames
aerodynamics

All Science Journal Classification (ASJC) codes

  • Chemical Engineering(all)
  • Mechanical Engineering
  • Physical and Theoretical Chemistry

Cite this

Hsieh, Wei Dong ; Hou, Shuhn Shyurng ; Lin, Ta-Hui. / Methane flames in a jet impinging onto a wall. In: Proceedings of the Combustion Institute. 2005 ; Vol. 30, No. 1. pp. 267-275.
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abstract = "Traditionally, research has focused on positive stretch in the stagnation flow and negative stretch along the Bunsen flame. Only a very limited amount of research has been devoted to studying the behavior of a conical Bunsen flame established in a stagnation flow, which is significantly affected by the combined effects of the curvature stretch and the aerodynamic straining. This investigation is aimed at studying the characteristics of laminar conical premixed flames in an impinging jet flow experimentally and theoretically. First, we analyze the transport processes of a nonreactive impinging jet flow numerically. For lower burner-toplate distance, the potential core becomes concave at the top. Hence, a conical Bunsen flame established in such a flow field may suffer positive flow stretch. The predicted flame shapes using a simple model incorporated with the numerical results agree well with the experimental observations. Flame shapes exhibit double-solution characteristics in a certain range of methane concentrations. Experimentally, by following different paths of adjusting methane concentration (decreasing from rich to lean or increasing from lean to rich), two different flame configurations (planar or conical flame) may exist at the same flow conditions, namely burner-to-plate distance, inlet velocity, and methane concentration. At the higher (or lower) critical methane concentration, the transition from a flat flame to a conical flame (or from a conical flame to a flat flame) occurs. The calculation of stretch and measurement of flame temperature for the low inlet velocity, 0.8 m/s, show that the stretch of a conical flame established in a stagnation flow is negative (dominated by the flame curvature). However, it is important to emphasize that at high velocity, e.g., Uin = 1.6 m/s, a negatively stretched flame tip can suffer positive flow stretch. This significant finding has been verified in the experiment since the conical flame tip is higher than the positively stretched flat flame.",
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Methane flames in a jet impinging onto a wall. / Hsieh, Wei Dong; Hou, Shuhn Shyurng; Lin, Ta-Hui.

In: Proceedings of the Combustion Institute, Vol. 30, No. 1, 01.01.2005, p. 267-275.

Research output: Contribution to journalConference article

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