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Title: Appearance, temperature, and NO{sub x} emission of two inverse diffusion flames with different port design

Abstract

Experiments were carried out to investigate the appearance, temperature distribution, and NO{sub x} emission index of two inverse diffusion flames, one with circumferentially arranged ports (CAPs) and the other with co-axial (CoA) jets, both burning LPG with 70% butane and 30% propane. Flame appearances were investigated first with a fixed fueling rate at different airflow rates equivalent to air jet Reynolds numbers (Re) of 1000 to 4500; and then at a fixed airflow rate with different fueling rates equivalent to overall equivalence ratios (F) of 1.0 to 2.0. The CAP flame is found to consist of two zones: a lower entrainment zone and an upper mixing and combustion zone. The CoA flame in most cases is similar to a diffusion flame. The two-zone structure can be observed only at Re larger than 2500. The temperature distributions of the flames are similar at overall equivalence ratios of 1.0 and 1.2 for Re=2500, except that the corresponding CoA flame is longer. The flame temperature is higher in the CAP flame than the CoA flame at higher overall equivalence ratios. A measurement of centerline oxygen concentrations shows that the oxygen concentration reaches a minimum value at a flame height of 50 mm inmore » the CAP flame but decreases more gradually in the CoA flame. It can be concluded that there is more intense air-fuel mixing in a CAP flame than the CoA flame. Investigation of the emission index of NO{sub x} (EINO{sub x}) for both flames at Re=2500 and overall equivalence ratios of 1.0 to 6.0 reveals that the EINO{sub x} curve of each flame is bell-shaped, with a maximum value of 3.2 g/kg at F=1.2 for the CAP flame and 3 g/kg at F=2.2 for the CoA flame.« less

Authors:
; ;  [1]
  1. Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hung Hom, Hong Kong (China)
Publication Date:
OSTI Identifier:
20685989
Resource Type:
Journal Article
Resource Relation:
Journal Name: Combustion and Flame; Journal Volume: 144; Journal Issue: 1-2; Other Information: Elsevier Ltd. All rights reserved
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 03 NATURAL GAS; LIQUEFIED PETROLEUM GASES; PROPANE; BUTANE; FLAMES; TEMPERATURE DISTRIBUTION; COMBUSTION KINETICS

Citation Formats

Sze, L.K., Cheung, C.S., and Leung, C.W. Appearance, temperature, and NO{sub x} emission of two inverse diffusion flames with different port design. United States: N. p., 2006. Web. doi:10.1016/j.combustflame.2005.07.008.
Sze, L.K., Cheung, C.S., & Leung, C.W. Appearance, temperature, and NO{sub x} emission of two inverse diffusion flames with different port design. United States. doi:10.1016/j.combustflame.2005.07.008.
Sze, L.K., Cheung, C.S., and Leung, C.W. Sun . "Appearance, temperature, and NO{sub x} emission of two inverse diffusion flames with different port design". United States. doi:10.1016/j.combustflame.2005.07.008.
@article{osti_20685989,
title = {Appearance, temperature, and NO{sub x} emission of two inverse diffusion flames with different port design},
author = {Sze, L.K. and Cheung, C.S. and Leung, C.W.},
abstractNote = {Experiments were carried out to investigate the appearance, temperature distribution, and NO{sub x} emission index of two inverse diffusion flames, one with circumferentially arranged ports (CAPs) and the other with co-axial (CoA) jets, both burning LPG with 70% butane and 30% propane. Flame appearances were investigated first with a fixed fueling rate at different airflow rates equivalent to air jet Reynolds numbers (Re) of 1000 to 4500; and then at a fixed airflow rate with different fueling rates equivalent to overall equivalence ratios (F) of 1.0 to 2.0. The CAP flame is found to consist of two zones: a lower entrainment zone and an upper mixing and combustion zone. The CoA flame in most cases is similar to a diffusion flame. The two-zone structure can be observed only at Re larger than 2500. The temperature distributions of the flames are similar at overall equivalence ratios of 1.0 and 1.2 for Re=2500, except that the corresponding CoA flame is longer. The flame temperature is higher in the CAP flame than the CoA flame at higher overall equivalence ratios. A measurement of centerline oxygen concentrations shows that the oxygen concentration reaches a minimum value at a flame height of 50 mm in the CAP flame but decreases more gradually in the CoA flame. It can be concluded that there is more intense air-fuel mixing in a CAP flame than the CoA flame. Investigation of the emission index of NO{sub x} (EINO{sub x}) for both flames at Re=2500 and overall equivalence ratios of 1.0 to 6.0 reveals that the EINO{sub x} curve of each flame is bell-shaped, with a maximum value of 3.2 g/kg at F=1.2 for the CAP flame and 3 g/kg at F=2.2 for the CoA flame.},
doi = {10.1016/j.combustflame.2005.07.008},
journal = {Combustion and Flame},
number = 1-2,
volume = 144,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 2006},
month = {Sun Jan 01 00:00:00 EST 2006}
}
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