skip to main content
DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Structure and behavior of water-laden CH 4/air counterflow diffusion flames

Abstract

A counterflow configuration was used to measure thermal and species structure in water-vapor diluted nonpremixed methane–air flames. The motivation is to understand the chemical and thermal effects that water has when it is introduced as a diluent into the fuel side. Here, this work is relevant to combustion processes where water is incorporated naturally in the fuel; e.g., methane hydrates, and when water is added intentionally for emission reduction such as in flares and H 2O/fuel emulsions combustion. Experimental data are compared to 1-D computations. The agreement is generally very good, but the one dimensional counterflow diffusion model overpredicts flame temperature and major radical, OH, concentration very near extinction in highly diluted H 2O–methane/air diffusion flames. Changes in flame position, flame width, and peak temperature with the addition of water were measured. Flame temperatures were measured with thin filament pyrometry. OH-PLIF is used to characterize the flame reaction zone with water dilution; the OH distribution, flame position and thickness from the OH-PLIF images were measured. The results show that the OH intensity and reaction zone thickness decreases with the increase in water. Predictions and experiments demonstrate that water mainly acts thermally to lower the flame temperature until extinction. The OHmore » maximum intensity shifts towards the air side of the counterflow burner with water addition. OH is also measured with CO 2 dilution of the fuel stream, and the results are compared with H 2O addition, including comparisons with the OH molar peak predictions obtained using the GRI 3.0 mechanism and the CHEMKIN Pro one dimensional counterflow model. The study indicates that water’s chemical effects are to change the production and depletion of OH, H and O radicals, especially near extinction. Chemical kinetics simulation of the flame demonstrates good agreement in OH and flame temperatures over a wide range of dilution away from extinction, particularly for CO 2. Lastly, an over prediction of the water carrying capacity near extinction is found for highly water-diluted flames.« less

Authors:
 [1];  [1];  [2]; ORCiD logo [3];  [1]
  1. Univ. of California, Irvine, CA (United States)
  2. California State Univ., Los Angeles, CA (United States)
  3. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1548354
Alternate Identifier(s):
OSTI ID: 1548070
Report Number(s):
LLNL-JRNL-747307
Journal ID: ISSN 0010-2180; 932154
Grant/Contract Number:  
AC52-07NA27344
Resource Type:
Accepted Manuscript
Journal Name:
Combustion and Flame
Additional Journal Information:
Journal Volume: 196; Journal Issue: C; Journal ID: ISSN 0010-2180
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Water-laden; Counterflow; Dilution extinction; Nonpremixed; OH-PLIF

Citation Formats

Padilla, R. E., Escofet-Martin, D., Pham, T., Pitz, W. J., and Dunn-Rankin, D. Structure and behavior of water-laden CH4/air counterflow diffusion flames. United States: N. p., 2018. Web. doi:10.1016/j.combustflame.2018.06.037.
Padilla, R. E., Escofet-Martin, D., Pham, T., Pitz, W. J., & Dunn-Rankin, D. Structure and behavior of water-laden CH4/air counterflow diffusion flames. United States. doi:10.1016/j.combustflame.2018.06.037.
Padilla, R. E., Escofet-Martin, D., Pham, T., Pitz, W. J., and Dunn-Rankin, D. Mon . "Structure and behavior of water-laden CH4/air counterflow diffusion flames". United States. doi:10.1016/j.combustflame.2018.06.037. https://www.osti.gov/servlets/purl/1548354.
@article{osti_1548354,
title = {Structure and behavior of water-laden CH4/air counterflow diffusion flames},
author = {Padilla, R. E. and Escofet-Martin, D. and Pham, T. and Pitz, W. J. and Dunn-Rankin, D.},
abstractNote = {A counterflow configuration was used to measure thermal and species structure in water-vapor diluted nonpremixed methane–air flames. The motivation is to understand the chemical and thermal effects that water has when it is introduced as a diluent into the fuel side. Here, this work is relevant to combustion processes where water is incorporated naturally in the fuel; e.g., methane hydrates, and when water is added intentionally for emission reduction such as in flares and H2O/fuel emulsions combustion. Experimental data are compared to 1-D computations. The agreement is generally very good, but the one dimensional counterflow diffusion model overpredicts flame temperature and major radical, OH, concentration very near extinction in highly diluted H2O–methane/air diffusion flames. Changes in flame position, flame width, and peak temperature with the addition of water were measured. Flame temperatures were measured with thin filament pyrometry. OH-PLIF is used to characterize the flame reaction zone with water dilution; the OH distribution, flame position and thickness from the OH-PLIF images were measured. The results show that the OH intensity and reaction zone thickness decreases with the increase in water. Predictions and experiments demonstrate that water mainly acts thermally to lower the flame temperature until extinction. The OH maximum intensity shifts towards the air side of the counterflow burner with water addition. OH is also measured with CO2 dilution of the fuel stream, and the results are compared with H2O addition, including comparisons with the OH molar peak predictions obtained using the GRI 3.0 mechanism and the CHEMKIN Pro one dimensional counterflow model. The study indicates that water’s chemical effects are to change the production and depletion of OH, H and O radicals, especially near extinction. Chemical kinetics simulation of the flame demonstrates good agreement in OH and flame temperatures over a wide range of dilution away from extinction, particularly for CO2. Lastly, an over prediction of the water carrying capacity near extinction is found for highly water-diluted flames.},
doi = {10.1016/j.combustflame.2018.06.037},
journal = {Combustion and Flame},
number = C,
volume = 196,
place = {United States},
year = {2018},
month = {7}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Citation Metrics:
Cited by: 1 work
Citation information provided by
Web of Science

Save / Share: