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Title: Lifted methane-air jet flames in a vitiated coflow

Abstract

The present vitiated coflow flame consists of a lifted jet flame formed by a fuel jet issuing from a central nozzle into a large coaxial flow of hot combustion products from a lean premixed H{sub 2}/air flame. The fuel stream consists of CH{sub 4} mixed with air. Detailed multiscalar point measurements from combined Raman-Rayleigh-LIF experiments are obtained for a single base-case condition. The experimental data are presented and then compared to numerical results from probability density function (PDF) calculations incorporating various mixing models. The experimental results reveal broadened bimodal distributions of reactive scalars when the probe volume is in the flame stabilization region. The bimodal distribution is attributed to fluctuation of the instantaneous lifted flame position relative to the probe volume. The PDF calculation using the modified Curl mixing model predicts well several but not all features of the instantaneous temperature and composition distributions, time-averaged scalar profiles, and conditional statistics from the multiscalar experiments. A complementary series of parametric experiments is used to determine the sensitivity of flame liftoff height to jet velocity, coflow velocity, and coflow temperature. The liftoff height is found to be approximately linearly related to each parameter within the ranges tested, and it is most sensitivemore » to coflow temperature. The PDF model predictions for the corresponding conditions show that the sensitivity of flame liftoff height to jet velocity and coflow temperature is reasonably captured, while the sensitivity to coflow velocity is underpredicted.« less

Authors:
; ;  [1]; ;  [2]
  1. Mechanical Engineering Department, University of California, Berkeley, CA 94720 (United States)
  2. Combustion Research Facility, Sandia National Laboratories, Livermore, CA 94550 (United States)
Publication Date:
OSTI Identifier:
20681466
Resource Type:
Journal Article
Resource Relation:
Journal Name: Combustion and Flame; Journal Volume: 143; Journal Issue: 4; 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; METHANE; AIR; FLAMES; MATHEMATICAL MODELS; JETS; TEMPERATURE DISTRIBUTION; VELOCITY; TEMPERATURE DEPENDENCE

Citation Formats

Cabra, R., Chen, J.-Y., Dibble, R.W., Karpetis, A.N., and Barlow, R.S.. Lifted methane-air jet flames in a vitiated coflow. United States: N. p., 2005. Web. doi:10.1016/j.combustflame.2005.08.019.
Cabra, R., Chen, J.-Y., Dibble, R.W., Karpetis, A.N., & Barlow, R.S.. Lifted methane-air jet flames in a vitiated coflow. United States. doi:10.1016/j.combustflame.2005.08.019.
Cabra, R., Chen, J.-Y., Dibble, R.W., Karpetis, A.N., and Barlow, R.S.. Thu . "Lifted methane-air jet flames in a vitiated coflow". United States. doi:10.1016/j.combustflame.2005.08.019.
@article{osti_20681466,
title = {Lifted methane-air jet flames in a vitiated coflow},
author = {Cabra, R. and Chen, J.-Y. and Dibble, R.W. and Karpetis, A.N. and Barlow, R.S.},
abstractNote = {The present vitiated coflow flame consists of a lifted jet flame formed by a fuel jet issuing from a central nozzle into a large coaxial flow of hot combustion products from a lean premixed H{sub 2}/air flame. The fuel stream consists of CH{sub 4} mixed with air. Detailed multiscalar point measurements from combined Raman-Rayleigh-LIF experiments are obtained for a single base-case condition. The experimental data are presented and then compared to numerical results from probability density function (PDF) calculations incorporating various mixing models. The experimental results reveal broadened bimodal distributions of reactive scalars when the probe volume is in the flame stabilization region. The bimodal distribution is attributed to fluctuation of the instantaneous lifted flame position relative to the probe volume. The PDF calculation using the modified Curl mixing model predicts well several but not all features of the instantaneous temperature and composition distributions, time-averaged scalar profiles, and conditional statistics from the multiscalar experiments. A complementary series of parametric experiments is used to determine the sensitivity of flame liftoff height to jet velocity, coflow velocity, and coflow temperature. The liftoff height is found to be approximately linearly related to each parameter within the ranges tested, and it is most sensitive to coflow temperature. The PDF model predictions for the corresponding conditions show that the sensitivity of flame liftoff height to jet velocity and coflow temperature is reasonably captured, while the sensitivity to coflow velocity is underpredicted.},
doi = {10.1016/j.combustflame.2005.08.019},
journal = {Combustion and Flame},
number = 4,
volume = 143,
place = {United States},
year = {Thu Dec 01 00:00:00 EST 2005},
month = {Thu Dec 01 00:00:00 EST 2005}
}