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Title: Piloted jet flames of CH{sub 4}/H{sub 2}/air: Experiments on localized extinction in the near field at high Reynolds numbers

Journal Article · · Combustion and Flame
 [1]; ;  [2];  [3]
  1. Combustion Research Facility, Sandia National Laboratories, Livermore, CA 94551-0969 (United States)
  2. Department of Mechanical Engineering, Imperial College London, Exhibition Road, London SW7-2AZ (United Kingdom)
  3. Department of Aerospace Engineering, Texas A and M University, College Station, TX 778453-3141 (United States)

Measurements of temperature and major species concentrations, based on the simultaneous line-imaged Raman/Rayleigh/CO-LIF technique, are reported for piloted jet flames of CH{sub 4}/H{sub 2} fuel with varying amounts of partial premixing with air (jet equivalence ratios of {phi}{sub j} = 3.2, 2.5, 2.1 corresponding to stoichiometric mixture fraction values of {xi}{sub st} = 0.35, 0.43, 0.50, respectively) and varying degrees of localized extinction. Each jet flame is operated at a fixed and relatively high exit Reynolds number (60,000 or 67,000), and the probability of localized extinction is increased in several steps by progressively decreasing the flow rate of the pilot flame. Dimensions of the piloted burner, originally developed at Sydney University, are the same as for previous studies. The present measurements complement previous results from piloted CH{sub 4}/air jet flames as targets for combustion model calculations by extending to higher Reynolds number, including more steps in the progression of each flame from a fully burning state to a flame with high probability of local extinction, and adding the degree of partial premixing as an experimental parameter. Local extinction in these flames occurs close to the nozzle near a downstream location of four times the jet exit diameter. Consequently, these data provide the additional modeling challenge of accurately representing the initial development of the reacting jet and the near-field mixing processes. (author)

OSTI ID:
21235979
Journal Information:
Combustion and Flame, Vol. 156, Issue 11; Other Information: Elsevier Ltd. All rights reserved; ISSN 0010-2180
Country of Publication:
United States
Language:
English