Blowout of nonpremixed flames; Maximum coaxial air velocities achievable, with and without swirl

Journal Article · Sun Sep 01 04:00:00 EDT 1991 · Combustion and Flame; (United States)

DOI:https://doi.org/10.1016/0010-2180(91)90128-X· OSTI ID:5755051

Feikema, D F; Chen, R H; Driscoll, J F ^[1]

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1. Dept. of Aerospace Engineering, Univ. of Michigan, Ann Arbor, MI (US)

This paper demonstrates how to optimize parameters in order to maximize the amount of coaxial air that can be provided to a nonpremixed jet flame without causing the flame to blow out. Maximizing the coaxial air velocity is important in the effort to reduce the flame length and the oxides of nitrogen emitted from gas turbines and industrial burners, a majority of which use coaxial air. Previous measurements by the latter two authors have shown that a sixfold reduction in the NO{sub x} emission index of a jet flame is possible if sufficient coaxial air can be provided without blowing the flame out. The coaxial air shortens the flame and forces the reaction zone to overlap regions of higher gas velocity, which reduces the residence time for NO{sub x} formation. The present work concentrates on demonstrating ways to prevent flame blowout when the following two constraints are imposed: the coaxial air velocities must be sufficient to shorten the flame to a specified length (in order to reduce NO{sub x} emissions) and the coaxial air flow rate must be sufficient to complete combustion without the need for ambient air, which is a common practical constraint. The zero swirl case is considered first, and the effects of adding swirl are measured and directly compared. The following were systematically varied: fuel velocity, air velocity, fuel tube diameter, air tube diameter, fuel type, and swirl number.

• OSTI ID: 5755051
• Journal Information: Combustion and Flame; (United States), Journal Name: Combustion and Flame; (United States) Vol. 86:4; ISSN 0010-2180; ISSN CBFMA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400800* -- Combustion
Pyrolysis
& High-Temperature Chemistry
42 ENGINEERING
420400 -- Engineering-- Heat Transfer & Fluid Flow
421000 -- Engineering-- Combustion Systems
54 ENVIRONMENTAL SCIENCES
540120 -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (1990-)
ACCIDENTS
AIR FLOW
AIR POLLUTION CONTROL
BLOWOUTS
BURNERS
CHALCOGENIDES
CHEMICAL REACTION KINETICS
COAXIAL FLOW REACTORS
COMBUSTION KINETICS
CONTROL
EQUIPMENT
FLAMES
FLUID FLOW
FLUID FUELED REACTORS
FUELS
GAS FLOW
GAS FUELED REACTORS
GAS TURBINES
HOMOGENEOUS REACTORS
KINETICS
MACHINERY
NITROGEN COMPOUNDS
NITROGEN OXIDES
OXIDES
OXYGEN COMPOUNDS
POLLUTION CONTROL
REACTION KINETICS
REACTORS
SIZE
TURBINES
TURBOMACHINERY
VELOCITY
VORTEX FLOW