Optimization and structure of gas jet diffusion flames in venturi-cascade burners

Conference · Wed Jul 01 04:00:00 EDT 1998

OSTI ID:20013007

Qubbaj, A R

An experimental study to control the pollutant emissions (CO, NO and soot) of diffusion flames by modifying the air infusion rate into the flame is presented. The modification was achieved by installing a cascade of venturis around a burning gas jet. A propane jet diffusion flame at burner-exit Reynolds number of 5100 was examined with different venturi sizes and spacing distributions. Temperature and the concentrations of CO{sub 2}, CO and NO in the exhaust products were measured before and after the modification and the optimal conditions were obtained. The optimal venturi diameter was between D/d=27.5 and D/d=35, where d is the burner-exit diameter and D is the venturi throat diameter. The optimal arrangement was the equal spacing configuration in which the venturis were distributed at equal intervals over the flame length. The venturi-cascading technique at its optimal conditions compared to the baseline case resulted in the following: (1) CO and NO emission indices decreased by 87% and 33% respectively; (2) the average volumetric soot concentration decreased by 24%; and (3) radiant fraction of heat release decreased by 10%. The thermal structure of the flame showed that, in the near-burner region, the venturi-cascaded flame had lower temperatures than the baseline case; however, in the mid-flame and far-burner regions it had higher temperatures.

• Research Organization: Univ. of Oklahoma, Norman, OK (US)
• OSTI ID: 20013007
• Country of Publication: United States
• Language: English

Related Subjects

03 NATURAL GAS
AIR POLLUTION ABATEMENT
BURNERS
CARBON DIOXIDE
CARBON MONOXIDE
COMBUSTION KINETICS
EXHAUST GASES
FLAMES
FUEL-AIR RATIO
GAS ANALYSIS
MORPHOLOGY
NITRIC OXIDE
PROPANE
SOOT
TEMPERATURE DISTRIBUTION