Effect of swirl on combustion in a short cylindrical chamber

✍ Scribed by Dehong Zhang; Philip G. Hill

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 812 KB
• Volume: 106
• Category: Article
• ISSN: 0010-2180
• DOI: 10.1016/0010-2180(95)00256-1

✦ Synopsis

Combustion of a swirling, stoichiometric, and homogeneous mixture of natural gas and air in a short cylindrical chamber has been studied experimentally and simulated numerically. Each mixture was given a steady-state swirling motion by a rotating roughened disc before being ignited at the center of the chamber. By using discs of differing roughness and by varying the disc speed, the intensities of swirl and turbulence could be varied independently so that the effects on combustion of mixture turbulence and swirl-induced buoyancy could be separately examined. Combustion rate and overall chamber heat transfer were inferred from chamber pressure-time records. High-speed schlieren photography showed the effect of swirl on the early flame kernel. With given swirling angular momentum, increased turbulence level always reduced burning duration and increased total heat transfer rate. With given turbulence level, increasing the swirl intensity from zero first decreased, then strongly increased, the burning duration. The swirling Reynolds number (based on chamber radius and peak tangential velocity) at which combustion duration was minimized was in the range 30,000-40,000. At high Reynolds number buoyancy forces appear to have a strongly inhibiting effect on flame propagation.