Emissions From Enclosed Swirl Stabilised Premixed Flames

Volume 3: Coal, Biomass and Alternative Fuels; Combustion and Fuels; Oil and Gas Applications; Cycle Innovations

1984

Self Cite

A swirler with good premixed performance has been tested with direct central propane injection and with direct central kerosene and gas oil injection using the swirler air for atomisation. The results have been compared with non swirling flow systems at the same test conditions. Direct propane injection results in a major extension of the stability limits compared with the premixed situation, but with liquid fuel injection the stability limits are generally worse than for premixed fuel and air. It is argued that the cause of this is the action of the centrifugal forces on the liquid droplets in the swirl flow which results in vaporisation in the outer swirl flow and weaker mixtures in the core recirculation region than for propane injection. The gas composition results support this conclusion. Direct propane injection caused a deterioration in the combustion efficiency and a large increase in NO x . The poor stability limits with liquid fuels prevented a high combustion efficiency and low NO x situation from being achieved. A comparison of the performance with non swirling systems showed that all emissions were higher with swirl for propane but that the swirler may have some advantages for liquid fuels.The SW3 swirl number was sufficiently low to ensure a good combustion efficiency, whilst being high enough to ensure a central recirculation zone (5,6). The full swirler design details are given in Table 1 and the test geometry is shown in Fig. 1. The premixed

“…The authors have previously investigated the performance of a range of swirlers with premixed fuel and air (6). The influence of swirl number and pressure loss were investigated.…”

Section: Axial Swirler Designmentioning

confidence: 99%

Section: Axial Swirler Designmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Gas and Liquid Fuel Injection Into an Enclosed Swirling Flow

Volume 3: Coal, Biomass and Alternative Fuels; Combustion and Fuels; Oil and Gas Applications; Cycle Innovations

1984

Self Cite

Centrifugal Mixing in Gas and Liquid Fuelled Lean Swirl Stabilized Primary Zones

Volume 2: Coal, Biomass and Alternative Fuels; Combustion and Fuels

Kowkabi

et al. 1985

Self Cite

A flat bladed axial swirler of 0.7 swirl number has been investigated in a 76 mm diameter combustor with all the combustion air passing through the swirler. Both liquid and gaseous fuels were used with eight injection points on the combustor wall just downstream of the swirler. This wall injection was aimed at the exploitation of centrifugal mixing forces acting on the burnt gas pockets at the wall to send them towards the centre and to displace higher density unburnt gas pockets to the wall and so promote mixing. For both kerosene and propane fuels there was a significant improvement in the combustion efficiency and NOX emissions compared with central fuel injection. For kerosene the NOX emissions were lower than for propane and very close to those for premixed fuel and air. However, for gas oil there was little improvement in performance with wall injection compared with central. This was attributed to the slower vaporisation rate with gas oil coupled with the centrifugal action on the liquid droplets with central injection.

Enclosed Swirl Flames: Interaction Between Swirlers in Lean Primary Zones

Volume 3: Coal, Biomass and Alternative Fuels; Combustion and Fuels; Oil and Gas Applications; Cycle Innovations

1986

Self Cite

Three axial vane swirlers were investigated in a simulated sector of an annular combustor. The influence of co and counter rotating swirl on combustion emissions and flame stability are studied with kerosene as the fuel and inlet temperatures up to 800K. Comparison is made with one of the swirlers in a single swirler can combustor. The results show that the influence of the relative swirl direction does not influence the flame stability but does influence the combustion efficiency and NOx emissions. However, both systems are superior to a single swirler can combustor.