الفهرس 
Inverse diffusion flame
CONCLUSIONS AND RECOMMENDATIONS FOR FUTURE WORKOnly 14 pages are availabe for public view
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Abstract
Diffusion flame is characterized by having a wide flammability range, however the high pollutant gas emissions limits the use of diffusion flame due recent concern about environmental restrictions. Inverse diffusion flame (IDF), on the other hand, has a wide range of flammability, but in the same time it reduces pollutant emissions. For IDF the central fuel jet and the outer air jets are interchanged. The high exchange of momentum increases the shear strain as the fuel is entrained to the higher velocity inner air jet. This leads to better mixing and higher combustion efficiency. In case an outer air jet is introduced to the IDF burner configuration, triple co-axial ports inverse diffusion flame (TPC-IDF) is formed. Accordingly, the fuel jet flows in the annuals between the inner and outer air jet, where the rate of exchange of momentum and shear strain is increased leading to better mixing and higher combustion efficiency. This leads to reduced pollutant gas emissions and more uniform temperature distribution.
The scope of the current experimental work is to investigate the effects of using, swirl, flow divergence and porous media, as well as the combination of those parameters, on the combustion performance of TCP-IDF. A burner consisting of three concentric tubes has been used to issue TCP-IDF. LPG gas fuel has been supplied in the annular tube between the inner and outer air jets. Swirl has been provided to the interior air flow via a helical groove of 85o angle of inclination to the burner axis. Flow divergence has been introduced by three flow divergence diffusers with divergence angles of 15o, 45o and 65o respectively. Meanwhile the mesh screens used to introduce porosity, where with 1mm and 2mm mesh sizes respectively. For all experiments the inner air jet, outer air jets and the annular fuel jet were all kept constant with an A/F ratio of 27.
The results indicated that the use of swirl reduced CO and UHC and increased peak temperature and NOx emissions of TCP-IDF. While the CO, UHC, peak temperature and NOx emission decreased with the increase in flow divergence angle. With regards to the increase in mesh size, it has been noticed that as the mesh size increase, NOx emissions increased, while the CO, UHC and peak temperature decreased with the increase in mesh sizing.
When examining the combination of various burner configurations, the combination of swirl with 65o flow divergence diffuser recorded the lowest CO and UHC emissions. While the combination that exhibited the lowest peak temperature and NOx emissions was that of swirl with 65o flow divergence diffuser and 1mm porous screen.