Studies on a nozzle-mix swirl burner with combustion staging
The present day energy crisis and the concern about increasing atmospheric pollution has focused attention in developing energy efficient, pollution free combustion systems. Among the pollutants the role of NOx is crucial because of its involvement in global warming, photochemical smog and acid rain as well as effects on human health. It is realized that nozzle-mix swirl burners play a major role in establishing stable mixing controlled diffusion flames which have got several important advantages, viz., high stability, flexibility in operation and better control over generation of pollutants. Swirl burners can be operated potentially as low NOx burners by controlling fuel jet penetration in relation to the recirculation zone. In the present work an attempt is made to study the effect of fuel injection mode on the temperature level at the burner mouth of a nozzle-mix swirl burner without and with combustion staging to examine its performance as a low NOx burner. The burner system employed consists of a helical swirler unit of diameter D = 42 mm which issues four spiraling air-jets at an helix angle of 17.6{degree}. The air-jets are guided by the pipe extension and further expanded in a 15{degree} half angle diffuser section. Indane (commercial butane) is injected centrally into the swirling air-jets in three different modes, viz., in the axial modes with a single hole and with multi-holes and in the radial mode with multi-holes with the same flow area. Near-burner-temperature field is measured with a Pt/Pt-13% Rh thermocouple without and with combustion staging. In the latter case, twelve secondary air-jets issuing from a distributor ring placed at the burner mouth are injected into the fuel-rich combustion zone. The test results obtained showed that the nozzle-mix swirl burner developed is capable of producing pre-mixed type of blue flames on account of the intense mixing of fuel and air-jets occurring over short distance at the burner head. The near-burner temperature field mapping showed that in radial fuel-injection mode, hotter flame zone as high as 1900K is present inside the burner quarl in unstaged combustion operated at an input equivalence ratio, IER=0.8. As regards fuel injection in the axial mode, the flame zone temperature at the burner mouth is found to be hotter for the fuel-injection with a single hole compared to fuel addition through multi-holes. This result points out that fuel jet momentum determines hotness of far-burner field. In conclusion it is highlighted that the nozzle-mix swirl burner tested can be operated as a low NOx burner for use in small scale industrial boilers, furnaces and incinerators.
- Research Organization:
- Indian Inst. of Tech., Madras (IN)
- OSTI ID:
- 20002751
- Resource Relation:
- Conference: 33rd Intersociety Energy Conversion Engineering Conference, Colorado Springs, CO (US), 08/02/1998--08/06/1998; Other Information: 1 CD-ROM. Operating system required: Windows 3.x; Windows 95/NT; Macintosh; UNIX. All systems need 2X CD-ROM drive.; PBD: 1998; Related Information: In: Proceedings of the 33. intersociety energy conversion engineering conference, by Anghaie, S. [ed.], [2800] pages.
- Country of Publication:
- United States
- Language:
- English
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