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Show show that a minimum input power is needed in order to keep C O emission below 25 ppm (3% 02) and U H C concentrations at the undetectable level. When operating above the minimum input power, the performance of the L S B is very encouraging. With N O x at 14 ppm and C O at 25 ppm, the L S B should be a prime candidate for use in furnaces and boilers. ACKNOWLEDGEMENT This work was supported by an exploratory grant from the California Institute of Energy Efficiency through the U.S. Department of Energy under Contract No. DE-AC03- 76F00098. NOMENCLATURE (j) = equivalence ratio £ = length of exit tube = 70 or 140 mm Ac / Ab = chamber cross-sectional area/burner cross-sectional area R = radius burner throat Rg = radius of air injectors R„*R*;r ,m- , So = geometric swirl intensity = - (--) Ae mt me = tangential mass flow = cos (20°) * mass of swirl air mt = total mass flow A9 = total area of injectors \J„ = reference flow velocity = (v a + v f )/(7t R ) v a = volumetric flow rate of combustion air v f = volumetric flow rate of fuel REFERENCES [1] Chan, C.K., Lau, K.S., Chin, W.K., and Cheng, R.K., "Freely propagating open premixed turbulent flames stabilized by swirl," in Twenty-fourth Symposium (International) on Combustion. Sydney (Australia): The Combustion Institute, 1992, pp. 519. [2] Yegian, D.T. and Cheng, R.K., 1995 AFRC Fall International Symposium, American Flame Research Committee, 1995. [3] Syred, N. and Beer, J.M., Combust. Flame 23:143 (1974). [4] Lilley, D.G., AIAA Journal 15:1063 (1977). [5] Beer, J.M. and Chigier, N.A.,Combustion Aerodynamics, Applied Science Publishers Ltd., London, 1972, p. 100. 10 |