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Show • In practice, it is desired to stabilize the flame below the first row of heater tubes. Operating ranges of the parameters are therefore defined based on the desired location of the combustion zone. • A significant effect of bed material on heat transfer shows an important contribution of heat radiation from the solid particles to the tube surfaces to the overall heat transfer. A quantitative assessment of the combined convective-radiative heat transfer requires an extensive experimental study as well as a further analysis. The data provide a basis to guide and validate the mathematical model that is being developed. As a result of the parametric study, an optimized design of the surface combustorheater and selection of the bed materials can be preliminary defined. The extensive data can provide a basis for the further development of high-efficiency and ultra low-emission water heaters, boilers, and process heaters for industrial and commercial applications. ACKNOWLEDGMENT The work described in this paper was jOintly supported by the Gas Research Institute (GRI) under GRI Contract No. 5090-260-1927, and by IGT's Sustaining Membership Program (SMP). The authors would like to thank Mr. Boris Kramnik and Mr. Walter Kunc for their contributions to the experimental system preparation and testing. REFERENCES 1. Ravich, M. B., "Gas and Its Utilization," Science, Moskva, 1974 (in Russian). 2. Ravich, T. W. and Sathe, S. B., "Heat Transfer Characteristics of Porous Radiant Burners," Collected Papers in Heat Transfer, Yang, K. T., Ed., ASME ~, 147-55, 1988. 3. Kunc, W. and Khinkis, M. J., "Combustion System: A Porous Matrix Burner and a Surface Combustor," GRI Topical Report, Contract No. 5082-241-0772, 1987. 4. Khinkis, M. J., Kunc, W. and Xiong, T-Y., "Experimental Evaluation of a High-Efficiency Surface Combustor-Heater Concept with Low Pollutant Emissions." Paper presented at . the AFRC 1989 International Symposium on Combustion in Industrial Furnaces and Boilers, Short Hills, New Jersey, September 25-27, 1989. 16 |