摘要:

The development of pulse combustor systems is still hampered by insufficient understanding of the underlying principles. These can be addressed to a large degree by combined experimental/analytical investigations. This paper describes the development of a comprehensive model representing the entire pulse combustor system, including the combustor, tailpipe, decoupler, air and fuel lines and air and fuel flapper valves. The model is being used in conjunction with the experimental program at Georgia Tech, simulating one of the operating pulse combustors. Predictions are shown of pressures, temperatures, mass flows, heat fluxes and flow velocities in the system. This includes a baseline configuration as well as two parametric studies.

ISSN:0010-2202    

DOI:10.1080/00102209308935320

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

This paper describes an investigation of the effect of combustion air staging upon NOxemissions from coal burning Rijke pulse combustors, which offer many advantages in domestic and industrial heating applications. This NOxreduction technique was investigated because of its demonstrated effectiveness in steady state coal combustors. The basic configuration of the investigated Rijke pulse combustor consisted of a vertical tube in which unpulverized coal was burned on a rotating bed located at a distance of L/4, where L is the combustor length, from the combustor entrance. Combustion air was supplied from below the bed and its reaction with the bed resulted in spontaneous excitation of the fundamental acoustic mode of the combustor. The resulting acoustic and pressure oscillations in the bed resulted in bed fluidization and intensification of the combustion process.

ISSN:0010-2202    

DOI:10.1080/00102209308935321

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A bench-scale Rotary Kiln Incinerator Simulator was retrofitted with a frequency-tunable pulse combustor in order to enhance the efficiency of combustion. The pulse combustor excites pulsations in the kiln and increases the completeness of combustion by promoting better mixing within the system.

ISSN:0010-2202    

DOI:10.1080/00102209308935322

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Two hot-water boilers with rated inputs of 147 and 220 kW hadNOxemissions near 40 and 50 ppm (3%O2), respectively, without flue-gas recirculation. With recirculation,NOxwas reduced to 20-25 ppm for the larger boiler and to less than 20 ppm for the smaller one. Emissions of CO were not correlated withNOx; they depended on overall equivalence ratio and on design of the combustion chamber, but remained within the acceptable range of <400 ppm (air-free) when the equivalence ratio was below 0.89. Besides its effects onNOx, recirculation strengthened the pressure wave and slightly improved the overall thermal efficiency. These effects were due to the slower burning rate with recirculation and a resulting closer match between the heat release and the pressure wave. Similar effects on wave amplitude and efficiency were produced by delaying the mixing of the incoming streams of air and natural gas, butNOxwas scarcely affected.

ISSN:0010-2202    

DOI:10.1080/00102209308935323

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The effects of halogen injection on the acoustical characteristics of a two-dimensional dump combustor are studied. The dump combustor used is one whose acoustic modes have been well characterized in prior experiments (Logan, et al., 1991). Experimental observations indicate that an increase in halon addition typically causes a slight reduction in the dominant acoustic frequency, then, at a critical percentage of halon, a switch to a higher frequency mode. It is postulated that the addition of halon into the premixed fuel and air causes a reduction in the laminar flame speed and a subsequent increase in the effective time lag between velocity (or pressure) perturbations and periodic heat release. This time lag is then found, through one-dimensional acoustic modeling, to result in the possibility of a mode switch in the device, consistent with experimental observations.

ISSN:0010-2202    

DOI:10.1080/00102209308935324

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor