【摘要】 建立了三维(360°)贴体坐标及复杂曲面几何计算模型;数值模拟了花瓣稳燃器的流场;理论分析了花瓣稳燃器的流场特性及掺混特性,研究了花瓣稳燃器的稳燃原理。花瓣稳燃器的设计使得风粉气流与回流烟气的热混合边界增长;除中心回流区外在每个花瓣后面都形成一个径向回流区,与中心回流区融合在一起,引导煤粉气流与高温烟气对流混合,提高了二者的热质交换强度,延长了煤粉在回流区内的循环时间,为煤粉颗粒的着火燃烧提供了稳定热源,有利于煤粉特别是低挥发分煤及低负荷的着火与燃尽。本文工作为花瓣稳燃器的优化设计提供了理论依据。更多还原

【Abstract】 A calculation model of three-dimensional(360°) curvilinear coordinates and complex curved-surface geometry has been set up to conduct the numerical simulation of the flow-field of a petal-shaped combustion stabilizer along with a theoretical analysis of the flow field characteristics and mixing-dilution ones of the stabilizer.The operating principle of the latter’s combustion stabilization has been studied.The specific design of the petal-shaped combustion stabilizers has made it possible to lengthen the thermal mixing boundary between "air"-"pulverized-coal"-"gas-flow" and flue gas return-flow.Apart from a central return-flow zone,a radial return-flow zone has been formed behind each petal to fuse with the central return-flow zone.By introducing a convection mixing of pulverized-coal gas flow with high-temperature flue gas flow,the heat-mass exchange strength of both flows was enhanced,and the circulation time of the pulverized-coal in the return zone prolonged,thus providing a stable heat source for the ignition and burning of pulverized-coal particles.This will be conducive to the ignition and burning-off of the pulverized-coal,especially for low-volatile coal and in case of operation at a low load.The research results of the authors can provide a theoretical basis for the optimized design of petal-shaped combustion stabilizers.更多还原