回流区分级着火燃烧机制及工业应用-工程热物理专业论文.docx

华中理工大学博士学位论文ABSTRACT 华中理工大学博士学位论文 ABSTRACT The principles and applications stepped firing in recirculation investigated．The main points follows． Through the water fiow-visualisation and the cold air wake flow behind slitting bloif- body,the variation law and discriminant of slitting flow variance in recirculation are found． The influnence of slitting flow mcirculation and the slitting flow weakening law are studied．Throu【gh combustion experiment with slitting bluff-body,the existence and supedority of the mechanism ofstepped firing in recirculation are proved． Theeonce：pt ofgemeralized recimulation is presented and the flame stabilizing model in gemeralized recirculatlon is estabilished．By the method of firingehain througIl heat recirculating，the principle for small of first—fired fuel-air flow igniting main flow investigated．Using method similar lumped parameters balance model，the variations of velocity,density and temperature of fuel-air in recirculation with slitting flow and flame stabilizing conditions discussed． Based principles of stepped firing in new jet and revolving-pour burners are designed and manufactured which used for different power boilers industral furnages with combustion of pulverized coal，poor-gas fuel-oil．The burners are tested and improved in practice and good results are finally achieced in variant degrees including strenthening flame stability,adapting boiler capacities and rank of coal，raising combustion and transfer efficiency,and lowering the temperature ofweste gas the boiler tail． The velocity temperature numerical simulation three dimentions in four-corner-burners boiler is conducted．The veloeity and distribution of gas in the old and transformed boiler are compared which iS helpful optimize the parameters of the burners for design and operation． In addition，multiple burners forming revolving flame through diffusing combustion is recomended substitute traditional fumace with straight-·pour flame for round-·section tube pattem f