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利用CFD软件模拟了一个大型加热炉的新型设计方案并对其合理性、可行性进行了分析。该方案将12个直焰蓄热式燃烧器布置在炉顶两侧、燃烧器出口向下安装;并相应设计45°炉衬转角使炉气作90°转向时有导流作用。采用标准k-ε模型、离散坐标模型(DO模型),系统地研究了该方案升温、保温初期、保温末期,相应燃烧器不同能量供应方式对有效加热区内速度场、温度场的影响。通过模拟发现:火焰出口高速射流区域是温度最高区域,设计中需要留有充分空间使其在有效加热区外,在此区域外的炉膛上部区域,速度场稳定且流速低,仅受高温辐射传热影响,低温烟气回流影响较小,温度相对均匀;模拟中发现因直焰燃烧器的高速燃气动能充沛,气流直冲而下,顺着特制的45°炉衬斜面90°转向后继续顺着炉底行进,约70%的炉气可以穿过垫铁和工件使之均匀加热,并达到对侧炉墙,在炉内形成均匀流场。模拟显示,在30 s的一个供热周期内,燃烧器由全能量供应30 s变为全能量供应10 s、或全能量供应5 s,铸锭表面温度差由90℃减小到15℃以内,完全满足工艺要求。
Using CFD software to simulate a large heating furnace of the new design and its rationality and feasibility analysis. In this scheme, 12 direct-fired regenerative burners are arranged on both sides of the roof and the burner outlet is installed downwardly. Correspondingly, a 45 ° lining angle is used to guide the furnace gas to make a 90 ° turn. Using standard k-ε model and discrete-time coordinate model (DO model), the effects of different energy supply modes of burner on velocity field and temperature field in the effective heating zone are systematically studied in the initial stage of heat preservation, initial heat preservation and final heat preservation. Through the simulation, it is found that the high-speed jet region of the flame outlet is the highest temperature region, and sufficient space should be left in the design to be outside the effective heating zone. In the upper region of the furnace outside this region, the velocity field is stable and the flow velocity is low. The influence of heat and low-temperature flue gas backflow is relatively small, and the temperature is relatively uniform. The simulation shows that the high-speed gas with straight-flame burners has plenty of kinetic energy, and the air current goes straight down, and continues to follow the special 45 ° furnace lining ramp 90 ° At the bottom of the furnace, about 70% of the furnace gas can pass through the horn and workpiece to heat it evenly and reach the opposite furnace wall to form a uniform flow field in the furnace. The simulation shows that during a heating period of 30 s, the burner can be supplied from the all-energy supply for 30 s to the all-energy supply for 10 s or the all-energy supply for 5 s, and the temperature difference on the ingot surface can be reduced from 90 ° C. to 15 ° C. , Fully meet the technical requirements.