Transient molten steel flow in a slab continuous casting mold has been calculated using large eddy simulation, considering heat transfer and solidification. The transport of bubbles in the liquid pool of the solidifie...Transient molten steel flow in a slab continuous casting mold has been calculated using large eddy simulation, considering heat transfer and solidification. The transport of bubbles in the liquid pool of the solidified shell has been considered according to the dispersed phase model. A mathematical model has been used to evaluate the influence of bubble size, casting speed, and adsorption of nonmetallic inclusions on bubble removal and bubble distribution within the solidified shell in the mold. The results show that the ratio of bubbles floating to the top surface decreases with increasing casting speed and decreasing bubble diameter. Nonmetallic inclusion adsorption has a weak effect on the bubble.展开更多
耦合多种碳排放源识别方法,分析石油焦煅烧过程中的碳排放源。通过数学模型的搭建,以某石油焦煅烧企业为例,计算并分析整个生产过程中的碳排放量。研究结果表明:整个煅烧过程中的总碳排放为0.509904 t CO_(2)/t_(煅烧焦),净碳排放量为0....耦合多种碳排放源识别方法,分析石油焦煅烧过程中的碳排放源。通过数学模型的搭建,以某石油焦煅烧企业为例,计算并分析整个生产过程中的碳排放量。研究结果表明:整个煅烧过程中的总碳排放为0.509904 t CO_(2)/t_(煅烧焦),净碳排放量为0.141942 t CO_(2)/t_(煅烧焦),挥发分燃烧碳排放在总碳排放中占比最大,为68.51%。最后指出,降低生产过程碳排放和加强余热回收利用,是今后煅烧企业节能减碳的发展方向。展开更多
Through coupling electromagnetic field equations with turbulent flow equations,the numerical prediction has been conducted on the flow field of molten steel and the trajectory of inclusion particle in the continuous c...Through coupling electromagnetic field equations with turbulent flow equations,the numerical prediction has been conducted on the flow field of molten steel and the trajectory of inclusion particle in the continuous casting mold effected by electromagnetic field.The difference between the maximum and the minimum of the shear stress on mold wall is used to scale the impingement strength of molten steel discharged from immersed nozzle to the solidifying shell on the narrow wall of mold.The flow field of molten steel in the mold is changed greatly and the impingement strength of the jet is reduced while electromagnetic field is applied.It is found that the successful control of flow field depends on the current and location of coil.At the same time,the new floating paths of inclusion particles are formed and the upward particles that are far away from the solidifying zone on the narrow wall of mold change their moving directions with the change of flow field,so that the particles can avoid being entrapped by the solidifying shell.展开更多
文摘Transient molten steel flow in a slab continuous casting mold has been calculated using large eddy simulation, considering heat transfer and solidification. The transport of bubbles in the liquid pool of the solidified shell has been considered according to the dispersed phase model. A mathematical model has been used to evaluate the influence of bubble size, casting speed, and adsorption of nonmetallic inclusions on bubble removal and bubble distribution within the solidified shell in the mold. The results show that the ratio of bubbles floating to the top surface decreases with increasing casting speed and decreasing bubble diameter. Nonmetallic inclusion adsorption has a weak effect on the bubble.
文摘提出了一种在热风炉燃烧器顶部增加空气喷嘴的新型结构,并利用计算流体力学方法建立了炉内燃烧、烟气流动、烟气与格子砖耦合传热的三维数学模型,对比分析了传统顶燃式热风炉与3种带有顶部射流结构的热风炉内流场、CO和温度的分布特点.结果表明:增加顶部空气射流后,燃烧室内形成中心空气与外层空气裹挟煤气的燃烧方式,提高了理论燃烧温度及燃料利用率;与传统顶燃式热风炉相比,顶部6喷嘴和12喷嘴热风炉的蓄热体截面平均温度提升了大约13 K,各个截面的均匀度提升了0.03%~0.5%,送风温度提升了10 K.
文摘耦合多种碳排放源识别方法,分析石油焦煅烧过程中的碳排放源。通过数学模型的搭建,以某石油焦煅烧企业为例,计算并分析整个生产过程中的碳排放量。研究结果表明:整个煅烧过程中的总碳排放为0.509904 t CO_(2)/t_(煅烧焦),净碳排放量为0.141942 t CO_(2)/t_(煅烧焦),挥发分燃烧碳排放在总碳排放中占比最大,为68.51%。最后指出,降低生产过程碳排放和加强余热回收利用,是今后煅烧企业节能减碳的发展方向。
基金This project is sponsored by China Academic Association
文摘Through coupling electromagnetic field equations with turbulent flow equations,the numerical prediction has been conducted on the flow field of molten steel and the trajectory of inclusion particle in the continuous casting mold effected by electromagnetic field.The difference between the maximum and the minimum of the shear stress on mold wall is used to scale the impingement strength of molten steel discharged from immersed nozzle to the solidifying shell on the narrow wall of mold.The flow field of molten steel in the mold is changed greatly and the impingement strength of the jet is reduced while electromagnetic field is applied.It is found that the successful control of flow field depends on the current and location of coil.At the same time,the new floating paths of inclusion particles are formed and the upward particles that are far away from the solidifying zone on the narrow wall of mold change their moving directions with the change of flow field,so that the particles can avoid being entrapped by the solidifying shell.
