【摘要】 气泡的尺寸直接影响着气泡与钢液之间的传热、传质和动量传输过程。冶金生产工艺的复杂性和高温环境限制了常规气泡微细化方法的应用，导致钢液中气泡的尺寸普遍较大，严重限制了冶金工艺的生产效率。基于此，本文提出周期性双向旋转的电磁场以诱发钢液周期性地产生高强度湍流流动，从而对气泡进行微细化作用。利用数值模拟的方法研究了不同磁感应强度电磁场下钢液流动的湍流强度。当磁感应强度增加至240mT时，钢液的湍流流动可以满足气泡破碎的需求。分析了周期性双向旋转电磁场对钢液湍流流动的影响，并考察了气泡微细化效果。钢液中10mm以上大气泡的比例降低至3.09%，相比于无电磁场条件减少了27.47%。直径为0.5～1mm的气泡数密度占比为40.03%，小于5mm气泡的比例高达92.10%，相比于无电磁场下提高了80.25%。对比了不同旋转周期电磁场作用下钢液的湍流强度，以及相应的气泡微细化效果，最佳的旋转周期为3～5s。更多还原

【Abstract】 The size of bubbles directly influences the heat,mass,and momentum transfer processes between the bubbles and molten steel.The complexity of metallurgical processes and the high-temperature environment limit the application of conventional bubble refinement methods,resulting in generally large bubble sizes in molten steel,which severely restricts the production efficiency of metallurgical processes.This study proposes the periodically bidirectional rotating electromagnetic field to induce high-intensity turbulent flow in molten steel periodically,thereby achieving bubble refinement.Using numerical simulation methods,the turbulence intensity of molten steel under electromagnetic fields with different magnetic flux densities was investigated to determine the magnetic flux density suitable for bubble refinement.When the magnetic flux density increased to 240 mT,the turbulent flow of molten steel met the requirements for bubble breakup.The effect of the periodically bidirectional rotating electromagnetic field on the turbulent flow of molten steel was analyzed,and the bubble refinement effectiveness was examined.The proportion of large bubbles larger than 10 mm in the molten steel decreased to 3.09%,a reduction of 27.47%compared to conditions without the electromagnetic field.The number density proportion of bubbles in the 0.5-1 mm diameter range reached 40.03%,and the proportion of bubbles smaller than 5 mm was as high as 92.10%,an increase of 80.25%compared to conditions without the electromagnetic field.The turbulence intensity of molten steel under electromagnetic fields with different rotation periods and the corresponding bubble refinement effects were compared,with the optimal rotation period range identified as 3-5s.更多还原