Mass transfer of phosphorus in high-phosphorus hot-metal refining was investigated using CaO-FetO-SiO2 slags at 1623 K. Based on a two-film theory kinetic model and experimental results, it was found that the overall ...Mass transfer of phosphorus in high-phosphorus hot-metal refining was investigated using CaO-FetO-SiO2 slags at 1623 K. Based on a two-film theory kinetic model and experimental results, it was found that the overall mass transfer coefficient, which includes the effects of mass transfer in both the slag phase and metal phase, is in the range of 0.0047 to 0.0240 cm/s. With the addition of a small amount of fluxing agents A1203 or Na20 into the slag, the overall mass transfer coefficient has an obvious increase. Silicon content in the hot metal also influences the overall mass transfer coefficient. The overall mass transfer coefficient in the lower [Si] heat is much higher than that in the higher [Si] heat. It is concluded that both fluxing agents and lower [Si] hot metal facilitate mass transfer of phosphorus in liquid phases. Fur- thermore, the addition of Na20 could also prevent rephosphorization at the end of the experiment.展开更多
针对LF精炼炉钢液温度控制过度依赖人工经验的问题,马钢长材事业部以120 t LF精炼炉为研究对象,基于能量平衡原理,计算分析LF精炼过程中输入电能、合金化、炉渣热效应、钢包内衬散热、渣面辐射、吹氩搅拌和烟气热损失等热量对钢液温度...针对LF精炼炉钢液温度控制过度依赖人工经验的问题,马钢长材事业部以120 t LF精炼炉为研究对象,基于能量平衡原理,计算分析LF精炼过程中输入电能、合金化、炉渣热效应、钢包内衬散热、渣面辐射、吹氩搅拌和烟气热损失等热量对钢液温度的影响,建立LF精炼钢液温度的预测模型。经过跟踪实际生产试验、测温校正并优化模型,使模型取得了良好的应用效果。模型预测温度与实际测量值偏差绝对值≤5℃的比例为97.73%,偏差绝对值≤6℃的比例为100%。展开更多
The heat transfer analysis was performed for an industrial ladle furnace （LF） with a capacity of 55-57 t in Turkey. The heat losses by conduction, convection and radiation from outer and bottom surfaces, top and ele...The heat transfer analysis was performed for an industrial ladle furnace （LF） with a capacity of 55-57 t in Turkey. The heat losses by conduction, convection and radiation from outer and bottom surfaces, top and electrodes of LF were determined in detail. Finally, some suggestions about decreasing heat losses were presented.展开更多
The available studies in the literature on physical modeling of the vacuum circulation (RH, i.e. Ruhrstahl Heraeus) refining process of molten steel have briefly been reviewed. The latest advances made by the author ...The available studies in the literature on physical modeling of the vacuum circulation (RH, i.e. Ruhrstahl Heraeus) refining process of molten steel have briefly been reviewed. The latest advances made by the author with his research group have been summarized. Water modeling was employed to investigate the flow and mixing characteristics of molten steel under the RH and RH KTB (Kawasaki top blowing) conditions and the mass transfer features between molten steel and powder particles in the RH PTB (powder top blowing) refining. The geometric similarity ratio between the model and its prototype (a multifunction RH degasser of 90 t capacity) was 1:5. The effects of the related technological and structural factors were considered. These latest studies have revealed the flow and mixing characteristics of molten steel and the mass transfer features between molten steel and powder particles in these processes, and have provided a better understanding of the refining processes of molten steel.展开更多
Contextual refinement is a compositional approach to compositional verification of concurrent objects.There has been much work designing program logics to prove the contextual refinement between the object implementat...Contextual refinement is a compositional approach to compositional verification of concurrent objects.There has been much work designing program logics to prove the contextual refinement between the object implementation and its abstract specification.However,these program logics for contextual refinement verification cannot support objects with resource ownership transfer,which is a common pattern in many concurrent objects,such as the memory management module in OS kernels,which transfers the allocated memory block between the object and clients.In this paper,we propose a new approach to give abstract and implementation independent specifications to concurrent objects with ownership transfer.We also design a program logic to verify contextual refinement of concurrent objects w.r.t.their abstract specifications.We have successfully applied our logic to verifying an implementation of the memory management module,where the implementation is an appropriately simplified version of the original version from a real-world preemptive OS kernel.展开更多
基金financially supported by the Fundamental Research Funds for Central Universities of China (No. CDJZR 14130001)
文摘Mass transfer of phosphorus in high-phosphorus hot-metal refining was investigated using CaO-FetO-SiO2 slags at 1623 K. Based on a two-film theory kinetic model and experimental results, it was found that the overall mass transfer coefficient, which includes the effects of mass transfer in both the slag phase and metal phase, is in the range of 0.0047 to 0.0240 cm/s. With the addition of a small amount of fluxing agents A1203 or Na20 into the slag, the overall mass transfer coefficient has an obvious increase. Silicon content in the hot metal also influences the overall mass transfer coefficient. The overall mass transfer coefficient in the lower [Si] heat is much higher than that in the higher [Si] heat. It is concluded that both fluxing agents and lower [Si] hot metal facilitate mass transfer of phosphorus in liquid phases. Fur- thermore, the addition of Na20 could also prevent rephosphorization at the end of the experiment.
文摘针对LF精炼炉钢液温度控制过度依赖人工经验的问题,马钢长材事业部以120 t LF精炼炉为研究对象,基于能量平衡原理,计算分析LF精炼过程中输入电能、合金化、炉渣热效应、钢包内衬散热、渣面辐射、吹氩搅拌和烟气热损失等热量对钢液温度的影响,建立LF精炼钢液温度的预测模型。经过跟踪实际生产试验、测温校正并优化模型,使模型取得了良好的应用效果。模型预测温度与实际测量值偏差绝对值≤5℃的比例为97.73%,偏差绝对值≤6℃的比例为100%。
文摘The heat transfer analysis was performed for an industrial ladle furnace （LF） with a capacity of 55-57 t in Turkey. The heat losses by conduction, convection and radiation from outer and bottom surfaces, top and electrodes of LF were determined in detail. Finally, some suggestions about decreasing heat losses were presented.
文摘The available studies in the literature on physical modeling of the vacuum circulation (RH, i.e. Ruhrstahl Heraeus) refining process of molten steel have briefly been reviewed. The latest advances made by the author with his research group have been summarized. Water modeling was employed to investigate the flow and mixing characteristics of molten steel under the RH and RH KTB (Kawasaki top blowing) conditions and the mass transfer features between molten steel and powder particles in the RH PTB (powder top blowing) refining. The geometric similarity ratio between the model and its prototype (a multifunction RH degasser of 90 t capacity) was 1:5. The effects of the related technological and structural factors were considered. These latest studies have revealed the flow and mixing characteristics of molten steel and the mass transfer features between molten steel and powder particles in these processes, and have provided a better understanding of the refining processes of molten steel.
基金supported by the National Natural Science Foundation of China under Grant No.61632005。
文摘Contextual refinement is a compositional approach to compositional verification of concurrent objects.There has been much work designing program logics to prove the contextual refinement between the object implementation and its abstract specification.However,these program logics for contextual refinement verification cannot support objects with resource ownership transfer,which is a common pattern in many concurrent objects,such as the memory management module in OS kernels,which transfers the allocated memory block between the object and clients.In this paper,we propose a new approach to give abstract and implementation independent specifications to concurrent objects with ownership transfer.We also design a program logic to verify contextual refinement of concurrent objects w.r.t.their abstract specifications.We have successfully applied our logic to verifying an implementation of the memory management module,where the implementation is an appropriately simplified version of the original version from a real-world preemptive OS kernel.
