The available studies in the literature on physical and mathematical modeling of the argon oxygen decarburization (AOD) process of stainless steel have briefly been reviewed. The latest advances made by the author wi...The available studies in the literature on physical and mathematical modeling of the argon oxygen decarburization (AOD) process of stainless steel have briefly been reviewed. The latest advances made by the author with his research group have been summarized. Water modeling was used to investigate the fluid flow and mixing characteristics in the bath of an 18 t AOD vessel, as well as the 'back attack' action of gas jets and its effects on the erosion and wear of the refractory lining, with sufficiently full kinematic similarity. The non rotating and rotating gas jets blown through two annular tuyeres, respectively of straight tube and spiral flat tube type, were employed in the experiments. The geometric similarity ratio between the model and its prototype (including the straight tube type tuyeres) was 1:3. The influences of the gas flow rate, the angle included between the two tuyeres and other operating parameters, and the suitability of the spiral tuyere as a practical application, were examined. These latest studies have clearly and successfully brought to light the fluid flow and mixing characteristics in the bath and the overall features of the back attack phenomena of gas jets during the blowing, and have offered a better understanding of the refining process. Besides, mathematical modeling for the refining process of stainless steel was carried out and a new mathematical model of the process was proposed and developed. The model performs the rate calculations of the refining and the mass and heat balances of the system. Also, the effects of the operating factors, including adding the slag materials, crop ends, and scrap, and alloy agents; the non isothermal conditions; the changes in the amounts of metal and slag during the refining; and other factors were all considered. The model was used to deal with and analyze the austenitic stainless steel making (including ultra low carbon steel) and was tested on data of 32 heats obtained in producing 304 grade steel in an 18 t AOD vessel. The changes in the bath composition and temperature during the refining process with time can be accurately predicted using this model. The model can provide some very useful information and a reliable basis for optimizing the process practice of the refining of stainless steel and control of the process in real time and online.展开更多
为实现碳纤维增强复合材料的高质高效切割,采用水导激光加工技术对CFRP进行微槽加工,通过正交实验法、单因素实验法研究了激光功率、扫描速度和扫描路径重叠率对热影响区宽度和材料去除率的影响规律,并以此为目标进行了优化。结果表明:...为实现碳纤维增强复合材料的高质高效切割,采用水导激光加工技术对CFRP进行微槽加工,通过正交实验法、单因素实验法研究了激光功率、扫描速度和扫描路径重叠率对热影响区宽度和材料去除率的影响规律,并以此为目标进行了优化。结果表明:激光功率、扫描路径重叠率对热影响区宽度和材料去除率的影响显著;当激光功率35 W、扫描速度4 mm/s和扫描路径重叠率40%时,热影响区宽度为184.484μm,材料去除率为0.068 mm ^(3)/s,能获得较小的热影响区宽度和较高的加工效率。展开更多
跨介质航行体入水瞬间会受到巨大的冲击载荷,极易导致结构破坏甚至内部器件失灵。为发展有效的降载方法,本文基于VOF(Volume of Fluid)多相流模型,研究头部喷气航行体入水过程的载荷特性和流体动力特性,分析喷气压力、喷气高度对降载效...跨介质航行体入水瞬间会受到巨大的冲击载荷,极易导致结构破坏甚至内部器件失灵。为发展有效的降载方法,本文基于VOF(Volume of Fluid)多相流模型,研究头部喷气航行体入水过程的载荷特性和流体动力特性,分析喷气压力、喷气高度对降载效果的影响,并探索头部喷气降载方法有效性的入水速度范围。研究结果表明,头部喷气使自由液面下凹形成空腔,并能极大地降低航行体所受阻力和冲击力,延缓了航行体撞水时间,从而实现冲击载荷控制;喷气压力和喷气高度对入水空泡形态及冲击压力峰值的影响都不大,合理的选择既能达到降载效果又能节约喷气量;入水速度为50 m/s时,降载量高达76.51%,但当入水速度为300 m/s时,降载量仅为39.92%。因此,针对高亚声速跨介质入水问题,需进一步探索主被动相结合的复合降载方法。展开更多
文摘The available studies in the literature on physical and mathematical modeling of the argon oxygen decarburization (AOD) process of stainless steel have briefly been reviewed. The latest advances made by the author with his research group have been summarized. Water modeling was used to investigate the fluid flow and mixing characteristics in the bath of an 18 t AOD vessel, as well as the 'back attack' action of gas jets and its effects on the erosion and wear of the refractory lining, with sufficiently full kinematic similarity. The non rotating and rotating gas jets blown through two annular tuyeres, respectively of straight tube and spiral flat tube type, were employed in the experiments. The geometric similarity ratio between the model and its prototype (including the straight tube type tuyeres) was 1:3. The influences of the gas flow rate, the angle included between the two tuyeres and other operating parameters, and the suitability of the spiral tuyere as a practical application, were examined. These latest studies have clearly and successfully brought to light the fluid flow and mixing characteristics in the bath and the overall features of the back attack phenomena of gas jets during the blowing, and have offered a better understanding of the refining process. Besides, mathematical modeling for the refining process of stainless steel was carried out and a new mathematical model of the process was proposed and developed. The model performs the rate calculations of the refining and the mass and heat balances of the system. Also, the effects of the operating factors, including adding the slag materials, crop ends, and scrap, and alloy agents; the non isothermal conditions; the changes in the amounts of metal and slag during the refining; and other factors were all considered. The model was used to deal with and analyze the austenitic stainless steel making (including ultra low carbon steel) and was tested on data of 32 heats obtained in producing 304 grade steel in an 18 t AOD vessel. The changes in the bath composition and temperature during the refining process with time can be accurately predicted using this model. The model can provide some very useful information and a reliable basis for optimizing the process practice of the refining of stainless steel and control of the process in real time and online.
文摘为实现碳纤维增强复合材料的高质高效切割,采用水导激光加工技术对CFRP进行微槽加工,通过正交实验法、单因素实验法研究了激光功率、扫描速度和扫描路径重叠率对热影响区宽度和材料去除率的影响规律,并以此为目标进行了优化。结果表明:激光功率、扫描路径重叠率对热影响区宽度和材料去除率的影响显著;当激光功率35 W、扫描速度4 mm/s和扫描路径重叠率40%时,热影响区宽度为184.484μm,材料去除率为0.068 mm ^(3)/s,能获得较小的热影响区宽度和较高的加工效率。
文摘跨介质航行体入水瞬间会受到巨大的冲击载荷,极易导致结构破坏甚至内部器件失灵。为发展有效的降载方法,本文基于VOF(Volume of Fluid)多相流模型,研究头部喷气航行体入水过程的载荷特性和流体动力特性,分析喷气压力、喷气高度对降载效果的影响,并探索头部喷气降载方法有效性的入水速度范围。研究结果表明,头部喷气使自由液面下凹形成空腔,并能极大地降低航行体所受阻力和冲击力,延缓了航行体撞水时间,从而实现冲击载荷控制;喷气压力和喷气高度对入水空泡形态及冲击压力峰值的影响都不大,合理的选择既能达到降载效果又能节约喷气量;入水速度为50 m/s时,降载量高达76.51%,但当入水速度为300 m/s时,降载量仅为39.92%。因此,针对高亚声速跨介质入水问题,需进一步探索主被动相结合的复合降载方法。
