结晶器内渣膜组织结构演变及传热定量化研究

项目名称： 结晶器内渣膜组织结构演变及传热定量化研究

项目编号： No.50874125

项目类型： 面上项目

立项/批准年度： 2009

项目学科： 生物科学

项目作者： 文光华

作者单位： 重庆大学

项目金额： 36万元

中文摘要： 基于结晶器内渣膜形成过程和热流模拟装置，提出了结晶器内渣膜热流定量化表征方法，研究了冷却速度、保护渣原料类型和化学成分对结晶器内渣膜组织结构和热流的影响规律，建立了实验室测试热流与工厂实际结晶器热流（拔热量）之间的定量关系。结果表明：1）最大（液渣）热流密度、特征时间、弯月面区域热流密度和平均热流密度四个参数可以表征保护渣的传热能力；2）平均热流密度能够有效地反映保护渣在实际结晶器内综合传热能力，可将此参数作为评价保护渣传热能力的关键参数；3）渣膜最大冷却速率界于29-88℃s之间，与工厂实际结晶器内冷却速率范围吻合；4）增加冷却强度，渣膜中析晶率降低，渣膜热流密度增加；5）改变原料类型对保护渣的粘度、熔点和固渣膜析出的晶体种类没有影响，但析出的枪晶石晶体形貌和尺寸大小不同；6）工厂实际连铸结晶器热流（拨热量）与实验室保护渣测试热流和拉速之间存在一定的函数的关系；7）保护渣粘度与平均热流密度之间存在明显的线性关系，由此说明在设计保护渣时，保证合理的粘度参数至关重要。

中文关键词： 连铸；结晶器保护渣；组织结构；渣膜传热；定量化

英文摘要： Based on an apparatus that can simulate formation process of mold slag film and measure horizontal heat transfer through the slag film，a method to characterize heat flux through the slag film was put forward. Effects of cooling rate, raw material type and chemistry of slags on solid slag film structure and heat flux were investigated. The relation between heat extraction in mold and heat flux through slag film by simulator was established. The key results are listed as follows: 1) Four parameters were selected as a standard to characterize the heat transfer of the mold slag, namely the maximum heat flux (liquid slag), characteristic time, heat flux at meniscus, and average heat flux. 2) The average heat flux is a key factor to indicate the overall heat transfer in casting mold. 3) The maximum cooling rate through slag film is in range of 29-88℃s, which is the same as cooling rate of plant mold. 4) As cooling rate increases, crystal ratio of slag film decreases, which results in increase of heat flux through slag film. 5) The raw material has minor effect on viscosity, melting point and crystalline phase of the mold slag; whereas, it affects the formation and size of crystal. 6) There is a function relation among average heat flux through slag film by simulator, casting speed and heat extraction in plant mold. 7) There is a linearity relation between average heat flux through slag film by simulator and viscosity of slag, which suggests that selection of rational viscosity parameter is very important for designing mold fluxes.

英文关键词： continuous casting;mold fluxes; morphology and structure;heat transfer through slag film;quantification