Houfa SHEN
,
Richard A.Hardin
,
Robert MacKenzie
,
C.Beckermann
材料科学技术（英）
A three-dimensional heat transfer model for continuous steel slab casting has been developed with realistic spray cooling patterns and a coupled microsegregation solidification model that calculates the solidification path for multi-component steels. Temperature and composition dependent properties are implemented in a database for 15 chemical species.Considerable effort is made to accurately model the spray cooling heat transfer. Each spray nozzle position and distribution is considered, including variations of the spray patterns with flow rate,and spray overlap. Nozzle type,layout, nozzle-to-slab distance, and spray span and flux are variable.Natural convection, thermal radiation and contact cooling of individual rolls are computed. The present model provides more comprehensive information and realistic slab surface temperatures than results from a model using the “averaged” treatment of boundary conditions. Cooling operating conditions and parameters of individual spray nozzles can be analyzed to optimize nozzle spray distribution, improve product quality, and troubleshoot issues such as nozzle clogging that may arise during production. One spray cooling correlation is used for the entire machine, achieving as good or better agreement with surface temperature measurements than was found previously for the model using an “averaged” treatment of boundary conditions and using three machine-segment-dependent correlations.
关键词:
Steel
,
null
,
null
张向东
,
扈晓飞
硅酸盐通报
为研究二灰改良风积砂土在低温条件下的动力参数变化规律,采用改进的Hardin双曲线模型,通过室内冻土动三轴试验,展开不同试验条件下二灰改良风积砂土在负温条件下的动力特性研究.试验结果表明:随掺灰比的增加,改良风积砂土的动剪切模量先升高后下降,改良效果以掺灰比30%~40%为最佳;相同掺灰比下,冻土的动剪切模量随围压和频率的增加而增加,随冻融循环次数和温度的增加而减少.结合试验结果,对负温条件下的二灰改良风积砂土的最大动剪切模量变化规律进行了回归分析,得出最大动剪切模量与围压、频率和温度三者之间的线性方程.该成果可为解决实际工程问题提供科学性参考依据,具有一定的社会经济效益.
关键词:
二灰土
,
风积砂土
,
冻土动三轴
,
动剪切模量
,
冻融循环
,
动力分析
