Abstract: In order to solve the problem of quantitative description for molten steel flow characteristics in multi-strand tundish, the shortage of two traditional analytical models for flowing character multi-strand tundish is investigated in detail. While the number of the tundish strand is more, the parallel model used for flow characteristics of multi-strand tundish occur the phenomenon of the actual residence time is greater than the theoretical residence time. Determining the minimum response time is difficult point for the whole analysis approach studying the flowing character in multi-strand tundish. The existing processing methods for the minimum response induces the calculating plug volume fraction lower than actual one. Meanwhile, based on the hypothesis of combined model, the residence time distribution function for flow characteristics of molten steel in tundish is analyzed. The relationship between the standard variance of the residence time distribution function and the minimum response time is established. Then the standard variance analysis model is proposed to quantitatively describe molten steel flow characterization in tundish. This model adopts the residence time distribution function variance instead of the minimum response time to determine the plug volume fraction of the flow in tundish. Using the average value of the tracer concentration of each strand is equivalent to the overall RTD (Residence Time Distribution) curve. Therefore, the standard deviation of the overall residence time distribution function of the multi-strand tundish is the root mean square average of the one of the residence time distribution function of each strand. In this work, based on the standard variance analysis model, the whole standard variance model is proposed for melton steel flow characterization in the multi-strand tundish. Compared with the traditional multi-strand tundish analysis model, the whole standard variance analysis model used for characterizing the flow fluid in multi-strand tundish not only solves the difficulty of determining the minimum response time for the whole analysis approach, but also avoids the occurrence of negative dead volume with the parallel model. Physical modeling is carried out to study RTD curves in a five-strand tundish, and the reasonability and the excellent feature of the proposed model are verified.

Key words: continuous casting, tundish, RTD curves, flow characterization, analysis model

摘要： 为了解决多流中间包内钢液流动特性定量描述问题，本工作基于组合模型假设，深入解析描述中间包内钢液流动特性的停留时间分布(Residence Time Distribution, RTD)函数，建立了停留时间分布函数标准差与中间包活塞区体积分数的等式关系，提出了一种定量描述中间包钢液流动特性的标准差分析模型。该模型采用停留时间分布函数标准差替代传统模型中最小响应时间作为求解活塞区体积分数的参数。同时，基于多流中间包总体停留时间分布函数标准差是各流停留时间分布函数标准差的均方根平均值，将该标准差分析模型推广至多流中间包流动特性分析，形成总体标准差分析模型。与传统多流中间包分析模型相比，该方法解决了总体分析方法中最小响应时间难以确定的问题，同时，也避免了采用并联分析模型时产生死区体积分数为负的现象。最后，通过对比不同模型下的五流中间包RTD曲线，验证了总体标准差分析模型描述多流中间包流动特性的准确性和优点。

关键词: 连铸, 中间包, RTD曲线, 流动特性, 分析模型