**Jinyin Xie, Bo Wang and Jieyu Zhang \***

State Key Laboratory of Advanced Special Steel, Shanghai Key Laboratory of Advanced Ferrometallurgy, School of Materials Science and Engineering, Shanghai University, Shanghai 200444, China; xjy\_1215@shu.edu.cn (J.X.); bowang@shu.edu.cn (B.W.)

**\*** Correspondence: zhangjieyu@shu.edu.cn

Received: 12 November 2019; Accepted: 14 January 2020; Published: 21 January 2020

**Abstract:** Higher requirements for steel smelting technology have been put forward based on the increasing awareness of energy conservation and environmental protection. In the field of iron making, carbon reduction processes are often used. In this study, molten iron was smelted by designing a C-H2 smelting reduction method. Although previous researchers have studied this through a large number of physical and numerical simulations, they have not yet refined general laws from the perspective of dimensional analysis. In this paper, a double-row side blow hydraulics simulation was carried out in the C-H2 smelting reduction furnace, and an entire list of dimensionless groups of input and output parameters was proposed based on its hydraulics simulation data. The expressions between the dimensionless group of mixing time and dimensionless groups such as Capillary number (Ca) and Lagrange group (La1) were obtained by multiple linear regression based on the experimental research results and data analysis. By verifying the calculated and experimental values of the dimensionless group of mixing time, it can be seen that both have a good positive correlation. This study provides a better methodology for controlling key parameters and lays the foundation for the optimal design of the process parameters for the C-H2 smelting reduction furnace.

**Keywords:** C-H2 smelting reduction furnace; double-row side nozzles; dimensional analysis; mixing time; multiple linear regression
