The optimization of flow control devices(FCDs) for a T-type five-strand billet caster tundish was carried out by water modeling and numerical simulation. In water modeling experiments, flow characteristics of the bare...The optimization of flow control devices(FCDs) for a T-type five-strand billet caster tundish was carried out by water modeling and numerical simulation. In water modeling experiments, flow characteristics of the bare tundish and tundish conf igurations with designed U-type baff les and a round turbulence inhibitor were analyzed using residence time distribution(RTD) curves. Mathematical models for liquid steel in the real plant tundish were established using the fluid dynamics software package Fluent. The flow field, the temperature field, and the RTD curves of liquid steel in the proposed tundish conf igurations were obtained. The results of numerical simulation and water modeling were validated with each other by the predicted and experimental RTD curves. The results of flow field and temperature field were used to ref lect the actual state of a real plant tundish and to choose the optimal FCD. Finaly, from the whole performance of the multi-strand tundish, the optimal scheme was determined by combining the results of water modeling and numerical simulation. With the optimal tundish equipped with U-type baffle with def lector holes and round turbulence inhibitor, not only was the flow characteristic of each strand improved, but also the difference of flow characteristics between multiple strands was smaller.展开更多
The adhesion of fine iron ore particles during fluidized bed reduction was studied using pressurized visible fluidized bed laboratory equipment.The results showed that the optimal operating parameters for pure hydroge...The adhesion of fine iron ore particles during fluidized bed reduction was studied using pressurized visible fluidized bed laboratory equipment.The results showed that the optimal operating parameters for pure hydrogen reduction under high pressure were reduction temperature of 1073 K,particle size of 0.18-0.66 mm,pure H_(2) linear velocity of 0.8 m/s,reduction pressure of 200 kPa,and reduction time of 50 min.When plastic particles were mixed into the fluidized bed,the optimal parameters were reduction temperature of 973 K,particle size of 0.18-0.66 mm,pure H_(2) linear velocity of 0.8 m/s,reduction pressure of 100 kPa,mass content of plastic particles of 8%,and reduction time of 65 min.The chemical reaction resistance is much higher than the inner diffusion resistance at the initial stage of the reaction,whereas,in later stage,the inner diffusion resistance exceeds the chemical reaction resistance.The contact area of iron atoms or iron whiskers gradually decreases with the increase in reduction pressure from 0.20 to 0.45 MPa,and the sticking trend gradually decreases.Adding plastic particles in the fluidized reduction process of fine iron ore can effectively inhibit the adhesion among fine iron ore particles.展开更多
基金financially supported by the National Natural Science Foundation of China(51504002)
文摘The optimization of flow control devices(FCDs) for a T-type five-strand billet caster tundish was carried out by water modeling and numerical simulation. In water modeling experiments, flow characteristics of the bare tundish and tundish conf igurations with designed U-type baff les and a round turbulence inhibitor were analyzed using residence time distribution(RTD) curves. Mathematical models for liquid steel in the real plant tundish were established using the fluid dynamics software package Fluent. The flow field, the temperature field, and the RTD curves of liquid steel in the proposed tundish conf igurations were obtained. The results of numerical simulation and water modeling were validated with each other by the predicted and experimental RTD curves. The results of flow field and temperature field were used to ref lect the actual state of a real plant tundish and to choose the optimal FCD. Finaly, from the whole performance of the multi-strand tundish, the optimal scheme was determined by combining the results of water modeling and numerical simulation. With the optimal tundish equipped with U-type baffle with def lector holes and round turbulence inhibitor, not only was the flow characteristic of each strand improved, but also the difference of flow characteristics between multiple strands was smaller.
基金the National Natural Science Foundation of China(No.51974001)the University outstanding young talents funding program(No.gxyq2019016).
文摘The adhesion of fine iron ore particles during fluidized bed reduction was studied using pressurized visible fluidized bed laboratory equipment.The results showed that the optimal operating parameters for pure hydrogen reduction under high pressure were reduction temperature of 1073 K,particle size of 0.18-0.66 mm,pure H_(2) linear velocity of 0.8 m/s,reduction pressure of 200 kPa,and reduction time of 50 min.When plastic particles were mixed into the fluidized bed,the optimal parameters were reduction temperature of 973 K,particle size of 0.18-0.66 mm,pure H_(2) linear velocity of 0.8 m/s,reduction pressure of 100 kPa,mass content of plastic particles of 8%,and reduction time of 65 min.The chemical reaction resistance is much higher than the inner diffusion resistance at the initial stage of the reaction,whereas,in later stage,the inner diffusion resistance exceeds the chemical reaction resistance.The contact area of iron atoms or iron whiskers gradually decreases with the increase in reduction pressure from 0.20 to 0.45 MPa,and the sticking trend gradually decreases.Adding plastic particles in the fluidized reduction process of fine iron ore can effectively inhibit the adhesion among fine iron ore particles.
