Abstract: Numerical simulation of hot blast flow in the bustle of a 2580m³ blast furnace in ANSTEEL was carried out to explore the internal mechanism of non-uniform blast distribution by tuyeres. The results show that， under the condition of uniform tuyere size， the main stream in the bustle is not unidirectional， but with back flow. The hot blast enters the bustle pipe and directly impact the branch pipes beside the 0° position， resulting in large blast volume in the neighbor tuyeres. After entering the bustle pipe， two streams of blast will collide finally at the opposite of the inlet of the bustle pipe(i.e. at the 180° position)， resulting in large blast volumes in the corresponding tuyeres. After the collision， part of the blast flow moves backward along the lower part and the inner side of the bustle pipe. At the 90° and 270° positions of the bustle pipe， the backward flows collide again with forward flow， resulting in large blast volumes in the corresponding tuyeres. By comparing and analyzing the practical tuyere-size adjustment measures of the blast furnace in ANSTEEL， it is found that the adjustment measures were basically consistent with the results of the present study.

Key words: blast furnace; bustle pipe; hot blast; flow characteristic; blast distribution