# Effect of Furnace Structure on Burden Distribution and Gas Flow in Sinter Vertical Cooling Furnace
## 5 Conclusions  
To improve the serious problem of the \"short circuit\" of gas flow in the sinter vertical cooling furnace, a Venturi furnace type was proposed based on the structure of the vertical cooling furnace. The DEM-CFD model was used to study the influence of the Venturi furnace type on the burden distribution and gas flow. The conclusions were as follows:  
1. The Venturi furnace type changed the direction of the high \(D_{\rm nv}\) channel from vertical to inclined-vertical through wall tilt and reduced \(D_{\rm nv}\) from \(>\)0.033 m to 0.028-0.03 m in the vertical part of the variable-diameter section, which shortened the length of the high \(D_{\rm nv}\) channel and reduced its influence scope. At the same time, a new high \(D_{\rm nv}\) channel would gradually form in the center area. 2. The improvement in voidage in the Venturi furnace type was mainly concentrated in the variable-diameter section. Compared with the existing furnace type, the Venturi furnace type could increase the minimum and average value of voidage from 0.28 and 0.315 to 0.31 and 0.33, respectively, making the voidage fluctuate twice along the longitudinal direction, thus changing the original U-shaped distribution into a W-shaped distribution. At the same time, the longitudinal fluctuation range of the voidage could be reduced from 0.28-0.39 to 0.298-0.37, and thus, the voidage in the middle area could always be maintained at a high level, which was conducive to more cooling gas entering the middle area and reducing the influence of high-voidage channels in the sidewall and center area. 3. After the Venturi furnace type was adopted, the cooling gas flow direction in the rectangular furnace cavity changed from vertical to vertical-inclined-upward, which was beneficial for increasing the gas-solid contact. In terms of the gas velocity, the cooling gas velocity significantly increased. In the vertical section, the average gas velocity was 2.34 m/s, which was 30.73% higher than the velocity of 1.79 m/s of the existing furnace type. In the variable-diameter section, the average gas velocity was 3.52 m/s, which was 72.55% higher than the velocity of 2.04 m/s of the existing furnace type. In terms of the airflow short circuit, the high-speed gas channel in the vertical section still existed, and another high-speed channel would be formed in the center area. However, the length of the two channels was reduced from 3.11 m of the existing furnace type to 2.52 m, thereby reducing the scope of its influence area. In the variable-diameter section, the high-speed gas channel disappeared, and the cooling gas velocity was evenly distributed transversely, which was conducive to weakening the airflow \"short circuit\". 4. For the Venturi furnace type, the total gas pressure drop reached 6410 Pa, which was 54.83% higher than the pressure drop of 4140 Pa for the existing furnace type. Therefore, in the design of the Venturi furnace type, both the improvement in the gas velocity distribution and the increase in the pressure drop should be controlled within a reasonable range. 5. This study provides new improvement measures for improving the burden segregation and gas flow in a vertical cooling furnace, which can provide theoretical guidance for the structure optimization of the vertical cooling furnace in Meishan Steel. At the same time, it can also provide a reference for the optimization of the vertical gas-solid heat-exchange furnace for granular materials with a wide particle size distribution and poor permeability. Conceptualization, H.L. ; data curation, T.Q. ; funding acquisition, H.L. ; investigation, H.L. ; methodology, T.Q. ; project administration, H.L. ; resources, H.L. ; software, T.Q. ; supervision, Y.Z. ; writing--original draft preparation, T.Q. ; writing--review and editing, H.L. All authors have read and agreed to the published version of the manuscript.