高爐風徑區之數值模擬研究

Numerical Investigation of the Raceway in the Blast Furnace

楊祖昂(Yang Tsu-Ang)

指導教授 ： 蔡建雄

國立屏東科技大學/工學院/車輛工程系所/碩士(2011年)

https://doi.org/10.6346/NPUST.2011.00189

摘要

本研究以計算流體力學的方法，利用歐拉多相流加上粒子動力學模式預測全焦操作於高爐風徑區的形狀。文中研究鼓風嘴風速、焦炭直徑、孔隙度這些參數分析對高爐風徑區的形狀與大小。並且利用動態網格模型來取代鐵水造成焦炭層的移動對風徑區的影響，最後使用離散元素法的套裝軟體EDEM與FLUENT的耦合來觀察粒子在風徑區的運動狀況以及受力分佈。計算結果顯示，全焦操作的風徑區受到鼓風嘴風速增大而變大，隨著焦炭直徑變大、孔隙度變大而變小。焦炭層的移動速度越大對風徑區的影響越大。當焦炭Froude 數小於5.83×10-4對於不考慮焦炭燃燒的風徑區呈現準穩態情形，但對考慮焦炭燃燒的風徑區會呈現流體化的趨勢。使用離散元素法模擬可以看到風徑區前方的粒子受到撞擊後所承受的力量最大，由此可推測高爐風徑區中焦炭會從這個地方破碎形成小粒子填滿焦炭之間的間隙形成鳥巢區。風速從小增加到大再由大變到小，在同一個速度下，風徑區大小會有多重解，呈現磁滯現象。使用多流體模式則無法模擬出此磁滯現象。

關鍵字

高爐 ； 風徑區 ； 全焦燃燒 ； 磁滯現象 ； 離散元素法 ； 計算流體力學

並列摘要

The phenomena of coke combustion in the blast furnace raceway are investigated utilizing CFD method. The model simulates of raceway shape and size in the blast furnace. The structure of the raceway is calculated using multi-fluid Eulerian model coupled with kinetic theory. The parameters that affect the shape and size of raceway are studied in details, including the mass flow rate of carrier gases, coke size and porosity. The movement of the raceway caused by the change of hot metal level is simulated by the dynamic mesh model. For the analysis of particle moment and its shear stress distribution in the raceway, the discrete element method (DEM) software EDEM is applied as a sub-model in this study. With all coke operation, the calculated raceway size is increased with the increase of blast velocity, whereas the raceway becomes smaller when the coke size or the porosity of the coke bed is increased. The calculation results indicate that the raceway shape is significantly influenced when the hot metal movement speed is increased. Without considering coke combustion within the raceway, the raceway remains quasi-steady when the coke Froude number is less than 5.83×10-4. On the other hand, the fluidization of raceway is found when coke combustion is taken into account. The calculation results also show the particles in front of raceway have highest impact strength. This may cause the generation of coke debits. As a result, the boundary of raceway, so-called bird’s nest, will be filled with coke debits. According to the examination in this study, the raceway hysteresis phenomena can not be simulated by using multi-fluid model.

並列關鍵字

Blast Furnace ； Coke Combustion ； Raceway ； Hysteresis ； DEM ； CFD

參考文獻

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