Prediction model for the migration trajectory and velocity of ore-rock dispersions in an orepass storage section
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摘要: 為準確預測溜井儲礦段內礦巖散體運移狀態,以放礦漏斗中心線與溜井中心線重合的溜井結構為研究對象,建立了溜井儲礦段礦巖運移軌跡和速度預測模型。首先,根據筒倉卸載過程中顆粒運動特點和理想流體流動單元流動特點的相似性,分析儲礦段內礦巖運移規律;其次,引用流動網絡概念和Beverloo經驗公式,建立了儲礦段礦巖運移網絡,分析了儲礦段礦巖運動截面與礦巖運移速度的關系;最后,在一定的假設條件下,根據流線和等位面分布特征,建立了礦巖位移、運移軌跡和速度方程。研究結果表明:(1)礦巖進入儲礦段后依次經過勻速區、變速區,分別進行勻速直線下向運動、變速曲線運動;(2)當放礦口傾角較小時存在平衡區,該區域下礦巖不發生位移,導致“空環效應”;(3)單位時間內放出礦巖質量和穿過同一等位面的礦巖質量相等。所建立的預測模型表明,勻速區內礦巖運移狀態與儲礦段和放礦口斷面直徑、礦巖粒徑等有關,變速區內礦巖運移狀態還與礦巖所處位置、放礦口傾角等有關。Abstract: For the accurate prediction of the migration state of ore-rock dispersions in the ore pass storage section, a prediction model of an ore pass trajectory and velocity was established by taking the orepass structure, which coincided the centerlines of the ore drawing funnel, and the orepass as the research objects. First, during the silo unloading process, the movement law of ore-rock dispersions in the ore-storage section was analyzed according to the similarity of the particles’ movement characteristics and the flow characteristics of an ideal fluid flow unit. Next, the ore-rock migration network was established based from the flow network concept and the Beverloo empirical formula. Analysis was then conducted on the relationship between the section and the velocity of the ore-rock movement in the ore-storage section of ore pass. Finally, under certain assumed conditions, the displacement equation, the migration trajectory, and the velocity of the ore-rock moving in the ore-storage section were established according to the distribution characteristics of streamline and equipotential surface. Results reveal that after entering the ore-storage section of the ore pass, the ore-rock will pass through two speed zones: (1) a uniform speed zone leading to a uniform linear downward motion and (2) a variable speed zone leading to a variable speed curve motion. When the dip angle of the ore draw-hole is small, an “empty ring effect” is achieved, where no displacement of the lower ore-rock is observed. Finally, the quality of the ore-rock drawing-out in a unit time is found to be equal to that of the ore-rock passing through the same equipotential surface. The predicting model reveals the dependency of the ore-rock migration state in the uniform speed zone with a number of parameters such as the diameter of the section of ore-storage and ore-discharge, ore-rock particle size. Conversely, the ore-rock migration state in the variable speed zone is mainly related to the ore-rock’s location and the inclination angle of ore draw-hole.
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Key words:
- predicting model /
- ore-rock dispersions /
- migration law /
- trajectory /
- velocity /
- storage section of orepass
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圖 4 溜井儲礦段礦巖運移規律(1—溜井儲礦段邊界;2—流線; 3—礦巖勻速運動區;4—礦巖變速運動區;5—平衡區)。(a)無平衡區時;(b)有平衡區時
Figure 4. Ore-rock migration law in the ore-storage section of orepass (1—boundary of ore-storage section in orepass; 2—streamline; 3—uniform velocity area of ore-rock motion; 4—variable speed area of ore-rock motion; 5—equilibrium area): (a) nonequilibrium area; (b) equilibrium area
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參考文獻
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