(1. 中南大學(xué)機電工程學(xué)院，長沙 410083；
2. 中南大學(xué)交通運輸工程學(xué)院，長沙 410075；
3. 中南大學(xué)建筑與藝術(shù)學(xué)院，長沙 410083)
摘 要: 針對物料的散體顆粒性質(zhì)，采用離散單元法建立顆粒物料的運動模型，計算物料在回轉(zhuǎn)窯內(nèi)的運動與混合過程。通過“顆粒接觸數(shù)”定義混合指數(shù)，分析物料在回轉(zhuǎn)窯內(nèi)的徑向混合。結(jié)果表明：模型所得物料的混合形態(tài)與實驗觀測結(jié)果相符，回轉(zhuǎn)窯轉(zhuǎn)動6至8圈后，徑向混合形態(tài)趨于穩(wěn)定；根據(jù)“顆粒接觸數(shù)”定義的混合指數(shù)能更合理地描述物料的混合程度，物料混合指數(shù)與時間成指數(shù)函數(shù)關(guān)系；混合速度隨回轉(zhuǎn)窯轉(zhuǎn)速的增加而增大，轉(zhuǎn)速越高，混合程度達到飽和所需時間越短，但是所需的轉(zhuǎn)動圈數(shù)會增多；轉(zhuǎn)速較低時，混合速度隨填充率的減小而增大，但是轉(zhuǎn)速增加到20 r/min后，混合速度隨填充料的減小而減小；回轉(zhuǎn)窯轉(zhuǎn)速越高，物料動能的耗散性越強。
關(guān)鍵字: 回轉(zhuǎn)窯；一元物料；固體顆粒；徑向混合；離散單元法
（1.College of Mechanical and Electrical Engineering, Central South University, Changsha 410083, China;
2. College of Traffic and Transportation Engineering, Central South University, Changsha 410075, China;
3. School of Architecture and Art, Central South University, Changsha 410083, China）
Abstract:Accounting for the dispersed properties of granular materials, a motion model of granular materials was established using three-dimensional discrete element method, then, the motion and mixing process of material in the rotary kiln were calculated by the model. On this basis, the transverse mixing of granular material within the rotary kiln was analyzed using an improved mixing index which could evaluate the degree of mixing quantitatively. The results, being consistent with the experimental observations qualitatively, show that the transverse mixing becomes stable after six to eight revolutions of the rotary kiln. Mixing index improved on particle contact-numbers can evaluate the mixing degree of material more reasonably. There is an exponential function relationship between the mixing index and time, two kinds of materials have an initial state of complete separation. The mixing rate increases with increasing rotational speed of rotary kiln. Then, the higher the speed is, the shorter the time is needed for material to reach a complete mixing situation, but the number of revolution needed will be more. When the low rotating speed is less than 20 r/min, the mixing rate increases with the decrease of filling lever. The higher the speed, the stronger the kinetic energy dissipated in granular material.
Key words: rotary kiln; mono-disperse material; solid particle; transverse mixing; discrete element method
