(1. 中南大學(xué) 機(jī)電工程學(xué)院，長(zhǎng)沙 410083；
2. 中南大學(xué) 交通運(yùn)輸工程學(xué)院，長(zhǎng)沙 410083；
3. 邵陽(yáng)學(xué)院 機(jī)械與能源工程學(xué)院，邵陽(yáng) 422004)
摘 要: 滾筒導(dǎo)熱系數(shù)對(duì)物料在外熱式回轉(zhuǎn)窯內(nèi)的傳熱特性影響巨大，將離散元方法與傳熱模型相結(jié)合，使用EDEM及C++等軟件模擬外熱式回轉(zhuǎn)窯內(nèi)物料的傳熱過(guò)程，研究滾筒導(dǎo)熱系數(shù)對(duì)物料平均溫度、物料溫度標(biāo)準(zhǔn)差及物料總傳熱系數(shù)的影響規(guī)律，進(jìn)而從微觀上對(duì)回轉(zhuǎn)窯內(nèi)物料傳熱的兩個(gè)步驟進(jìn)行區(qū)分建模，并分別討論滾筒導(dǎo)熱系數(shù)在傳熱每一步驟中所起的作用。結(jié)果表明：在滾筒導(dǎo)熱系數(shù)不斷增大的過(guò)程中，回轉(zhuǎn)窯內(nèi)物料溫度分布依次呈現(xiàn)出“整體緩慢加熱-不規(guī)則冷核-規(guī)則冷核”特征；滾筒導(dǎo)熱系數(shù)在一定范圍內(nèi)增大對(duì)物料傳熱有促進(jìn)作用，超出一定范圍后，繼續(xù)增大對(duì)傳熱無(wú)顯著影響；物料溫度標(biāo)準(zhǔn)差增大階段，滾筒導(dǎo)熱系數(shù)越大，物料均勻性越差，隨著加熱進(jìn)行，滾筒導(dǎo)熱系數(shù)的增大對(duì)物料溫度均勻性有促進(jìn)作用；顆粒從筒壁吸收的總熱量及相互接觸顆粒間傳遞的總熱量均隨滾筒導(dǎo)熱系數(shù)的增大而增大。
關(guān)鍵字: 回轉(zhuǎn)窯；外熱式；顆粒；傳熱；導(dǎo)熱系數(shù)；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 410083, China;
3. College of Mechanical and Energy Engineering, Shaoyang University, Shaoyang 422004, China）
Abstract:The drum thermal conductivity has a great influence on the heat transfer characteristics of the solids in the externally heated rotary kiln. The discrete element method was combined with heat transfer model, and EDEM and C++ were used to simulate the heat transfer process of the solids in the externally heated rotary kiln. The effects of drum thermal conductivity on the solids average temperature, standard deviation of temperature and the overall heat transfer coefficient were studied. The two steps of the solids heat transfer in the rotary kiln were modeled separately, and the roles of drum thermal conductivity in each step of heat transfer were discussed. The results show that during the process of increasing drum thermal conductivity, the solids temperature distribution in the rotary kiln presents the characteristics of “integral slow heating-irregular cold core-regular cold core”. In a certain range, the increase of drum thermal conductivity promotes the heat transfer of the solids. After exceeding a certain range, it continues to increase without significant effect on heat transfer. When the solids standard deviation of temperature increases, the greater the drum thermal conductivity is, the worse the uniformity of the solids becomes. With the heating, the increase of drum thermal conductivity promotes the uniformity of the solids temperature. The total heat absorbed by the particles from the drum and the total heat transferred between the particles in contact with each other increase with the increase of drum thermal conductivity.
Key words: rotary kiln; externally heated; particles; heat transfer; thermal conductivity; discrete element method
