沥青搅拌设备烘干筒参数对骨料温升的影响
Influence of rotary dryer parameters on aggregates temperature？？rise in asphalt mixing plant

为了提高烘干筒的传热效率，以LB4000型沥青搅拌设备的烘干筒为研究对象，在分析烟气流体、固态骨料以及烘干筒壁之间辐射、对流、接触多种传热过程耦合作用的基础上，针对料帘区域建立了一维轴向传热模型，采用4阶Runge？？Kutta算法分工况对模型进行了数值求解；分析叶片圆周数量和烘干筒转速对骨料温升的影响，采用基于？？Eulerian？？？？Eulerian算法的离散元？擦魈辶ρя詈戏抡妫？EDEM？？FLUENT）对烘干筒的传热过程进行了数值模拟，并对传热模型进行验证。研究结果表明：骨料进料率和料帘换热面积是影响骨料温升的主要因素，料帘特性对烘干筒传热效率有重要影响，平均每增加1 m？？2料帘换热面积，骨料的最终加热温度升高约1.3 ℃；叶片圆周数量由15片增加到20片，有利于增大料帘料量，加大换热面积，骨料最终加热温度明显升高，且骨料进料率越小温升幅度越大；提高烘干筒转速可增大料帘料量，但同时会缩短骨料在筒内的滞留时间，当烘干筒回转角速度为0.8 rad/s时，料帘换热效率与骨料在筒内滞留时间的匹配最佳，骨料最终加热温度最高，增大或减小烘干筒转速均会对骨料温升产生不利影响；在优化烘干筒结构参数，提高传热效率的同时，应避免因料帘与烟气换热过于充分而造成排烟温度过低，对后续的引风除尘系统带来不利影响。
To improve heat transfer efficiency of rotary dryer, based on the rotary dryer of LB4000 series asphalt mixing plant and the analysis of coupling effect of heat radiation, convection and contact transfer processes between flue fluid, solid aggregates and drum wall, one？？dimension axial heat transfer model was established for aggregates curtain area, the model was solved by the fourth order Runge？？Kutta method to analyze the influence of the blade circumference and rotational speed of rotary dryer on aggregate temperature rise, based on the EDEM？？FLUENT. The results show that aggregates feed rate and heat transfer area of aggregates curtain are the main factors affecting the aggregates heating temperature，the characteristic of aggregates curtain has an important influence on the heat transfer efficiency of rotary dryer with an average increase of 1 m？？2 heat transfer area, the aggregates heating temperature is raised by about 1.3 ℃. The increase of blade circumference from 15 to 20 is beneficial to the increase the amount of aggregates curtain, the area of hear transfer, finale heating temperature of aggregates, and the smaller the aggregates feed rate, the higher the temperature rise increase rotational speed of rotary dryer can increase the amount of aggregates curtain, but also can shorten the residence time of them in the drum, and when the rotational speed is 0.8 rad？s？？？？-1？？, the heat transfer efficiency of aggregates curtain is matched perfectly with the residence time of aggregates, in the drum aggregates heating temperature is the highest, so that increasing or decreasing the rotational speed will both have an adverse effect on the aggregates temperature rise, while optimizing the rotary dryer parameters and improving the heat transfer efficiency, it should be avoided that heat transfer between aggregates curtain and gas is too full to cause the low exhaust gas temperature, which will lead to adverse effects on the following dust？？removal system. 2 tabs, 8 figs, 26 refs