滚筒式污泥干燥器特性仿真及结构优化
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摘要
针对目前用滚筒干燥器进行污泥干化过程中热能利用率低等问题,运用Fluent软件与EDEM软件耦合仿真模拟其干燥过程,研究了在考虑颗粒物料相互碰撞作用以及热气流对物料的牵引作用时,滚筒结构对物料的运动路径及其干化效果的影响.提出虚拟吸热量的概念,描述物料在受热干化时气固两相复杂的热交换过程;通过仿真,分析滚筒内扬料板的分布、入料螺旋的长度对物料在滚筒内运动路径及其干化效果的影响,并进行优化设计.研究结果表明:对于规格一定的滚筒干燥器,其扬料板分布形式是影响污泥滚筒干燥器热效率的重要因素;在改进扬料板分布、入料螺旋长度后,滚筒干燥器热效率提高11.2%.
To solve the problem of low thermal efficiency in the process of drying sludge in roller dryer,the drying process was simulated by Fluent software and EDEM softwares. Considering the collision of granular material and the thermal traction to material,the influence of roller structure on motion path and drying efficiency of materials was investigated. The concept of virtual heat absorption was put forward to describe the complex gas-particle two-phase heat exchange process when the material was dried by heating. By simulation,the effects of hopper plate distribution and feed screw length on motion path and drying efficiency of material in the roller were analyzed to conduct design optimization. The results demonstrate that for the roller dryer with a certain specification,the distribution of hopper plates in the roller dryer is important affecting factor on thermal efficiency. After improving the distribution of hopper plate and the length of feed screw,the thermal efficiency of roller dryer can be increased by 11. 2%.
To solve the problem of low thermal efficiency in the process of drying sludge in roller dryer,the drying process was simulated by Fluent software and EDEM softwares. Considering the collision of granular material and the thermal traction to material,the influence of roller structure on motion path and drying efficiency of materials was investigated. The concept of virtual heat absorption was put forward to describe the complex gas-particle two-phase heat exchange process when the material was dried by heating. By simulation,the effects of hopper plate distribution and feed screw length on motion path and drying efficiency of material in the roller were analyzed to conduct design optimization. The results demonstrate that for the roller dryer with a certain specification,the distribution of hopper plates in the roller dryer is important affecting factor on thermal efficiency. After improving the distribution of hopper plate and the length of feed screw,the thermal efficiency of roller dryer can be increased by 11. 2%.
引文
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[14]王博,刘旭,刘清涛.Pro/E自顶向下方法在现代机械产品设计中的应用[J].重庆理工大学学报(自然科学),2015,29(7):40-43.WANG B,LIU X,LIU Q T.Application of top-down method in modern mechanical product design based on Pro/E[J].Journal of Chongqing University of Technology(Natural Science),2015,29(7):40-43.(in Chinese)
[15]李秀敏,张晓林.回转圆筒干燥器主要技术参数的确定[J].工业炉,2011,33(6):43-45.LI X M,ZHANG X L.Determination of main technical parameters of rotary cylinder dryer[J].Industrial Furnace,2011,33(6):43-45.(in Chinese)
[16]马学文,翁焕新,章金骏.颗粒状污泥的干燥特性及表观变化[J].环境科学,2011,32(8):2358-2364.MA X W,WENG H X,ZHANG J J.Drying characteristics and apparent change of sludge granules during drying[J].Environmental Science,2011,32(8):2358-2364.(in Chinese)
[17]ZHANG Y H,REESE J M.The drag force in two-fuid models of gas-solid flows[J].Chemical Engineering Science,2003,58(8):1641-1644.
[18]SHAHHOSSEINI S H,SADEGHI M T,GOLSEFATAN H R.Dynamic simulation of an industrial rotary dryer[J].Iranian Journal of Chemical Engineering,2010,7(2):68-77.
[2]刘广文.干燥设备设计手册[M].北京:机械工业出版社,2009.
[3]黄志刚,税国双,肖君.转筒干燥器中颗粒物料传热过程的数值仿真与实验研究[J].机械设计与制造,2006(1):24-26.HUANG Z G,SHUI G S,XIAO J.Numerical simulation and test study on particulate materials heat transfer in rotary dryer[J].Mechanical Design and Manufacturing,2006(1):24-26.(in Chinese)
[4]HUANG Z G,WENG Y X,FU N,et al.Modeling the total residence time in a rotary dryer[J].International Journal of Food Engineering,2015,11(3):405-410.
[5]李妙玲,姚永玉,赵红霞.回转式烘干机扬料板结构和扬料量关系的数值分析[J].煤矿机械,2017,38(3):50-52.LI M L,YAO Y Y,ZHAO H X.Numerical analysis on relation of lifting plate structure and uplift capacity in rotary dryer[J].Coal Mine Machinery,2017,38(3):50-52.(in Chinese)
[6]李妙玲,赵红霞,姚永玉.回转式烘干机物料空间运动建模和数值分析[J].化工进展,2017,36(4):1187-1191.LI M L,ZHAO H X,YAO Y Y.Estimation models and mathematical analysis of particle transportation in a rotary dryer[J].Chemical Industry and Engineering Progress,2017,36(4):1187-1191.(in Chinese)
[7]VIKTOR S,MARTIN M,OLIVER B,et al.Coupled DEM-CFD simulation of drying wood chips in a rotary drum-baffle design and model reduction[J].Fuel,2016,184:896-904.
[8]WEN H F,ZHANG K.Coupling discrete-element method and computation fluid mechanics to simulate aggregates heating in asphalt plants[J].Journal of Engineering Mechanics,2015,141(3):04014129.
[9]黄文景,杨建红,王小宁.滚筒干燥器能耗分析及参数优化设计[J].筑路机械与施工机械化,2017,34(1):81-86.HUANG W J,YANG J H,WANG X N.Study on energy consumption and parameter optimization of rotary dryer[J].Road Machinery&Construction Mechanization,2017,34(1):81-86.(in Chinese)
[10]施重驹,张宪,钟江,等.基于多相流耦合的热风杀青过程与杀青机结构优化研究[J].机电工程,2015,32(8):1050-1055.SHI Z J,ZHANG X,ZHONG J,et al.Study on de-enzyme process and structure optimization of tea hot-air cylinder dryer based on multiphase flow theories[J].Journal of Mechanical&Electrical Engineering,2015,32(8):1050-1055.(in Chinese)
[11]CHEN S J,YANG J H.Simulation and experiments on the drying outcome of drying drums[J].International Journal of Precision Engineering and Manufacturing,2016,17(1):109-117.
[12]LISBOA M H,VITORINO D S,DELAIBA W B,et al.A study of particle motion in rotary dryer[J].Brazilian Journal of Chemical Engineering,2007,24(3):365-374.
[13]TAIWO A F,ABOWEI M F N,PUYATE Y T,et al.Effects of drying parameters on the drying kinetics of fermented ground cassava using a rotary dryer[J].International Journal of Food Engineering,2011,6(6):61-64.
[14]王博,刘旭,刘清涛.Pro/E自顶向下方法在现代机械产品设计中的应用[J].重庆理工大学学报(自然科学),2015,29(7):40-43.WANG B,LIU X,LIU Q T.Application of top-down method in modern mechanical product design based on Pro/E[J].Journal of Chongqing University of Technology(Natural Science),2015,29(7):40-43.(in Chinese)
[15]李秀敏,张晓林.回转圆筒干燥器主要技术参数的确定[J].工业炉,2011,33(6):43-45.LI X M,ZHANG X L.Determination of main technical parameters of rotary cylinder dryer[J].Industrial Furnace,2011,33(6):43-45.(in Chinese)
[16]马学文,翁焕新,章金骏.颗粒状污泥的干燥特性及表观变化[J].环境科学,2011,32(8):2358-2364.MA X W,WENG H X,ZHANG J J.Drying characteristics and apparent change of sludge granules during drying[J].Environmental Science,2011,32(8):2358-2364.(in Chinese)
[17]ZHANG Y H,REESE J M.The drag force in two-fuid models of gas-solid flows[J].Chemical Engineering Science,2003,58(8):1641-1644.
[18]SHAHHOSSEINI S H,SADEGHI M T,GOLSEFATAN H R.Dynamic simulation of an industrial rotary dryer[J].Iranian Journal of Chemical Engineering,2010,7(2):68-77.