刮膜式分子蒸馏器传热特性及壁面优化  

Characteristics of heat transfer and wall optimization in the wiped film molecular distiller

作　　者：邓立文[1] 许松林[1] 

机构地区：[1]天津大学化工学院,天津300350

出　　处：《化工进展》2016年第9期2685-2692,共8页Chemical Industry and Engineering Progress

基　　金：国家自然科学基金项目(21176170)

摘　　要：使用CFD软件建立了刮膜式分子蒸馏器的三维模型,以EHP-EHS混合物为研究对象,并通过编写用户自定义函数(UDF),研究刮膜式分子蒸馏过程传质存在时的传热特性,得到充分发展的温度场及流场,分析了蒸发壁面温度的分布及转子转速对其影响和局部Nu数的分布。结果表明:液膜表面的升温过程是周期地和波动地达到动态稳定温度的;转子转速越大,周期越小,温度波动次数越多,温度稳定性越好;局部Nu数在刮膜器刮擦的位置突增,刮膜器的刮擦作用是影响平均Nu数增大的主要因素。经过壁面优化,液体湍流程度增大,传热效果得到不同程度的增强,凸起矩形排列、三角形排列、螺旋形排列时平均Nu数分别是光滑蒸发面的1.32倍、1.23倍、1.04倍,为进一步优化刮膜式分子蒸馏器提供参考。In this paper,a two phase flow of di-（ethylhexyl）-phthalate and di-（ethylhexyl）-sebacate（EHP-EHS） mixture with a three dimensional model was simulated by CFD software with UDF,by which the heat transfer characteristics of wiped molecular distillation process was studied with full developed temperature and flow field. The results showed that the change of film surface temperature is periodic and waved. With faster rotor speed,the period is shorter,the number of fluctuations is bigger and the film surface temperature is more stable. The Nu number increases sharply where the wiper wipes and the wiped wiper effect is the main factor influencing the increase of average Nu number. With the optimization of the evaporating cylinder,the liquid turbulence increases. The average Nu number of rectangular arrangement,triangular arrangement and the spiral arrangement of fins on the evaporating cylinder are 1.32,1.23 and 1.04 times as large as the smooth one,respectively,which provide a reference for further optimization of wiped film molecular distiller.

关 键 词：刮膜式分子蒸馏 计算流体力学 传热 壁面优化 

分 类 号：TQ021.3[化学工程] TQ051.8