脉冲喷动微波真空干燥器内喷动流化动力特性的数值研究  

Numerical study on spout fluidization dynamics in pulsed- spout microwave- vacuum dryer

作　　者：李静[1] 金光远[1,2] 张慜[1,2] 崔政伟[1] 仲建勋 

机构地区：[1]江南大学食品先进制造装备技术江苏省重点实验室,江苏无锡214122 [2]江南大学食品科学与技术国家重点实验室,江苏无锡214122

出　　处：《食品工业科技》2015年第11期79-83,共5页Science and Technology of Food Industry

基　　金：江苏省博士后基金项目;江苏省青年基金项目(BK20130150)

摘　　要：为探索脉冲喷动微波真空干燥系统(PSMVD)中气固喷动流化床的动力特性,采用基于无粘性两相流理论,使用计算流体力学欧拉-欧拉方法(CFD)对二维喷动流化床中喷动流化特性进行了数值研究,对喷动流化床的动力特性和颗粒运动分布特征进行了揭示,这些因素影响颗粒空间位置分布和其微波加热的均匀性。结果表明,采用欧拉-欧拉双流体模型,成功获得脉冲喷动微波真空干燥腔内的二维喷动流化床的喷动流化动力特性;喷动流化过程在特定气流喷动速度下有一个初始阶段和准稳态流化阶段;喷动速度是控制颗粒在喷动床中颗粒位置的重要因素,存在一个影响流化模式转变的关键喷动速度;射流穿透深度和喷射速度之间存在线性关系。The dynamic characteristics of gas-particle spout fluidized bed in a microwave-vacuum drying system (PSMVD)were investigated.The spout fluidization process in a Pseudo-2-D spouting bed was monitored by computational fluid dynamics( CFD) using the inviscid Two-fluid theory based on Euler-Euler method.The dynamic characteristics of the spout fluidized bed and the effect of spout elevation on the particle movement were revealed, which could be used to improve the uniformity of particle mixing and microwave heating.The results revealed that mathematical model succeeded to demonstrate the dynamic characteristics of gas-particle spout fluidized bed in a microwave-vacuum drying system;the spout fluidization process includes isolated,merged and transitional jets and the fiuidization at specific spout gas velocity had a start-up stage and a quasi-steady fluidization stage.The spout velocity was an important factor controlling particle status in the spout fluidized bed and a critical velocity was identified for effect transition of the flow pattern.There was an approximately linear correlation between the jet penetration depth and the spout velocity.

关 键 词：真空微波干燥器 喷动流化床 气固两相流 数值模拟 

分 类 号：TS255-35[轻工技术与工程—农产品加工及贮藏工程]