物料干燥过程—传质传热最优化方法的研究

论述了多孔介质干燥过程中传质传热的数学模型及干燥过程最优化准则的建立；并且动用控制理论产物料干燥过程传热的动态优化方法－－准则约束法，且得到了最优解。     

干燥过程热质传递的简化模型

对多孔介质体积平均理论进行简化,得到简化的热质传递干燥模型,用一个理论式表达模型中有效扩散系数。对香蕉片千燥的研究表明,模型的预测值与实验结果相     

流化床喷雾造粒过程的传热传质

This article presents a mathematical model of heat and mass transfer for the process of fluidized-bed spray granulation, which can be applied in the analysis of bed temperature profile, temperature and humidity of outlet gas and moisture content of particles. Effects of operation parameters on the batch granulation are investigated. The theoretical calculation agrees reasonably well with the experimental data.Keywords fluidized-bed spray granulation, mathematical model, heat and mass transfer     

多孔毛细物料整体间断加热干燥过程中耦合的传热传质问题和应力分析

应用Luikov理论和有限元方法求取物料在间断加热干燥不同瞬间的温度、湿度及应力分布,并用自编程序试算的结果与文献中的实验值或理论解进行了比较,本文介绍的方法可望用于求取间断加热干燥过程的最佳操作参数.     

超常传递过程干燥基础研究的新领域（一）

系统综述了近年来在传热传质学、化学工程以及干燥基础研究领域所出现的以超常传递过程为特征的研究新动向。在此基础上。提出了干燥领域今后应大力开展的基础研究课题。     

冲击干燥的研究现状及应用

冲击干燥是借助喷嘴产生的高速气流冲击到湿物料表面而携走水分的过程。由于冲击流动产生大的湍流 ,因而具有较高的传热、传质系数 ,可以有效地缩短干燥时间。综述了冲击流技术的理论研究和应用研究进展 ,论述了冲击流技术的应用前景。     

聚丙烯流化床降温干燥数学模拟

分析了聚丙烯流化床干燥器(D502)的特点,根据其特点建立了降温干燥数学模型,确定了模型成立的条件,采用工业数据进行了计算分析,该模型具有实用价值。     

微波真空组合干燥技术的研究

微波真空干燥是综合微波干燥和真空干燥各自优点的一项新技术,将微波干燥的快速高效性和真空干燥的低温高质相结合,在真空条件下利用微波对物料进行干燥处理,从而实现物料的快速低温干燥。着重阐述了微波真空组合干燥技术的机理、特点、干燥动力学以及影响微波真空干燥的重要因素,并对微波真空组合干燥的应用研究进行了介绍。     

不粘煤的微波－对流干燥研究

从不粘煤的特性出发，讨论了不粘煤工业干燥的要求；从微波－对流综合干燥传热传质原理分析，论证了这种干燥方式用于不粘煤干燥，在降低温度、控制负荷、提高经济性等方面都有显著成效，并以翔实的试验数据为理论分析作了辅证。     

连续锦纶干燥塔的数学模型研究及数值仿真

针对某干燥塔的结构特点及运行过程中传热传质特性,建立了该干燥塔中干燥过程的传热传质微分模型,并用试验数据验证其合理性。运用经典龙格库塔法获得该模型的数值结果,分析了传热传质过程中干燥氮气温湿度和锦纶切片温湿度沿塔高的分布情况。通过仿真优化操作条件,提高了干燥塔的干燥能力。     

Deformation Behavior of Ceramic Slabs by Nonuniform Drying

ABSTRACT

The presenr paper is to study the transient deformation characteristics of molded ceramics undergoing nonunifom drying. The linear viscoelasticity was assumed for the strain-stress analysis. Three dimensional equations of the strain-stress as well as heat and moisture transfer werc solved numerically by the Galerkln finlle element melhod using isoparametric parameters of twenty-nodes so to allow easily the application to any feature of ceramics. Both the analysis and experiments were carried out to be compared on the behavior of drying and deformation for a slab clay in preheating and constant drying rare periods. When the bottom surface of the slab uras shielded to model the nonuniform drying. a warp phenomrnon to the opposite side of the shielded surface was observed experimentally as drying by hot air heating proceeds. The behavior could be successively simulaled by the present theoretical model. The degree of warp became rcmarkabel with a rise in air temperature or nonuniformity of drying. The surface area exposed to the atmosphere was subjected to a comparatively large tensional stress through drying. The tensile sltresses on the top surface were significantly larger than on the bottom surface.     

A Mathematical Model for Vacuum Far-Infrared Drying of Potato Slices

A mathematical model of mass and heat transfer for vacuum far-infrared drying of potato slices is introduced in this study on the basis of energy and diffusion equations. The finite difference method is used to mathematically simulate the sample temperature and moisture content in different drying conditions. Calculated results are compared with the experimental findings at varying conditions of heater temperature (120°C, 140°C, and 160°C), chamber pressure (1500, 8000, and 15000 Pa), sample thickness (0.004, 0.006, and 0.008 m), and radiation distance (0.08, 0.12, and 0.16 m). Comparison results show that the model fits well the changes in sample temperature and moisture content at different times of drying, with the values of the coefficient of determination close to 1.0 and the relative error values less than 10%.     

Mathematical model for intermittent microwave convective drying of food materials

Intermittent microwave convective drying (IMCD) is an advanced technology that improves both energy efficiency and food quality in drying. Modeling of IMCD is essential to understand the physics of this advanced drying process and to optimize the microwave power level and intermittency during drying. However, there is still a lack of modeling studies dedicated to IMCD. In this study, a mathematical model for IMCD was developed and validated with experimental data. The model showed that the interior temperature of the material was higher than the surface in IMCD, and that the temperatures fluctuated and redistributed due to the intermittency of the microwave power. This redistribution of temperature could significantly contribute to the improvement of product quality during IMCD. Limitations when using Lambert’s law for microwave heat generation were identified and discussed.     

不粘煤的微波－对流干燥研究

从不粘煤的特性出发，讨论了不粘煤工业干燥的要求；从微波－对流综合干燥传热传质原理分析，论证了这种干燥方式用于不粘煤干燥，在降低温度、控制负荷、提高经济性等方面都有显著成效，并以翔实的试验数据为理论分析作了辅证。     

高初始含湿多孔介质喷雾干燥过程的热质耦合传递

多孔介质是大量干燥过程的主体,由于实际多孔介质干燥过程的复杂性,建立通用的干燥过程传热传质模型十分困难。通过分析喷雾干燥过程中高初始含湿多孔介质与干燥介质之间的传热传质机理以及各因素对传热传质的影响,根据马歇尔方程探讨了干燥介质与料雾之间的水蒸汽分压差在干燥过程中的变化情况,反映了多孔湿介质在喷雾干燥操作中的传热传质过程的几种特性,为确定实际生产中喷雾干燥器的操作条件指明了新的出路。     

Fundamental Research on Drying Process in Institute of Engineering Thermophysics, CAS

Some results of our fundamental research on drying processes are summed up in this article. It consists of three parts: (1) Multistage fluidized bed drying, including particle flowing characteristics, heat and mass transfer between particles and drying medium, drying characteristics of drying materials; (2) Impinging stream drying, the flowing and drying characteristics of a vertical impinging stream dryer, one-stage and multistage semi-circular impinging stream dryer and combined vertical and semi-circular impinging stream dryer are discussed; (3) The effects of rapid transient heat and mass transfer on drying processes, such as time and space scales for nonFourier or nonFickian and influence of extreme heat and mass transfer are also discussed.     

Fundamental Research on Drying Process in Institute of Engineering Thermophysics,CAS

Abstract

Some results of our fundamental research on drying processes are summed up in this article. It consists of three parts: (1) Multistage fluidized bed drying, including particle flowing characteristics, heat and mass transfer between particles and drying medium, drying characteristics of drying materials; (2) Impinging stream drying, the flowing and drying characteristics of a vertical impinging stream dryer, one-stage and multistage semi-circular impinging stream dryer and combined vertical and semi-circular impinging stream dryer are discussed; (3) The effects of rapid transient heat and mass transfer on drying processes, such as time and space scales for nonFourier or nonFickian and influence of extreme heat and mass transfer are also discussed.