摘要:

In this paper a survey is given concerning to the stochastic modelling approaches in transport processes with a special emphasis on application possibilities for simultaneous heat and mass transfer in drying.

ISSN:0737-3937    

DOI:10.1080/07373930008917725

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

A thermomechanical model of drying of capillary-porous materials whose material constants depend on moisture content and temperature is presented in the paper. The finite element method is used for the solution of two-dimensional problem of convective drying of a prismatic bar. The moisture distributions, temperature distributions, drying induced strains and stresses for various drying medium parameters are determined. The effect of these parameters on moisture distribution and in particular on drying induced stresses is discussed.

ISSN:0737-3937    

DOI:10.1080/07373930008917726

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The paper presents a computer simulated processes and illustrate how the drying induced stresses are influenced by the rate of drying. It is shown that the moisture transport coefficient, and thus the rate of drying, depends on the thermal state of the drying material, defined by the wet-bulb temperature. Through these simulated processes one can observe the evolution of the moisture content and stress distributions during drying at constant, but in each process different, wet-bulb temperatures. A convective drying process of a bar with rectangular cross-section is considered as example, and a two-dimensional initial-boundary value problem is solved numerically with the use of the finite element method. The numerical results are visualised in spatial diagrams.

ISSN:0737-3937    

DOI:10.1080/07373930008917727

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

This work presents a general model to describe momentum, heat and mass transfer for moving boundary problems. The equations are obtained supposing an instantaneous superposition of a moving volume with velocity Vs(Lagrangean reference frame) over a stationary volume in the stream velocity v (Eulerian reference frame)The set of equations for multicomponent single-phase systems is applied to porous media (multi-phase systems) using the volume-averaging method. Depending on the assumptions about the behaviour of the system, it is possible to obtain the different models proposed in the literature, showing the generality of the model proposed in this work. Numerical results were compared to experimental data of Kaolin drying during the shrinking stage. These results showed a good agreement.

ISSN:0737-3937    

DOI:10.1080/07373930008917728

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The main objective in this work is to study and deduce a governing equation for net mass transfer in moist air and turbulent flow. Development of simple and reliable steady state models for turbulent moist air-drying has been considered to be quite well covered in literature. However, the lack of necessary background information concerning classical drying models is now being rectified through research carried out with new approaches, which are initiated by advancement in laboratory equipment.

ISSN:0737-3937    

DOI:10.1080/07373930008917729

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The paper presents a study aimed at extending the neural network mapping ability. In traditional modelling, operational process parameters (gas/material temperature, air velocity, etc.) are the inputs and outputs to and from the network. In this approach dimensionless numbers (Re, Ar, H/d) were used as inputs to predict the heat transfer coefficient in a fluidised bed drying process. To produce the data set necessary to train the networks, drying trials of different materials in a fluidised bed were carried out.

ISSN:0737-3937    

DOI:10.1080/07373930008917730

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Experiments have been performed on a pilot scale, cylinder-on-cone spray dryer fitted with a vaned-wheel atomiser to observe air flow patterns, with and without water spray. A combination of tufts, smoke streams and a laser light sheet, was used to provide information about regions of recirculation, flow stability, spray trajectories and wall deposition. While atomiser-induced swirl dominated the flow patterns under typical operating conditions, some instability was observed, although different in type, for situations with and without atomiser rotation. Clockwise eddies were observed to form and collapse between the wall and the strongly anti-clockwise swirling core created by anti-clockwise atomiser rotation. Without swirl, large portions of the recirculation zones at the walls were observed to have a weak tendency to change randomly between clockwise, anticlockwise and chaotic behaviour.

ISSN:0737-3937    

DOI:10.1080/07373930008917731

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Experimental data on vacuum drying of chemical and microbial synthesis products under laboratory and industrial conditions are presented. Kinetic relations of vacuum drying of dispersed materials with the removal of a multicomponent liquid system are verified on both laboratory and industrial scale dryers under different operating conditions. The results of the research were generalised and a number of empirical relations needed for drying process calculation are given. The relation between heat transfer coefficient and heat flux and motive force for the vacuum drying process is established.

ISSN:0737-3937    

DOI:10.1080/07373930008917732

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The aim of this work was to investigate rheological properties of apple cubes undergoing convective drying. Compression-relaxation test was used to follow changes of properties under investigation.

ISSN:0737-3937    

DOI:10.1080/07373930008917733

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The desorption characteristics of raw meat and salted meat were studied in the relative humidity range of 15 to 94·5 per cent at the storage temperatures of 5°, 13° and 26°C and at 0, 0·08, 0·20 and 0·30 kg NaCI/kg (d.m. of meat) salt (NaCI) content. Results indicate that for awbetween 0·75 and 0·945 the equilibrium water content for raw and various salted meats increased with the increase of NaCI content and decreased with the increase of temperature.

ISSN:0737-3937    

DOI:10.1080/07373930008917734

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor