Internal heating effect and enhancement of drying of ceramics by microwave heating with dynamic control

Itaya, Yoshinori; Uchiyama, Shigeru; Mori, Shigekatsu

doi:10.1007/978-1-4020-5480-8_4

Cited by 6 publications

(3 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This problem has been investigated by several authors; e.g., elastic stresses were analyzed in Ketelaars, [6,13] Felcyn et al, [14] and Musielak; [15,16] viscoelastic behavior was studied in Itaya et al, [17,18] Banaszak and Kowalski, [19,20] and Kowalski and Rajwska; [21] and damage of clay because of drying was reported in Banaszak and Kowalski, [20] Kowalski et al, [22] Musielak, [23] Augier et al, [24] and Itaya et al [25] Detailed descriptions of drying-induced strains and stresses could be found in Kowalski. [26] Problem of stress generation during drying was also modeled by Scherer.…”

Section: Introductionmentioning

confidence: 99%

Permanent Strains in Clay-Like Material During Drying

Musielak

Mierzwa

2009

Drying Technology

View full text Add to dashboard Cite

One of the characteristic features of clay-like materials is the change of their mechanical properties during drying as the moisture content is changed. At high moisture contents they are viscoelastic and then become elastic-plastic and finally brittle-elastic or even stiff. Elastic strains are reversible but viscous and plastic strains are not reversible. The permanent strains are usually undesirable in dried products because they cause warping. In brittle materials, on the other hand, microcracks and cracks are generated. The number of cracks depends on the material properties, sample shape, and drying conditions. The aim of this work is to examine experimentally the permanent strains during drying.The samples used in experiments were made of different materials (two types of clay and kaolin) and were dried convectively. Constant but nonsymmetric drying conditions were applied. The strains of the samples were measured online using a video camera.

show abstract

Section: Introductionmentioning

confidence: 99%

Permanent Strains in Clay-Like Material During Drying

Musielak

Mierzwa

2009

Drying Technology

View full text Add to dashboard Cite

show abstract

“…Several articles on convective and microwave drying [2][3][4][5][6][7][8][9][10][11][12] concern mainly experimental survey on the microwave (MW-related, MW-assisted, or MW-enhanced) combination drying. Some articles present the numerical simulations of the drying induced stresses based on a different drying model than that used in this article.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Effectiveness and Stress Development during Convective and Microwave Drying

Kowalski

Mielniczuk

2007

Drying Technology

View full text Add to dashboard Cite

The aim of the article is to study the effectiveness of convective and microwave drying with respect to drying time and stress generation in clay-like dried bodies. The theoretical analysis of stresses was confined to the constant drying rate period because clay shrinks and the stresses are generated mainly in this period. The theoretical prediction of stress development was validated using an acoustic emission method by monitoring the micro-and macrocracks formation caused by the stresses. Apart from the stress analysis, the combined convective-microwave drying was examined experimentally during whole process in order to show that the volumetric heat supply due to microwave heating enhances convective drying and, apart from this, such a combined drying process develops less stress in dried material. The theoretical and experimental studies were performed on a kaolin sample in the form of a thin plate. INTRODUCTIONThe negative feature of drying processes of capillaryporous materials is the problem of drying-induced stresses responsible for the material destruction. The tendency to stress generation increases with the rate of drying and the size of the drying body. Therefore, the efforts are made to find methods of stress minimizing and thus avoiding the drying body destruction when the drying rate increases.The main aim of this article is to prove the hypothesis that a combined convective-microwave drying shortens the drying time and also diminishes the tendency to stress generation. The hypothesis is based on the statement that the volumetric heat supply, as it takes place in microwave heating, increases the temperature inside the body and thus causes a coincidence of the thermodiffusional and the diffusional moisture fluxes. Such a flux coincidence raises the moisture outflow and moderates its distribution

show abstract

“…The paper by Zhang et al 1 presents a review of microwave-related drying methods for fruit and vegetables. Combined drying methods like convective-microwave, [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] convective-microwave-infrared, 19 microwave-vacuum, 20,21 microwave-infrared, 22,23 solar, 24 and other methods [25][26][27][28][29] have been proposed to improve the effectiveness of drying, i.e., to minimize the drying time and the consumption of energy as well as to improve the quality of the dried products. The variety of these drying methods is wide, but, however, they do not embrace the drying kinetics for the process as a whole, which is treated in this article.…”

Section: Introductionmentioning

confidence: 99%

Heat and mass transfer during microwave‐convective drying

2009

View full text Add to dashboard Cite

The article presents a mathematical model of drying that describes the kinetics of combined microwave-convective drying for the process as a whole. Based on this model, the drying curves and the temperature evolutions of the drying body were constructed by a number of computer-simulated drying programs, which were chosen to follow the respective experimental processes carried out on a cylindrical sample made of kaolin. The experimental data allowed both the estimate of material coefficients arising in the model and the validation of the theory. A very satisfactory correlation of the theoretical predictions with the experimental data is found. The main novelty of this article is the mathematically complete drying model that describes all periods of the microwave-convective drying process. Application of such a complete model is necessary if we want to optimize drying processes with respect to drying time and consumption of energy via computer simulations.

show abstract

Internal heating effect and enhancement of drying of ceramics by microwave heating with dynamic control

Cited by 6 publications

References 13 publications

Permanent Strains in Clay-Like Material During Drying

Permanent Strains in Clay-Like Material During Drying

Analysis of Effectiveness and Stress Development during Convective and Microwave Drying

Heat and mass transfer during microwave‐convective drying

Contact Info

Product

Resources

About