Influence of ceramic supports on microwave heating for composite dielectric food slabs

Abstract

A detailed theoretical analysis has been carried out to study efficient heating of one‐dimensional (1‐D) composite dielectric food slabs due to microwaves. Current study involves processing of beef with oil layers with/without ceramic support for various cases, such as the support and/or oil layer is directly exposed to microwaves (case 1), the beef layer is directly exposed to microwaves (case 2) and oil‐beef layers and the ceramic supports are exposed to microwaves at both the sides (case 3). A preliminary analysis on microwave heating has been carried out for beef‐oil composite without any support and the maxima in average power corresponding to resonances occur at various sample thicknesses for all cases. The detailed spatial distribution for various cases illustrates that for small oil thicknesses, heating rate is less and greater heating rate would correspond to larger oil thicknesses specially for case 1. The similar analysis has been extended for all cases with oil layer directly attached with ceramic supports (Al2O3 and SiC). The detailed analysis on spatial distribution of temperature and power during one side incidence illustrate that the greater thermal runaway occurs for case 2 with Al2O3 support corresponding to smaller oil thickness whereas SiC support may cause thermal runaway for larger oil thicknesses. For distributed microwave incidences (case 3), it is observed that Al2O3 support may cause thermal runaway whereas SiC support may reduce the thermal runaway, based on suitable distribution of microwaves at both sides. © 2006 American Institute of Chemical Engineers AIChE J, 2006

Role of metallic and composite (ceramic–metallic) supports on microwave heating of porous dielectrics

“…Similar assumptions are also found in earlier literature [5][6][7][8][9][10][11]. The wave propagation due to uniform electric field, E x , obtained from Maxwell's equation is…”

“…A generalized heating strategy for materials due to uniform plane waves was derived. A theoretical analysis of microwave heating of food slabs supported by ceramic plates was also carried out by Basak and Meenakshi [11,12]. Their study involves processing of beef with oil layers with or without support for various cases.…”

Microwave material processing—a review

“…111 Further investigations for other materials such as oil and beef samples reported that the supporting plate (ceramic and/ or metallic) may drastically alter the heating effects with a range of dielectric properties. 69,[112][113][114][115] It was observed that beef samples would exhibit greater thermal runaway especially with SiC plate in the presence of both sides distributed microwave incidence, whereas the oil samples would exhibit smaller thermal runaway effects with both sides equidistributed microwave incidence irrespective of any ceramic plates. 69,112 It was observed the average power absorption was enhanced for samples (beef-air and beef-oil) in presence of Al 2 O 3 support whereas the average power was smaller with SiC support for porous dielectric materials such as beef-air (b/a) and beef-oil (b/o).…”

Role of ceramic composites and microwave pulsing on efficient microwave processing of pork meat samples

“…Current study involves samples with/without supporting plate. Lateral dimensions (along x and y axes) are assumed to be very large compared to the total thickness of the sample (along z axis including ceramic layer) and similar modeling assumptions are also found in earlier literatures (Ayappa, Davis, Crapiste, et al, 1991;Ayappa et al, 1992;Basak & Meenakshi, 2006a, 2006bBasak & Priya, 2005). Based on the assumptions, one dimensional slab has been considered.…”

“…Modeling on microwave heating of food samples is primarily governed by electromagnetic wave propagation which is based on two formulations: (1) Lambert's exponential law (Ayappa, Davis, Crapiste, et al, 1991;Barringer et al, 1995;Basak, 2004;Curet, Rouaud, & Boillereaux, 2008;Liu, Wang, & Sakai, 2005;Mao, Watanabe, & Sakai, 2005;Yang & Gunasekaran, 2004) and (2) Maxwell's equations (Ayappa, Davis, Crapiste, et al, 1991;Ayappa et al, 1992;Basak, 2004;Basak & Kumaran, 2005;Basak & Meenakshi, 2006a, 2006bBasak & Priya, 2005;Campanone & Zaritzky, 2005;Curet et al, 2008;Liu et al, 2005;Regier et al, 2001;Yang & Gunasekaran, 2004). Lambert's law is a simple power formulation which states that microwave power decays exponentially as a function of distance of penetration into the sample.…”