Raisul Islam - Academia.edu (original) (raw)
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School of Oriental and African Studies, University of London
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Although a detailed mathematical model incorporating all physical mechanisms of moisture and heat... more Although a detailed mathematical model incorporating all physical mechanisms of moisture and heat transfer in the material would yield valuable design information, it is not feasible to do this on a routine basis for the design of dryers. A simple liquid diffusion model was developed in this report to quantitatively assess the influence of various operating parameters of engineering interest in drying of heat-sensitive materials. Heat of wetting, temperature and moisture dependent effective diffusivity and thermal conductivity, changes in product density and drying -induced ideal shrinkage of the product are considered in this model. The effects of combining convection with conduction, radiation and volumetric heating using a microwave field are simulated in view of the increasing interest in multimode heat input drying processes. Numerical results are reported on drying of potato slices to demonstrate how the moisture and temperature profiles as well as drying performance are affected by multi-mode heat input. Effects of stepwise change of drying air temperature, air relative humidity, flipping of product and performance of sun drying are computed and discussed. This model can be extended to two and three dimensional geometries including effects of drying on quality parameters.
Although a detailed mathematical model incorporating all physical mechanisms of moisture and heat... more Although a detailed mathematical model incorporating all physical mechanisms of moisture and heat transfer in the material would yield valuable design information, it is not feasible to do this on a routine basis for the design of dryers. A simple liquid diffusion model was developed in this report to quantitatively assess the influence of various operating parameters of engineering interest in drying of heat-sensitive materials. Heat of wetting, temperature and moisture dependent effective diffusivity and thermal conductivity, changes in product density and drying -induced ideal shrinkage of the product are considered in this model. The effects of combining convection with conduction, radiation and volumetric heating using a microwave field are simulated in view of the increasing interest in multimode heat input drying processes. Numerical results are reported on drying of potato slices to demonstrate how the moisture and temperature profiles as well as drying performance are affected by multi-mode heat input. Effects of stepwise change of drying air temperature, air relative humidity, flipping of product and performance of sun drying are computed and discussed. This model can be extended to two and three dimensional geometries including effects of drying on quality parameters.