الفهرس 
LITERATURE SURVEYOnly 14 pages are availabe for public view
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Abstract
The main objective of the present thesis is to give the results of theoretical and experimental investigations of a desiccant packed bed. The theoretical work deals with solving the partial differential equations which governing the performance of desiccant packed bed in which solid silica gel is used as a desiccant material.
For this purpose, the finite difference scheme is proposed and investigated theoretically as well as numerically by solving the equation describing the mass diffusion in the particle of silica gel. This results in a tridiagonal system, which is solved by using Thomas Algorithm. Also, the equation of the mass transfer of water vapor and the energy balance equations in both the air stream and the solid desiccant are solved using the fourth order Runge – Kutta method.
The analysis is carried out for typical inlet conditions for the desiccant bed of 28oC dry bulb temperature and 66% humidity ratio.
Experiments are conducted with different desiccant masses (5, 10 and 15 kg) and air mass flow rates (7.4 and 10.2 kg/min) during dehumidification operation mode to evaluate the performance characteristics of desiccant packed bed. The reactivation of the desiccant bed at different regeneration temperatures and air flow rates as well as desiccant masses is also investigated.
The experimental results showed that the average relative humidity decreases by 3.5% and 54% and time of saturation increases when the desiccant mass increases from 5 to 10 kg. The saturation time increases by 51% and the average relative humidity decreases by 1.7% when the mass of desiccant increases from 10 to 15 at a given inlet air conditions and flow rate also, the bed exit relative humidity increases with the air flow rate and the saturation time of desiccant increases when the air flow rate decreases.
The average relative humidity at the bed exit increases by 2% and the saturation time decreases by 39% as air flow rate increases.
The theoretical results showed that the water content in desiccant bed increases with time. At the same layer thickness, by decreasing desiccant masses, the water content in desiccant for the layer thickness 2.5 cm at desiccant mass 10 kg is greater than that of water content in desiccant for the same layer thickness at desiccant mass 5 kg, while at desiccant mass 15 kg is greater than that of at desiccant mass 5 kg and the mass fraction in humid air for surface increases with time at layer thickness for all masses also it is increases with layer thickness increases at same time and desiccant mass.
These studies are reported in graphical forms. On the other hands, a complete computer program of the theoretical work is well established