food product characteristics like shape, size, loading density, etc. contribute to the overall moisture transfer (moisture diffusion within food product and convective moisture removal over food product–air interface). In order to study the influence of these variables on drying kinetics, each variable with a wide range of values has been considered for experimentation. The drying kinetic curve for individual value of given variable can be obtained by keeping other variables constant at their base values. The base values of these variables chosen for experiments are absorbed thermal energy: 750 W/m2; air mass flow rate: 0.011 kg/s; food product thickness: 8 mm and loading den- sity: 2.16 kg/m2. The plot between experimental dimension- less moisture content and drying time generates drying characteristic curve for a given food product-dryer system combination under specified operating condition. The experimental dimensionless moisture content and drying time data for each test condition has been non-linearly regressed in the form of equation, commonly used in thin layer drying by means of least squares curve fitting method. The equation in terms of moisture content ratio and drying time can be expressed as (Dincer and Dost, 1996):
1.2 1.0 0.8 0.6 0.4 0.2
0.00 5000
10000 Drying time (s)
0.009 kg/s 0.011 kg/s 0.017 kg/s 0.022 kg/s
15000 20000
/1⁄4Mt 1⁄4koexpð