Determination of Heat and Mass Transfer Parameters During Hot Air Drying of Carrot
Carrot of three different sizes (5×5×5 mm3, 10×10×10 mm3 and 15×15×15 mm3) were dried in a temperature controllable hot air dryer at 50°C. The heat and mass transfer parameters including surface mass transfer coefficient (hm), heat transfer coefficient (hc), effective moisture diffusivity (Dm) and mass transfer Biot number (Bi) were obtained from the experimental study along with drying kinetics and thin-layer modelling. The average drying rate was observed between 0.4030 and 0.4257 kg/kg-hr. on dry basis (db). Dm was in the range of 2.9743×10-10 to 1.1255×10-09 m2/s and increased with increase in sample size. However, hm and hc were in the range of 2.3636-2.8415×10-06 m/s and 1.9515-5.6971 W/m2K respectively and decreased with increase in sample size. Four thin-layer models were applied and compared with the experimental data. Logarithmic model was found to predict the variation of moisture profile most accurately during carrot drying with R2 values of greater than 0.9968.