Drying injera must be done in a chamber with uniform and optimum drying temperature and airflow speed to obtain quality product under optimum drying time. In this study, the drying process of Injera has studied by considering the mass loss, moisture content removal, and drying rate at a controlled drying parameters (drying temperature and airflow speed) to determine the minimum possible drying time, and apply the optimum drying parameters as a boundary condition on CFD. The effects of the variations of the drying parameters on the drying time were determined with 94.53%, R2 and 1×10-9, X2 values. With RSM, the optimum drying temperature, airflow speed, and drying time were determined to be 84.444 0C, 0.7879 m/s, and 146.402 minute respectively with a confidence level of 99%. The target of this study was to improve the efficiency of a multi-tray Injera dryer by optimizing the drying chamber design and configurations and applying the optimum drying parameters as a boundary condition on CFD. The focus was made on supply zone gap, configuration of baffles and number of supply fans to obtain improved airflow speed and temperature distribution uniformity. A multi tray injera dryer with 32 number of trays and 42 Kg drying capacity has designed. Then, a 3D fluid model modeled with SOLIDWORKS and imported to ANSYS. Parametrization and optimization of position of supply fans has conducted to improve the airflow speed and temperature distribution through RSM on ANSYS. The effect of variation of supply zone gap and baffle angle on airflow speed and temperature distribution uniformity indexes were determined with ANOVA & RSM after applying CFD on each geometrical configurations made by DOE. CFD simulation with optimum drying parameters to improve the airflow speed and temperature distribution shows a significant effect due to the changes in supply zone gap, arrangement of baffles, baffle angle, no of fans & their configuration. Specifically, the no of supply fans and their position showed more significance with 99.9% 𝑅2. Compared to a dryer model with exhaust fan at the top, a dryer with a revolved outlet showed an improved efficiency in terms of airflow speed uniformity on each trays with average airflow speed of 0.8 m/s, standard deviation of 0.07 and p-value of 0.000 at 99.84% confidence level. Keywords: Derkosh, Oven drying, Drying parameters optimization, Supply zone gap, Baffle angle, Multi tray dryer.