In this current contribution, a parametric investigation of air flow rate at the inlets of solar air collector was carried out. Through a developed Matlab code effort was made to show the effect of the air flow rate on solar collector outlet temperature. From the simulation results a database of outlet temperature and corresponding flow rate variation with time was created. Then, isotherm contours were deduced and plotted. For drying temperature kept constant at a given value regardless the meteorological conditions fluctuation, the flow rate variation with time was fitted by smoothing spline function. The simulation study was done for three different meteorological scenarios: Clear sky day, partly cloudy day and cloudy day. It has been found also that drying with variable flow rate at optimum temperature equal to 50 +/- 1 degrees C the amount of air that was aspired at the inlet was 1207.8 kg. By contrast, drying with constant flow rate a total 625.5kg of air was aspired and it might result in fluctuation in drying temperature which affects the dried product quality. Thus variable flow rate allows a gain ratio in the aspired air amount of 93% and better product quality. This is valid for clear sky day. In case of partly and cloudy day, flow rate gain ratio was 104% and 78% respectively.