IMPACT OF VARIABLE PASSAGE SECTION AND ZIGZAG ABSORBER ON THE THERMAL PERFORMANCE OF A THERMO-SOLAR CONVERTER FOR DRYING

This paper presents a numerical study of a two-dimensional lami-nar airflow transferred in a thermo-solar collector with forced convection. Sim-ulations were processed to determine and analyze the dynamic and thermal fields under the influence of variation of collector configuration. Two cases of collector geometry (model of narrowing at exit and model of widening at entry) were studied and compared to the simple case uniform solar collector based on variations in temperature and velocity at the collector outlet for an input velocity varying between 0.04 and 0.11 m/s. The results show that the collector equipped with a zigzag-shaped absorber with a narrowing of the sec-tion at the outlet or widening at the inlet contribute to the thermal and dynamic improvement of the flow in the air stream compared with a simple case. The best performing case is recorded for the narrowest case of the exit shrinkage model where the exit velocity has been increased by 250%. this velocity re-duces the drying time and increases the efficiency of the evacuation of the humid air leaving the chamber.