Hot air flow simulations of the wet station dryer module for the solar cell cleaning were conducted. Air incident angles such as to the substrates ($45^{circ}$), to the bottom ($90^{circ}$), and to the wall ($135^{circ}$) were considered. Based on the simulated velocity and temperature profiles, appropriate incident angle was proposed, and it was well matched to experimental results. Additionally, uniform and non-uniform air hole sizes of the tube were compared for the uniform air flow distribution through the batch.