Experimental and Numerical Study on Inlet Pressure and Reynolds Number in Tangential Input Pressure-Swirl Atomizer

Tangential input pressure-swirl atomizers are frequently employed in the aerospace and energy sectors. Previous studies have mainly focused on investigating the effects of geometrical parameters on spray characteristics, while a few studies have comprehensively analyzed fluid characteristics. Hence, this study focused on analyzing the spray characteristics in tangential input pressure-swirl atomizers by assessing the effects of fluid mass flow rate (inlet pressure) and the type of working fluid (Reynolds number) through both experimental and numerical methodologies. Initially, the atomizer was designed and constructed based on specific parameters, including a fluid mass flow rate of 80 g/s, kerosene as the fluid type, and the spray cone angle of 90 degrees, followed by testing at various inlet pressures. Experimental results indicated that as the inlet pressure increased, the spray pattern transitioned from an oval shape to a fully developed configuration. Additionally, it was observed that both the fluid mass flow rate and spray angle increased with rising inlet pressure, initially at steeper rates before leveling off. The study then employed numerical simulations, which revealed that airflow was drawn into the spray's center, exhibiting a twisting pattern in the velocity vectors and flow lines along the periphery. Furthermore, increasing the inlet pressure from 1.37 to 9.9 bar resulted in a significant reduction of 58.421% in average droplet diameter and 36.981% in fluid film thickness, while the fluid mass flow rate and spray angle experienced increases of 300% and 42.741%, respectively. The relationship between inlet pressure and discharge coefficient was found to be ambiguous, as an initial decrease of 33.066% was followed by an increase of 18.686%. Additionally, the results indicated that raising the Reynolds number from 33,832 to 198,524 led to increases of 44.26%, 13.33%, and 10.87% in spray angle, average droplet diameter, and discharge coefficient, respectively.