Pressure swirl atomizer: Study on the effects of internal mixing air, its mass flow rate, and temperature on spray key characteristics

Although using high-velocity airflow is common in some types of atomizers, including airblast atomizers, researchers have not considered this idea in pressure swirl atomizers. The present study aimed to address this gap by experimental and numerical methods. First, the atomizer was designed and manufactured based on mass flow rate of 0.08 kg/s, the pressure difference of 3 bar, and the kerosene liquid and tested. Then, by simulation the effects of lack of high-velocity airflow, adding high-velocity airflow, increasing its mass flow rate and temperature were investigated. The results showed that by adding high-velocity airflow and increasing its mass flow rate from 0.02 to 0.03 kg/s, the Sauter mean diameter (SMD) extremely decreased from 4.0360 × 10−4 to 0.1638 × 10−4, then to 0.1315 × 10−4, but for the 0.03 kg/s, the spray pattern was not desirable. Although adding high-velocity airflow increased the spray cone angle from 74.5° to 80.3°, from 0.02 to 0.03 kg/s, it was decreased by 14.5°. Adding high-velocity airflow extremely reduced the discharge coefficient (Cd) by 94.65% but for 0.03 kg/s, the distribution of the spray was asymmetric, due to asymmetric distribution of velocity at the atomizer outlet. The study of the effects of high-velocity airflow temperature in 300, 350, and 375 K showed that although it caused an increase in the spray angle from 80.3° to 85.0° and then to 90.4°, due to the insensitivity of the velocity and kinetic energy of turbulence to temperature SMD and Cd, both decreased only approximately 0.49%.