Study on duplex air-blast atomizers spray in the engine real operation conditions

Abstract

Air-blast atomizers are widely used in passenger aircraft engines. In these atomizers, high-speed airflow is used for improved fuel atomization, and as a result, better combustion. The key purpose of this research is to investigate the duplex air-blast atomizers according to the engine data in the real operational conditions with the help of experimental method and numerical solution. When analyzing the variations in fuel sprays under different application conditions, it is important to consider not just one but multiple parameters such as fuel mass rate, air mass rate, and combustion chamber pressure. However, analyzing the individual effects of these parameters can be challenging as they change simultaneously. To address this, a dimensionless number namely K was defined, which takes into account the combined effect of fuel mass rate, air mass rate, and combustion chamber pressure. The results showed that when K decreased by 31.25%, the spray angle of nozzle 1 and nozzle 2 increased by 10.09% and 48.15%, respectively, while the average droplet diameter caused by primary breakup for nozzle 1 and nozzle 2 decreased by 76.29% and 71.57%, respectively. The secondary breakup was somewhat similar, and for nozzle 1 and nozzle 2, the average droplet diameter decreased by 76.5% and 71.88%, respectively. It is worth noting that the average error for spray cone angle in the simulation compared to the experimental results was 6.47%. The results of this research, in addition to causing a better understanding of the atomization processes in air-blast atomizers, can be useful for aerospace engineers.