Reliability study on skewness of doublet impinging injectors

Abstract

The atomization characteristics of skewed like-on-like impinging injectors were studied using water as a simulant. The shadowgraph technique and Laser deflection analyzer were used to understand the variances in spray mode, breakup length, and spray angles with the fraction of skewness under different angles of impingement, pressure, and Weber number. The range of reliability of performance from the perspective of the manufacturer was determined through quantitative and qualitative analyses of atomization and spray characteristics. The three different modes of spray breakup were well mixed, reflective, and transmissive. The breakup length decreased with the increase in spray angle up to a certain fraction of skewness. The spray fan angle and SMD in skewed impinging injection were directly proportional to the fraction of skewness. A large fraction of skewness provided the spray sheet with a small droplet size at the center of the spray sheet and large droplet sizes with rising radial distances toward the edge of the sheet. This paper attempts to define the maximum allowable misalignment and basic reliability limit for the design and evaluation of performance of impinging injectors in terms of fraction of skewness. Values at the perfect impingement condition were used as references for the significant reduction in the manufacturing cost of impinging injectors.