Droplet cluster evolution and collective gasification of droplet groups in a fuel spray: A comparative study under non and conditions

In this paper, the goal is to understand the influence of spray combustion on the evolution of droplet clus-ters and collective gasification processes of droplet groups in a fuel spray. Experiments were conducted in an acetone spray from a pressure swirl injector under both non-reacting and reacting conditions for the same fuel flow rate through the injector. The PIV technique was employed to capture Mie-scattering images of the spray and to measure droplet velocity, while droplet sizing was achieved by application of the ILIDS tech-nique. Voronoi analysis of the PIV images facilitated identification of droplet clusters. Accordingly, the cluster length scale and local droplet number density within clusters could be obtained. In addition, the Group evap-oration/combustion number ( G) for individual clusters was also evaluated. Either in the presence or absence of spray combustion, wide range of cluster size exists in the spray which highlights multi-scale clustering of droplets. Accordingly, G varies in a broad range that indicates multi-mode evaporation/combustion of the droplet clusters. Distinct behavior of droplet clusters is identified depending on the cluster size relative to the mean cluster area. While the evolution of small clusters is not sensitive to the presence of the spray flame, the length scale of the large-scale clusters and gasification process of such groups of droplets are modified due to spray combustion compared to the non-reacting condition.& COPY; 2022 The Combustion Institute. Published by Elsevier Inc. All rights reserved.

Automated summary

The aim of this study is to investigate the impact of spray combustion on the evolution of droplet clusters and the collective gasification processes of droplet groups. Experiments were conducted on an acetone spray using a pressure swirl injector under both non-reacting and reacting conditions. PIV technique was employed to capture Mie-scattering images of the spray and measure droplet velocity, while droplet sizing was achieved using the ILIDS technique. Voronoi analysis of the PIV images allowed for the identification and measurement of droplet clusters. The study found that both the size distribution of droplet clusters and the evaporation/combustion behavior of the clusters varied significantly in the presence of spray combustion compared to the non-reacting condition.