Simple analytical expressions for spray penetration were derived in two limiting cases, i.e., the initial stage and the two phase flow regime. The effects of droplet drag and entrainment of air were considered at the initial stage. Three ranges of Reynolds numbers were accounted for, i.e., Re ≤ 0.2 (Stokes flow), 0.2 < Re ≤ 500 (Allen flow), and 500 < Re ≤ 105 (Newton flow). The characteristic time of droplet breakup in the spray was estimated for bag and stripping breakup mechanisms. For realistic Diesel spray parameters, the droplet breakup occurred almost immediately after the droplets leave the nozzle, shortening the initial stage and the rapid conversion of the flow to the two phase stage. The analysis of experimental data based on Phase Doppler Anemometry for a hollow cone gasoline spray injected into the ambient conditions exhibited three different regimes in the spray formation close to the nozzle. The first regime corresponded to the initial stage. The second stage was observed when there were no droplets in the middle zone in the upper part of the spray, while the third stage was observed when the injection process was finished. In the regions far from nozzle, cone edges were broken into smaller droplets that spread towards the middle. The inertia of droplets fonning vortices was large enough to enable them to penetrate through the cone edge. Original is an abstract.
|Number of pages||1|
|Journal||International Symposium on Combustion Abstracts of Accepted Papers|
|Publication status||Published - 1 Jan 2000|
|Event||28th International Symposium on Combustion - Edinburgh, United Kingdom|
Duration: 30 Jul 2000 → 4 Aug 2000