Binary Collisions and Coalescence of Droplets in Low-pressure Fuel Injector

Fatma B.M. Ahmed, Nobuyuki Kawahara, Eiji Tomita

Research output: Contribution to journalArticlepeer-review

Abstract

The phenomena of binary collisions and coalescence of droplets was investigated from experimental studies but still are missing from real applications such as from fuel injector. The main purpose of the current study is to investigate the phenomena of binary collisions and coalescence of droplets from a practical port fuel injector. To accomplish this, direct microscopic images are taken from high speed video camera coupled with a long-distance microscope and Barlow lens using the backlighting method. Experimental optimization of the spatial resolu-tion and the depth -of -field of the long-distance microscope and Barlow lens are achieved. Experimental results from the direct microscopic images are compared with predictions from empirical equations for different collision regimes. Droplet sizes and velocities of experimental coalescence droplets from collisions are compared with the values predicted by the equations. The main results of this study are: The probability of collision and coalescence is very low in a port fuel injector. The tangential velocity components of small droplets play an essential role in shape deformation during collisions and coalescence of the droplets. The previous published empirical equations to calculate dimensionless parameters, the Weber number, the droplet diameter ratio, and impact parameter are appli-cable to the coalescence of droplets in a port fuel injector.

Original languageEnglish
Pages (from-to)1963-1974
Number of pages12
JournalThermal Science
Volume25
DOIs
Publication statusPublished - 2021

Keywords

  • coalescence
  • collision
  • direct microscopic image
  • droplet collision regimes
  • high speed video camera
  • port fuel injector

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment

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