Measurements for a transient diesel fuel spray injected from a single hole injector have been carried out.
The measurements were conducted in a quiescent test chamber under conditions of atmospheric pressure and temperature. A Phase Doppler Particle Analyzer (PDPA) was used for simultaneous measurements for the sizes and velocities of the spray droplets. A Laser Doppler Anemometer (LDA) was used simultaneously with the PDPA system to cross check the velocity measurements. A common transmitter was used for the two systems. Also, Measurements for air entrainment velocity were carried out using the LDA with a conditional sampling technique. In addition to that, spray penetration has been studied using the LDA measurements and spray photographs. It has been found that, spray penetration is well presented by the correlation proposed by Hiroyasu et al. Both droplet sizes and velocities are varied in a symmetrical pattern with respect to the spray axis with peak values on the spray axis. Droplet velocity decays along the spray axis in a moderate way due to the effect of droplet radial diffusion. Air entrainment to the spray increases as the spray is developed. Near the tip of the spray air effuses outside
the spray. It was noticed that the accuracy of velocity measurements of the PDPA is affected by hostile
conditions in the dense spray, specially near the injector tip and on the spray axis. This shortcoming needs a refinement for the technique.