Asymmetric Transverse Acoustic Excitation of a Hollow Cone Spray Sheet With Air Swirl

The objective of this study was to experimentally observe the effects of externally perturbing a hollow cone spray sheet with acoustic excitation. These effects were quantified by measuring changes in the spray breakup length, swirl angle, and oscillatory behaviour of the sheet edge. We used a pressure swirl nozzle embedded into a swirler with 60° vane angles and a geometric swirl no. of SG = 0.981. Water was used to produce a hollow cone spray sheet and air was used as our swirler agent. For asymmetric forcing, only one side of the spray chamber was attached to a transverse duct (aligned perpendicular to the spray axis) along with two speakers. The duct harmonics were found to be 115 Hz, 204 Hz, and 313 Hz. Our experimental modes were also found to be comparable with results obtained numerically using the acoustic solver package from ANSYS. Our results show that for most cases the spray edges, cone angle, and breakup length responds to the acoustic forcing. While the cone angle increased with air swirl, for some cases without acoustic forcing the breakup length increased with air swirl.

Variation in Ignition Delay with Changing the Environment inside the Combustion Chamber for Different Sprays

Ignition delay is very important parameter which influences the entire combustion process and emissions generated inside the engine. An experimental study was conducted to observe the variation in ignition delay with changing environment inside the combustion chamber for different sprays. Two types of nozzles namely pintle nozzle and single hole nozzle were used for creating hollow cone spray and solid cone spray respectively. This study was carried at different injection pressures (100 bar, 150 bar and 200 bar), different HST (350°C, 450°C and 550°C) and different air pressures (10 bar, 15 bar, 20 bar and 25 bar) for obtaining the value of ID. A digital Oscilloscope is used to record ID and optical method was used for detecting the flame. Results of the experiments show that air pressure, injection pressure and HST all are responsible for variation in ID but HST is more strongly affect the ID compared to other parameters. However at high value of HST and injection pressures variation in ID is less. Variations in the values of ID are more for Solid cone spray than Hollow Cone spray although ID is decreased for both sprays at almost all injection pressures. The dependency of types of spray is more prominent in lower temperature ranges compared to higher temperature ranges.

Visualization and Analysis Studies of Hollow Cone Spray under low Air Cross Flow Velocity under Atmospheric Condition

This study deals with the atomization of hollow cone spray water with low air cross flow. The visualization of the hollow cone spray by shadowgraphy, from the nozzle exit. The diameter of the nozzle allows to observe different modes of breakup and different structures (ligaments, helices, ...). The treatment of these images makes it possible to determine the drop size distribution of the spray droplets in function of length scales of the downstream flow. In the measurements of water hollow cone spray with injection pressures of 25kPa and air velocity of 10 m/sec. The calculations at the exit of the injector, in two planes perpendicular, and the average droplet sizes in the presence of air low cross flow conditions. The structure and characteristics of the whole and sectional body of the spray are investigated at different times. The results show the droplet trajectory profile of the liquid droplets is in a good an agreement with analytical solution.