Experimental investigation of the spray structure of novel flow blurring twin-fluid atomizer

The spatial distribution of spray plays a key role in liquid fuel combustion, which dictates the local mixture fraction and the flame temperature distribution, especially for the gas turbine engines. Swirl stabilized combustor is used to carry out the investigation into spray structure. Effect of bulk mean velocity of swirl flow and atomizing air to liquid ratio (ALR) on spray structure is qualitatively characterized by Mie Scattering Imaging. Typical architecture of flow blurring atomizer consists of side (cross flow) entry of atomizing air into central liquid (in this case water) jet stream just upstream of injector exit. Space/gap, 'h', just before injector exit where side entry of atomizing air occurs was kept at 20% of the liquid jet diameter (d = 2 mm). The swirl number based on fixed vane angle was 1.0 and the bulk mean velocity of the swirl flow was varied from 0 m/s to 5 m/s with a constant co-flow velocity of 0.4 m/s to create confining effect for swirl flow and provide full optical access. The experimental results show that the spray spreads radially with the increase of bulk velocity of the swirl flow and the corresponding core spray height reduces. In addition, secondary droplet breakup is enhanced at higher swirl flow rate creating fine droplets that increase the droplet surface area per unit volume of liquid resulting in increased Mie scattering intensity owing to increase in surface area for constant liquid flow rate of 0.39 g/s. © 2018 Solar Turbines Incorporated