Development And Study Of High Efficiency Atomizing Spray Nozzles For Low-quality Fuel Oil

With the oil deep processing potential increases, the low-quality combustion technology has been paid more and more attention. For the low-quality fuel oil, the higher the colloid and asphaltene are contained, and the more obvious the viscoelasticity is, the harder to perform the good atomization, the flame with sparks flew away, ash fallen seriously. The fuel oil is apt to adhere to the edge of the nozzle, and for this reason, the nozzle burning accidents frequently happen. Through the investigation and research, a kind of strong shear air atomizing spray nozzle is developed, the internal flow characteristics and mixing characteristics are studied by numerical simulation, and the atomization effect is verified by the experiment.The research shows that the nozzle structure with double cylinder swirlers has obvious shear function to the oil flow. With the helix angel of cylindrical cyclone increasing, the tangential velocity of air becomes larger, the shear force to the fuel oil strengthens, the two-phase mixing uniformity increases. When the inlet air pressure increases properly, the mixing uniformity of two-phase increases, and the nozzle atomization effect improves. As the number of flutes increase, the maximum velocity of the nozzle outlet becomes larger, the volume fraction of oil decreases, and the atomization effect becomes better. Compared with the nozzle with double cylinder swirlers, the nozzle with cone-cylinder swirler sprays out by the form of hollow cone, so it has a better dispersion effect. The experimental results verify the atomization effect, with the backflow resistance increasing, the flow rate increases, but has a large fluctuation; if the backflow resistance keeps constant, the flow rate of the spray nozzle decreases greatly with the air pressure increases. For a given nozzle if the backflow resistance keeps constant, the gas lock pressure exits; with the backflow resistance increases, the gap between the air lock pressure and the backflow resistance becomes larger, which shows that the increase of the backflow resistance will cause rise to operation flexibility.