Features of metastable superheated water atomization when being discharged through convergent-divergent nozzles at different superheat values

Experiments with the metastable superheated water atomization proved the significant increase of the submicron droplets mass fraction at the outlet of convergent-divergent nozzle from 0.45-0.55 to 0.75-0.9 with an increase of the inlet water temperature from170to255°C. Two different approaches to dimensionless treatment of the atomization processdata and determining the boundary of the zone of flashing predominance are compared. The analysis of two approaches to dimensionless treatment of experimental and calculating results concerning transition to predominating role of nucleation in the process of superheated liquid atomization in convergent-divergent nozzles is done.

Interpreting Liquid Atomization Efficiency

Liquid atomization involves several mechanisms transforming a bulk of liquid into small droplets. The atomization efficiency usefulness is questionable considering its low values (0.01-1%). This work presents a general definition for atomization efficiency and explains why the Sauter mean diameter is the appropriate characteristic drop size (and no other mean diameter value). Finally, future directions are suggested for developing injector design tools from atomization efficiency.

Study on the atomization zones of the nozzle in the processes of material primary processing

It can divide the atomization effect in the direction of the nozzle axial injection into the jet area and the non-jet area by using the second crushing theory. On this basis, according to the feed liquid atomization particles discrete degree index of characteristics particle size of feed liquid atomization, it divides the injection zone into the atomization area and the diffusion area, so as to realize the axial direction of jet nozzle injection zone, atomization zone and the diffusion zone accurately. Simulation and experiment are used to verify the three zones of atomization nozzle. The division of three zones drives the study from the whole space of liquid distribution in the roller to atomization zone, clears the key zone of the roller in tobacco primary processing, and provides a basis for further work.

Improved Atomization via a Mechanical Atomizer with Optimal Geometric Parameters and an Air-Assisted Component

Atomization of liquid media is a key aim in various technological disciplines, and solutions that improve spray performance, while decreasing energy consumption, are in great demand. That concept is very important in the development of liquid fuel spray atomizers in high-efficiency microturbines and other generator systems with low inlet pressure and a wide range of power supply. Here we present a study of the liquid atomization characteristics for a new mechanical atomizer that has optimal geometric parameters and a preliminary swirl stage. In our air-assisted atomizer, air is introduced through a swirl chamber positioned at the exit of the mechanical atomizer. The optimized mechanical atomizer alone can achieve D32 drop diameters in the range of 80 to 40 µm at water supply pressures of 2 to 5 bar, respectively. The addition of an air swirl chamber substantially decreases drop sizes. At an air–liquid ratio (ALR) equal to 1, water pressures of 2.5 to 3 bar and air supply pressures 0.35 to 1 bar, D32 drops with diameters of 20–30 µm were obtained. In an air-assisted atomizer the parameters of the mechanical atomizer have a much stronger influence on drop diameters than do characteristics of the air-swirl chamber. Using a mechanical atomizer with optimal geometrical dimensions allows limiting the liquid supply pressure to 5 bar; but when an air-assisted component is introduced we can recommend an ALR ≈ 1 and an air supply pressure of up to 1 bar.