Impact of the spraying parameters of coal-water slurries and their properties on droplet primary atomization in a jet

Relevance. Modern environmental and power challenges dictate the need to switch to clean energy technologies. This is the basis for an active search and creation of innovative sources of energy and fuel. One of the most promising approaches to meeting such requirements while maintaining electricity production at thermal power plants is the use of multicomponent fuel mixtures, for example, coal-water slurries. Aim. Experimental studies of the fragmentation processes of the coal-water slurries jet (quantity, size, shape) at short distances from the nozzle, depending on the spraying parameters and the slurry properties. Object. Experimental studies were carried out with coal-water slurries based on lignite (2B grade) with addition of 1 and 2% by weight of carbon black. A slurry consisting of coal and water, without the addition of the third component, was used as a reference sample. Methods. Coal-water slurries were prepared using a homogenizer with a cavitation effect. A pneumatic nozzle with an internal mixing of the slurry and the spraying agent were used to spray the coal-water slurries. The average size of fuel droplets after spraying was determined using the Interferometric Particle Imaging method. Droplet velocities were determined using the Particle Image Velocimetry method. Results and conclusions. The effect of spraying parameters and the component composition of the slurries on droplet shape, size and velocity was experimentally proven. It was found that the third component, nano dispersed carbon black, contributes to a significant increase in the kinematic viscosity of the slurry and a slight change in its density. Large (more than 1 mm) slurry fragments were proved to be present in a jet in the immediate vicinity of the nozzle at low air pressure (0,1 MPa). Fuel droplets have the shapes of spheres, elongated ellipsoids, and droplets. The spray mode at air pressure of 0,2 MPa is transitional – from a coarse-dispersed gas droplet jet to a finely dispersed one. The number of large droplets and fragments of the slurry increases to 88% with the addition of 2% by weight of nano dispersed carbon black. For citation: Gvozdyakov D.V., Zenkov A.V. Impact of the spraying parameters of coal-water slurries and their properties on droplet primary atomization in a jet. Bulletin of the Tomsk Polytechnic University. Geo Assets Engineering, 2026, vol. 337, no. 7, pp. 36-48. https://doi.org/10.18799/24131830/2026/7/5324