Search

The research presents the numerical modeling findings of the secondary breakup of droplets of coal water slurries containing petrochemicals (CWSP) droplet with the filter cake content of 50 % for different Weber number values. The modeling method of the secondary droplet breakup is based on the VOF method for interface resolution, LES model for describing turbulence, and the technology of adapted dynamic grids. This technology enables the grid to be automatically concentrated in the region of large solution gradients during the calculation. The implementation of such a highly detailed grid allowed resolving secondary droplets with the dimensions down to 15 μm. We established the droplet breakup modes depending on the Weber number ranging from 36 to 342. The structure of the stream behind droplets was studied in detail and the numerical method was tested. The results are in good agreement with the results of known experiments.

The paper presents an experimental study of oscillatory response in the Francis turbine of hydraulic unit. The experiment was performed on large-scale hydrodynamic test-bench with impeller diameter of 0.3 m. The effect of air injection on the intensity of pressure pulsations was studied at the maximum pressure pulsations in the hydraulic unit. It was revealed that air delivery into the water-conveyance system of the turbine results in almost two-fold reduction of pressure pulsations.

The paper presents testing results of the numerical technique to simulate the agitation process of concentrated suspensions. The simulating technique is based on Eulerian two-fluid model of granular media, k-w SST URANS turbulence model, and sliding mesh approach. The results obtained show a good qualitative and quantitative agreement between calculation and experiment in terms of the shape and location of the phase interface and the distribution of the solid phase along the height.

In this paper, the study of ferromagnetic nanoparticles behaviour in the constant magnetic field is carried out. For numerical simulation we have used Euler-Lagrange two-component approach. Using numerical simulation we have studied the growth of deposition of nanoparticles on the channel walls depending on the Reynolds number and the position of the magnet. The flow pattern, the concentration field and the trajectory of nanoparticles as a function of the Reynolds number were obtained. The good qualitative and quantitative agreement between numerical simulation and experiments was shown.