## 3 Results and Discussion  
### Size Distribution of the Fuel Aerosol  
The evolution of size distributions for aerosol particles was observed using the three different distances from the nozzle. The camera and light source were placed at 0.2 m, 0.4 m and 0.6 m from the nozzle. Thus the aerosol properties were analysed inside the range of propagation distances where the size and velocity change a lot. The further propagation goes without drastic changes of the size and velocity distribution because to the moment aerosol have dried enough even with room temperature. Together with this, particle concentration has decreased to much making interaction of them negligible. The measured size distributions are shown in Figure 2. As one can see, the size distributions of CWS particles changes a lot during the 60 cm propagation. The distribution at 20 cm distance consists of two sharp peaks (Figure 2a). It reflects the earlier mentioned [16] process of the slurry segregation when excessive amount of water (which has weak enough adhesion to coal particles) form the small water droplets (left peak). The right peak corresponds to the slurry droplets whose size is a bit bigger than mean size of the coal particles. The right wing of the distribution shows presence of the agglomerates of coal particles sticked together by water. Further, the propagation of aerosol leads to essential decrease of the both sharp peaks due to the drying of small droplets. The pure water droplets mostly disappear and small coal particles inside the water shell mostly determine the left side of the distribution in Figure 2b. The main lobe has maximum near 500 \(\upmu\)m size and the 1-st moment of the distribution corresponds to approximately 550 \(\upmu\)m. The normalization factor for vertical axes corresponds to initial number of aerosol particles at L = 0.2 m (about 200-250 thousands for one experiment). The drying eliminates smallest components of aerosol (pure water droplets) that leads to decrease of the overall particle number and, therefore, to decrease of the dominating fraction value. However, together with this, drying leads to destruction of certain amount of the agglomerates making back the increase of the smaller fraction weight. But in the case of the Figure 2c the left peak corresponds to the small slurry droplets that necessarily contain the coal particle inside. The final shape of the size distribution for CWS shows presence of two modes of slurry droplets inside the aerosol flow: the small agglomerates of 1-2-3 coal particles and the big agglomerates containing up to dozen of them. Taking in account the decrease of the aerosol particle density due to the increase of the cloud volume, further propagation leads to self-similar decay of the distribution shown in Figure 2c. Looking onto the size distribution for CWSP aerosol (Figure 2d-f), one can see that evolution of the aerosol with propagation distance differ a lot from the CWS case. The first principal effect of the petrochemicals is much smaller amount of the small size pure liquid droplets. The water-oil emulsion interacts with coal particles much stronger and, thus, there is much weaker segregation of slurry components. One can see, that shape of the distribution is very close at different distances. It means,that effects of drying have much smaller influence onto the aerosol droplet sizes. The most probable size become smaller but the first statistical moment of the size distribution keeps almost constant. Appearance of the narrow peak at the left side of the size distribution after 0.4 m propagation of CWSP aerosol shows that effect of water evaporation is still present here. However, it does not make strong effect onto the ratio of the particle sizes. Therefore, one can conclude that changes of the size distribution of CWSP aerosol are much more predictable. The shape of distribution does not change during the first meter of the propagation. In general, the fractions of certain sizes of CWSP aerosol particles are almost the same at different cross-sections along the flow.