## 5 Results and Discussion  
### The Influence of the Constructive Parameters of the Shelf on the Profile of Gas Flow Velocities  
As a result of the free cross-section narrowing of the vertical channel, the inclined perforated shelf installation in the workspace of the shelf device causes a local increase in the velocity and turbulence of the gas flow in the outloading space and a change in the profile of gas flow velocities under the surface of the shelf and above it. As can be seen from Figure 4 (curves 1 and 2), a decrease in the value of the \(L_{cd}\)/\(L_{dev}\) ratio from 0.5 to 0.15 significantly increases the uneven distribution of the gas flow over the section of the workspace in the device in comparison with the installation of the perforated grid completely overlying the section of the workspace in the device (an analogue of the fluidized bed device (Figure 4, curve 4)), or the free channel (a pneumatic tube device (Figure 4, curve 5)). In this case, the width of the zone where the gas flow comes through the outloading space decreases, its absolute velocity and the profile of gas flow velocities in the workspace of the device is changed. If \(L_{cd}\)/\(L_{dev}\) = 0.5 and the degree of the shelf perforation is 15% (Figure 4, curve 1) in the above-shelf space, the absolute values of the gas flow velocities are practically constant over the section of this space and reach a maximum only in the outloading space and above it. If \(L_{cd}\)/\(L_{dev}\) = 0.15 (Figure 4, curve 2) the velocity profile has two maximum values: in the zone above the outloading space and at the middle level of the inclined shelf. This fact is explained by the differential \"dividing\" effect of the inclined shelf on the profile of  
Figure 4: The distribution of gas flow velocities along the section length of the device where the shelf is installed: 1—\(L_{cd}\)/\(L_{dev}\) = 0.5, \(\psi\) = 15%; 2—\(L_{cd}\)/\(L_{dev}\) = 0.15, \(\psi\) = 15%; 3—\(L_{cd}\)/\(L_{dev}\) = 0.15, \(\psi\) = 30%; 4—\(L_{cd}\)/\(L_{dev}\) = 0; 5—\(L_{cd}\)/\(L_{dev}\) = 1. Tilt angle of the shelf—\(\gamma\) = 25\({}^{\circ}\). Gas flow velocity in the free cross-section—1.2 m/s. gas flow velocities in or another one quantity through the outloading space and the holes in the inclined shelf. In the first case, the inclined shelf does not cause such a significant unevenness in the profile of gas flow velocities in the workspace of the device beyond its input point. In the second case, due to an increase in the resistance to the gas flow, caused by a sharp narrowing of the free cross-section in the device, significant swirlings arise at the inclined shelf edge. It defines the presence of a zone with a reduced gas flow velocity in the space above the end of the shelf. An increase in the perforation degree of the inclined shelf to 30% (Figure 4, curve 3) levels out the unevenness of the velocity profile over the cross-section of the workspace in the device since the gas flow is redistributed into the holes of the shelf due to a reduction of the hydraulic resistance of the shelf to its access. A comparison of the experimental (Figure 4) and theoretical velocity profiles (Figure 3) shows a sufficient coincidence between the nature of the gas flow velocities change along the cross-section of the workspace in the device. The absolute value of the gas flow velocity in the outloading space with a decrease in the \(L_{cd}\)/\(L_{dev}\) ratio from 0.5 to 0.3 grows insignificantly for a shelf with a perforation degree from 0% to 30% (Figure 5). Under the conditions of the further decrease in the \(L_{cd}\)/\(L_{dev}\) ratio up to 0.15, the gas flow velocity in the outloading space increases by 2.5-3 times in comparison with the average gas flow velocity in the free cross-section of the device. With a decrease in the perforation degree of the shelf cross-section, this growth is more significant since the hydraulic resistance to the gas flow through the holes of the shelf contact is increased and the gas flow is redistributed towards the outloading space.