## 5 Results and Discussion
### Features of Interphase Heat Transfer in a Layer Weighted on a Shelf  
The influence of the gas flow velocity on the interphase heat transfer process intensity is represented by the dependence Nu = \(f\) (Re) (Figure 8). One can see from the graph (Figure 8, line 1) that the interphase heat transfer intensity between the gas flow and particles for the \"gravitationally falling layer\" mode increases slightly with an increase in the gas flow velocity in the free cross-section of the device, at \(40<\) Re \(<600\). It is proved by the fact that the particles of material coming from the loading nozzle move along the surface of the shelf with a sufficiently high velocity, the contact time of the particles with gas jets coming from the holes of the shelf is small. Owing to the insufficient contact time of the rapidly moving layer of material with the gas flow, the Nusselt criterion values obtained for the interphase heat transfer conditions on the inclined shelf surface under conditions of the \"gravitationally falling layer\" mode implementation in the workspace of the device come into the Nu \(<5\) area. The empirical correlation for the \"gravitationally falling layer\" mode is the following [57]  
\[\text{Nu}=1.5\cdot\text{Re}^{0.2}\text{ (if }40<\text{Re }<600), \tag{17}\]  
where the Nusselt criterion Nu = \(\alpha\cdot d_{p}/\lambda_{g}\); \(\alpha\)--heat transfer coefficient from the surface of particles to the gas flow, W/(m\({}^{2}\cdot\)K); \(\lambda_{g}\)--gas heat (thermal) conductivity coefficient, W/(m\(\cdot\)K); Reynolds criterion Re = _W-d\({}_{p}\)/v_; W--gas flow velocity in the free cross-section, m/s. The \"weighted layer\" mode initially (at Re = 30-170) is characterized by a gradual increase in heat transfer intensity, and then (at Re > 170) a significant increase in interphase heat transfer intensity is observed as a result of the material layer formation blown by the gas flow on the inclined shelf surface (Figure 8, line 2). This situation is explained by the improvement of the conditions for \"washing\" particles with a gas flow, \"opening\" of their surface, and also due to additional turbulization of the boundary film as a result of an increase in the relative velocity of neighboring particles. In the weighted material layer in the area above the outloading space, the active heat transfer surface increases due to intensively circulating material particles throughout the entire weighted layer space. In the weighted layer mode, the most intensifying effect is exerted by a gas jet entering the weighted layer of material through the outloading space at a sufficiently high velocity. Due to the expansion of the gas flow at the exit from the space of the outloading gap, intense interaction is ensured over the entire area of the weighted layer in the filtration mode. When the material is unloaded, the lower part of the weighted layer partially overlaps the outloading space. It causes a slight increase in the gas flow velocity in this zone and its part is redistributed into the holes of the shelf. In this case, the uniform filtration mode of the material layer by the gas flow is replaced by the gas jet \"breakthrough\" through the material weighted layer over the outloading space. Therefore, such a variable mode defines the pulsating nature of the material particles interaction with the gas flow, not only in the layer of material weighted over the outloading space, but also in the layer moving  
Figure 8: The effect of gas flow velocity on the interphase heat transfer intensity: \(I\)—\"gravitationally falling layer” mode; \(2\)—”weighted layer” mode; \(3\)—the fluidized bed on a horizontal grid. along the inclined shelf surface. It increases the phase contact intensity, and, accordingly, the heat transfer coefficient in the weighted layer mode in comparison with the fluidized bed (Figure 8, line 3). The experimental studies enabled to identify the \"active\" heat exchange zone of the shelf unit--the outloading space zone.