## 3 Results and Discussion
### Cooling Uniformity
For this reason, it is recommended to use pneumatic not hydraulic atomizers wherever it is necessary to maintain the high uniformity of material cooling. Comparison of the Amount of Energy Dissipating from the Surface During Boiling and Forced Single-Phase Convection  
In industrial processes, the control of temperature field changes in the entire volume of the cooled material is essential. Changes in the temperature field determine the properties and structure of the material during its production process. In the case of thermally thick materials, a too-high temperature inside the deeper layers of the material after the completion of the cooling process may contribute to an increase in temperature in the surface layers due to heat conduction. To prevent this phenomenon, such materials, after the boiling process is finished, are still cooled in technological line under the conditions of single-phase forced convection. In this paper, the determination of the amount of energy dissipating from the sensor surface \(A_{2}\) during cooling due to boiling and single-phase forced convection is presented. Additionally, a system that ensures the lowest temperature at point P4 when the surface temperature reached 100 \({}^{\circ}\)C and 60 \({}^{\circ}\)C was selected. The amount of energy dissipating from a cooled surface resulting from the boiling process was determined using Formula (35):  
\[E_{B}=\int_{\tau=\tau_{B}}^{\tau=\tau_{S}}HF(\tau)d\tau \tag{35}\]  
where  
\(\tau_{B}\)--time to start boiling, s;  
\(\tau_{S}\)--time in which the cooled surface to reach the temperature of 100 \({}^{\circ}\)C, s.  
The amount of energy dissipating from a cooled surface caused by single-phase cooling was calculated using Formula (36):  
\[E_{S}=\int_{\tau=\tau_{S}}^{\tau=\tau_{E}}HF(\tau)d\tau \tag{36}\]  
where  
\(\tau_{E}\)--time of single-phase cooling ending, s.  
For all considered types of cooling, the periods at which the individual stages of cooling occurred were defined. In Figure 28, the average HF values on the \(A_{2}\) surface with marked periods of air cooling, boiling and single-phase forced cooling obtained for cooling the sensor with the AAS system at a pressure of 0.1 MPa are presented. In this case, the boiling process started at time \(\tau_{B}\) and finished when the surface temperature reached 100 \({}^{\circ}\)C, at point \(\tau_{S}\). Cooling under the conditions of single-phase forced convection was considered when the sensor surface temperature reached 100 \({}^{\circ}\)C within the time in which the surface temperature dropped to 60 \({}^{\circ}\)C, \(\tau_{E}\). This approach made it possible to compare the amount of energy dissipating from the cooled surface during each stage of cooling for all three cooling systems (Figure 29). The highest amount of energy dissipating during boiling was obtained for the WS system for all three pressures, with the lowest for the AAS system. In the case of cooling with the WS system, the amount of energy dissipating from the surface during the boiling process was the highest. Despite that, the value of the temperature at control point P4 was quite high (Table 4). The lowest temperature at point P4 was achieved for the JET system with a water-supplied pressure of 0.05 MPa. During single-phase convection, a similar trend was observed. The ability of water to remove heat from the cooled surface in this system was the lowest (Figure 23). The JET system guarantees obtaining the lowest temperatures in the deeper layers of the material, both in terms of two-phase and single-phase convection. In the case of cooling thermally thin materials, the WS or the AAS system are the best solution for cooling. The AAS system provides six-times-lower water consumption in relation to the JET system. It also ensures the highest uniformity of temperature distribution during nucleate-boiling and single-phase convection. Figure 28: The ranges of air cooling, boiling and forced single-phase convection, AAS, \(A_{2}\), \(p=0.1\) MPa.