## 3 Results and Discussions
### Heat Loss Characteristics of the Drying System  
The reduction of heat loss was another effective method to improve the energy utilization level of the drying system. In order to further validate the feasibility of the optimized drying process, the variations in heat-loss rates in outlet air (\(\mathcal{Q}_{air,out}\)), outlet corn (\(\mathcal{Q}_{out}\)) and outlet flue gas from the RA (\(\mathcal{Q}_{fg,0}\)) and the total heat-loss rate in components (\(\sum\mathcal{Q}_{loss}\)) with drying time for the three drying processes were investigated; the results are shown in Figure 6a, and the heat-loss rate of the whole drying system (\(\sum\mathcal{Q}_{loss,whelsystem}\)) for the three drying processes are depicted in Figure 6b. Obviously, it can be seen from Figure 6a that the \(\mathcal{Q}_{c,out}\) for the three drying processes increased with the increase in drying time. It can be deduced from Equation (34) that \(\mathcal{Q}_{c,out}\) is proportionate to \(T_{c}\) while inversely proportionate to \(Mc\); during the drying process, \(T_{c}\) increased with drying time, while \(Mc\) decreased with drying time, which may help to explain the trends of the \(\mathcal{Q}_{c,out}\) for the three  
Figure 4: Comparison of the drying performance under different processes.  
drying processes; similar findings have been reported by [PERSON] et al. in 2019 for paddy grain industrial drying processes [20]. On the other hand, the \(\overset{\bullet}{Q}_{fg,0}\) varied in a relatively small range for the processes of \(\alpha=75^{\circ}\) and \(\alpha=90^{\circ}\), while for the optimized drying process, the \(\overset{\bullet}{Q}_{fg,0}\) in the first cycle (0-90 min) was obviously lower than that in the other four drying cycles, which might be due to the fact that the \(T_{fg,0}\) and \(v_{fg}\) in the first cycle (\(\alpha=45^{\circ}\)) were lower than those in the second, third, fourth and fifth drying cycles. Moreover, obviously, it can be concluded from Figure 6a that for each of the drying processes, the \(\overset{\bullet}{Q}_{c,out}\) were larger than the \(\overset{\bullet}{Q}_{fg,0}\) and \(\overset{\bullet}{Q}_{air,out}\) indicating that the heat loss in outlet corn should primarily be optimized for the purpose of energy-saving drying; the reduction of the grain discharging rate (\(\overset{\bullet}{m}_{c}\)) and the \(T_{c}\) may be helpful to decrease the \(\overset{\bullet}{Q}_{c,out}\), as recommended by [PERSON] et al. for paddy-grain drying in an industrial paddy dryer [40]. By comparing the \(\sum\overset{\bullet}{Q}_{loss}\) for the three drying processes, it can be deduced that the \(\sum\overset{\bullet}{Q}_{loss}\) in the first drying cycle for the optimized process was lower than that of the other two processes under the same drying time, indicating that the optimized drying process shows a better thermal performance in the first cycle than the other two processes. Moreover, as can be seen in Figure 6b, the \(\sum\overset{\bullet}{Q}_{loss,wholesystem}\) for the optimized drying process, \(\alpha=75^{\circ}\) and \(\alpha=90^{\circ}\) were ascertained to be 36,132.874, 40,459.801 and 44,788.154 MJ, respectively, indicating that the optimized drying process shows a better heat loss performance of the whole drying system than that of the processes of \(\alpha=75^{\circ}\) and \(\alpha=90^{\circ}\).  
Figure 5: The wavelength and the heat-recycled performance of the RA under different drying processes.