## 3 Result and Discussion
### The Temperature Field Distribution  
Some temperature monitoring locations in the test were selected to analyze the partial insulation tunnel temperature field distribution. Figure 5a shows that the cooling effect of PTI on the final temperatures of the upper monitoring locations was more obvious, while in the lower monitoring location, only the temperature of sensor 115 had a drop of 2.3 \({}^{\circ}\)C. The temperatures of sensors 111 and 118 dropped faster when there was insulation, but their respective equilibrium temperatures were the same in both cases. This is because the  
Figure 4: The ATWA changes with the ventilation time.  
ventilation duct was arranged at a low level, so that the cooling capacity of the airflow was sufficient to cool the lower location, and the temperatures of sensors 111 and 118 reached the current limit value. If the temperature is to be further reduced, other ventilation parameters can only be changed. When thermal equilibrium was reached, the temperature of monitors 108 and 118 were the highest because the monitoring locations were arranged on a plane perpendicular to the air outlet direction, and these were followed by monitoring locations 105 and 115. Monitoring locations 101 and 111 are located directly in front of the VDO of auxiliary ventilation, so their temperatures decreased most obviously, and their final temperatures were the lowest values under the same conditions. After adding a movable TIL, the cooling capacity of airflow can be preserved to reduce the cooling limit value of the upper monitoring locations. It is worth noting that a local vortex zone will appear in the center of the workspace during the process of auxiliary ventilation [31; 32]. It is challenging to cool down and renew the air in the vortex zone without increasing the air volume, where monitoring locations 105 and 115 are situated. However, due to the effect of PTI, the heat exchange between the ventilation airflow and the air in the vortex zone is enhanced, and the temperature at the vortex position is significantly lowered. The average temperature of the 105 and 115 sensors dropped by 3.3 \({}^{\circ}\)C, while the temperatures of the sensors fell from 33.5 \({}^{\circ}\)C to 29.2 \({}^{\circ}\)C and from 31.3 \({}^{\circ}\)C to 29.0 \({}^{\circ}\)C, respectively.  
Figure 5: The temperature field with partial insulation in the tunnel. (**a**) The temperatures of the monitoring locations in the workspace changes with the ventilation time. (**b**) The temperature distributions in the working area with insulation.  
To better illustrate the temperature distribution, the stable temperature values of the monitoring locations were plotted as cloud maps. Figure 5b represents the temperature cloud maps of the working zone. The upper section has a significantly higher temperature than the lower section. Three factors contribute to this phenomenon. First, the shape of the tunnel is arched, meaning the rock above has a greater heat dissipation area than the rock below. Secondly, since the partial insulation layers are in the form of baffles, the heat that fails to be emitted from the surrounding rock on both sides will be emitted from above through the gap between the PTI layer and the wall of the mine tunnel. Finally, the lower temperature can be reduced even more because the ventilation duct is set at a low level. Due to the presence of the vortex zone, the temperature is higher in the center of the working area than it is at the end closest to the VDO when viewed from a longitudinal perspective.