# Analysis of Flow Field Characteristics in the Three-Phase Jet Fire Monitor Head
## 4 Conclusions  
Numerical simulations were conducted to investigate the effects of varying the main structural parameters of the fire monitor head on the IFF under a water flow rate of 70 L/s. The main findings are as follows:  
1. As \(A_{p}\) increases from 90\({}^{\circ}\) to 120\({}^{\circ}\), the peak value of TKE in the IFF decreases significantly. The average TKE at the nozzle outlet decreases by 20%, and the PD at the inlet and outlet of the flow passage in the monitor head decreases by 1.73%. This indicates that increasing \(A_{p}\) within a certain range can effectively reduce energy losses. Although the uniformity index \(\gamma_{o}\) of the nozzle increases slightly with the increase in \(A_{p}\), the velocity difference between the upper and lower parts of the IFF decreases by 83.2%, and the velocity difference between the upper and lower sides of the nozzle outlet decreases significantly. The velocity distribution uniformity of the IFF is significantly improved. Increasing the powder-pipe bending angle is beneficial for improving the stability of the nozzle jet under the premise of ensuring the processability of the TPJFM head.
2. Increasing the length of the supporting blade is beneficial for reducing the average TKE at the nozzle outlet, but has little effect on the uniformity of the velocity distribution at the nozzle outlet and the PD at the inlet and outlet of the TPJFM head. With the increase in \(L_{f}\), the velocity components in the X and Y directions at the cross-section d decrease significantly, and the average TKE at this location decreases by 22.37%. The local TKE in the IFF decreases significantly. Within the limited space of the supporting blade, increasing its length can reduce local pressure loss to a certain extent.
3. As \(L_{pf}\) increases from 25 mm to 75 mm, the TKE gradually decreases. The average TKE of cross-section c and cross-section d decreases by 21% and 48%, respectively. The nozzle outlet velocity distribution uniformity index reaches its optimum when \(L_{pf}\) = 45 mm. The average TKE at the nozzle outlet decreases by 22%, and the PD at the inlet and outlet of the flow passage in the TPJFM head decreases by 0.9%.  
Figure 19: Line chart of changes in boundary parameters of IFF with different \(L_{pf}\).  
Comprehensive analysis shows that when \(L_{pp}\) = 65 mm, the nozzle outlet can obtain a higher velocity distribution uniformity and lower TKE, while keeping the PD at the inlet and outlet of the flow passage in the monitor head at a low level.  
Within certain ranges, reasonable increases in \(A_{p}\) and \(L_{pf}\) improve the flow characteristics of the IFF, reduce local pressure losses and peak TKE, thereby lowering the average TKE at the nozzle outlet and the PD across the monitor head inlet and outlet. Increasing the supporting blade length helps enhance the flow characteristics of the IFF, promoting smoother flow.  
Conceptualization, H.G. and L.Z.; methodology, H.G.; software, L.Z.; validation, H.G., L.J. and L.Z.; formal analysis, L.J.; investigation, H.G.; resources, H.G.; data curation, H.G.; writing--original draft preparation, H.G.; writing--review and editing, H.G.; visualization, H.G.; supervision, X.Z.; project administration, H.G.; funding acquisition, X.Z. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the key research and development of Shandong province, China, grant number 2019 SDZY01.  
Not applicable.  
The original contributions presented in the study are included in the article, further inquiries can be directed to the corresponding author.  
I would like to thank [PERSON] for supporting this research and [PERSON] for her strong support and encouragement for the research work.  
The authors declare no conflicts of interest.