## 3 Results and Discussion  
### CFD Analysis  
The results obtained regarding the air/water speed for the three positions of the adjustment nozzle according to the distance between the seat and the valve, are presented in Table 5, and its variation graphs are described in Figures 10 and 11. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**Position of**} & \multicolumn{6}{c}{**Seat-to-Valve Distance, \(H\) [mm]**} \\ \cline{2-9}  & \multicolumn{2}{c}{**H1**} & \multicolumn{2}{c}{**H2**} & \multicolumn{2}{c}{**H3**} & \multicolumn{2}{c}{**H4**} \\ \cline{2-9}  & **Air** & **Water** & **Air** & **Water** & **Air** & **Water** & **Air** & **Water** \\ \hline S0 & 3080 & 107 & 3210 & 112 & 3060 & 108 & 3160 & 109 \\ \hline S1 & 2490 & 86.7 & 2940 & 104 & 3115 & 111 & 3020 & 105 \\ \hline S-1 & 2850 & 99.8 & 2900 & 104 & 3010 & 105 & 3010 & 106 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Maximum air speed values, [m/s]. Figure 9: Residual plots. The first significant observation is the impact of the nozzle position on maximum airspeed. Across all seat-to-valve distances (\(H\)), the S0 configuration consistently yielded higher airspeed values compared to S1 and S-1. This suggests that positioning the nozzle at the same level as the seat (S0) promotes higher airflow velocities. Within each nozzle position category (S0, S1, and S-1), variations in seat-to-valve distance (\(H\)) also affect maximum airspeed values. For instance, in the S0 configuration, the highest airspeed of 3210 m/s was achieved at H2, while in the S1 configuration, the maximum airspeed of 2940 m/s occurred at H3. These findings imply that the choice of seat-to-valve distance is a critical factor in determining airflow velocity. Figure 11: Water speed distribution. Figure 10: Air speed distribution. Notably, the S-1 configuration showed relatively consistent airspeed values across different seat-to-valve distances (\(H\)), with values ranging from 2850 m/s to 3010 m/s. This suggests that the S-1 configuration may be less sensitive to variations in seat-to-valve distance, providing stability in airflow performance. In case of water environment, the results from Figure 11 show that the fluidvelocity is significantly influenced by the position of the adjusting nozzle. Notably, when the nozzle is in the S1 position, the fluid velocity is generally lower compared to the S0 and S-1 positions. For instance, the highest fluid velocity observed in the S0 position is 112.0 m/s, whereas the highest fluid velocity in the S1 position is 111.0 m/s. The lowest value of fluid velocity corresponds to the S1/H1 configuration. The seat-to-valve distance also plays a role in affecting the fluid velocity of water through the relief valve. In general, smaller seat-to-valve distances tend to result in lower water velocity's compared to larger distances. This trend indicates that increasing the distance between the seat and valve allows for increased water flow. Also, to obtain a higher distance between the seat and valve the overpressure was higher as specified in the standard for the safety valve analyzed. Graphical representations of the results obtained from the CFD simulation regarding pressure, shear stresses and turbulent kinetic energy are depicted in Figures 12-17 for the plate and Figures 18-23 for the seat. It is evident that pressure varies considerably across different configurations. In the S0 configuration, the pressure increases with seat-to-valve distance. In the S1 and S-1 configurations, pressure values generally increase until H3, after decrease. This suggests that nozzle position and seat-to-valve distance interact to influence pressure distribution within the valve. Similar to pressure, shear stress exhibits variations across different combinations of seat-to-valve distances and nozzle positions. For all positions of adjusting nozzle, the maximum shear stress is recorded at H3 distance and is almost equal for all the analyzed configurations.