# Evaluation of Different Internal Designs of Hydraulic Nozzles under an Accelerated Wear Test
## 3 Results
only one exit orifice. The results of the nozzle orifice dimensions could explain the higher resistance of the TTj60 nozzle to wear compared with the TT and DG nozzles. Agricultural nozzles can be classified according to size (discharge rate), which represents the nominal flow rate of these nozzles, and are given a certain color for each nozzle according to the size. As the TTj60 nozzle is the same size (nominal flow rate is 1.18 L/min) as the TT and DG nozzles but with double orifices, these TTj60 nozzle double orifices must be smaller in dimension. This leads to a question whether the size (or the nominal flow rate) of the TTj60 nozzle has an effect on the wear behavior of such a nozzle. This question could be answered by further studies on this type of nozzle (TTj60) of different sizes and possibly of different materials. The results for the virtual coefficient of variation (CVV) in Table 4 show that the spray distribution of the nozzles set for every nozzle type after finishing the acceleration test was within the allowed threshold (CVV values under 10%) set by ISO 16122-2 [23]. However, a few values were higher than 10% CVV during certain test periods for the tested nozzle types. For example, the CVV exceeded the 10% allowed limit for the TT nozzle after 40, 60, 80, and 90 h of wear. This was noticed for the TTj60 nozzle only after 80 and 90 h of wear, but then it decreased again to the allowed limit after 100 h of wear (9%). The allowed limit for CVV was exceeded for the DG nozzle only in the middle of the wear test (after 40 h of wear); the registered value was 11%. For better visualization, only a few positions of the spray swath (patternator width) and only selected wear intervals were considered in Figure 6a-c. The intent was to show the change in the spray distribution in a certain position during the wear periods of the TT, TTj60, and DG nozzles. The X-axis in this figure represents the position of the graduated tubes that were used in the patternator table. The numbers on this axis refer to the tube position starting from the left to the right of the table. As mentioned above, not all the fifty positions on this axis are shown in this figure. Instead, only chosen positions with five tubes intervals were included. The Y-axis represents the quantity of water (ml) collected in each tube along the patternator table. We did not observe a clear trend of the changes in the spray distribution during the different wear periods. However, we saw that the spray \begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline
**Nozzle** & **Spray Distribution** & & & & & & **Hours of Wear, h** & & & & & \\
**Type** & **Characteristics** & **0** & **10** & **20** & **30** & **40** & **50** & **60** & **70** & **80** & **90** & **100** \\ \hline \multirow{4}{*}{TT} & Average \({}^{*}\), mL & 193.3 & 200.7 & 199.5 & 210.1 & 194.0 & 196.5 & 199.8 & 208.1 & 215.4 & 214.5 & 218.5 \\  & SD \({}^{**}\) & 7.1 & 6.6 & 12.5 & 7.6 & 20.6 & 14.7 & 22.4 & 11.4 & 28.5 & 21.3 & 15.1 \\  & CVV & 4\% & 3\% & 6\% & 4\% & 11\% & 8\% & 11\% & 6\% & 13\% & 10\% & 7\% \\  & Average, mL & 196.1 & 202.7 & 193.6 & 203.7 & 194.1 & 191.2 & 195.0 & 198.1 & 200.7 & 206.5 & 206.6 \\  & SD & 11.5 & 10.9 & 7.0 & 8.8 & 15.4 & 15.2 & 13.9 & 11.8 & 24.8 & 21.2 & 18.8 \\  & CVV & 6\% & 5\% & 4\% & 4\% & 8\% & 8\% & 7\% & 6\% & 12\% & 10\% & 9\% \\  & Average, mL & 213.2 & 211.8 & 213.4 & 220.7 & 215.0 & 212.5 & 216.4 & 213.3 & 211.4 & 222.9 & 227.1 \\ DG & SD & 8.1 & 13.5 & 13.5 & 11.6 & 23.3 & 18.3 & 18.9 & 14.0 & 15.5 & 12.6 & 11.9 \\  & CVV & 4\% & 6\% & 6\% & 5\% & 11\% & 9\% & 9\% & 7\% & 6\% & 5\% \\ \hline \hline \end{tabular}  
* Average value of the water quantity collected in every patternator vessel (virtual 10 cm width) of the spray swath. ** Standard deviation of the values of spray quantity collected in the patternator vessels.  
\end{table} 
Table 4: The spray distribution characteristics at different wear intervals for the TT, TTj60, and DG nozzles.