# Drift Potential Characteristics of a Flat Fan Nozzle: A Numerical and Experimental Study
## 4 Results and Discussion
### Comparison and Analysis of Data and Results  
The results of the measurement of droplet size under seven different wind speeds and three spraying conditions are summarized in Table 2.  
The analysis of the test data revealed that as the wind speed increased, \(D_{\
u 0.1}\) gradually decreased, and \(D_{\
u 0.5}\) and \(D_{\
u 0.9}\) gradually increased. \(D_{\
u 0.9}\) exhibited a significantly steeper increment compared to \(D_{\
u 0.5}\). Moreover, V100 and the droplet spectrum width gradually increased. For the practical scenario, the spatial particle statistics method of the laser particle sizer was used to calculate the number of particles per unit area of space. When the statistical rate per unit time remained unchanged, as wind speed increased, small particle \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Nozzze Type/Spray** & \multicolumn{8}{c}{**Wind Speed (m/s)**} \\
**Pressure/(No. MPa)** & **0** & **1** & **2** & **3** & **4** & **5** & **6** \\ \hline \multirow{4}{*}{Lu120-015, 0.3} & \(D_{\
u 0.1}\)/um & 84.24 & 82.47 & 79.35 & 72.77 & 72.71 & 71.69 & 69.26 \\  & \(D_{\
u 0.5}\)/um & 174.74 & 176.68 & 177.67 & 179.31 & 187.53 & 191.22 & 195.32 \\  & \(D_{\
u 0.9}\)/um & 264.55 & 276.32 & 281.54 & 289.48 & 298.35 & 309.74 & 318.81 \\  & \(\mathrm{V100\%}\) & 11.84 & 12.17 & 13.76 & 14.73 & 14.63 & 14.27 & 14.01 \\  & Droplet & & & & & & & \\  & spectrum & 1.03 & 1.10 & 1.14 & 1.21 & 1.20 & 1.24 & 1.28 \\  & width & & & & & & & & \\ \hline \multirow{4}{*}{Lu120-03, 0.3} & \(D_{\
u 0.1}\)/um & 81.98 & 76.80 & 73.49 & 71.97 & 70.25 & 69.34 & 66.60 \\  & \(D_{\
u 0.5}\)/um & 171.02 & 172.14 & 175.64 & 178.86 & 182.71 & 186.34 & 190.52 \\  & \(D_{\
u 0.9}\)/um & 261.29 & 269.51 & 276.36 & 279.76 & 287.91 & 295.78 & 304.32 \\ \cline{1-1}  & \(\mathrm{V100\%}\) & 13.86 & 14.82 & 15.64 & 15.98 & 17.32 & 18.19 & 18.32 \\ \cline{1-1}  & Droplet & & & & & & & \\  & width & & & & & & & \\ \hline \multirow{4}{*}{Lu120-03, 0.3} & \(D_{\
u 0.1}\)/um & 96.62 & 91.75 & 89.37 & 87.91 & 85.46 & 83.17 & 82.78 \\  & \(D_{\
u 0.5}\)/um & 216.58 & 217.82 & 221.95 & 225.24 & 230.16 & 234.31 & 237.34 \\ \cline{1-1}  & \(D_{\
u 0.9}\)/um & 340.53 & 371.55 & 386.36 & 404.53 & 418.26 & 431.53 & 440.86 \\ \cline{1-1}  & \(\mathrm{V100\%}\) & 11.84 & 12.17 & 13.76 & 14.73 & 15.63 & 16.27 & 16.01 \\ \cline{1-1}  & \(\mathrm{D_{\
u 0.9}}\)/um & 1.13 & 1.28 & 1.34 & 1.41 & 1.45 & 1.49 & 1.51 \\ \cline{1-1}  & width & & & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Droplet spectrum parameters under different spraying conditions. size droplets were carried by the airflow and moved at great speeds and therefore were counted fewer times. In contrast, large particles moved slower and therefore were counted several times. Consequently, the overall measured particle size was too large [42; 43]. A comparison of the simulation and test data showed differences in other particle size parameters, except for the \(D_{\mathrm{v0.5}}\) value and change trend, which remained identical. The error in the simulation results occurred due to the error of the statistical method of discrete-phase particles. It approximately replaces the nozzle spraying particles at 0.35 m in the laser particle sizer through statistics of a series of sprayed particles for a short duration. The statistical methods were different, and thus the results were also quite different. Figure 9 presents the results of the measurement and calculation of droplet drift under three wind speeds and three spraying conditions. Figure 9a-c presents the mass of rhodamine-B on the polyethylene line under lateral wind speeds of 1 m/s, 3 m/s, and 6 m/s and three spraying pressures, i.e., Lu 120-015 (0.3 MPa), Lu 120-015 (0.4 MPa), and Lu 120-03 (0.3 MPa), respectively. The three-bar charts show that, for the same spraying conditions, the droplet flux value of the nozzle on the 2 m plane in the downwind direction gradually decreases from bottom to top at a wind speed of 1 m/s. At wind speeds of 3 m/s and 6 m/s, the flux increases first and then decreases.