## 2 Materials and Methods
The measuring system of the bench is located on a movable triaxial crosshead providing movement of the laser beam (measurement space v) relative to the fluid stream under test. The measurement step value \(\Delta\)x = 25 mm corresponds to the distance between the center of the individual grooves on the groove table. The stepwise movement of the measuring point was carried out with a positioning accuracy of 10 \(\upmu\)m. The measurement distance in the vertical axis (z) was h = 400 mm, which is in accordance with the range specified  
Figure 1: Diagram of use of two measurement methods. Figure 2: 2D laser LDA/PDA analyzer from Dantec Dynamics. in ISO/FDIS 25358:2018 [39]. The liquid pressure for all the nozzles tested was 3 bar and within their operating range. The pressure of the spray liquid was measured directly in front of the nozzle with an accuracy of 0.1 bar. Spray spectrum studies were conducted as a function of varying measurement time. The study began for a time of T = 120 s at each discrete measurement point. Subsequently, the tests were implemented for times T = (80, 60, 40, 20, 10) s. Time was measured to the nearest 0.1% for each time interval. To determine the volume distribution, also known as the spray density, the coefficient of variation, denoted CV, should be used [40]. To calculate the CV, the standard deviation (\(\sigma\)) and volume (\(\overline{V}\)) were determined using the following equations:  
\[\mathrm{CV}=\frac{\sigma}{\overline{V}}\cdot\mathrm{100\%} \tag{1}\]  
where \(\sigma\) is the standard deviation for the sample, and \(\overline{V}\) is the arithmetic mean of the results. \[\sigma=\sqrt{\frac{\sum_{i=1}^{n}\left(V_{i}-\overline{V}\right)^{2}}{n-1}} \tag{2}\]  
\[\overline{V}=\frac{1}{n}\cdot\sum_{i=1}^{n}V_{i} \tag{3}\] \begin{table}
\begin{tabular}{l l} \hline \multicolumn{2}{c}{**Measurement Parameters**} \\ \hline size range of measured particles & 1-1600 \(\mathrm{\SIUnitSymbolMicro m}\) \\ \hline resolution of measured quantities & \(\pm\)0.05 \(\mathrm{\SIUnitSymbolMicro m}\) \\ \hline maximum number of particles & \(>\)300,000 particles/s \\ \hline range of measured velocity components at any vector turn & 0-300 \(\mathrm{\SIUnitSymbolMicro m/s}\) \\ \hline resolution of measured speeds & 0.002\% \\ \hline \multicolumn{2}{c}{Physical Parameters of the Transmitting and Receiving Probe} \\ \hline probe focal length & 700 \(\mathrm{\SIUnitSymbolMicro m}\) \\ \hline wavelength of laser beams & 660 \(\mathrm{\SIUnitSymbolMicro m}\) and 785 \(\mathrm{\SIUnitSymbolMicro m}\) \\ \hline laser power per pair of beams for the first component & 90 \(\mathrm{\SIUnitSymbolMicro m}\) \\ \hline laser power per pair of beams for the second component & 70 \(\mathrm{\SIUnitSymbolMicro m}\) \\ \hline diameter of the laser beam at the front lens & 2.75 \(\mathrm{\SIUnitSymbolMicro m}\) \(\pm\) 0.25 \(\mathrm{\SIUnitSymbolMicro m}\) \\ \hline type of bonnet of the receiving probe & B \\ \hline medium droplet size & 644.2 \(\mathrm{\SIUnitSymbolMicro m}\) \\ \hline special filter & slit: 0.2 \(\mathrm{\SIUnitSymbolMicro m}\) \\ \hline scattering angle & 43.5 \(\mathrm{\SIUnitSymboldeg}\) \\ \hline phase validation ratio & 15\% \\ \hline burst detector SNR level & 2 \(\mathrm{\SIUnitSymboldeg}\) \\ \hline level validation ratio & 4 \\ \hline data collection mode & burst \\ \hline relative refractive index & 1.334 \\ \hline confidence & 84.98\% \\ \hline best scattering & 138 \(\mathrm{\SIUnitSymboldeg}\) \\ \hline \end{tabular}
\end{table} 
Table 1: Main parameters of the 2D LDA/PDA analyzer. where \(V_{i}\) is the volume of liquid in the \(i\)-th groove of the measurement table or the \(i\)-th measurement point using a 2D LDA/PDA analyzer, and \(n\) is the number of measurement points. The coefficient of variation, CV (1), was determined from the standard deviation of the sample (2) and the arithmetic mean of the results (3).