# Temperature Fields of the Droplets and Gases Mixture
## 2 Experimental Set-Up and Procedure
### Droplets  
To generate a sprayed water flow, we used a system comprised of a water reservoir, feeding channel, and spraying nozzle 12. The nozzle was the same as in [20; 21]. To determine the droplet flow characteristics (droplet velocity \(U_{\text{d}}\) and droplet radius \(R_{\text{d}}\)), we used a panoramic optical system. The initial droplet flow velocity \(U_{\text{d}}\) was measured via the PIV optical technique [22]. The initial droplet radius in the sprayed flow was measured via the SP technique [23]. Nozzle 12 generated droplets with a radius \(R_{\text{d}}\)=0.06-0.18 mm. The initial droplet flow velocity was 2-3 m/s throughout the series of experiments. The volume concentration of droplets in the sprayed flow \(\gamma_{\text{d}}\) was 3.8\(\cdot\)10\({}^{-2}\) l/m\({}^{3}\). It was chosen as an average value from the practical applications mentioned in the Introduction and the experiments in [9; 10]. When processing the flow images obtained by SP, we divided all the droplets in each frame into \(m\) groups. For each group, we calculated the mean radius (\(R_{\text{dm}}\)) and number (\(n\)) of droplets in the group, volume \(V_{\text{m}}\) = \(n\)-4/3-\(\pi\)\(\cdot\)\(R_{\text{dm}}\)[3]. Then, we determined the notional volume of the observation area: \(V_{\text{a}}\) = \(x\)\(\cdot\)\(y\)-\(\eta\). After that, we calculated the volume concentration of droplets in the observation area for each frame: \(\gamma_{\text{d}}\) = \(V_{\text{m}}\)/\(V_{\text{a}}\). If the droplet concentration deviated from the values \(\gamma_{\text{d}}\)\(\approx\)3.8\(\cdot\)10\({}^{-2}\) l/m\({}^{3}\) by more than 10%, the experiment was disregarded in the subsequent analysis. During the experiments estimating \(\gamma_{\text{d}}\) and \(R_{\text{d}}\), we determined that the spray event duration (\(t_{\text{imp}}\)) did not affect the flow characteristics. Moreover, at the initial (lasting less than 0.15 s) and final (lasting less than 0.1 s) stages, the \(\gamma_{\text{d}}\) values can deviate from the mean ones by 15-20%. This effect was not taken into consideration when analyzing the results. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Type of Flammable Liquid**} & \multicolumn{6}{c}{**Component Concentration**} \\ \cline{2-7}  & **O\({}_{2}\), \%** & **CO\({}_{2}\), \%** & **CO\({}_{2}\), \%** & **CO\({}_{2}\), \%** & **CO\({}_{2}\), \%** & **CO\({}_{2}\), \%** \\ \hline Kerosene & 12.02 & 6.21 & 0.13438 & 0.0038 & 0.0041 & 0 \\ Kerosene [9] & 11.71 & 6.79 & 0.12567 & 0.0044 & 0.0046 & 0.00013 \\ Industrial ethanol [9] & 14.9 & 4.4 & 0.0577 & 0.0017 & 0.0018 & 0 \\ Acetone [9] & 15.68 & 3.87 & 0.0308 & 0.0027 & 0.00287 & 0 \\ Gasoline [9] & 12.9 & 5.85 & 0.1585 & 0.0036 & 0.0039 & 0 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Average concentrations of CO\({}_{2}\), CO, NOx, NO, SO\({}_{2}\), and O\({}_{2}\) in kerosene combustion products, as well as data from the work in [9]. All the said parameters (\(\gamma_{\mathrm{d}}\), \(U_{\mathrm{d}}\), and \(R_{\mathrm{d}}\)) were measured in the same area that was further used to measure the gas-vapor mixture temperature (Figure 1). During the experiment, water was repeatedly sprayed into the inner portion of cylinder 7, towards the high-temperature combustion products or heated air flow. Spray event duration (\(t_{\mathrm{imp}}\)) varied in the range of 1 to 5 s. Spraying was repeated every 30 s. An electronic timer of 0.1 s time increment was used for time recording. Each experiment involved 10 to 15 injections. At least 10 experiments were conducted for each set of initial parameters (\(\gamma_{\mathrm{d}}\), \(t_{\mathrm{imp}}\), \(R_{\mathrm{d}}\), \(U_{\mathrm{d}}\), and \(U_{\mathrm{a}}\)).