# Experimental and Numerical Evaluation of Toxic Pool Evaporation
## 2 Experimental Set-Up
### Experimental Design  
As previously mentioned, the objective of this study was to determine a realistic evaporation rate for ammonia under various conditions. To meet this objective, we carried out 6 tests at the small scale and 5 at the medium scale. For both configurations, concentrations were precisely measured before running the tests, since this parameter is of primary importance for evaporation modelling. Table 1 below lists the smaller scale tests, with the comparison reference test highlighted in blue (test no. 3). On the basis of the small-scale test results, we designed a series of 5 tests at the medium scale in order to confirm the small-scale observations and, when required, to go further. The reference test for medium-scale tests is also highlighted below in blue (test no. 1). Tests marked with a star (tests no. 1, 2, and 5) in Table 2 correspond to those made with comparable conditions during small- and medium-scale tests (such tests are crucial to discuss the influence of the scale factor). Significant variations of the mass concentration and initial temperatures of the pool can be noticed. Since the installations are opened to the outdoors, temperature control was not possible. Therefore, a 10 \({}^{\circ}\)C difference can be seen between the two scales, which should be kept in mind when interpreting the results. As for the concentration, the difference was due to the fact that we chose to give the actual measured concentration rate instead of the manufacturer's 29% value; this also shows that when dealing with real situations for risk management, the actual concentration can differ from the estimated one. This actual concentration was measured in our chemistry laboratory (ion chromatography). During the experiment, the pool was filled with the ammonia solution, and evaporation was considered to start after the pool was completely filled. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Test No.**} & \begin{tabular}{c} **Mass** \\ **Concentration** \\ **of the Pool (\%)** \\ \end{tabular} & \begin{tabular}{c} **Air Velocity** \\ **(m/s)** \\ \end{tabular} & \begin{tabular}{c} **Ambient** \\ **Turbulence** \\ \end{tabular} & \begin{tabular}{c} **Pool** \\ **Surface (m\({}^{2}\))** \\ \end{tabular} & \
\begin{tabular}{c} **Initial Pool** \\ **Temperature** \\ **(\({}^{\circ}\)C)** \\ \end{tabular} &
\begin{tabular}{c} **Ambient Air** \\ **Temperature** \\ **(\({}^{\circ}\)C)** \\ \end{tabular} \\ \hline
1 & 17.0\% (21\%) & 1 m/s & Low & 0.1 & 3 \({}^{\circ}\)C & 1.1 \({}^{\circ}\)C \\
2 & 18.6\% (21\%) & 1 m/s & Low & 0.1 & 4.7 \({}^{\circ}\)C & 6.5 \({}^{\circ}\)C \\ \hline
3 & 29.4\% (20\%) & 1.0m/s & Low & 0.1 & 0.3 \({}^{\circ}\)C & 3.2 \({}^{\circ}\)C \\ \hline
4 & 29.5\% (29\%) & 1.5 m/s & Low & 0.1 & 2.2 \({}^{\circ}\)C & 3.3 \({}^{\circ}\)C \\
5 & 29.0\% (29\%) & 0.5 m/s & Low & 0.1 & 2.2 \({}^{\circ}\)C & 2.2 \({}^{\circ}\)C \\
6 & 26.5\% (24.6\%) & 1 m/s & Low & 0.1 & 1.4 \({}^{\circ}\)C & 4.5 \({}^{\circ}\)C \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Presentation of the small-scale tests. Concentration given by the provider is given in brackets ().