## 3 Heating Experimental Study to Dryout  
### Experimental Set-Up  
Figure 1 depicts the mechanism of evaporation in a porous media limited by an overlying water-free surface due to the heat addition from below at temperatures above the saturation ([PERSON] [21], [PERSON] [29]), and Figure 2 shows a photograph and a drawing of the experimental set-up used to study the response of porous media to bottom heating. The porous medium was placed in a cylindrical stainless steel cell (boiling cell) of 15 cm in internal diameter and 14 cm in height. The interior of the cell was painted to prevent galvanic corrosion. An aluminum plate of 14.8 cm in diameter and 4 cm in height was located at the bottom of the cell, with 3 cm inside. For the electric heating of the aluminum plate, a DC power supply was used with voltage and current ranges of 220 V and 5 A, respectively. The instrumental error for voltage and intensity were 1.0 V and 0.01 A, respectively. Several layers of insulating material to prevent heat losses as much as possible covered the ensemble. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Property/Material** & \(\mathbf{\hat{d}_{p}}\) **(m)** & \(\mathbf{\rho}\) **(kg\(\cdot\)m\({}^{-3}\))** & \(\mathbf{S_{e}}\) **(m\({}^{-1}\))** & \(\mathbf{c_{p}}\) **(J\(\cdot\)kg\({}^{-1}\)K\({}^{-1}\))** & \(\mathbf{\lambda}\) **(W\(\cdot\)m\({}^{-1}\)K\({}^{-1}\))** \\  & & & & **20 \({}^{\circ}\)C** & **20 \({}^{\circ}\)C** \\ \hline Bronze & \(2.355\times 10^{-4}\) & 8614.05 & 25,443.56 & 376.00 & 71.00 \\ Sand & \(2.960\times 10^{-3}\) & 2613.95 & 2027.03 & 527.90 & \(31.39\times 10^{-2}\) \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Physical properties of the solid phase. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Porous Medium** & \(\mathbf{\epsilon}\) & \(\mathbf{k^{\prime}}\) **(m\({}^{2}\))** & \(\mathbf{\lambda_{ef}}\) **(W\(\cdot\)m\({}^{-1}\)K\({}^{-1}\))** \\ \hline B+W & 0.360 & \(3.92\times 10^{-11}\) & 7.44 \\ B+DS & 0.360 & \(3.92\times 10^{-11}\) & 6.95 \\ S+W & 0.380 & \(4.41\times 10^{-10}\) & 0.357 \\ S+DS & 0.380 & \(8.41\times 10^{-10}\) & 0.330 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Saturated porous media characteristics. A tray for collecting the liquid displaced from the porous medium during the heating process was placed above the cell. A non-deformable layer of nylon fabric was placed between the cell and tray to avoid the displacement of the solid matrix of the porous medium as a consequence of the boiling process of the fluid phase. The boiling cell was equipped with various T-type thermocouples, as shown in Figure 2. The measurement of the temperature on the heating plate was carried out with three thermocouples at different heights, one of which was located at the center (T7) and the other two at 1.5 cm on both sides of the center (T6 and T8). The temperature of the porous medium measured with five thermocouples at different heights and radii, from T2 to T5, and the liquid accumulated in the cuvette with one thermocouple (T1). The thermocouples of the heating plate were introduced through small holes of different lengths, and finally sealed with heat-conductive adhesive. After the calibration of the T-type thermocouples, the accuracy in the measurement of the temperature was \(\pm\)1.0 \({}^{\circ}\)C.  
The measurement of pressure was carried out with four piezometric probes with a precision of \(\pm\)2.45 N/m\({}^{2}\) (\(\pm\)0.25 mm.w.c.). They were located inside the porous medium, at different heights and distances from the plate (P1 to P4). The level of liquid in the tray was measured by using a limimeter (with an accuracy of \(\pm\)0.5 mm). In addition, temperature and humidity data were also collected. Figure 1: Evaporation in a porous media limited by an overlying water-free surface due to the heat addition from below at temperatures above the saturation. Figure 2: Scheme and photography of the boiling cell and radial position of the instrumentation.