## 4 Parameter Sensitivity Analysis
### Calculation Model for Mass Diffusivity  
The physical parameters of water, steam, noncondensable gases and various materials are repeatedly used in the calculations, so the calculated values of these physical parameters affect the accuracy of the results to some extent. It can be seen from Equation (11) that the value of the mass diffusion coefficient \(D_{\text{AB}}\) has an impact on the mass condensation rate. Different calculation models of the mass diffusion coefficient will cause a disturbance to the condensing amount of steam per unit area. According to the principle of the heat/mass transfer analogy, combined with Equations (12) and (13), it can be seen that the condensing heat transfer rate is also further affected by \(D_{\text{AB}}\). Therefore, a sensitivity analysis of the mass diffusion coefficient is performed here. When representing the mass diffusivity of steam to other mixed noncondensable gases, the Wilke and Lee model and the Fuller model were selected in this paper to calculate the mass diffusion rate of steam to a single noncondensable gas [30], and after obtaining the binary mass diffusivity, the final calculation result was obtained using [PERSON]'s model for the mass diffusivity of steam to mixed gases. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**No.** & **Wisconsin** & **2 Nodes** & **5 Nodes** & **10 Nodes** \\ \hline
1 & 85.28 & 83.3033 & 83.30575 & 83.3083 \\
2 & 116.935 & 118.4498 & 118.4575 & 118.4649 \\
3 & 120.45 & 117.2453 & 117.2528 & 117.26 \\
4 & 113.645 & 113.0738 & 113.0805 & 113.0871 \\
5 & 196.605 & 193.7196 & 193.7462 & 193.7713 \\
6 & 233.79 & 240.1341 & 240.1856 & 240.2329 \\
7 & 233.895 & 244.776 & 244.8291 & 244.8777 \\
8 & 226.695 & 235.2196 & 235.268 & 235.3124 \\
9 & 296.38 & 315.387 & 315.4822 & 315.5691 \\
10 & 301.405 & 318.3065 & 318.4039 & 318.493 \\
11 & 299.725 & 313.5457 & 316.6421 & 316.7304 \\
12 & 190.97 & 199.0317 & 199.0647 & 199.0952 \\
13 & 196.47 & 200.126 & 200.1576 & 200.1863 \\
14 & 190.47 & 193.7491 & 193.7791 & 193.8068 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Influence of the number of nodes on heat transfer coefficient for a horizontal condensing plate. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**No. ** & **Wisconsin** & **2 Nodes** & **5 Nodes** & **10 Nodes** \\ \hline
1 & 70.8 & 75.87777 & 75.87933 & 75.8811 \\
2 & 101.38 & 110.402 & 110.4073 & 110.413 \\
3 & 98.47 & 109.2021 & 109.2072 & 109.212 \\
4 & 97.52 & 105.0613 & 105.0658 & 105.071 \\
5  
The Wilke and Lee model is expressed as  
\[D_{\text{AB}}=\frac{\left[3.03-\left(0.98/M_{\text{AB}}^{1/2}\right)\right]\left(1 0^{-3}\right)T^{3/2}}{PM_{\text{AB}}^{1/2}\sigma_{\text{AB}}^{2}\Omega_{\text{D}}} \tag{14}\]  
The Fuller model is expressed as  
\[D_{\text{AB}}=\frac{0.00143T^{1.75}}{PM_{\text{AB}}^{1/2}\left[\left(\sum_{v} \right)_{A}^{1/3}+\left(\sum_{v}\right)_{B}^{1/3}\right]^{2}} \tag{15}\]  
where: \(D_{\text{AB}}\)--mass diffusion coefficient;  
\(P\)--total gas pressure;  
\(T\)--gas temperature;  
\(M\)--molar mass. Parameter values such as \(\sigma_{\text{AB}}\), \(\Omega_{\text{D}}\) and \(\sum_{v}\) can be obtained by looking up the parameter table [30]. By selecting two different binary mass diffusivity calculation models, the final heat transfer coefficient obtained from the code was compared with the experimental data from the Wisconsin condensation heat transfer experiment, as shown in Figure 4. The results show that although there is a significant difference between the condensation heat transfer coefficient calculated using the code and the experimental data, the results calculated using different mass diffusivity models are indeed different, and the deviation is about 5-10%. The results from the Wilke and Lee model were significantly closer to the experimental data than those from the Fuller model, indicating that physical parameters have an effect on the accuracy of the calculated results. Figure 4: Influence of mass diffusivity model on condensation heat transfer coefficient. (**a**) Vertical condensing wall.