## 3 Experiments
### Simulation Model Input Conditions
\begin{tabular}{c c c c} \hline \hline
**Type** & **Type** & **Type** & **Type** \\ \hline R1 & \(Urea(g)\to HNCO(g)+NH_{3}(g)\) & \(4.900\times 10^{3}\) & 2.3 & [23] \\ R2 & \(HHCO(g)+H_{2}O(g)\longrightarrow NH_{3}(g)+CO_{2}(g)\) & \(2.500\times 10^{5}\) & 6.22 & [23] \\ R3 & \(Urea(m)+HNCO(l)\longrightarrow B\ddot{u}pert(m)\) & \(3.517\times 10^{11}\) & 7.545 & [24] \\ R4 & \(Urea(m)\longrightarrow HNCO(l)+NH_{3}(g)\) & \(2.000\times 10^{4}\) & 7.4 & [24] \\ R5 & \(B\ddot{u}pert(m)+HNCO(g)\longrightarrow Cya(g)+NH_{3}(g)\) & \(9.397\times 10^{20}\) & 15.868 & [24] \\ R6 & \(2\ddot{B}iuret(m)\longrightarrow Cya(g)+HNCO(g)+2 NH_{3}(g)\) & \(2.327\times 10^{24}\) & 38.155 & [25] \\ R7 & \(B\ddot{u}pert(s)+HNCO(g)\longrightarrow Ammellide(s)+H_{2}O(g)\) & \(5.244\times 10^{18}\) & 24.85 & [25] \\ R8 & \(Cya(s)+NH_{3}(g)\longrightarrow Ammellide(s)+H_{2}O(g)\) & \(7.013\times 10^{20}\) & 29.665 & [26] \\ R9 & \(2\ddot{B}iuret(m)\longrightarrow Ammellide(s)+HNCO(g)+NH_{3}(g)+H_{2}O(g)\) & \(2.327\times 10^{26}\) & 25.776 & [24] \\ R10 & \(Ammelide(s)+NH_{3}(g)\longrightarrow Ammeline(s)+H_{2}O(g)\) & \(2.518\times 10^{21}\) & 31.063 & [26] \\ R11 & \(B\ddot{u}pert(m)\longrightarrow Urea(m)+HNCO(l)\) & \(1.107\times 10^{21}\) & 20.823 & [24] \\ R12 & \(Cya(s)\longrightarrow 3 HNCO(g)\) & \(1.001\times 10^{3}\) & 11.842 & [24] \\ \hline \hline \end{tabular} 
\begin{tabular}{c c c} \hline \hline
**Type** & **Type** & **Type** \\ \hline R1 & \(Urea(g)\to HNCO(g)+NH_{3}(g)\) & \(4.900\times 10^{3}\) & 2.3 & [23] \\ R2 & \(HHCO(g)+H_{2}O(g)\longrightarrow NH_{3}(g)+CO_{2}(g)\) & \(2.500\times 10^{5}\) & 6.22 & [23] \\ R3 & \(Urea(m)+HNCO(l)\longrightarrow B\ddot{u}pert(m)\) & \The pore structure of the carrier has the characteristic of being narrow and long, and the number of pores is numerous, making it impossible to establish a detailed three-dimensional model for calculation. Therefore, the resistance characteristics of the carrier are added to the calculation model by adding source terms to the momentum equation. The viscosity term and the inertia term are two parts of the momentum source term, and the calculation formula for the resistance in the carrier region is as follows:  
\[f=-(P_{v}+P_{i}|v_{\mathrm{s}}|)\cdot v_{\mathrm{s}}, \tag{6}\]  
where \(P_{v}\) is the viscous resistance coefficient tensor, \(P_{i}\) is the inertial resistance coefficient tensor, \(v_{\mathrm{s}}\) is the surface flow velocity. According to the pressure drop curve of the carrier, the viscous resistance coefficient and inertial resistance coefficient were fitted, and the viscous resistance coefficient values were 1520 kg.m\({}^{-3}\cdot\) s\({}^{-1}\) and 2.32 kg.m\({}^{-4}\), respectively. Based on the adaptive polyhedral mesh and boundary layer mesh generation strategy, the entire computational domain is discretized spatially and divided into two parts: the fluid domain and the solid domain. The basic size of the global mesh is 0.01 m, and the minimum can reach 2 mm. In the fluid domain, polyhedral grids are used, and two layers of boundary layers are set up. The total thickness of the boundary layer mesh is 2.1 mm, with a growth rate of 1.2. Since the minimum mesh size can reach 1/5 of the basic size, the fluid domain mesh is refined in the region near the wall surface, and the refined mesh region plays a certain role in the boundary layer. For the purpose of reducing computational resources, the number of layers of the boundary layer is set to 2. The solid area belongs to a thin-walled structure and is divided into two layers of thin body meshes. The relevant parameters are shown in Table 3.  
In order to achieve a common node between two computational domain meshes at the interface, the solid domain mesh generation is first completed, and then the fluid domain mesh generation is carried out.