## Materials and Methods
### Physical Model and Governing Equation  
The storehouse used in this experiment is a three-dimensional physical model with the dimensions of 0.6 m \(\times\) 0.6 m \(\times\) 0.6 m (length \(\times\) width \(\times\) height). To save the calculation time, the mathematical model of paddy storage without manual intervention was simplified. The main assumptions are as follows: (1) a continuous medium paddy; (2) incompressible ideal air; (3) interconnected pores of the grain pile; (4) negligible thermal radiation between grain particles or between grain and air (ignored); and (5) negligible shrinkage or deformation of grain particles (ignored). In addition, a paddy is a living organism with water absorption and desorption features.  
Continuity Equation:  
\[\frac{\partial u_{j}}{\partial x_{j}}=0 \tag{1}\]  
Momentum conservation Equation:  
\[\rho_{a}\frac{\partial u_{i}}{\partial t}=-\frac{\phi\mu u_{i}}{K}-\frac{ \partial p}{\partial x_{i}}+\delta_{ij}\rho_{a}g\beta(T-T_{0}) \tag{2}\]  
Energy conservation Equation:  
\[(\rho_{b}C_{b})\frac{\partial T}{\partial t}+(\rho_{a}C_{a})u_{j}\frac{ \partial T}{\partial x_{j}}=\frac{\partial}{\partial x_{j}}\left[k_{b}\frac{ \partial T}{\partial x_{j}}\right]+\rho_{b}h_{fg}\frac{\partial W_{g}}{ \partial t}+\rho_{b}q_{h}Y_{Co_{2}} \tag{3}\]  
Water conservation Equation:  
\[\rho_{b}\frac{\partial W_{g}}{\partial t}+u_{j}\left(\frac{\sigma}{R_{\rm T}T} \right)\frac{\partial W_{g}}{\partial x_{j}}=\frac{\partial}{\partial x_{j}} \left(D_{M}\frac{\partial W_{g}}{\partial x_{j}}\right)+\frac{\partial}{ \partial x_{j}}\left(D_{T}\frac{\partial T}{\partial x_{j}}\right)-u_{j}\left( \frac{\omega}{R_{\rm T}T}\right)\frac{\partial T}{\partial x_{j}}+\rho_{b}q_ {w}Y_{Ho} \tag{4}\]  
In the above Equations, \(D_{M}=D_{eff}\sigma\), \(D_{T}=D_{eff}\omega\), \(D_{eff}=\frac{D_{T}\phi}{\tau R_{*}}\), and \(u_{j}\) (\(j\) = 1, 2, 3) is the air flow rate in the direction \(x_{j}\), \(u_{1}\) = \(u\), \(u_{2}\) = \(u_{3}\) = \(v\). In the rectangular Cartesian coordinate system, \(x_{1}\) = \(x\), \(x_{2}\) = \(y\), \(x_{3}\) = \(z\), \(\phi\) is the porosity of paddy bulk grain pile; \(t\) is the time (s); \(p\) is the air flow pressure (Pa); \(\beta\) is the coefficient of air expansion; \(\rho_{a}\) and \(\rho_{b}\) are the air density and bulk grain density, respectively (kg/m\({}^{3}\)); \(\mu\) is aerodynamic viscosity (Pa\(\cdot\)s); \(K\) is permeability(m\({}^{2}\)); \(g\) is the acceleration of gravity (m\({}^{2}\)/s); \(T\) is the temperature of grain pile (K); \(C_{a}\) and \(C_{b}\) are the specific heat capacity of the air and bulk grain pile, respectively (J\(\cdot\)kg\({}^{-1}\cdot\)K); \(h_{fg}\) is the heat of evaporation from the grain pile (J/mg); \(W_{g}\) is the moisture content of the grain pile (g/kg); \(q_{h}\) is the heat released by the respiration of grains (J/mg); \(q_{w}\) is the respiratory water yield of the grain pile (kg/mg); \(Y_{Ho_{2}}\) is the amount of water released by the grain pile in a day; \(Y_{Co2}\) is the release rate of co\({}_{2}\) in one day; \(D_{v}\) is the diffusion coefficient of moisture in the air (m\({}^{2}\)/s); and \(\omega\) is the moisture content of air, \(\tau\) is tortuosity.