Modelling and Simulation Heat Transfer in Wheat Stored in a Simulated Sealed Pit

A mathematical model was developed to predict the change of temperature distribution with time in the radial and axial directions in a simulated sealed cylindrical pit. The finite difference method was used in the model to calculate the conductive heat transfer. The model can predict the grain temperatures in the pit during the storage period using input data of initial grain temperature, storage time and number of spatial elements in both radial and axial directions. Other input data include the finite difference spatial increment in both directions, the finite time increment, temperatures of soil surrounding the pit and the physical properties of grain, pit wall material and surrounding soil. To validate the model, predicted temperatures were compared with measured data for wheat of Apollo variety being stored in a simulated sealed pit for a period of 70 days. The wheat was stored in a cylindrical mild steel tank with 0.6 m in both diameter and height. The initial grain temperature was 15°C. Both measured and predicted wheat temperatures attained equilibrium state within a short period of storage (2 to 6 days) and the equilibrium was maintained throughout the experiment period. The conductive heat transfer model predicted the grain temperatures accurately and within the bounds of the experimental error. The standard error of estimate between measured and predicted was 0.12°C -0.25°C.