On‐site test and numerical analysis on temperature field of an underground grain silo under static storage

Abstract Grain temperature is one of the most important factors affecting grain security. The temperature field of the underground ecological granary was investigated by field experiment and numerical simulation. The experiment was carried out in the underground grain silo (UGS), a full‐scale engineering model. The UGS temperature data for one consecutive year were obtained through daily on‐site periodic monitoring. Based on the boundary conditions of UGS, including ambient air temperature, heat transfer coefficient, and underground constant temperature zone, a two‐dimensional rotational axisymmetric model is constructed. Then the temperature field of UGS was analyzed by numerical method. The simulation results coincide with the test results, and the conclusions are as follows: (1) The average temperature of UGS is maintained at around 20°C, the upper zone is easy to be affected by the outside, but the central and bottom zone are relatively stable. (2) The average temperature of grain is always below 17°C, and the temperature of the surface layer has inevitable fluctuations due to the influence of the ambient air temperature. (3) The average temperature of grain changes significantly in the early stage, but as time goes on, the grain temperature tends to the temperature in the constant temperature zone. Practical Applications Compared with the traditional above‐ground granaries underground granary has the advantages of land saving, grain storage capacity per unit area and long‐term storage of grain at low temperature. Now we have built two large underground granaries to study the various properties of underground granaries, which will be put into normal use later. By studying the temperature field of underground granary, exploring the change of temperature field of long‐term grain storage is beneficial to the popularization and application of underground granary, which is of great significance to ensure food security.