Which is more suitable for ventilating grain silos: axial flow fans or centrifugal fans?

Which is more suitable for ventilating grain silos: axial flow fans or centrifugal fans?

Due to the differences between axial flow fans and centrifugal fans, the scope of application for these two types of fan units also varies. For instance, when it comes to ventilation and cooling in grain silos, axial flow fans perform exceptionally well in all respects, so they are recommended. Why are centrifugal fans not suitable? This is related to the differences between the two. It is well known that centrifugal fans generate very high airflow and pressure, which causes the direction of the medium’s flow within the duct to change. In contrast, axial flow fans produce much lower airflow and pressure. From an installation perspective, centrifugal fans are more complex, requiring the use of a motor and fan connected via a shaft. The motor in an axial flow fan is housed internally, making installation very straightforward. To maximise the ventilation efficiency of both centrifugal and axial flow fans, the former is typically installed at the inlet and outlet of an air conditioning unit, whilst the latter is usually positioned in the middle or at the front end of the duct. It is clearly the outlet of the other section. If centrifugal fans are used in barns, condensation may form on doors, windows and walls, and a small amount of condensation may appear on the surface of the grain; however, as long as the centrifugal fan is stopped and the windows are opened, the axial flow fan can then be switched on to expel the hot, humid air from inside the barn. Axial flow fans ventilate gradually, which not only prevents condensation but also allows the temperature of the middle and upper layers of grain to rise slowly; as ventilation continues, the grain temperature will steadily decrease. However, due to the significant difference between ambient air temperature and grain temperature, to minimise the gap between the two and suppress condensation, please ensure that the first ventilation session is scheduled during the day. Subsequently, with the aim of lowering the ambient temperature, as atmospheric humidity is relatively high and night-time temperatures are comparatively low, using axial flow fans to ventilate the granary at night not only reduces water loss but also enhances the cooling effect by utilising the lower night-time temperatures.