Study on the Modified Ventilation Network on the Ventilation Effect and Ozone Migration Characteristics in Grain Pile

Abstract

Grain is an important material for human survival. However, the expanding world population is contributing to a growing grain shortage. In order to reduce the loss of grain due to pests and mold during storage, mechanical ventilation as the main method of ventilation has crucial research significance. This article proposed and analyzed the ventilation effect and the migration characteristics of ozone in the grain pile under the modified ventilation network (MVN) and compared it with the original ventilation network (OVN). The study found that the temperature, moisture, and ozone concentration in the grain pile of the two ventilation networks are not evenly distributed in the vertical direction, showing a layered pattern. That is, with an increase in grain stack height, the temperature and moisture content of the grain stack are higher, and the ozone concentration is lower. Moreover, in the pre-ventilation period, the average temperature decline rate of the MVN was 1.25 °C/d, which was better than that of the OVN (0.84 °C/d), and the maximum temperature difference between the MVN and the OVN was 0.89 °C. The vertical ducts added to the MVN improved the ventilation effect, maintaining high ozone concentrations within the grain pile. Notably, on the sixth day of fumigation, the average ozone concentration of the MVN exceeded that of the OVN. The MVN can solve the shortcomings of the OVN, where air intake and fumigation gas rise slowly in the vertical direction. These findings hold substantial significance for optimizing ventilation network structures, devising effective fumigation strategies, and enhancing the insecticidal effects of grain storage.