Design and Test of an Embedded Conical Air-Assisted Spray Device for Disinfection in Large-Scale Pig Farms

Spray disinfection is a necessary measure to reduce virus infection in modern large-scale pig farms. At present, spray disinfection in pig barns in China mainly relies on manual backpack-type, semi-automated and fixed equipment, which have associated problems such as high labor intensity, short spraying range, disinfectant waste and unstable distribution of droplet deposition. To solve these problems, an embedded conical air-assisted spray device for disinfection was designed in this paper. The nozzle is centrally embedded in the conical air duct outlet to form a coaxial gas−liquid-coupled atomization structure. High-speed airflow from the axial fan extends the spraying range. Using the method of computational fluid mechanics (CFD), simulation models of the conical duct and the cylindrical duct are established. The results show that when the fan’s rotation rate is the same, the outlet airflow speed of the former is 39.57% higher than that of the latter, and the area-weighted average speed uniformity index rises by 8.33%. Tests on device obstacle avoidance and spray performance were carried out. The results show that the overall success rate for obstacle avoidance was 93.3%. Under enclosed pig-barn conditions, the average spraying range of the device was 5.45 m, which was 64.16% higher than that of the spraying operation without airflow assistance. When the device sprayed under the three-zone comprehensive optimal parameters, the average coefficient of variation of the lateral droplet deposition mass was 10.23%, demonstrating that the overall spray deposition coverage is relatively uniform. The research carried out can provide a theoretical and engineering reference for the design and parameter optimization of similar sprayers for disinfection in large-scale pig farms.