CFD investigation on a novel pen partition-attached jet air supply for mitigating heat stress among lactating sows

Abstract

To effectively mitigate heat stress among lactating sows, this study proposed a novel pen partition-attached jet air supply (PJAS) and compared its performance with commercial ceiling jet air supply (CJAS) by using computational fluid dynamics (CFD). Each PJAS unit, comprising a circular distribution duct with 5 slot orifices at each side, was installed at the pen partition between two adjacent pens to direct air towards lactating sows to enhance convective heat removal. The cooling performances of air supplier were primarily evaluated by assessing the convective heat flux from lying sows. The effect of jet angles induced by PJAS and CJAS on convective heat flux were investigated as well as the consequence of reducing the inlet dimension of CJAS. The results revealed that reducing the inlet dimension of CJAS doubled the speed of supplied air. However, it also limited the amount of air impinging on sow due to the narrowing of the inlet air jet. Consequently, the combined effect only marginally increased the convective heat flux when the inlet area of CJAS was reduced. By placing air supplier closer to lactating sows, the air jet induced by PJAS impinged on sows’ bodies directly and therefore significantly increased the convective heat removal. Compared to CJAS, PJAS required approximately 45% less ventilation rate to induce the same convective heat flux. When the ventilation rate was identical, PJAS could increase the convective heat flux by up to 27.6%. These results highlight PJAS as a promising energy-efficient localized cooling device for mitigating heat stress among lactating sows. To determine the optimal design and control strategy of PJAS based on industrial requirements, further research is still needed.