The effect of air deflector angle on ventilation systems in laying hen houses during summer based on CFD analysis.

Negative pressure ventilation serves as the primary method for environmental control in poultry houses, with deflector plates functioning as one of the most effective active control devices within this system. However, the precise control mechanism by which deflector plates influence ventilation system performance remains unclear. This study investigated the impact of varying deflector plate angles (ranging from 15° to 90°) on ventilation performance through a combined experimental and numerical simulation approach, adjusting the opening angle of the deflector plates. Experimental results indicate that deflector plate angle significantly impacts ventilation efficiency and thermal environment. Increasing the deflector plate angle expands the air intake area and reduces airflow velocity, enabling more cage areas to fall within the comfortable wind speed range of 0.5-2 m/s while minimizing uneven airflow distribution within the poultry house. Larger angles elevate overall cage area temperatures, whereas smaller angles minimize indoor temperature fluctuations, keeping more laying hens within the comfort temperature zone. The optimal angle range for balancing ventilation requirements and ensuring animal welfare is between 60° and 75°. This study also established a theoretical model for predicting mass flow based on deflector plate angle, with calculated values exhibiting a relative error of less than 9.49% compared to experimental data. Experimental verification of the deflector plate angle's impact on laying hen house ventilation systems provides a theoretical basis for optimizing ventilation system design.\.