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Simulation study of ventilation characteristics of solar greenhouse under natural ventilation

In order to improve the ventilation efficiency of greenhouse under the condition of no wind or low wind speed and to ensure the supply of carbon dioxide to plants, a CFD greenhouse three-dimensional thermal pr roof vent height essure ventilation model was established to simulate with the background of Zhengzhou regional climate environment, and the changes of temperature distribution, pressure distribution, flow field and roof ventilation flow inside the greenhouse were studied by raising the roof vent height and changing the roof ventilation area. The results show: Increasing the roof ventilation area effectively increases the roof ventilation flow rate, and the roof ventilation flow rate increases when the ratio of roof ventilation area to greenhouse floor area reaches 2%-4%. The ratio of roof ventilation area to greenhouse area 2%-4% flow rate increase is higher, 4%-6% flow rate increase is significantly lower, when increased to 4%, the increase of roof ventilation flow rate will have a significant decrease. Because the thermal pressure ventilation relies on the heat source from the sun, the internal wind generated is more stable.