摘要
Uniformity of air flow in extraction openings in exhaust air channels for manure gas exhaustion is determined by the distribution of pressure. The areas required in extraction vents and in extraction ducts are determined by the uniformity of air flow desired along the duct and by the loss of pressure that can be accepted. The area ratio between the vents and the cross section of the exhaust air duct will have a strong influence on both uniformity of flow and loss of pressure. The following ventilation properties were studied： Uniformity of air flow; Variations in static pressure along a duct; Air velocity at different distances from the vents. The area ratio should be about 1 for uniform exhaustion. The studies showed that the relative variation in air velocity is independent of the level of the ventilation rate. The uniformity of the exhaust distance is influenced in about the same way by the area ratio as the air velocity in the exhaust vents. Thus, it is important that the area ratio is not too high if a good exhaust function should be guaranteed. The studies also demonstrated that the uniformity of the exhaust distance is independent of the ventilation flow rate. The exhaust ventilation range is, maximally 0.3 m from the vents. The static friction coefficient was on average 0.80.
