Study Of Pressure Loss Coefficient In HVAC Fittings

In HVAC industries, equipments choosing, ventilation effect, system optimizing, and system efficiency are all influenced by the pressure loss directly. So, the study of reducing the local loss coefficient is significance in HVAC industries and energy saving.This paper refers to a direction of study that probe into pressure loss coefficient in HVAC fittings and the method of reducing the local loss coefficient. One elbow, 45-shape tee and T-shape tee were studied by experiment, CFD and visualization, analyzing pressure and velocity distributing in ducts, revealing pressure loss mechanism. In this paper, the HVAC fittings has been improved in many ways and achieved in different method.The conclusion of this paper show that in the procession of one elbow improving, the effect of fiber grid is remarkable. After improving, the distribution of the pressure and the velocity is more rational. So, it can gain rational air flow. T-shape tee, improved by wire meshes, which is as wide as 1/4 duct wide. The reducing rations of pressure loss coefficient are 32.6% in branch and 59% in main duct. When the wire meshes is as wide as 1/2 duct wide, the reducing rations of pressure loss coefficient are 32.6% in branch and 59% in main duct. 45-shape tee improved by wedge-shaped component is remarkable. When it is 10cm thick, he reducing rations of pressure loss coefficient are 17.8% in branch and 4.1% in main duct. When it is 20cm thick, the reducing ration of pressure loss coefficient is 5.4% in branch but in main duct, the loss coefficient is raise.