Effect on pressure loss of separation and orientation of closely coupled HVAC duct fittings.

The effects on pressure loss of the separation and orientation of closely coupled duct fittings in RVAC systems were investigated using computational fluid dynamics to analyse the pressure distribution in a system containing two 90° bends in two common configurations; an S bend and a U bend. Fittings that are separated by less than 8 to 10 hydraulic diameters· of the duce behaved in very different ways depending upon the orientation of the fittings in relation to one another. Further in depth analysis is required to produce accurate and comprehensive pressure loss coefficient data, and thus improve HVAC systems design.