Pressure Drop in a Bending Duct

Abstract

We have developed a method of cooling high-power-density CPU modules within a bending duct. The method uses a jet-duct system made of an air duct and axial fans. This system has slit orifices upstream from the CPU modules. Pressure drops in this system are calculated as four values : wringing loss in the chamber, friction loss in the duct, extrusion loss from the duct, and wringing loss in the slit orifice. These loss values agree with the experimentally measured losses to within an error of ±10%. The calculation showed that when the duct width is small, the wringing loss in the chamber account for the major part of the total loss.