Shape Design of Internal Flow with Minimum Pressure Loss

Stanitz in his classical paper on duct design presented a design for a deceleration free 90°-curved nozzle. For given inlet and outlet sections of a 2D curved nozzle, however, there is an infinite number of deceleration free duct shapes. This paper explains how these shapes are designed in an inviscid flow context, and provides insight into the optimum design in a viscous flow context. Viscous results, in both 2D and 3D examples, are given using a CFD program. The results show that inviscid flow data is valuable in the design; the energy losses are affected by the geometry of the flow passage, especially in high Reynolds number flows.