POTENTIAL FLOW IN ELBOWS

Potential flow in 2D circular-arc elbows, accelerating elbows and cons tant-area elbows (similar to radial turbomachine flow channels) is sol ved by numerical methods. For circular-arc elbows, a formula is obtain ed which predicts velocities at mid-turn. For other locations, it is s hown that velocity distributions can be collapsed into a single non-di mensional plot; a suitable explicit empirical approximation is also pr esented. Guidelines are thence obtained to allow estimation of minimum acceptable upstream and downstream computational domain length, magni tude of expected velocity changes, and velocity gradients; this should be of assistance in the planning of computational solutions to simila r flow situations. Solutions for accelerating elbows and constant-area elbows are also presented to illustrate foreseeable similarities and differences with circular-arc elbows.