Tests on a tip turbine volute with circular cross-sections and a gooseneck outlet

Model tests were made on a volute des igned by a method that takes into account wall friction, a free vortex flow pattern, and compressibility. The tests indicated that a free vortex flow pattern does prevail over most of the volute, witb some deviation at both tbe beginning and end of the scroll. Because of a secondary flow in the volute, the effect of friction differs irom that anticipated in the design method. Near the re-entry region tbe outcoming flow shows a greater deviation than elsewhere from ideal behaviour.