A Study of Vortex Throttles Part 1: Experimental

Abstract

Measurements have been made to determine the performance of various designs of vortex throttle using both air and water. Two basic types of throttles were used, square-edged and round-edged. Performance is expressed mainly in terms of Reynolds number and Euler number. The effect of changes in geometry on performance is studied and comparison made between performance for compressible subsonic flow and for incompressible non-cavitating flow. The maximum values of Euler number found for throttles with a unity tangential to axial port area ratio were about 66 for square-edged throttles and about 71 for round-edged throttles. The results agree with those of Zobel, although better performance than found by Zobel was obtained with a slightly modified axial port geometry. In one case severe cavitation was found to slightly improve throttle performance, with the indication that a throttle could be made with performance independent of cavitation. Some recommendations are given for optimum throttle design.