The Cheng Rotation Vane (CRV® ) consists of a set of stationary vanes in a cylindrical body which is placed immediately upstream of an elbow or tee in a piping system. The CRV® eliminates elbow induced turbulence which negatively impacts the performance of pumps, compressors, control valves, flow meters, and other equipment. The CRV® inputs to the flow a counteracting gyroscopic motion to the resultant elbow induced gyroscopic motion, and enables the fluid to negotiate the turn through the elbow and then exit the elbow with a flat velocity profile. This results in an even distribution of process fluid through any cross-section of the elbow and transforms the elbow into the equivalent of a straight length of pipe, and there is no additional pressure drop with the use of a CRV®.

An instantaneous picture of water flowing through a pipe turn. The colored dyes trace the fluid motion guided by fluid potential flow and the gyroscopic turning of the elbow. Note that the separations occupy a large percent of the flow area.

The CRV causes prerotation of the water before entering the elbow. Only the gyroscopic motion of the CRV can cancel the gyroscopic effects of the elbow to yield an equal streak line geometry and uniform flow profile as in a straight pipe.

Geometry

Streak Lines