Aerodynamic Torque Characteristics of Butterfly Valves in Compressible Flow

Abstract

The results of an experimental investigation of the aerodynamic torque characteristics of butterfly valves under compressible flow conditions are reported. Both three-dimensional prototype valves and two-dimensional planar models have been studied at choked and unchoked operating points. Other parameters investigated include the operating pressure ratio across the valve, the valve disk angle, and the disk shape. The results demonstrate the importance of flow separation and reattachment phenomena on the valve aerodynamic torque characteristics, the importance of disk shape at intermediate angles, and the sensitivity of the torque to the valve disk geometry near the leading and trailing edges where extreme pressure gradients can occur.