Structural Conceptual Design and Flow Characteristics of Coaxial Counter-Rotating Ball Valve

A control valve that can precisely control flow rate and pressure is used in various process lines. The globe valve has been widely applied as a control valve owing to fast opening, closure, and precise flow control. Furthermore, an equal flow coefficient percentage of a globe valve can be provided as the inherent flow characteristics required for a typical control valve. The flow path, however, changes rapidly at a low opening rate. Recently, a ball valve was considered as a control valve owing to its simple structure and requires only a quarter-turn of the stem to be fully opened and closed. There are disadvantages to these characteristics, such as opening starting at the side of the flow path, and the inherent flow characteristics do not appear in an equal flow coefficient percentage. In the present study, a coaxial counter-rotating ball valve was proposed through a structure conceptual design, in which opening can start at the center of the flow path. The computational fluid dynamics analysis was carried out to assure whether the equal percentage of flow coefficient was satisfied due to change of the opening rate. The flow coefficient C-v with a range of 1.05 similar to 110.49 was increased exponentially at the opening rate of 20 similar to 100%. In addition, the availability of the proposed vale as a flow control valve was reviewed by comparing C-v with a V-port ball valve commercially used.