Capacity Testing and Local Flow Analysis of a Geometrically Complex Trim Installed within a Commercial Control Valve

Industrial control valves often handle flows with very high pressure drops (conditions often referred to as severe service). In order to cope with such pressure drops, geometrically complex valve trims with many stages of pressure drops, are designed to prevent undesirable side effects such as cavitation etc. There are many different product designs for control valve trims produced by different manufacturers. One such design uses cylindrical obstructions in the flow field to control the pressure drop. The design of these trims is based on their capacity (Cv) values. With the advent of advanced computational tools, such as Computational Fluid Dynamics based codes, it has become possible to numerically test these trims over a wide range of flow conditions. Hence, this study presents capacity testing and local flow analysis of a complex geometry trim, installed within a commercial control valve for severe service. The results show that the capacity of this particular design of trim decreases as the valve opening position decreases.