Effects of the geometrical features of flow paths on the flow capacity of a control valve trim

Control valves are an integral part of a number of energy systems, such as those used in chemical and nuclear industries. These valves are used to regulate the amount of fluid flow passing through these systems. A key component of a control valve is its trim, which in case of a multi-stage continuous-resistance trim consists of a staggered arrangement of columns. Flow passing through the channels formed between adjacent columns (also called as flow paths), loses a significant amount of its energy and regulates the pressure field. As the geometrical features of these flow paths dictate the flow capacity of the trim, systematic investigations have been carried out to analyse the complex flow behaviour within these flow paths. Well-verified computational fluid dynamics based solver has been used to investigate the effects of the geometrical features of flow paths on the flow capacity of the trim, at various valve opening positions. It has been noticed that reducing the size of flow paths increases the flow capacity of the trim, however, at a critical flow path size, the inherent opening characteristics of a trim have been observed to alter. In order to recover the original opening behaviour of the trim, careful manipulation of the flow paths is required, which has been successfully achieved in the present investigation.