Dependence of flow coefficient on the cone angle and relative opening of natural gas control ball valves

Abstract

Natural gas control ball valves are fluid control devices that regulate the flow and direction of the medium in a natural gas transportation system, and nowadays the requirements for valve intelligence are increasing. To implement the intelligent control of the valve system, the precise acquisition of the operating parameters of the control ball valve was studied in this paper. A numerical simulation of the internal flow field of a V-shaped ball valve was conducted based on a finite volume method and an renormalization group (RNG) k–ε turbulence model. A valve performance test bench was established, and the pressures at the inlet and outlet of the valve at various relative openings were measured, in which the accuracy of the numerical model was verified. Through numerical simulations, the internal flow characteristics at various relative openings and spool cone angles were studied. By comparing the influence of three different relative openings on the valve internal flow field, it was found that the valve showed better flow characteristics under the relative opening of 80%, and the increase of the cone angle effectively improved the unstable flow in the valve. An accurate expression between the external parameters of the valve operating condition and the internal flow was established, and the expression is the theoretical basis to implement intelligent control. This study provides strong technical support for an efficient operation of natural gas pipelines.