Dynamic mechanical property and flow performance of ball valve for hydrogen-blended natural gas pipeline

Abstract

The blending of hydrogen into natural gas (NG) transmission networks holds significant importance for addressing the challenges of long-distance hydrogen transportation and large-scale renewable energy integration. This study focuses on the hydrogen-blended applicability of key ball valve components in existing long-distance NG pipelines. By comprehensively considering the physical characteristics of hydrogen-blended natural gas (HBNG) and material characteristics, a dynamic thermal-fluid-mechanical coupling numerical model of the ball valve was developed, integrating the multiphysics fields. The mechanical property, flow performance, and dynamic behavior of the ball valve under the NG and HBNG environments were intuitively compared. The influences of operating parameters and rotational modes on the ball valve's sealing specific pressure, thermal gradient, and flow coefficient in the HBNG environment were studied further. The findings indicate that HBNG induces greater flow instability within and downstream of the valve compared to NG. During valve closure, the dynamic sealing specific pressure and flow coefficient of the ball valve in the HBNG environment are generally smaller than those in the NG environment, while simultaneously increasing sealing surface failure risks. The slow-to-fast rotational motion of the valve ball is more conducive to maintaining the dynamic flow performance and seat sealing performance of the ball valve. This research provides fundamental insights for evaluating the feasibility of hydrogen blending in the ball valve of long-distance NG pipelines.