Study on the eccentric jet-flow characteristics induced by the opening regulation with a gate valve

Abstract

Valve-induced flow characteristics were often concerned in many fluid transportation and control industries. In this paper, the eccentric jet-flow characteristics induced by a gate valve have been studied by considering the influence of valve opening regulation. The experimental setup of monitoring the downstream pressures along the pipeline was developed, and corresponding numerical simulation was employed. The downstream-monitoring pressure distribution caused by valve opening regulation was investigated to verify the flow simulation. The generation mechanism of eccentric jet-flow was revealed as a strong pressure gradient caused by the throttling effect at the valve throat. It was found that the eccentric jet-flow evolved in the pipeline was accompanied by shearing vortices, extremely under a small valve opening. The pressure and axial velocity distributions at various downstream cross-sections of the eccentric jet-flow evolving in the pipeline were analyzed. The axial velocities on four monitoring lines in downstream cross-sections were extracted, and the radial location of the maximum axial velocity was derived to assess the eccentric characteristics of jet-flow. A dimensionless parameter of velocity eccentric ratio was introduced to quantify the eccentric intensity of the evolving jet-flow in the downstream pipeline, and its correlation with the pipeline length could be adequately expressed by a natural decreasing exponential curve via fitting analysis. By virtue of that correlation, the critical pipeline length was proposed that can be used as the judgment to the terminal of the eccentric jet-flow evolving in the downstream pipeline. This study was helpful to characterize the valve-induced flow characteristics in scientific research and provide useful insight into fluid and mechanical engineering.

Study on the effect of structural parameters of the convergence flow conditioner on eccentric jet flow rectification

“…As shown in Figure 2 above, the calculation domain was divided into five parts: upstream pipeline, valve core, valve pocket, flow conditioner, and downstream pipeline. According to the previous research on the numerical simulation of the flow characteristics in pipeline (Chen et al, 2021a; Liu et al, 2021), the calculation domain was determined from 5 D upstream of the valve to 12 D downstream of the flow conditioner to improve the stability of full flow field. The whole computational area was meshed by three-dimensional structured grids to ensure the grid quality and improve the computational efficiency.…”

“…To sum up, the above researches mainly focused on the rectification effect of unstable flow caused by disturbing elements such as elbows or variable cross-section tubes. However, under the flow regulation of a valve in pipeline, a distinct flow type of eccentric jet flow can be produced at the outlet of the valve and developed along the pipeline (Chen et al, 2021a; Liu et al, 2021). This eccentric jet can seriously affect flow stability and the accuracy of downstream flow signal acquisition (Jin et al, 2018; Tao et al, 2020).…”

Numerical Analysis of the Erosion Mechanism inside the Tube Sockets of Main Steam Thermometers in a Coal-Fired Power Plant

“…In the past research work on numerical simulation for three-dimensional fluid flow inside pipelines [21][22][23], a certain two-dimensional slice of pipelines was often chosen to describe the flow characteristics by showing the distributions of velocity or streamlines. In this study, using the definition of velocity circulation, the three-dimensional flow characteristics inside the tube sockets were analyzed in synergy with the mathematical treatment of relevant statistics.…”