Numerical study on residual rate of fluidized solidified slurry in pumping for scour repair around monopile. (15th May 2023)

• Record Type: Journal Article
• Authors: Li, Ruyu; Wu, Xiaoni; Chen, Jinjian
• Is Part Of: Ocean engineering. Volume 276(2023)
• Publication Date: 2023-05-15
• Subjects: Solidified slurry -- Scour protection -- Residual rate -- CFD approach; Ocean engineering -- Periodicals; Ocean engineering; Periodicals; 620.4162
• DOI: 10.1016/j.oceaneng.2023.114072
• Languages: English
• ISSNs: 0029-8018

Abstract

Abstract: A new scour countermeasure for monopile foundation using solidified slurry have been proposed recently. The fluidized solidified slurry is pumped to the seabed area around pile for scour protection or into the developed scour holes for scour repair as the fluidized material solidifies gradually. During this complex process with pumping and solidification, the flow and diffusion of solidified slurry can result in the material loss and deterioration. However, there is still not a comprehensive and reasonable analysis on the state of retention of the fluidized solidified slurry in this process. Thus, the effect of scour protection can't be evaluated effectively. The current work focuses on the residual rate of fluidized solidified slurry during the pumping operation, which is the ratio between volume of the solidified slurry remaining in the scour pit and that pumped into. A series of multiphase flow (the ambient seawater and the solidified slurry) numerical simulations using a computational fluid dynamics (CFD) approach were conducted to investigate the effects of pumping location, current velocity, pumping velocity and material property of solidified slurry on the residual rate of fluidized solidified slurry. It was found that the pumping location near and at the downstream of the monopile with a lower pumping pipe nozzle is optimal for a higher residual rate of fluidized solidified slurry. Solidified slurry with smaller slump flow value pumped at a lower current velocity and higher pumping velocity contributes to a higher residual rate. Based on a comprehensive parametric study, an empirical formula is established to calculate the final residual rate of the solidified slurry for theoretical reference and practical application. This work provides an important insight in understanding the residual rate of solidified slurry in application to scour protection of monopile. Highlights: The residual rate of solidified slurry in pumping for scour repair around monopile is evaluated. Multiphase flow model is adopted to describe the flow and diffusion of solidified slurry pumped into the scour pit. Optimal pumping location is determined. The effects of current velocity, pumping velocity and material property of solidified slurry on residual rate are investigated.