止水バンド形状の違いが損失係数に与える影響

抄録

  The number of unexpected accidents in agricultural pipelines is increasing in Japan. Appropriate repair and reinforced construction of pipeline methods is critical to extend a pipeline’s life. An internal-leaking preventive joint band method is one measure that can extend pipeline life. The internal-leaking preventive joint method repairs with a band the place where such problems as water leakage occurs. When the band is installed in a pipeline, local loss occurs because the pipe’s inner diameter is locally reduced. But the band’s shapes vary, no magnitude of the band’s local loss has been established yet. We investigated the influence of different band shapes on the loss factor measurements of a single band by both hydraulic model and numerical experiments. Our results found that the loss factor was about 0.8 times that of the non-rounded band edge when the band edge was rounded, and changing the bandwidth from 19 to 50 mm had no effect on the loss factor.