ABSTRAKT

In order to prevent the hold-up phenomenon in a transport pipeline for Sidoarjo’s mud slurry, we anticipate a practical application of spiral pipe. From the practical point of view, it is very important to give a clear explanation about the non-Newtonian flow characteristics of slurries. Pressure loss occurring in the bend of curved pipe will be higher than in a straight pipe. The purpose of this study was to investigate the effect of swirling flow on the near-wall region of curved spiral pipes to prevent sedimentation. Three curved spiral pipes with ratio pitch to diameter, P/D₀ = 4.8 and 7.1, and three curved circular pipes were used. The values of the ratios of the radius of the curvature to the pipe radius, R/a, were 12 and 18. The value of the curved angle, θ, was 180°. The diameter of the particle of mud slurry was 5 · 10⁻³ mm and the density was 1.28 · 10³ kg/m³ for weight concentration, Cw = 50 %. The power law exponent was about 0.9 to 1 for mud slurry solutions of 50 and 30 % weight concentrations. The velocity distribution obtained by using a multi-hole Pitot tube shows that the maximum value of the axial velocity component exists near the center of the tube axis in the curved spiral pipes. Effects of swirling flow in curved spiral pipe were represented by different velocity profiles, and the value velocity distribution near the wall is faster than in curved circular pipe with the same pressure loss. Maximum thickness of low velocity in the near-wall region occurred in curved circular pipe. Spiral pipes can prevent sedimentation of mud slurry.