St. Petersburg Mining University (Russia):

Aleksandrov V. I., Doctor of Engineering Sciences, Professor, Head of Chair, victalex@mail.ru

Mekhanobr Engineering CJSC (Russia):
Kibirev V. I., Ph. D. in Engineering Sciences, Head of Department

The paper presents analytical calculations of specific pressure loss in hydraulic transport of the Kachkanarsky MCC iron ore processing tailings slurry. The calculations are based on the results of the experimental studies on specific pressure loss dependence upon hydraulic roughness of pipelines internal surface, lined with polyurethane coating. The experiments proved that hydraulic roughness of polyurethane coating is by the factor of four smaller, than that of steel pipelines, resulting in decrease of hydraulic resistance coefficients entered into calculating formula of specific pressure loss — the Darcy—Weisbach formula. Relative and equivalent roughness coefficients are calculated for pipelines with polyurethane coating and without it. Comparative calculations show that hydrotransport pipelines polyurethane coating application is conductive to specific energy consumption decrease in hydraulic transport of the Kachkanarsky MCC iron ore processing tailings slurry by the factor of 1.5. The experiments were performed on a laboratory hydraulic test rig with a view to estimate character and rate of physical roughness change in pipe samples with polyurethane coating. The experiments showed that following 484 hours of operation, roughness changed in all pipe samples inappreciably. As a result of processing of the experimental data by the mathematical statistics methods, an empirical formula was obtained for calculation of operating roughness of polyurethane coating surface, depending on pipeline operating duration with iron ore processing tailings slurry.

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