The study of the surface texture of pipes with the purpose
of increasing their transporting capacity

Summary

The results of exploratory research on the transportation of water and sand in specially designed laboratory and work benches including a platform with replaceable modular polymer elements (troughs) with artificial roughness are presented. The methodology of experiments on large benches with modular piped elements using photo- and film equipment as well as devices for determining velocity, filling and slope is presented. The nature of the turbulence zones with a different texture of the inner surfaces of the troughs in the form of obstructions of different height is revealed. The results of hydraulic experiments are presented in two modes: single-phase (water without foreign inclusions) and two-phase (water mixed with sand of different fractional composition). According to the results of experimental studies the areas of effective operation of modular troughs for sand transportation for various textures of artificial roughness of pipes of sewer systems were identified. The expediency of using corrugated inner walls of pipelines transporting wastewater for the efficient removal of sand belts settled on the bottom and walls of the pipes is substantiated.

Key words

simulation , transporting capacity , gravity sewers , artificial pipe roughness , microturbulence

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Association between inner pipeline surface with the phenomenon of microturbulence at low liquid flows

Summary

The results of field-scale studies of developing the effect of microturbulence at low flows of liquid in a pipeline are presented. The possibility of increasing the pipeline transporting capacity with account of the current development of trenchless technologies and modified configuration of the inner surface of polymer pipes has been analyzed. The applicability of these studies for increasing the flow transporting capacity is denoted; the analogies to the demonstration of the natural phenomena of liquid flow transportation are set. The pipeline chute profile with artificial obstacles that create conditions for suspended solids breaking off and transfer is marked as the
most perspective one. The design of a special patented test-bench for studying by optical means the turbulence and liquid flow transporting capacity is described. The technique of working with the test-bench is presented; the types of working surfaces with options of artificial obstacle arrangements are described. Comprehensive pilot studies of microturbulence analysis, suspended solids removal and flow transporting capacity in open chutes with different texture of their inner surfaces were carried out with the use of optical means. The occurrence of microturbulence effect in the process of studies at different liquid flows was registered alongside with the increase of the efficiency of suspended solids transportation by liquid flow. The recommendations on the form and location of obstacles on the inner pipe chute surface are given.

Key words

polymer pipeline , liquid flow velocity , turbulence , trenchless technologies of renovation , transporting capacity , surface texture