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UDC 621.644.01.004.69
Orlov V. А., Averkeyev I. A., Koblova E. V.
Hydraulic component of alternative pipe materials and protective coatings in trenchless renovation of pressure pipelines
Summary
The results of experimental hydraulic studies of trenchless renovation of pressure pipelines with different protective coatings are analyzed. The studies were carried out in the laboratory of the Water Supply Faculty of the Moscow State Civil Engineering University. The cross-plots of specific resistance – diameter of pipelines made of different materials (protective coating) relationship are presented. The solution of the task of evaluating hydraulic compatibility of some pipe materials and protective coatings used in the relative technologies of trenchless renovation is given.
Key words
pressure pipeline , hydraulic resistance , trenchless renovation technology , pipe protective coating
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UDC 628. 334.2.004.69
Kalinin A. V.
Hydraulic resistance of a traditional grit chamber
Summary
The experimental results of studying the grain-size distribution of sludge deposits in large combined sewers are presented. The curves of the grain-size distribution of sludge deposits are given. A formula calculating the hydraulic resistance of a traditional grit chamber in relation to the changes in dimensions in proportion to filling with sediments is proposed. Grit chambers are installed in large-size sewers upstream sewer siphons in the place of pollutants deposits accumulated because of grade reduction or local resistance.
Key words
sludge , sand catching chamber , grain-size distribution of deposits , hydraulic resistance , combined sewer
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DOI 10.35776/VST.2021.04.08
UDC 628.144:532.542
Orlov V. А., Zotkin S. P.
Study of changes in the coefficient of hydraulic friction of materials of pressure pipes at different temperatures
Summary
Reducing the cost of electricity for the mechanical transportation of water through pressure pipelines by reducing the hydraulic resistance of the inner walls of the pipes is of current importance. This circumstance predetermines the need for appropriate hydraulic testing of alternative materials that can be used in the design and construction of pipeline systems. The aim of the study is to identify the nature of the change in the value of hydraulic friction depending on the temperature conditions of the transported water and the environment in certain ranges, with the subsequent possible control of the transportation process with a minimum of energy costs. The set goals are achieved by experimental computational and analytical approaches to determining the dynamics of changes in the hydraulic parameters of pipelines made of various materials. A comprehensive analysis of the experimental and calculated data obtained using patented automated systems for determining the coefficients of hydraulic friction for a polyethylene pipe and a pipe made of unplasticized polyvinylchloride, and the dynamics of changes in these coefficients depending on the temperature of the transported water and the temperature conditions of pipeline laying is presented.
Key words
pressure pipeline , hydraulic resistance , electrical energy consumption , temperature conditions , computerized calculations
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UDC 628.22
Sapoukhin А. А., Kurochkina V. A.
On the calculation of hydraulic radius value
Summary
The effect of the flow cross-sectional shape on the hydraulic resistance through the hydraulic radius – the ratio of the cross- (or hydraulic) flow section to its wetted perimeter is considered. With the help of the given parameter the entire variety of the flow cross sectional shapes is limited to two types: for pressure flows – circular, axially symmetric shape; for gravity flows – rectangular, very wide shape. The refined mathematical model of the correlation between the hydraulic radius and hydraulic flow parameters as well as the relationship for determining hydraulic radius, relationship parameter values for the most frequently occurring interlocking canals is presented.
Key words
hydraulic radius , hydraulic resistance , shear stress , cross-sectional shape , flow geometry
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UDC 628.144:532.542
Prodous O. A., Terekhov L. D.
Comparative evaluation of using charts by different authors for hydraulic calculation of pressure polyethylene pipelines
Summary
The results of hydraulic calculations carried out with the use of charts compiled by different authors are compared. The example of hydraulic calculations of a pipeline with a diameter of 160 mm for certain flow rate and pressure as well as the analysis of the hydraulic characteristics obtained from the charts by different authors for hydraulic calculations of pressure polyethylene pipes with practical conclusions are presented. The demand for such a comparison is driven by the inquiries from engineering companies busy with designing pressure polyethylene pipelines and experiencing difficulties with choosing the right charts for precise hydraulic calculations; and by the significant errors in the process of determining specific head losses along the length – hydraulic resistance that ultimately influences energy consumption of pumps during water transportation.
Key words
hydraulic design , polyethylene pipes , hydraulic resistance , specific head losses , calculation error
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UDC 66.045.53
Merentsov N. A., Lebedev V. N., Persidskii A. V., Golovanchikov A. B., Kashirin S. E., Kashirina Iu. A.
Heat-mass-exchange packing for evaporative cooling with a developed drip irrigation mode (to be discussed)
Summary
A new heat-mass-exchange packing supporting an intensive drip flow mode for evaporative cooling of water in the water recycling systems of industrial enterprises is presented. The data of an experimental study in the field of hydrodynamics of a new cascade heat-mass-exchange packing supporting intensive drip flow mode are given. The characteristics of the packing device are given in comparison with packings that have received wide industrial application. A classification technique for processing experimental data for heat-mass-exchange packings as a criterion dependence of the modified Reynolds criterion on the hydraulic resistance coefficient is presented. The technique provides for a shot time test of packing materials for their industrial use. Heat-mass-exchange packings focused on the process of evaporative cooling of recycling water will extend over a certain range on the graph λ = f(Rem). An algorithm for calculating the main geometrical and process parameters of a small-sized sectional fan-type cooling tower with intensive drip flow modes for cooling industrial recycling water is presented. The prospect of using the developed heat-mass-exchange packings in the form of a module for disinfecting recycling water in the electric field is noted. This will ensure the constancy of the surface properties of the packing elements and the maintenance of the initial hydrodynamic characteristics, as well as will allow partial preventing the biofilm from overgrowing microorganisms of all heat exchange surfaces of the process equipment.
Key words
recycling water system , hydraulic resistance , hydrodynamic mode , heat exchange packing , retaining ability , small-sized cooling tower
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UDC 628.144:532.542
Prodous O. A., Vasil'eva M. A.
Simplified form of the normative dependence for hydraulic calculation of pipelines made of polymer materials (to be discussed)
Summary
Hydraulic calculation of pipelines (pipes) made of polymeric materials is regulated by the acting regulatory documents (SP 40-102-2000). In the aggregate a method (sequence) of hydraulic calculation of pipelines made of polymeric materials with the use of a simplified form of the normative dependence for determining hydraulic resistance coefficient is proposed. The calculation method is of practical interest because it is confined to the determination of three values included into the normative calculation dependence for the subsequent determination of head losses along the pipeline length. The hydraulic calculation method includes new parameters: hydraulic potential of a pipeline, effective fluid flow rate, effective roughness of the inside pipe surface, effective pipe diameter. These parameters and the Calculation Method have been included into the 3rd edition of the complemented material of Reference book «Tables for hydraulic calculation of pressure polyethylene pipes» (2017). The simplified form of the normative dependence and the method of making hydraulic calculations of pipelines made of polymeric materials can be considered to be included into the revised version of SP 40102-2000.
Key words
hydraulic design , hydraulic resistance , calculation method , polymer pipes , hydraulic roughness
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