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UDC 628.144:532.542/.543
Prodous O. A., Terekhov L. D., Smolin E. S.
Analysis of the international and domestic computing dependencies for the calculation of the head loss in pipelines made of polymer materials
Summary
The computing dependencies regulated by the domestic and international standards for the hydraulic calculation of pressure pipes made of polymer materials are considered. The design values of hydraulic characteristics of 600 mm diameter pressure polyethylene pipes obtained at a test installation (600 mm diameter pipe lined with polyethylene, 35.04 m section length) were compared. The comparative analysis of the computing dependencies used both in Russia and abroad for calculating the head loss in the pipes made of polymer materials was carried out. The priority sequence of using the international and domestic dependencies for hydraulic calculations of pipelines made of polymer materials is recommended.
Key words
pipeline , polymeric materials , hydraulic design , pressure losses , calculation formulae , analysis of computing dependencies
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UDC 532.542.9
Boldyrev Vladimir Vasil'evich
Hydraulic calculations of a water curtain as a pipeline with cocurrent flow
Summary
The need for water curtains arises at over load of any toxic and explosive liquids and gases; and with account for the continuous growth of overload amounts owing to the construction of new terminals it is necessary to design water curtains more and more often. The analysis of hydraulic calculations of a water curtain in a distribution pipeline is presented. When calculating through nozzles the expediency of using the widely known flow rate coefficient instead of an unknown departmental coefficient is shown. At present formulas for calculating the total flow through the water curtain nozzles and head loss in a distribution pipeline are lacking. The method of calculating such a pipeline (pipeline with concurrent flow) is known from the hydraulics. However, it cannot be used because it is suitable for the constant specific flow rate, and the specific flow rate of the water curtain is not constant. The task of making hydraulic calculations of a water curtain for a distribution pipeline has been formulated as follows: determining such pressure and flow rate values that provide for the set flow and pressure for the last (most remote) nozzle is required. When determining head losses in a distribution pipeline the flow rate value before the pipeline multiplied by the decreasing coefficient is used. It was stated that this coefficient depended on the ratio of the diameter of the distribution pipeline to the nozzle diameter. The diagram and formula describing the above-noted dependency are presented together with an example of the calculations illustrating the use of the obtained dependencies.
Key words
hydraulic design , pressure losses , firefighting water system , water curtain , distribution pipeline , flow coefficient
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UDC 628.144:532.542
Prodous O. A., Iakubchik P.
Hydraulic calculation of pipelines made of polymeric materials
with account of the roughness parameters of the pipe inner surface (for discussion)
Summary
A method of hydraulic calculation and a calculation dependence for determining the coefficient of hydraulic resistance λ with account of the characteristics of pipe wall roughness Ra and Sm that affect the accuracy of calculating the head loss along the length according to the Darcy–Weisbach formula are presented. It is recommended to take into account the values of these parameters in the hydraulic calculation. It is proposed to develop a method of in-process control of the Ra and Sm parameter values for using in standards for pipes made of different polymeric materials. A mathematical dependence is proposed for calculating the equivalent roughness coefficient Kэ that depends on the value of the integral roughness parameter Ra. The formula provides for recalculating the Ra value into the Kэ value eliminating hydraulic experiments.
Keywords
pressure losses , pipelines made of polymeric materials , pipe wall roughness , method of in-process control of roughness parameters
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UDC 628.16.067.1
Filatov A. I.
On some specific features of calculating drainage-distribution systems of large area rapid filters
Summary
Two main methods of calculating drainage-distribution systems for uniform washing of rapid filters are known: as regards the relation of the total surface area of drainage slots to the filter area and as regards the so-called relation of the total surface area of drainage slots to the cross-sectional area of the collecting manifold. The second method seems to be more consistent since it provides for the direct link between the values of the recoverable dynamic pressure in the pipes and the total head loss in the drainage required for the uniform filter wash. When using this method for calculating large area filters it is suggested to take into consideration the head loss at the sudden expansion of the cross section of the wash water flow at the head of the central (side) canal.
Key words
rapid filter , drainage-distribution system , pressure losses , wash uniformity , central canal
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UDC 628.144.001.2
Primin Oleg, Bortkevich V. S., Mirkis V. I., Kantor L. I., Vinarskii S. L.
On designing water supply schemes of the Russian cities
Summary
The summary on the water supply conditions in the country is presented. Supplying the population with sufficient amount of drinking water of the required quality and environmental safety of water use have been very important issues in Russia that differ for different regions and population groups. In general it is related not only to the replacement of the outdated equipment and elimination of the general technical backwardness, but in the first place to the need to solve legal, organizational and economic problems. To provide for the stepwise implementation of the set tasks of upgrading and reconstructing municipal water supply and wastewater disposal systems in Russia as well as for the economic encouragement of their development the RF Government approved and put into effect the new regulatory documents – Federal Law of December 7, 2011 No. 416-FZ «On water supply and wastewater management» and «Regulations for development and approval of water and wastewater management schemes and requirements to their maintenance». The guidance issues of designing municipal and communal water supply schemes by the example of Ufa and Irkutsk are considered. The sections to be included into the municipal water supply schemes alongside with the principles of supplying drinking water to the population of certain municipal entities are presented. Successful designing regional water supply schemes is ensured by the availability of the background information on the technical condition of the system; water intake conformance to the project water demand; hydrogeolical survey and confirmed operating inventory of the potential reserve water sources; availability of the master plans of territorial development.
Key words
water flow , objectives , water supply scheme , water consumption , electronic model , pressure losses
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DOI 10.35776/MNP.2020.02.10
UDC 628.144:532.542
Prodous O. A., Terekhov L. D.
Evaluation of the impact of production tolerances on pipes made of polymer materials on the energy demands of pumping units
Summary
A comparison of the hydraulic potential of pressure water and wastewater pipelines made of polymeric materials is given. The values of production tolerances on the pipe wall thickness and their nominal outer diameter should not necessarily be taken into account while choosing the characteristics of pumping units for these pipelines, since the discrepancy in the energy consumption of pumps under the specified feed conditions does not exceed 0.11%. While designing pipelines made of polymer materials, it is proposed to take into account the value of the actual internal diameter of the pipelines, which ensures the accuracy of selecting the pump.
Key words
pressure losses , hydraulic potential , pump characteristics
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UDC 628.1/.2:621.644.075
Prodous O. A., Terekhov L. D.
Selection of polyethylene pipe grades for trenchless rehabilitation of water and wastewater pipelines
Summary
In the world practice different methods of trenchless rehabilitation of water and wastewater pipes are used. Selecting a method of trenchless rehabilitation is recommended solely after having compared the cost of the set of process equipment, its payback period and hydraulic characteristics of the pipeline before and after the rehabilitation. A method of substantiating the selection of polyethylene pipe grades for trenchless rehabilitation of water and wastewater pipelines is presented. The method of selecting the diameter of polyethylene pipes is as follows: for a certain pipe material the inner diameters of the pipeline under rehabilitation and pulled through polyethylene pipe are determined according to the existing standards; the ratio between the inner diameter of the pipeline of the section under rehabilitation and the outer diameter of the polyethylene pipe pulled through (by any method) should differ by only one standard size by grades; for comparison the hydraulic characteristics of the pipeline before and after the trenchless rehabilitation are determined by tables (handbooks); the cost of the process equipment, payback period and the hydraulic characteristics of the pipeline before and after the rehabilitation are compared. Thereafter the diameter of the pulled through polyethylene pipes is accepted. A comparative analysis of the hydraulic parameters for two methods of trenchless rehabilitation with the use of 160–400 mm diameter polyethylene pipes was carried out. The results of comparing the hydraulic characteristics of a pipeline in the process of rehabilitation with and without host pipe destruction are presented.
Key words
water supply , pipeline , trenchless repair , sewerage , polyethylene pipes , pressure losses
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UDC 628.144:532.542
Prodous O. A.
Predicting head loss in pipelines made of different polymer materials
Summary
The availability of manufacturing tolerances for the outer diameter and wall thickness in the operating standards for pipes made of different polymer materials results in changes in the values of the calculated inner diameter, flow velocity and friction loss. The demand for the calculation of head loss for the subsequent count in the operation of pipelines made of different polymer materials is shown. It is proposed to set regulated maximum values of pipe wall roughness and include them into the operating standards for pipes: to develop the limits of the altitudinal roughness parameter Ra; to develop the method of in-process monitoring of the roughness parameter Ra during pipe manufacture similar to GOST 12586.0-83 «Reinforced-concrete pressure vibrohydromoulded pipes». Based on this method the manufacturer of the pipes will have to enter the numerical values of roughness parameter Ra into the passport of the pipe lot so that it will be possible to predict friction losses for the length of the designed pipeline; to recommend an instrument for in-process monitoring of the inner wall roughness parameter of pipes made of polymer materials upon the substantiation of the choice; to prepare the method of in-process monitoring of the wall roughness parameter of pipes made of polymer materials for including it into the requirements of GOST 18599-2001, Р 52134-2003, Р 54560-2011.
Key words
pressure pipeline , pressure losses , polymer pipes , roughness , parameter monitoring method
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UDC 628.16.067.1
Filatov A. I.
Method of designing tubular porous rapid filter drainage
Summary
In recent years the specialists of water treatment plants pay much attention to rapid filter drainage systems of porous type. This design excludes the drawbacks typical for drainage systems with supporting gravel layers, major of them being gravel layer slip that causes frequent filter reloading (typically every 3–5 years). The method and basic formula for calculating tubular porous drainage are presented. In view of specific design tubular porous drainage calculations differ significantly from calculating widely used tubular perforated drainage systems of high resistance with supporting gravel layers. In the latter the pressure loss required for uniform filter wash occurs in one stage – in drainage openings. In tubular porous drainage design the pressure is successively lost in two stages – in the openings and outside porous layer, or in three stages – in the upper drain openings, inner porous layer, bottom drain openings. The summarized pressure loss in the mentioned two stages must provide for 95% uniformity of filter wash.
Key words
water supply plant , rapid filter , pressure losses , tubular porous drainage , wash uniformity
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UDC 621.644:621.643.2-034.13
Prodous O. A., Dzhanbekov B. A.
Pipes with polyurethane coating for the construction of the Teberda group water main
Summary
The problem of drinking water deficiency in the southern regions of Russia (at the North Caucasus) can be solved by the construction of a large-diameter and long water main for water transportation from the artesian sources located in the Karachay-Cherkessia Republic. The analysis of the advanced efficient durable polymer materials for pressure pipelines having the high hydraulic potential and operating in the zone of extreme seismicity was carried out. The economic efficiency of using ductile iron pipes with polyurethane inner coating in the construction of the Teberda group large-diameter water main is shown. The specific head losses along the length of a 500 mm water main are cited that are 2.5 times less than the specific head losses in pressure polyethylene pipes of the same diameter.
Key words
pipeline , polymeric materials , pressure losses , drinking water deficiency , pump energy consumption
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