Polymer Pipes Research Articles

Achieving superior low-temperature mechanical performances by nacre-like alternating microlayered structures in PP/POE-based pipes

The poor low-temperature mechanical performance significantly constrains the use of polypropylene (PP) pipe in frigid climates. Here, the PP/POE-based pipes were successfully manufactured using an independently-developed microlayer pipe coextrusion technology, including 8-, 32–, 128-, and 512-layer. The low-temperature mechanical performance of the 512-layer pipe is significantly improved, compared with the blend pipe, its drop hammer impact damage energy and axial tensile breaking energy are increased by 200% and 1100%, respectively. The results from DSC, WAXD, and SAXS indicate that all the microlayer pipes and the blend pipe have almost the same crystal structure. Therefore, the unparalleled low-temperature mechanical performance is attributable to the ultrathin microlayer structures, which dissipated energy by morphological variation of the dispersed phase POE and the effective initiation and termination of craze. Briefly, the self-developed microlayer pipe coextrusion technology provides an effective strategy for the preparation of low-temperature mechanical performance robust PP pipe, and provides a simple and universal method for building an ideal polymer pipe material.

Multi-objective frequency–time domain transient-based creep identification of leaky polymer pipes

Determining the creep function of polymer pipes is crucial to accurately predicting hydraulic behaviour during transient events. This research presents a novel multi-objective framework that uses transient frequency and time domain pressure data to determine the creep function parameters for a viscoelastic pipeline, accounting for the potential presence of leaks. The innovation of this approach is attributed to employing two pressure signal indicators unaffected by leakage: the resonance frequencies and the zero crossing times, which refer to the moments when the transient pressure signal crosses the steady-state pressure signal. To ensure the efficiency and uniqueness of using these determinants to estimate the accurate creep function parameters, a multi-objective optimization problem is defined and applied to identify the creep function parameters inversely. The developed approach has undergone validation and analysis through different intact and leaky experimental tests and numerical simulations on a high-density polyethylene pipeline. The results and findings confirm that the proposed method could precisely determine the creep function of polymer pipes.

Addressing multi-step inverse heat transfer problems via reduced order models in a cooling process for polymer pipes with sparse measurements

In modern polymer pipe extrusion processes with connected post-processing steps, the intermediate cooling and conditioning process is essential for the resulting product quality. In such cases, computationally efficient models are required for real-time process control and optimization. Unfortunately, heat transfer coefficients are rarely known for actual production processes, leading to an inverse heat transfer problem. Existing methods mainly rely on computationally intensive numerical models or on data intensive neural networks. Both are not suitable, if only sparse measurements are available and a fast execution time is required. In contrast to that, we propose to use a proper orthogonal decomposition and project the governing heat equation onto extracted basis functions via the Galerkin method. This leads to an efficient and accurate reduced order model, which can be used for parameter identification and subsequent process control. Regarding the identification, we address the ill-posed problem with well-known relative constraints, l2 regularization and decomposition of coefficients based on the Nusselt number. Simulation and experimental results show that the heat transfer coefficients are consistently identified and robust against initial parameter guesses despite sparse and noisy temperature measurements. Consequently, the proposed method can be efficiently applied in cooling and conditioning processes in polymer extrusion and related applications such as identifying the heat transfer coefficients and thermal resistance in pressurized surge lines of nuclear power plants and brick walls in melting furnaces respectively.

Application of Nanomaterials in the Production of Multilayer Electrically Conductive and Heat-Resistant Polymer Pipes

Application of Nanomaterials in the Production of Multilayer Electrically Conductive and Heat-Resistant Polymer Pipes

Influence of temperature-time conditions of polymer pipes welding at low temperatures on the structure and properties of materials of joints part ii. Experimental studies

Influence of temperature-time conditions of polymer pipes welding at low temperatures on the structure and properties of materials of joints part ii. Experimental studies

A study of valve-induced water hammer in a woven-jacket fire hose

ABSTRACT The dynamic response of a woven fire hose during valve-induced water hammer events is investigated through a combination of experimental and numerical studies. Unlike conventional polymeric pipes, fire hoses made of synthetic fibres exhibit unique characteristics, transitioning from pliancy to increased rigidity as the pressure within the hose rises. This study explores the transient behaviour of woven fire hoses under variable initial conditions. Experimental studies reveal a direct correlation between the initial piezometric head and the fire hose’s transient response. Numerical simulations employ the viscoelastic Kelvin–Voigt model, proving its suitability for accurately simulating valve-induced hydraulic transients in woven fire hoses. Notably, even a single Kelvin–Voigt element exhibits a relatively good fit with experimental data, accurately reproducing pressure peaks, while the inclusion of two elements enhances the model’s capability, achieving the near-perfect reproduction of pressure oscillations.

Penerapan Teknologi Biopori Sebagai Upaya Mengurangi Genangan Air di Dusun Baroeh Gampong Jantho Aceh Besar

Gampong Jantho is one of the villages that has frequent waterlogging problems. The village is located below a hill range. The southern area of the village, named Dusun Baroeh, is lower than other ones. Additionally, Dusun Baroeh is also isolated from waterways by a road made of concrete and pavement. When rain occurs, Dusun Baroeh always faces waterlogging. Rainwater seepage also transports organic waste and deposits, together with waterlogging. Therefore, one effort to overcome this problem is to create a biopore infiltration hole by utilizing a polymer pipe and organic waste. The implementation of this technology results from a problem-solving perspective through the public opinion pull of villagers, field observations, problem formulation, planning of appropriate technology, and the implementation of biopores. The biopore infiltration holes were placed in six different sites that have frequent waterlogging: three sites in the residents' yards, one site on the footpath, and two sites in the residents' gardens. These biopores work by opening and expanding the water flow from stagnant surfaces to porous soil. This technology is expected to accelerate water infiltration, improve groundwater quality, and reduce stagnant water, which can spread disease.

Justification of the method for calculating the calibration sleeve for the production of thermoplastic pipes

The task of improving the quality of the production of pipes for engineering networks of various purposes with forecasting performance takes on special importance in the face of increased demand in modern conditions. A significant influence on the solution of this problem is found in the organization of heat exchange in the calibrated device. Based on the theoretical analysis of heat exchange during pipe calibration, an improved method is proposed, which consists of calculating the temperature field in the pipe wall during the movement of the pipe billet through different zones of the calibrator with controlled thermal resistance between the surfaces of the polymer pipe and the calibrator. This approach makes it possible to determine the intensity of heat removal, depending on the state of the pipe material during solidification at a given speed of movement of the workpiece, taking into account the change in the thermophysical properties of the pipe material and to more accurately determine the rational heat exchange surface in the calibrator, which is expressed in the length of its sleeve. The proposed method was approved when calculating the calibrator during the production of a polyethylene pipe with a diameter of 500 mm and a wall thickness of 30 mm with a pipe production speed of 8 m/min. in which the calculated length is 862 mm, the working length of the sleeve is 880 mm, the convergence is 98 %.

Assessment of Environmental Impact on Glass-Fiber-Reinforced Polymer Pipes Mechanical and Thermal Properties.

Glass-fiber-reinforced polymer (GFRP) composites are widely used due to their high strength-to-weight ratio and corrosion resistance. However, their properties can degrade under different environmental conditions, affecting long-term reliability. This study examines the effects of temperature and chemical environments on GFRP pipes. Specimens were exposed to salt water and alkaline solutions at 20 °C and 50 °C. Diffusion coefficients and tensile and flexural properties were measured. Advanced techniques (TGA, FT-IR, and XRD) showed a 54.73% crystallinity difference between samples at 20 °C/air and 50 °C/salt water. Elevated temperatures and alkaline conditions accelerated degradation, with diffusion coefficients 68.38% higher at 50 °C/salt water compared to at 20 °C/salt water. Flexural strength decreased by 47.65% and tensile strength by 13.89%, at 50 °C/alkaline compared to 20 °C/air. Temperature was identified as the primary factor affecting mechanical performance, while alkaline environments significantly influenced tensile and flexural modulus. These results underscore the importance of considering environmental factors for the durability of GFRP composites.

Rapid recovery of old steel piping capacity with energy saving effect by reducing hydraulic resistance values

The design of repair work for the reconstruction of pressure steel pipelines using Swagelining technology by pulling pre-compressed polymer pipes into old pipelines is considered. Information on regulatory and technical documentation and the field of application of advanced technology, on installation and operation conditions, as well as on the comparative assessment of energy consumption after reconstruction of dilapidated sections of pipelines with polymer pipes with the possibility of minimizing energy consumption during water transportation under conditions of non-thermal operation of the pipeline with changes in hydraulic characteristics is presented.

ОСОБЕННОСТИ ПРОИЗВОДСТВА ПОЛИМЕРНЫХ ТРУБ МЕТОДОМ ЭКСТРУЗИИ

The features of the production of polymer pipes by extrusion are considered. The need for quality control of raw materials, as well as technological parameters at all stages of the process, has been identified

Development of correction coefficients for cable cross-sections selection in polymeric cable channel

Relevance. The need to develop correction coefficients for selecting cable sections when laying in the polymeric cable channel in the Russian Federation. Currently, there are no recommendations fixed by the state standards for laying cable power lines in polymer pipes. Aim. To develop correction factors for laying cable power lines in the polymer cable channel. Objects. Cable transmission lines laid underground in polymer pipes. Methods. Numerical simulation of combined frequency-stationary method; determination of correction factors based on interpolation of model results; evaluation and analysis of comparison of cables in corrugated and smooth polymer pipes. Results. Calculations of the long-term current load for cables laid in the polymeric cable channel showed the effectiveness of this method of laying cable lines. The use of pipes with smooth walls makes it much more efficient to remove heat from cables into the environment (compared to a corrugated pipe), which allows you to increase the capacity of the same cable by about 25%, depending on the number of pipes laid nearby. Based on the results of the simulation of the thermal mode of corrugated and smooth polymer pipes, it can be concluded that corrugated pipe significantly complicates heat removal from the cable system to the environment (soil). This is due to the presence of air gaps in the ribbed structure of the corrugated pipe. The gaps filled with air act as a heat-insulating layer, unlike a smooth pipe in which this gap is absent. The developed coefficients will take into account the influence of the location of cables on their allowable current already at the design stage, which will reduce the cost of power transmission losses due to the wrong cable cross-section and high temperature.

К вопросу повышения качества скважин скважинного подземного выщелачивания урана в криолитозоне

The peculiarity of mineral deposits in Russia is that about 75 % of them are located in the cryolithozone (Academician of the Russian Academy of Sciences Melnikov V. P.). Uranium deposits, located in the cryolithic zone and mined by the in-situ leaching (ISL) method, are located in Transbaikalia and make a significant contribution to the all-Russian production of this metal. Difficult mining and geological conditions of mining require the adoption of extraordinary technical approaches to solving issues related to the development of such deposits. One of them is to improve the quality of construction of ISL uranium process wells and maintain their operational characteristics throughout the entire period of their operation. The relevance of the work is associated with the need to ensure efficient and environmentally safe uranium mining by in-situ leaching in the cryolicticsone. The object of the study is a deposit of in-situ uranium by ISL. The subject of the study is presented by peculiarities of construction of in-situ uranium leaching process wells in the cryolithozone. The purpose is to develop proposals to improve the quality of process wells. This paper examines the design elements of process wells that affect their operational characteristics, as well as the factors that influence the choice of decisions made The fulfillment of these tasks is complicated by the fact that polymer pipes, made of materials resistant to working solutions, are used as casing: low-density polyethylene, HDPE made of polyethylene PE100 (used earlier) and unplasticized polyvinylchloride NPVC with modifiers of frost resistance and impact strength (current used) or oriented NPVC with increased physical and mechanical characteristics (will be used in the future). Polymer pipes have significantly lower strength characteristics compared to steel pipes, which again requires non-standard solutions to ensure the reliability of production strings (PS) at various stages of the construction of process wells and during repair work on them. In this paper, issues related to the natural conditions of well construction, the stability of EC sections located in the cryolithozone zone and methods of its support, methods and materials for equipping the wellheads of technological wells are considered, information is provided on the results of laboratory work performed, separate stages of the technology for the application of the obtained viscoelastic.

ИНСТРУМЕНТЫ ЦИФРОВИЗАЦИИ В ПРАКТИКЕ ПРОЕКТИРОВАНИЯ ПРИ РЕКОНСТРУКЦИИ ПОДЗЕМНЫХ ТРУБОПРОВОДОВ БЕСТРАНШЕЙНЫМИ МЕТОДАМИ

The article focuses on the possibilities of multi-optional design of repair and rehabilitation works on dilapidated pressure pipeline networks with the use of automated complexes in order to achieve minimum energy costs in water transportation with regard to the temperature factor. Two automated programs based on hydraulic and energy calculation operations are presented as digital tools. As a basic variant of reconstruction of dilapidated pipelines, the trenchless Swagelining technology was accepted. It is realized by pulling pre-compressed polymer pipes into old pipelines with their subsequent straightening. The paper presents information on regulatory and technical documentation and the application of advanced technology, installation and operation conditions, as well as comparative assessment of energy consumption after reconstruction of dilapidated sections of pipelines with polymer pipes with the possibility of minimizing energy consumption during water transportation under non-isothermal conditions of pipeline operation.

MECHANICAL CHARACTERISATION OF FIBER-REINFORCED GLASS POLYMER COMPOSITE PIPES

This paper presents the details of experimental testing for the suitability of glass fibre-reinforced polymer (GFRP) pipes for gas transmission lines. Hydrostatic bursting pressure and split ring tests were performed on 150 mm (6 in.) and 250 mm (10 in.) diameter pipes made by both the pultruded and filament wound processes. The filament wound pipes were tested to evaluate the butt joint failure strengths. The classical lamination theory (CLT) was used to predict the elastic behaviour of these pipes. It was found that filament wound pipes offer superior resistance to internal pressures compared to pultruded pipes. Furthermore, the joints were found to be the most limiting component in terms of pipeline burst pressure capacity. The observed elastic behaviour by the employed hydrostatic pressure test method showed strong agreement with the CLT predictions which confirms its applicability for testing GFRP pipes for bursting pressure. Failure predictions between the experimental data and theory had minor discrepancies.

Research of resistance to hydro-abrasive wear of thermoplastic polymers used to protect the inner surface of hydraulic transport systems

The results of tests of materials for hydro-abrasive wear resistance, as well as the erosion values of studied materials, are presented. It has been found that the use of thermoplastic vulcanizates (TPV) as a co-extruded coating of the inner surface of polymer pipe systems can significantly increase the lifetime of slurry pipelines when exposed to hydraulic mixtures, in particular iron ore tailings. In a model test simulating actual operating conditions of the pipeline, it was shown that TPV and thermoplastic polyurethane (TPU) coatings are signifi cantly superior in wear resistance to high-density polyethylene (HDPE) and steel.

EVALUATION OF THE EFFICIENCY OF ELECTRIC LOGGING METHODS WHEN STUDYING TIGHTNESS OF CASING STRINGS IN WELLS OF URANIUM DEPOSITS

Link for citation: Sharapatov A., Assirbek N., Samanbetov N. Evaluation of the efficiency of electric logging methods when studying tightness of casing strings in wells of uranium deposits. Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 10, рр. 7-15. In Rus. The relevance. When exploiting uranium deposits using the method of in-situ leaching, many problematic issues arise. Among them, it is possible to distinguish a violation of the integrity and tightness of the polymer casing, which leads to leakage of solutions due to defects and threaded connections, colmatation, etc. With the help of geophysical wells surveys, namely current logging and resistivity logging, there is a technological possibility of obtaining actual data on the leakage of solutions into the near-wellbore space (their location, size). The distribution of solutions in the annulus lead to technological and environmental violations during the development of deposits. The main aim: comparative evaluation of the effectiveness of current logging and resistivity logging in solving technological problems – assessment of the integrity of polymer pipes and tightness of threaded connections in the casing of uranium wells and determination of the parameters of liquidation of wells with damaged columns based on the data of current logging or resistivity logging in the casing. Objects: artificial defects in the casing for experimental work: holes in pipes with different diameters and locations, leaky connections of casing pipes. Methods. The work was carried out at one of the sites of the Shu-Sarysu province uranium deposit and includes the following activities: preparation of polymer casing strings for the experiment; physical and technical justification of using geophysical wells surveys methods to study the problem; performing measurement work by current logging and resistivity logging methods; performing computational work using current logging, resistivity logging readings and obtaining values of a probabilistic parameter for evaluation of the state of the casing strings and the decision on the operation of wells; comparative analysis and drawing conclusions on the informativeness of borehole geophysical (electrical) methods. Results. Research results showed that to solve the problem of monitoring the technical condition of casing strings, the use of the resistivity logging method is optimal. The conclusions of the research are based on the analysis of the nature of changes in the diagrams of the electrical methods of current logging and resistivity logging, the sensitivity of the measured values of the electric field to defects in the casing. The quantitative values of the parameter % ANO – the amount of current leakage (anomalies) obtained by calculation according to current logging and resistivity logging data are probabilistic in nature. They made it possible to develop recommendations for making technological and/or managerial decisions on the condition of casing strings and the further use of production wells with various defects in them.

Investigation of methane and ethane diffusivity in the glass reinforced epoxy composite: Experimental and simulation

New polymeric pipes have been used to overcome difficulties created by metal pipes in gas transmission lines such as corrosion and leakage. In this work, diffusion and solubility cells are designed to determine the diffusivity and possible leakage of methane and ethane gases in the glass-reinforced epoxy (GRE) composite. A composite sample with a diameter of 5.95 mm and thickness of 1.40 mm to determine the diffusivity and a composite powder to estimate the gas solubility are used. The experiments are done under temperatures varied from 25 to 40 ℃ and a pressure of 20 bar. The results show that the diffusivity of both gases increases with increasing temperature; while gas solubility decreases. The highest diffusion coefficient of methane and ethane are observed at 8.23 × 10−11 and 7.94 × 10−11 m2/s at 40 ℃, respectively. Moreover, novel correlations for estimating gas diffusion coefficient and mass flow rate in terms of temperature are developed based on the experimental data with the correlation coefficients (R2) of 0.98 and 1 and the average relative error percent (AREP) less than 4.5% and 0.5%, respectively. Interestingly, CFD (Computational fluid dynamics) results show a good consistency with experimental data for gas concentration profiles through the composite with AREP ranges of 1.95–15.78%.

Optimization of interleaved structures with amorphous halloysite nanotubes for superior performance of CFRP pipes in various environmental conditions

The carbon fiber-reinforced polymer (CFRP) pipes are extensively used in various industrial sectors and are routinely exposed to diverse environmental conditions, making it imperative to enhance their performance and durability. To address this need, our study investigates the effects of incorporating amorphous halloysite nanotubes (A-HNTs) in different layers of five distinct layer arrangements on the bending and pipe stiffness properties of interleaved CFRP flat (F) and cylindrical (C) structures under various environmental conditions. Notably, the maximum moisture absorption rate of carbon/epoxy composites (A3), encompassing all layers of epoxy modified with A-HNTs, was 190 % lower than that of carbon/epoxy (E3) composites containing unmodified epoxy resin in all layers. Furthermore, F(A3) exhibited the highest flexural strength at 3141 MPa among all composites tested. A-HNTs significantly improved pipe stiffness, with C(A3) exhibiting remarkable stiffness enhancements of 314 % after moisture absorption and 268 % after drying compared to C(E3). The composite C(E2A1), which included a bottom layer of epoxy modified with A-HNTs, also demonstrated significant stiffness enhancements of 308 % after moisture exposure and 290 % after drying, compared to C(E3). Consequently, we recommend the use of A3 and E2A1 composites for industrial applications.

The Behavior of Polymeric Pipes in Drinking Water Distribution System-Comparison with Other Pipe Materials.

The inner walls of the drinking water distribution system (DWDS) are expected to be clean to ensure a safe quality of drinking water. Complex physical, chemical, and biological processes take place when water comes into contact with the pipe surface. This paper describes the impact of leaching different compounds from the water supply pipes into drinking water and subsequent risks. Among these compounds, there are heavy metals. It is necessary to prevent these metals from getting into the DWDS. Those compounds are susceptible to impacting the quality of the water delivered to the population either by leaching dangerous chemicals into water or by enhancing the development of microorganism growth on the pipe surface. The corrosion process of different pipe materials, scale formation mechanisms, and the impact of bacteria formed in corrosion layers are discussed. Water treatment processes and the pipe materials also affect the water composition. Pipe materials act differently in the flowing and stagnation conditions. Moreover, they age differently (e.g., metal-based pipes are subjected to corrosion while polymer-based pipes have a decreased mechanical resistance) and are susceptible to enhanced bacterial film formation. Water distribution pipes are a dynamic environment, therefore, the models that are used must consider the changes that occur over time. Mathematical modeling of the leaching process is complex and includes the description of corrosion development over time, correlated with a model for the biofilm formation and the disinfectants-corrosion products and disinfectants-biofilm interactions. The models used for these processes range from simple longitudinal dispersion models to Monte Carlo simulations and 3D modeling. This review helps to clarify what are the possible sources of compounds responsible for drinking water quality degradation. Additionally, it gives guidance on the measures that are needed to maintain stable and safe drinking water quality.