THEORETICAL ANALYSIS OF REDUCTION OF PRESSURE AND ENERGY LOSS DUE TO PIPE FRICTION THROUGH MODIFICATION OF DISPERS SYSTEMS

ABSTRACT

In the modern world, the most important factor for every industry is the use of energy-saving, high-economic efficiency technologies. Dispersed system hydraulic mixtures are transported through pipelines in the mining industry, construction process, and chemistry. Energy, resource and economical technologies are of great importance in the process of water transportation. The article presents ways to reduce pressure and energy loss due to friction during hydraulic transportation of dispersed system hydraulic mixtures through pipelines. Research conducted by world scientists on adding polymeric substances to reduce pressure and energy loss is analyzed. Types of friction, formulas for finding length and local resistance, analysis of flow regime, Reynolds number, flow temperature and viscosity are presented. The temperature, viscosity and Reynolds number correlation table and diagram are presented based on the analysis. The modification process and the method of modification by organic matter, the formulas for finding the coefficient of hydraulic friction after the addition of organic matter, and the characteristics of the modifier are theoretically analyzed.

АННОТАЦИЯ

В современном мире важнейшим фактором для каждой отрасли является использование энергосберегающих, высокоэкономичных технологий. Гидравлические смеси дисперсных систем транспортируют по трубопроводам в горнодобывающей промышленности, строительстве, химии. Большое значение в гидротранспортном процессе имеют энергетические, ресурсные и экономичные технологии. В статье представлены способы снижения потерь давления и энергии на трение при гидравлическом транспорте гидравлических смесей дисперсных систем по трубопроводам. Проанализированы исследования мировых ученых по добавлению полимерных веществ для снижения давления и потерь энергии. Представлен анализ видов трения, формул длины и местного сопротивления, режима течения, числа Рейнольдса, температуры течения и вязкости. На основе анализа представлены таблица и диаграмма корреляции температуры, вязкости и числа Рейнольдса. Теоретически проанализированы процесс модификации и способ модификации органическим веществом, формулы для нахождения коэффициента гидравлического трения после добавления органического вещества, характеристики модификатора.

Keyword: Viscosity, Reynolds number, modifier, friction force, dispersed system, gossypol resin, modification, turbulence.

Ключевые слова: Вязкость, число Рейнольдса, модификатор, сила трения, дисперсная система, госсиполовая смола, модификация, турбулентность.

Introduction. Dispersed system hydraulic mixtures are hydrotransported through pipelines in the mining industry, construction process and chemistry [1,2]. Due to the fact that this is the internal diameter of the pipe during the flow process of the dispersion system hydraulic mixtures, a friction phenomenon is formed. In the process of friction, the flow rate decreases, the pipe walls are eroded due to internal friction, and the pressure loss in the flow is observed. As a result of pressure loss, energy consumption increases. One of the most important tasks for increasing the productivity and durability of pipelines is to create methods for changing dispersed systems and to calculate the physical-chemical-mechanical properties of system phases, the composition of dispersed systems and their viscosity [3]. The purpose of the research work is to develop energy-saving methods in the implementation of hydrotransport of dispersed system hydraulic mixtures through pipelines in the mining industry, construction process, and chemistry, as well as to analyze new methods and technologies for improving hydraulic transportation, taking into account the concentration and mechanical composition of dispersed system hydraulic mixtures. consists of [4, 5].

The main problems in the hydrotransportation of dispersed system hydromixes are the reduction of the flow rate, erosion of the inner part of the pipe wall, corrosion, and pressure loss phenomena. The main task is to reduce energy consumption, pressure loss, and increase performance due to the reduction of frictional resistance by modifying dispersion systems.

Research on saving energy consumption by reducing friction was carried out by several scientists, including the English scientist chemist B. Toms, the Russian scientist I.A. Charniy, Azerbaijani scientist A.Kh. Mirzajonzoda, Vietnamese scientists Yu.G. Abrosimov and Hoang Zan Bin, in addition to V.A. Bazilevich, A.N. Shabrin and other scientists worked on reducing the friction coefficient by adding polymeric substances to the liquid [6, 7].

Research method. The research work uses the method of modification of dispersed systems to save pressure loss and energy consumption by reducing the friction of hydromixed flow.

Modification of dispersion systems is the process of penetration of a composition based on a liquid polymeric binder into the pores and capillaries of a particle of a dispersion system. [2-4].

In the process of modification, additional organic substances are added to the hydromix with a dispersed system, these substances create additional properties without changing the basic state of the hydromix, they reduce the friction effect of the flow on the pipe walls, reducing the value of the coefficient of hydraulic resistance - λ is effective in the hydrotransport of the hydromix serves. Darcy's equation for round pipes is used to find the friction force.

                                                       (1)

Here; λ is the coefficient of hydraulic resistance, l is the length of the pipe, d is the internal diameter of the pipe, v is the average flow rate.

In addition to friction, the pressure loss during the hydrotransport of the flow of dispersed hydromixes is also affected by local hydraulic resistance, which is determined by the Weissbach equation.

                                                               (2)

where: 𝛏 is the coefficient of local hydraulic resistance.

Local hydraulic resistances include taps, valves, siphons, valves, filters, elbows, pipeline contractions and expansions, etc., which cause additional pressure (energy) losses in the pipeline [7].

A number of methods are used to reduce the pressure loss and energy consumption in the pipes, i.e. the internal diameter of the pipe is reduced, the number of local hydraulic resistances can be reduced, but these methods do not have a significant effect, so the above-mentioned modification process is more commonly used.

The coefficient of friction of the flow of hydromixes with a modified dispersed system λ is determined by the following formula:

                               (3)

where: - the limiting dynamic speed (depending on the type of organic substance), when this speed is reached, pressure loss and energy consumption begin to decrease.

η is a coefficient corresponding to the type of organic substance and its concentration.

v is the velocity of hydraulic mixing in the pipe.

  - internal absolute roughness coefficient of the pipe wall.

η is found using the empirical formula depending on the type of organic substance:

η =1000*C                                                               (4)

Where C is the total concentration of organic matter, %.

If no organic substance is added to the hydromixture with a dispersed system, i.e. if C=0, formula (3) has the same form as Colebrook's formula [5]:

                                            (5)

When the flow mode is turbulent, the resistance coefficient is large, because in the turbulent flow, the flow particles move unevenly, a strong energy loss is observed during the rotational movement, and the rolling resistance is significant [7].

Research results

The flow of hydromixes with a dispersed system moves mainly in a turbulent mode. Before modification, it is necessary to study the mode of flow and determine the level of turbulence. Turbulence is defined as the Reynolds number.

                                                            (6)

Steady turbulent motion regime is observed when the Reynolds number is Re>10⁴. Reynolds number pipe diameter – d; flow rate – v; kinematic viscosity depends on 𝜈. As a result of theoretical studies, it became known that the smaller the kinematic viscosity, the greater the Re number and the higher the turbulence. The kinematic viscosity depends on the temperature of the hydromixture flow in the dispersed system, and the correlation is given in the following table (Table 1).

Table 1.

Dependence of kinematic viscosity on flow temperature

The table shows the kinematic viscosity corresponding to the temperature of the hydraulic mixture at an arbitrary diameter of the pipe and a random flow rate, the number of Re is found in the sequence using the formula (6). The diagram below shows how the Re number changes with temperature and kinematic viscosity.

Diagram 1. change of Re number under the influence of temperature and kinematic viscosity

We can conclude from the diagram that as the temperature increases, the viscosity decreases and the Re number increases. As a result, the higher the temperature of the hydromix with a dispersed system, the more turbulent the flow is. It is known that the increase in temperature reduces the viscosity, since the hydrotransport of dispersed system hydromixes is limited at high temperature, it is possible to reduce the viscosity and friction force using the modification method. In the modification process, gossypol resin, a secondary raw material of low-fat production, was selected as a modifier. Gossypol tar contains polyphenols, fatty acids, hydrocarbons, compounds containing nitrogen and phosphorus, as well as gossypol converting products. Its appearance is viscous-liquid mass, color - from dark brown to black, KOH acid number - 50-100 mg, ash content - 1.0-1.2% by weight, moisture and volatile substances - 4 - up to 6%, solubility in acetone–70–80 wt. %, specific gravity 3 – 0.98 – 0.99 g/cm, KOH saponification number 80–130 mg [2].

Efficiency in reducing pressure and energy loss by modifying dispersed system hydraulic mixtures is calculated through the values   of hydraulic friction coefficient λ.

                                                     (7)

Where: - coefficients of hydraulic friction, respectively, in the case of the dispersion system hydromix and gossypol tar additives [6].

Conclusion. Based on the results of the theoretical analysis, reducing the pressure and energy loss under the influence of friction force, increasing the work productivity and efficiency, and extending the service life were considered the main problems in the hydraulic transportation of dispersed system hydraulic mixtures through pipelines. In the process of modification, pressure and energy loss in a limited temperature range, additional factors such as the rate of diffusion of the modifier and its concentration, the type of pipe and the absolute coefficient of internal curvature are also taken into account. In addition, it is necessary to study the environmental impact of the modifier. Modification of the efficiency of the hydrotransport process is based on solving the above problems.

References:

1. Zheleznyakov G.V., Talmaza V.F. Dependence of the parameters of velocity profiles on hydraulic resistance. Hydrotechnical construction.– №8. – pp.33–35, (1973)
2. Ilkhomov Kh.Sh ,. Study of the interaction coefficient for a two-phase flow in a horizontal pipe. Uzbek journal of problems of mechanics. pp.48–51, (1995) 
3. Ibadullaev, A., Nigmatova, D., Teshabaeva, E. Radiation Resistance of Filled Elastomer Compositions. IOP Conference Series: Earth and Environmental Sciencethis link is disabled, 2021, 808(1), 012043
4. A. V. Karaushev Theory and methods for calculating river sediments. – L: Gidrometeoizdat, – p.272, (1977)
5. Arifjanov A.M., Latipov N.K., Babaev A.R. To the formation of the concentration field of the suspended flow in pipelines//Bulletin of the Tashkent Institute of Railway Engineers.– №1, – pp.49–54, (2018)
6. Grukolenko V.K., Grukolenko A.G. Analiz issledovaniy po snijeniyu poter napora v trubax pri pomoщi polimernыx dobavok (rusnauka.com)
7. V.A. Zvereva, A.V. Gulyakin Vliyaniye polimernыx dobavok na snijeniye energozatrat pri rabote nasosnыx ustanovok// VESTNIK INJENERNOY SHKOLЫ DVFU. 2013. № 3 (16)-14 b.
8. Makhkamov D. A., Chorshanbiev U. R., Babaev A. R. Laboratory Research of Multiple Flow Movement in Pipelines //Global Scientific Review. – 2022. – Т. 1. – С. 42-46.
9. Rakhimov, K., Babaev, A., Chorshanbiev, U., & Obidjonov, A. (2021). Modification of dispersion systems and its motion in cylindrical pipes. In E3S Web of Conferences (Vol. 264, p. 03026). EDP Sciences.
10. Teshabayeva, E., Ibadullayev, A., Chorshanbiyev, U., & Vapayev, M. (2022, June). Modification of composite elastomeric materials for polyfunctional purposes. In AIP Conference Proceedings (Vol. 2432, No. 1, p. 030082). AIP Publishing LLC.