Hydraulic Resistance Coefficient Research Articles

Justification of design parameters of a two-stage cyclone vortex funnel using computer simulation

It has been established that in mini-feed mills with a productivity of up to 5 t/h, pneumatic transport systems with a cyclone unloader are more promising due to the lower emission of finely dispersed components. However, there are fewer such workshops on the market due to the smaller loading -volume of horizontal mixers on which cyclones are installed compared to vertical mixers that perform the function of cyclone-unloaders, in which emissions of fine dust into the work area are higher, which negatively affects working conditions, health of workers, as well as fire safety of premises. To reduce emissions of fine dust into the exhaust pipe of the cyclone, a technical solution in the form of a two-stage cyclone was proposed. A preliminary experimental test on a laboratory model showed an increase in particle collection by 32% about the serial cyclone-unloader CR under the same initial conditions and in the same standard size. As part of the design of a full-size version of the proposed two-stage cyclone, computer modeling of the separation process was carried out in the FlowSimulation software environment with dimensions close to the commercially produced cyclone BCR-450 to identify the influence of the geometric parameters of the -vortex funnel on the process of separation of fine particles from the transporting air flow with variable geometric dimensions diameter and height of the vortex funnel in the range from 100 to 270 and from 100 to 235 mm, respectively. Preliminary rational geometric parameters of the vortex funnel diameter equal to 180 mm and height equal to 150 mm of the proposed technical solution with a hydraulic resistance coefficient of8.4 are substantiated.

Investigation of water heating efficiency in cavitation mode at initial stage of grain molasses preparation

BACKGROUND: Grain molasses are a valuable source of digestible protein and feed sugar for farm animals. At the initial stage of production of this feed mixture, the existing devices and water heating schemes are not effective enough. In this connection, a new device for accelerated heating of passive-type water has been developed.
 AIMS: evaluation of the effectiveness of the cavitator for heating water in the plant for the production of grain molasses.
 MATERIALS AND METHODS: for conducting studies, a cavitator made in the form of a cone with petals, the angle of the solution of which is 168ʹ, is installed in a glass pipe of the injection branch of the water circuit of the plant for the preparation of grain molasses. During the experiments, the petals were installed in the pipe straight or bent 15. Under laboratory conditions, a comparative experiment was carried out to heat water with a volume of 50 liters, starting from its temperature of 20C and through each degree to 30C, both with and without a cavitator. The process efficiency criteria were: time and specific energy consumption of water heating.
 RESULTS: as a result of the conducted studies, the values of the criteria for the efficiency of the water heating process using a cavitatora and without it are established. Linear dependence of water temperature on heating time is obtained. It has been shown that the created cavitation effect behind the base of the cone is not stable, but still more intense behind the cone with straight petals. It is noted that the coefficient of hydraulic resistance for a cavitator with bent by 15 lobes is 10% greater than with straight ones.
 CONCLUSIONS: use of a cavitatora when heating water at the initial stage of preparing grain molasses increases efficiency of the process by 20%.

Development of solar water heater collector with less hydraulic resistance

In this article analysis of ways and methods to improve the efficiency of existing structures of the solar water heater collector in the article. The practical significance of the research results is explained by the fact that the solar water heater collector developed for hot water supply systems is proposed to use a collector circuit with low hydraulic resistance, which allows you to reduce the hydraulic resistance coefficient in the heat transfer water pipe relative to the integrated pipe absorber, without reducing the heat transfer coefficient.

Digital core: study of textural heterogeneities in a rock

Relevance. When real fluid flows through channels of limited dimensions, it experiences a constant loss of mechanical energy (hydraulic resistance) due to the action of viscous friction. Hydraulic drag has two components: drag along the length of the flow and local drag. The drag along the length of the flow arises because the fluid encounters a force per unit area perpendicular to the direction of the flow. Local drag results from the viscous interaction between the fluid and the channel walls. Local hydraulic resistances include sudden and gradual constrictions/expansions (diffusers/confusions) of the fluid channel, angular and choke gaps. The value of the hydraulic resistance coefficient depends on the type of channel geometry, conditions of fluid entry (wettability of the rock texture) and on the flow regime. When fluid flows through channels of different cross-section, as the channel narrows, the flow velocity increases and the pressure, based on Bernoulli's equation, decreases. Objects. Polymictic sandstones of the Tyumen Formation. Methods. The developed algorithms for identifying areas of contraction/expansion (confusers/diffusers) in the rock texture (polymictic sandstone) are based on neural network reconstruction of core data. The study of geometric diversity of geological rock images is based on generalization of real spatial forms in combination with the axiom of hyperplanes. A methodical approach for finding distribution of inertial exciters (confusers/diffusers) affecting the character of multiphase flow front changes in the rock texture is based on the metrics for estimating possible distributions. Results. The paper introduces the initial stages of core digital transformation data. It was determined that the main problem of geological data digital projection on a large scale is the need to take into account the systems of inertial effects, both in the available volume of the rock and in the extrapolated space of it. In order to adequately represent the character of multiphase fluid flow for different scales, the authors have developed the algorithms for segmentation of geological images of fluid space with further identification of distribution laws of inertial exciters (confusers/diffusers) in the rock texture. For training and testing of the developed algorithms we used the computer tomography images of core material and detailed resolution images of rock sections. The source code of neural network algorithms was written in the Python programming language with the additional use of non-commercial libraries. The algorithms were tested on real data, confirming by experimental studies in the laboratory of digital research in oil and gas as part of the technological project "Digital Core" (Industrial University of Tyumen, Tyumen), the laboratory of the V.I. Shpilman Research and Analytical Center for Rational Subsoil Use (Khanty-Mansiysk), Core Research Laboratory (University of Tyumen, Tyumen).

CHOICE OF THE PARAMETERS OF TWISTED TAPES FOR HEAT TRANSFER INTENSIFICATION IN THE CHANNELS OF THE POWER EQUIPMENT COOLING SYSTEM

The paper presents the results of analyzing the efficiency of heat removal processes in the channels of the power equipment cooling system. The processes of heat transfer in the ventilation ducts of the cooling system for traction motors of diesel locomotive power plants are considered. The feasibility of using artificial intensification of heat transfer processes in the ducts with the help of spiral tapes is analyzed. Convective heat transfer intensifiers of this type are characterized by a significant increase in heat transfer coefficients, ease of manufacture, and low material consumption. Such devices can be used both in the design of new units and in the modernization of existing heat exchange equipment. The efficiency of intensification of heat transfer processes was evaluated by the level of reduction in the power of cooling system fans. The estimates were made assuming the same heat transfer coefficients in the channels with spiral strip inserts and in the channels without inserts. The length of the spiral tapes and the channel is the same. The effect of finning of the channel surface by the inserts was not taken into account. Known criterion equations were used to calculate the convective heat transfer coefficients and hydraulic resistance. It is shown that, despite the increase in hydraulic resistance coefficients and pressure losses in the channels of the air cooling system, the use of spiral tapes due to a noticeable decrease in the speed and, consequently, the cooling air consumption provides a reduction in fan power in a wide range of geometric parameters of spiral tapes while ensuring the required temperatures of equipment elements. The influence of the temperature of the walls of the cooling system channel on the required fan power when using artificial heat transfer intensifiers in the form of spiral tapes is estimated. Recommendations for the selection of geometric characteristics of spiral tapes are proposed, at which, taking into account the values of the channel wall temperature, a decrease in the power of the cooling system fans should be expected.

NUMERICAL SIMULATION OF PROCESS FLUID FLOW IN THE PIPES OF A COILED TUBING INSTALLATION

Today, one of the modern trends is the use of coiled tubing technologies and improvement of the composition of washing agents (liquids). The features of coiled tubing technological sections are considered – spiral pipe laying, the ratio of the main dimensions of flexible pipes, drum and guide sector. The presence of a pipe conveyor gives special responsibility for ensuring the movement of a string of flexible pipes within a given load range. The length of the pipes reaches 5000 m. The radial dimensions of the well are 150 mm. The stages of determining the main parameters of a pumping unit for supplying process fluid to a well are listed. When carrying out technological operations, the pump must overcome the hydrodynamic losses of direct and reverse fluid supply into the well. It is necessary to take into account the possibility of misalignment of cylindrical pipes. To carry out technological operations to intensify oil production, multicomponent process fluids are used. The presence of chemical and polymer additives in liquids has a significant impact on the properties of aqueous and hydrocarbon systems and forms gels of varying density, viscosity and rheology. It is known that even a small content of polymer additives in the solution (6–30 g/l) leads to non-Newtonian behavior of the washing fluid in the well pipes. The work uses experimental data obtained by Region LLC of Ukraine. For numerical modeling of the hydrodynamic characteristics of a process fluid, linear and nonlinear models of a viscous fluid are used. In all cases, steady flow was considered. Due to the fact that the work uses the academic version of the ANSYS CFD package with limited capabilities in terms of the number of cells, the computational areas were selected using simplified schemes. The following schemes are considered: spiral – guide – straight pipe, only the spiral part of winding the pipe on a drum, an annular space between cylindrical pipes with possible eccentricity. The results of numerous studies are used to predict hydraulic resistance coefficients in pipes and the characteristics of pumping equipment for supplying process fluid to a well. The results can also be used for verification strength calculations of flexible pipe columns for hazardous sections.

Study of the Rheological Properties and Flow Process of High-Viscosity Oil Using Depressant Additives

This article analyzes the dependence of the choice of the method of transportation of high-viscosity oil on the rheological characteristics of the oil in question. An analysis of existing rheological models of high-viscosity oil was carried out, and it was found that a number of models have certain features (model coefficients, their purpose, quantity) that affect the choice of a rheological model of oil. The dependences for determining the coefficient of dynamic viscosity when pumping high-viscosity oil with the addition of pour-point depressants were studied, and the dependence of the hydraulic resistance coefficient when depressants are added to the oil was obtained. A method for choosing a rational oil heating temperature and diluent concentration to achieve the maximum pipeline performance is substantiated.

Коефіцієнт гідравлічного опору тертя капілярів за малих чисел Рейнольдса

Heat transfer pump circuits with liquid or two-phase heat transfer fluids are widely used in thermal management systems in both space and ground applications. These systems play an important role in maintaining the optimal temperature and heat distribution in various processes and devices. Such systems use throttles to ensure efficient distribution of coolant flows through the hydraulic network. It is especially important to ensure the reliability of the system at low coolant consumption. Therefore, a rational approach is to manufacture throttles in the form of capillary segments. Capillary throttles can regulate the flow of coolant with high accuracy, which makes it possible to improve control over the thermal regime of the system. To calculate and determine the characteristics of such throttles, it is important to know the coefficient of hydraulic friction resistance λ, which is used in the Darcy formula. This coefficient depends on various factors, including the geometry of the throttle, physical properties of the heat transfer fluid, and flow conditions. Therefore, the aim of this study was to determine the value of the hydraulic friction resistance coefficient λ. In this work, experiments were performed with the shedding of copper capillaries of different internal diameters (0.8-1.2 mm) in water and isopropyl alcohol. The experiments were carried out in the laminar and transient regions, in the range of Reynolds numbers from 250 to 6050. Conclusions. In the laminar region (Re < 1185), it is recommended to use the Poiseuille formula. In the transitional and turbulent regions (1185 < Re < 6050), it is recommended to use the Blasius formula. The results of the experiments made it possible to obtain data on the value of the hydraulic friction resistance coefficient λ. These data can be used to calculate throttles in similar heat transfer systems. Moreover, the paper provides recommendations on the use of well-known formulas for calculating throttles, which allows engineers and designers to effectively implement these elements in their projects. Thus, the research conducted in this paper has important practical implications for the development and optimization of heat transfer systems in space and terrestrial applications.

Оцінка впливу канавок у дифузорі на втрати повного тиску

The subject of the study is the total pressure in the diffuser channel with passive control of the boundary layer. The object of this research is a diffuser channel with riblets. The mechanism of total pressure reduction due to the presence of longitudinal grooves on the streamlined surface is related to the strengthening of viscous forces acting in the transverse direction caused by them. These forces generate a relatively calm flow inside the riblets, which pushes out the turbulent flow, which causes surface friction, pushing it away from the surface. Thus, the process of generation and growth of elongated wall turbulent formations. In addition, in the presence of riblets, a change in the pressure field in the transverse direction is possible, as well as the creation of a quasi-two-dimensional flow in the immediate vicinity of the wall. In this work, the aim of research to investigate the influence of riblets on total pressure loss in the diffuser channel with the purpose of evaluating the influence of riblets on the change in the nature of the flow and the change in pressure, using numerical modeling. To study the nature of the flow in the diffuser channel, we resolved the following tasks: a diffuser channel was modeled with the following dimensions: length L=50 mm, hydraulic diameter at the inlet X=25 mm, hydraulic diameter at the outlet Y=40 mm, riblets diameter d=4 mm, number of riblets n =4 and n=8. The study was compared with a diffuser with the following dimensions: length L=50 mm, diameter at the inlet X=25 mm, diameter at the outlet Y=40 mm. To research the flow in the diffuser, the method of numerical experiment was chosen. An unstructured calculation grid was used in the diffuser for the research. The calculation of the turbulent gas flow was performed by numerically solving the averaged Navier-Stokes equations. During the numerical simulation of the flow, the Reynolds stress turbulent viscosity model will be used. As a result, using a diffuser with riblets increases the coefficient of hydraulic resistance compared to a smooth diffuser. The resistance reduction mechanism does not work due to the relatively short length of the diffuser and small longitudinal vortices of the riblets scale do not have time to form. There are pressure increasing instead of laminization of the flow and pressure decreasing. Scientific novelty - received new data on the effect of riblets in the diffuser channel on the total pressure loss coefficient. Practical significance - the obtained results can be used to control the boundary layer in diffuser channels (in diffuser compressor grates) to improve their characteristics.

Peculiarities of the Calculations of the Gas Turbine Cooling Systems

Gas turbine cooling systems have the branched networks of various channels whose hydraulic and heat exchange capabilities define the air flow required for the cooling of turbine parts and, thus, directly influence the efficiency of gas turbines. Cooling system elements are, in particular, the throttles, diaphragms, seals, openings that act as regulating parts or elements to maintain pressure in the system. As a rule, the channels of this type have a significant pressure drop, and therefore during the calculations it is necessary to very carefully consider a change in air density along the channel. Therefore, we present in this paper the method developed by the authors for determining the hydraulic resistance in the openings, and the data obtained by it perfectly agree with the experimental data. It is shown how to take into account the effect of the air compressibility on the coefficient of hydraulic resistance in the cooling channels that allows for the use of the numerous experimental dependencies for the coefficients of hydraulic resistance of incompressible liquids. A method of calculating hydraulic resistances of the openings by defragmenting their total hydraulic resistance into separate components has been proposed. A generalized dependence was established for the hydraulic resistance of the discharge openings in the discs and in the mounting gaps between the shanks of the blades and the discs, taking into account the transverse air flows.

Analytical and numerical investigations of fluid flow and heat transfer in turbulent slip incompressible flow in a cylindrical channel

Based on two analytical approaches (Prandtl model and von Kármán model), turbulent flow in a cylindrical channel with flow slippage on the wall was considered. The results of the analytical solution are supplemented with numerical simulations based on the lattice Boltzmann model (LBM). Validations of the analytical model against numerical computations showed their good agreement. The analytical model enabled obtaining relations for the velocity profile, hydraulic resistance coefficient and Stanton number, which make it possible to evaluate the influence of the slip effect (Kn) and the flow rate (Re) on their variation.

Prediction of test results to determine the hydraulic resistance coefficient of an axially symmetrical check valve

The urgency of the paper is determined by the necessity to predict the results of tests for determining the coefficient of hydraulic resistance of axially symmetrical check valve DN 100-600 with operating pressure up to 20 MPa and operating temperature from plus 50C to plus 3500C according to TS 6981-254-08847871-07. This paper suggests to reduce the volume of tests by excluding the tests for intermediate samples of valves (DN 100, DN125, DN 200, DN 300, DN 500, DN 600) situated in DN between the valve type models (DN 100, DN 175, DN 400) and replaced the tests by calculations in the programme module ANSYS CFX of the calculation complex ANSYS. The results of the tests for determining the coefficient of hydraulic resistance are given. An estimate of hydraulic resistance coefficient values is offered and recommendations for its determination are given. The experimental determination of hydraulic characteristics was carried out in the region of quadratic resistance and in absence of cavitation (the tests were done on water). The region of quadratic resistance comes at Reynolds numbers Re ≥ 2 × 104 for check valve of nominal diameters DN ≤ 250. The region of quadratic resistance ReKB is determined in the process of experimental determination of drag and flow capacity factors for valves of nominal diameters DN ≥ 250. The procedure of determination of ReKB is described in 7.2.3 of GOST 55508-2013. These test results for determination of hydraulic resistance coefficient for valves DN 150, DN 175, DN 400 according to TU 6981-254-08847871-07 can be used when developing acceptance test programs to set the number of tested samples according to the design features and number of versions of check valves (DN 100, DN125, DN 200, DN 300, DN 500, DN 600), replacing the testing by calculation.

THERMO-HYDRAULIC CHARACTERISTICS OF ADDITIVELY MANUFACTURED MINI-CHANNELS

The aim of this work is to analyze the heat transfer, hydraulic resistance and thermo-hydraulic performance of a new type of heat exchange channels made by additive technology. The main factors affecting the quality of products and determining the heat transfer and hydraulic resistance of the channels are noted. Well-known ratios for calculating hydraulic resistance and heat transfer are not suitable for such high roughness. Data on the AT resistance coefficient of the channels show that even at low Reynolds numbers there is a contribution of roughness. With increasing roughness, the intensification of resistance and heat exchange increases. The transition occurs at 700 < Re < 2000. Comparison of data on heat transfer augmentation and increase of hydraulic losses, as well as their thermo-hydraulic characteristics has been carried out. The hydraulic resistance coefficient of AT channels is significantly higher than the resistance coefficient of smooth channels. Heat transfer augmentation in wave-shaped channels is 2 times higher than augmentation in straight channels. Channels with pin fins allow to achieve a very high heat transfer augmentation (up to 8). Channels with internal grids provide high intensification, but have the highest hydraulic losses. The dependence of the Reynolds analogy factor on the resistance increase factor showed that the straight channels of all geometric forms fit on one dependence closed to the lower boundary line, and have a low hydraulic resistance. Data on channels with pin fins have a large spread. A number of points are above the upper boundary line, which refers to channels with low surface roughness.

EXPERIMENTAL AND NUMERICAL RESEARCH IN THE FLEXIBLE PIPES OF COIL TUBING INSTALLATIONS TAKING INTO ACCOUNT THE RHEOLOGY OF THE TECHNOLOGICAL FLUID

The current direction of the country's economic development is an intensive increase in hydrocarbon production on the territory of Ukraine, the introduction of new modern technologies and an increase in the efficiency of power equipment. One of the modern directions used in the oil and gas industry is the use of specialized equipment for coiled tubing units. Also, with the development of well drilling and oil production intensification technologies, modern multicomponent flushing (process) waters appear. The need for polymers is based on their ability to influence the properties of aqueous and hydrocarbon systems and form gels of different density, viscosity and rheology. Polymer systems are widely used due to their high cleaning, transporting and holding properties. Widely known polymer systems of technological solutions based on Xanthan Gum. Generalized information about the rheological parameters of fluids used to intensify the work of oil and gas wells is considered. The main rheological indicators of the studied liquid are the shear stress and the strain rate of the medium. These indicators are determined using an OFITE 900 rotational viscometer. The results of experimental studies of the properties of an aqueous solution with different concentrations of Xanthan gum from 0.6 to 8 g/l are presented. The study showed that an aqueous solution of gum creates a non-Newtonian behavior of the liquid. The coefficients of the rheological model of the solution were obtained by approximation of laboratory data. To simulate the hydrodynamic characteristics of a polymer system, a nonlinear viscous fluid model and a model with the introduction of effective viscosity are used. The results of studies of rheology indicators are used to determine the fluid flow regime, predict the hydraulic resistance coefficients in pipes and the energy characteristics of pumping equipment for supplying process fluid to the well. Experimental and calculated dependences of the influence of polymer additives on the resistance to the movement of liquids in coiled tubing of a coiled tubing unit are presented. The analysis of experimental and numerous hydrodynamic studies has been carried out. For numerical simulation of the hydrodynamics of non-Newtonian behavior of fluid in pipes, the open integrated platform OpenFOAM is used.

IMPLEMENTATION OF A MATHEMATICAL MODEL OF NONSTATIONARY GAS MOVEMENT IN A COMPLEX PIPELINE UNDER MIXED BOUNDARY CONDITIONS

The study of the movement of real fluid is necessary in the design of not only gas and oil pipelines, but also other hydraulic machines. Mathematical models of the unsteady movement of a liquid or gas are also necessary when solving a number of prob-lems in the operation of pipeline systems. Such tasks can be: pipeline condition monitoring, operating modes optimizing, emergency situations analyzing and others. Attempts to model the dynamics of pressure in pipelines with selection or pumping at given points led to systems of partial differential equations with boundary conditions between the zones of the pipeline section in question. If there are n sampling points (swapping), then we have to solve a system of n + 1 equations. This is due to cumbersome calculations, and sometimes with insurmountable difficulties. Use of the impulse function by Dirac M.A. Huseynzade and his students in oilfield mechanics and in pipe hydraulics made it possible to describe non-stationary processes in complex pipeline systems using a single equation. A section of a pipeline system is usually called «complex» if there are sampling-pumping points, pumping station or different sections of the pipeline have different coefficients of hydraulic resistance or diameters. This article discusses the horizontal section of the pipeline with sampling and pumping points. The problem is solved under mixed boundary conditions using a finite Fourier sine transform. Graphs of pressure dynamics for cases of selection, pumping and without them have been constructed. Special cases are considered. Calculation formulas convenient for practical application are obtained.

Influence of temperature of a magnetorheological fluid on damping of vibration disturbances by hydraulic mounts

The issues of dynamic stiffness coefficient control and increasing the damping ability of magnetorheological vibration mounts (MR-hydromounts) are considered. It is shown that in order to reduce the dynamic stiffness coefficient and increase the damping ability of the MR-hydromount it is necessary to reduce the coefficient of hydraulic resistance of the working magnetorheological fluid flow, which can only be achieved by increasing the number of throttle channels in the baffle plate. Calculation of the dynamic stiffness coefficient of the MR-hydromount depending on the magnetic field strength in the magnetorheological fluid and its heating temperature is presented. Keywords: inertial transformer, magnetorheological transformer, magnetorheological fluid, hydromount, working fluid, heating temperature, dynamic stiffness coefficient. gord349@mail.ru, acidwolfvx@rambler.ru, oxulkovs@mail.ru, aplehov@mail.ru, dm_titov@list.ru

Mismatch problem of the model and topology of oil pumping facilities

The mismatch of the model and the topology of real objects is important in modeling technological processes, which is the purpose of this paper. The problem is considered when modeling hot oil pumping in the "Kasymov–Bolshoy Chagan" oil pipeline. In this problem, the topology of objects consists of the linear part of the pipeline and technological equipment (pumps and heating furnaces) of the stations. The accuracy of the simulation results is determined by the calculations of pressure and temperature in the oil pipeline. The pressure in the pipeline is created by pumps at the stations and is determined by the dependence of the pressure and efficiency of the pump on the oil flow rate. These characteristics change depending on the service life of the pump. The identification of the actual dependences of the pressure and efficiency of the pump on the oil flow rate was carried out by the regression analysis of experimental data. The pressure in the linear part is determined by the hydraulic resistance of the pipeline. The actual dependence of the hydraulic resistance coefficient on the Reynolds number and wall roughness was obtained by regression analysis of experimental data. The temperature in the oil pipeline is created at the stations by heating furnaces. The identification of the actual characteristics of the heating furnace was also found by regression analysis of the experimental data. The temperature distribution in the linear part is determined by the heat transfer of oil with the surrounding environment. An undefined parameter for calculating heat transfer is the soil thermal conductivity, which depends on the type of rock and the degree of soil moisture. The soil thermal conductivity is determined in such a way that at a given oil flow rate, oil temperatures at the beginning of the section and soil at the section, the calculated oil temperature at the end of the section has the smallest discrepancy with the actual one. Thus, the determination of the actual dependencies of the objects makes it possible to increase the accuracy of the results of hot pumping modeling and eliminates the mismatches of the model and the topology of the objects.

HYDRO-GAS-DYNAMIC MODEL OF MOTION OF GAS-SATURATED LIQUID IN A CENTRIFUGAL POROUS PUMP


 
 
 An approach has been developed to the formation of a theoretical model of the movement of a gas- saturated liquid in the flow path of a porous centrifugal pump, as an assembly of the system for feeding the reaction mass of liquid-propellant rocket engines. The developed approach is based on a physical model of the turbulent motion of a gas-liquid mixture, within which conservation equations are used. Two models are proposed that describe the movement of a gas-liquid mixture in the flow path of a centrifugal porous pump in a two-phase one- dimensional formulation and a quasi-homogeneous one, complementing each other. A porous impeller of a closed- type centrifugal pump of constant width is considered. The energy losses of the gas-liquid mixture flow at the inlet to the pump impeller, as well as the losses of disk friction associated with rotation in a fixed housing, are not taken into account. The parameters of the viscous and inertial hydraulic resistance coefficients of the porous body are used. In particular, the influence of the static pressure gradient in a gas-saturated liquid and the friction force on the accumulation of gas at the inlet to the impeller and the stability of the liquid supply by the pumping unit is noted. The use of the developed approach makes it possible, by calculation methods, to evaluate the values of parameters characterizing the movement of gas-liquid media in centrifugal porous pumps of the designed systems for feeding propellant components to liquid-propellant rocket engines, to reduce the amount of experimental testing of new and modernized propulsion systems for space stages and launch vehicles.
 
 

Масштабирование гидравлической эффективности противотурбулентной присадки

The purpose of this article is to deduce the dependence of the hydraulic efficiency of drag-reducing agent on real objects on the hydraulic efficiency of drag-reducing agent in bench or laboratory conditions for two cases: smooth and rough pipeline wall. The method used in this article is a mathematical analysis of the dependenciesof the efficiency of drag-reducing agent in pipelines of different diameters with different roughness of the pipeline wall.This article analyzes the dependencies for calculating the coefficient of hydraulic resistance during flow in pipelines of various diameters. The dependence of the hydraulic efficiency of the drag-reducing agent on the diameterof the pipeline is analyzed. In the course of transformations, including using the Lambert function, an explicit dependence of the hydraulic efficiency of drag-reducing agent under conditions of different diameters for smooth pipes and an implicit dependence for rough pipes was revealed.

Hydraulic characteristics of pipelines restored using polymer hoses

Aging water supply and wastewater pipeline systems suffer from corrosion and damage. Trenchless restoration methods extend their lifespan and reduce repairing costs. However, there is no standard method for determining the hydraulic characteristics of restored pipelines, making it challenging to assess the feasibility of using different materials for restoration. This article focuses on changes in hydraulic characteristics after restoring pipelines with glass fiber and synthetic felt hoses. The study uses Bernoulli’s equation and the Chezy formula to estimate changes in the flow capacity of pipelines. Standard values for slopes, flow rates, and filling rates were used to calculate the hydraulic resistance coefficient, Chezy coefficient, and flow rate after laying polymer hoses. The results show that the flow capacity of restored pipelines increases, and there is no need for further hydraulic calculations to confirm the absence of a reduction in pipeline capacity after restoration. Therefore, trenchless restoration methods can be considered as effective means to extend the lifespan of aging pipeline systems and reduce engineering repairs costs.