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The investigation of critical flow model for supercritical pressure condition is relatively rare. Based on isentropic flow and thermal equilibrium assumptions, a model is derived to calculate discharge flow rate and critical pressure. Considering the influence of friction and local resistance, a correction coefficient is added which can be calculated from CFX analysis software. The model avoids the calculation of quality and is applicable to wide range which covering the subcooled water, two-phase mixture, steam critical flow under subcritical pressure and supercritical pressure. Reasonable agreement is shown between model predicted results and experiment data, illustrating the accuracy of the proposed model. [ABSTRACT FROM AUTHOR]

With the increase in high-rise buildings in cities, public flue exhaust systems have a direct impact on residential air quality and the living environment. Although existing studies have analyzed the problems in public flue exhaust systems through computational fluid dynamics (CFD) numerical simulations and experimental tests, these studies often lack an in-depth exploration of the specific impacts of individual components in the system. To solve this problem, this study not only thoroughly analyzes the key components in the public flue system, such as branch pipes, check valves, and tee pipes, but also develops a parametric public flue simulation system software based on C# and verifies the accuracy of the simulation through experiments. The study first determines the key parameters affecting the comprehensive resistance coefficient of the branch pipe, check valve, tee pipe, and other components through CFD simulation and experimental testing. Subsequently, a visualization program is developed using the C# language, which can quickly simulate and visualize the flow changes in the flue according to different building parameters such as the number of floors, height of floors, and size of the flue. The results confirm that the program can efficiently predict the flow distribution under different design options, providing a practical tool for the optimal design and performance evaluation of public flues, which is important for improving the air quality of the living environment. [ABSTRACT FROM AUTHOR]

Abstract With the increase in high-rise buildings in cities, public flue exhaust systems have a direct impact on residential air quality and the living environment. Although existing studies have analyzed the problems in public flue exhaust systems through computational fluid dynamics (CFD) numerical simulations and experimental tests, these studies often lack an in-depth exploration of the specific impacts of individual components in the system. To solve this problem, this study not only thoroughly analyzes the key components in the public flue system, such as branch pipes, check valves, and tee pipes, but also develops a parametric public flue simulation system software based on C# and verifies the accuracy of the simulation through experiments. The study first determines the key parameters affecting the comprehensive resistance coefficient of the branch pipe, check valve, tee pipe, and other components through CFD simulation and experimental testing. Subsequently, a visualization program is developed using the C# language, which can quickly simulate and visualize the flow changes in the flue according to different building parameters such as the number of floors, height of floors, and size of the flue. The results confirm that the program can efficiently predict the flow distribution under different design options, providing a practical tool for the optimal design and performance evaluation of public flues, which is important for improving the air quality of the living environment.

Abstract Most hot dry rock geothermal wells are small angle directional wells, and rock cuttings easily accumulate at the bottom of the borehole to form a cuttings bed, causing accidents such as drill sticking, reducing the rate of penetration, and drilling tool breakage. Accurately calculating the resistance coefficient and settling velocity of hot dry rock cuttings can improve cuttings transportation efficiency, design and optimize drilling hydraulic parameters, and is crucial to solving borehole cleaning problems. Through visual experiments, this paper obtained experimental data on the settlement of 167 groups of spherical pellets, 153 groups of granite cuttings, and 174 groups of carbonate cuttings in the Herschel-Bulkley fluid. First, a prediction model for the resistance coefficient of spherical pellets consistent with Herschel-Bulkley fluid was established. Based on this, form factor-Roundness is introduced as the starting point, and two prediction models for the resistance coefficients of granite cuttings and carbonate cuttings in the Herschel-Bulkley fluid were established. The average relative errors between the resistance coefficient model predictions and experimental measurements are 9.61% for granite cuttings and 6.59% for carbonate cuttings. The average relative errors between the predicted and measured values of settlement velocity are 7.27% for granite cuttings and 6.21% for carbonate cuttings, respectively, which verifies the accuracy and reliability of the prediction model. The research results can provide a theoretical basis and engineering application guidance for optimizing drilling fluid rheology and circulation displacement in engineering.

A compound channel's discharge capacity and boundary shear force can be predicted as a sum of the discharge capacity of different sub-regions once the apparent shear stress of the dividing line is reasonably quantified. The apparent shear stress was usually expressed as a coefficient multiplied by the difference between two squared velocities of two adjacent regions. This study investigated the range of the coefficient values and their influencing factors. Firstly, the optimal values of the coefficient were obtained based on experimental data. Then, comparisons between the optimal values and several parameters used in quantifying the apparent shear stress were conducted. The results show that the coefficient is mainly related to a morphological parameter of the floodplain and the ratio of resistance coefficients between the floodplain and the main channel. An empirical formula to calculate the coefficient was developed and introduced to calculate the flow discharge and boundary shear stress. Experimental data, including 142 sets of test data of symmetric-floodplain cases and 104 sets of one-floodplain cases, have been used to examine the prediction accuracy of discharges and boundary shear stress. For all these tests, the ranges of water depth of the main channel and the total width of the compound cross-section are about 0.05~0.30 m and 0.3~10 m, respectively; the Q range and the range of Froude numbers of the main channel flow are about 0.0033~1.11 m3/s and 0.3~2.3, respectively. Comparison with other methods and experimental data from both rigid and erodible compound channels indicated that the proposed method not only provided acceptable accuracy for the computation of discharge capacity and boundary shear stress of compound channels in labs but also gave insights for calculating discharge capacity in natural compound channels. [ABSTRACT FROM AUTHOR]

Inertia force coefficient CM and resistance coefficient CD of monofilament and rope used in tuna longline gear directly affect the computational speed and accuracy of numerical simulations of fishing gear. In this study, wave forces acting on seven types of monofilament and rope materials for tuna longline gear under regular wave conditions were investigated through wave tank experiments. CM and CD for respective materials were calculated using the Morison equation and employing the least squares method. The variations of CM and CD with Keulegan-Carpenter number KC and Reynolds number Re were analyzed. The results indicate that: (1) Under the same wave height, the wave forces acting on experimental materials gradually increase with increasing wave period. (2) Under the same wave period, the wave forces acting on experimental materials gradually increase with increasing wave height. (3) With increasing diameter, the wave forces acting on experimental materials also increase. (4) For three types of nylon monofilament, CD gradually increases with the increasing KC while CM remains relatively stable, and CM and CD exhibit an increasing trend with the increasing of Re. (5) For three types of polypropylene ropes, CM increases with the increasing KC and Re, while CD stabilizes at lower KC numbers and decreases gradually with the increasing Re. (6) Polypropylene ropes coated with asphalt exhibit relatively stable CM and CD values. The obtained CD and CM values from this experiment can be applied to the numerical simulations of longline fishing gear. [ABSTRACT FROM AUTHOR]

Most hot dry rock geothermal wells are small angle directional wells, and rock cuttings easily accumulate at the bottom of the borehole to form a cuttings bed, causing accidents such as drill sticking, reducing the rate of penetration, and drilling tool breakage. Accurately calculating the resistance coefficient and settling velocity of hot dry rock cuttings can improve cuttings transportation efficiency, design and optimize drilling hydraulic parameters, and is crucial to solving borehole cleaning problems. Through visual experiments, this paper obtained experimental data on the settlement of 167 groups of spherical pellets, 153 groups of granite cuttings, and 174 groups of carbonate cuttings in the Herschel-Bulkley fluid. First, a prediction model for the resistance coefficient of spherical pellets consistent with Herschel-Bulkley fluid was established. Based on this, form factor-Roundness is introduced as the starting point, and two prediction models for the resistance coefficients of granite cuttings and carbonate cuttings in the Herschel-Bulkley fluid were established. The average relative errors between the resistance coefficient model predictions and experimental measurements are 9.61% for granite cuttings and 6.59% for carbonate cuttings. The average relative errors between the predicted and measured values of settlement velocity are 7.27% for granite cuttings and 6.21% for carbonate cuttings, respectively, which verifies the accuracy and reliability of the prediction model. The research results can provide a theoretical basis and engineering application guidance for optimizing drilling fluid rheology and circulation displacement in engineering. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Northwest A & F University - Natural Science Edition is the property of Editorial Department of Journal of Northwest A&F University (Natural Science Edition) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this study, the bedform dimensions of an alluvial bed in a unidirectional flow were experimentally investigated. A series of flume experiments was conducted; 700 sets of flume and field data were used in developing formulae for predicting the bedform dimensions on alluvial beds in unidirectional flow. Bedform dimensions include the length and height of bedforms generated by the lower and upper flow regimes; the resistance coefficient for the flow in different flow regimes is introduced into the proposed formulae. The momentum boundary-layer thickness was introduced as an independent variable instead of the flow depth. Based on a large amount of flume and field data, the coefficients of each parameter were determined; four typical formulae were used to compare the accuracy of the proposed formulae. The experimental results show that the momentum boundary-layer thickness, hydraulic radius, and resistance coefficient for the flow in different regimes correlate well with the bedform dimensions. The calculation results show that the dimensionless particle size should not be ignored in the calculation of bedform dimensions. The bedform dimensions have an obvious trend of rapid increase with an increase in the ratio of flow depth to sand size (H/d). The bedform dimensions obtained using the van Rijn method and the Engelund and Hansen method did not represent the variation trend of the bedform length in the upper flow regime with an increase in H/d when H/d was greater than 103. The calculations using the proposed formulae are more accurate and reasonable than those in previous studies predicting the bedform height and length on an alluvial bed in a unidirectional flow. [ABSTRACT FROM AUTHOR]

Although earthworms are recognized for their excellent mobility in confined environments, little is known about the triaxial ground reaction forces (GRFs) they produce during locomotion. This study explores the triaxial GRF characteristics of the earthworm during rectilinear locomotion and their implications for robot development. A strain gauge-based triaxial miniature force plate is designed to measure the triaxial GRFs of Pheretima guillelmi during rectilinear locomotion. By correlating the time histories of the measured GRFs with recorded videos, the motion of one cycle of the earthworm is divided into three phases, and the relationship between the deformation of the earthworm’s body and the characteristics of the GRFs is established. Based on the experimental data of nine subjects, this study also statistically analyzes the characteristics of the GRFs and derives a model of the earthworm’s resistance coefficient during its rectilinear motion. Furthermore, this study presents models of resistance coefficients closely related to robot segment/section deformations for both discrete and continuous configurations of earthworm-like robots. The results of this study are instructive for understanding earthworm locomotion biomechanics and designing and regulating the interface between the earthworm-like robot and the ground. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Drainage & Irrigation Machinery Engineering / Paiguan Jixie Gongcheng Xuebao is the property of Editorial Department of Drainage & Irrigation Machinery Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

During the drilling process, cuttings settle under the action of gravity, which easily results in the formation of a cuttings bed, which then results in wellbore cleaning problems. The settling law of cuttings in drilling fluid is essentially a problem of solid–liquid two-phase settling. This study analyzes and summarizes the effects of the wall effect, the rheology of the fluid, particle shape irregularity, and particle concentration on the settling rate of particles and clarifies the problems faced by current research on the settling rate of particles and the development direction. Studies have shown that walls exert additional blocking effects on particles, thus reducing their settling velocity. The shear thinning effect of non-Newtonian fluids such as power-law fluids and Herschel–Bulkley fluids will reduce the viscosity of the liquid, thus increasing the settling velocity of the particles. Compared with spherical particles, irregular particles will obtain higher resistance in the fluid, leading to a decline in the particle settling velocity. The mutual interference between particles will result in an increase in the drag force on the particles and a decline in the settling velocity. However, when the particles are aggregated, the settling velocity will increase. This study can provide theoretical guidance for predicting the migration law of cuttings during the drilling of horizontal wells, and it has important significance for enriching the theory of solid–liquid two-phase flow. [ABSTRACT FROM AUTHOR]

A compound channel’s discharge capacity and boundary shear force can be predicted as a sum of the discharge capacity of different sub-regions once the apparent shear stress of the dividing line is reasonably quantified. The apparent shear stress was usually expressed as a coefficient multiplied by the difference between two squared velocities of two adjacent regions. This study investigated the range of the coefficient values and their influencing factors. Firstly, the optimal values of the coefficient were obtained based on experimental data. Then, comparisons between the optimal values and several parameters used in quantifying the apparent shear stress were conducted. The results show that the coefficient is mainly related to a morphological parameter of the floodplain and the ratio of resistance coefficients between the floodplain and the main channel. An empirical formula to calculate the coefficient was developed and introduced to calculate the flow discharge and boundary shear stress. Experimental data, including 142 sets of test data of symmetric-floodplain cases and 104 sets of one-floodplain cases, have been used to examine the prediction accuracy of discharges and boundary shear stress. For all these tests, the ranges of water depth of the main channel and the total width of the compound cross-section are about 0.05~0.30 m and 0.3~10 m, respectively; the Q range and the range of Froude numbers of the main channel flow are about 0.0033~1.11 m3/s and 0.3~2.3, respectively. Comparison with other methods and experimental data from both rigid and erodible compound channels indicated that the proposed method not only provided acceptable accuracy for the computation of discharge capacity and boundary shear stress of compound channels in labs but also gave insights for calculating discharge capacity in natural compound channels.

Copyright of Cotton Textile Technology is the property of Cotton Textile Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this paper, the optimization of the flow channel structure of the U-shaped air distributor is proposed. Fluent meshing was used to mesh the multipatch meshing of the original model of the grid air distributor, and then the CFD numerical simulation was carried out by using Fluent 2022R1 to obtain the internal air flow state of the air distributor flow channel. Through the orthogonal experimental design and a comprehensive analysis method, the optimal size structure for resistance performance is obtained as S = 60 mm, RL = 125 mm, L = 160 mm, D = 100 mm, the resistance coefficient of the new structure as 1.375, and the pressure loss as 56.87 Pa, by using 3D modeling software (SOLIDWORKS 2015) and Fluent. Compared with the initial scheme, the resistance coefficient and pressure loss are reduced by 3.03% and 6.29%, respectively. To summarize, the research in this paper offers a substantial contribution to the realm of energy conservation and emission abatement in ship air conditioning systems, simultaneously furnishing invaluable guidance for the design of air distributors. [ABSTRACT FROM AUTHOR]

In this study, the bedform dimensions of an alluvial bed in a unidirectional flow were experimentally investigated. A series of flume experiments was conducted; 700 sets of flume and field data were used in developing formulae for predicting the bedform dimensions on alluvial beds in unidirectional flow. Bedform dimensions include the length and height of bedforms generated by the lower and upper flow regimes; the resistance coefficient for the flow in different flow regimes is introduced into the proposed formulae. The momentum boundary-layer thickness was introduced as an independent variable instead of the flow depth. Based on a large amount of flume and field data, the coefficients of each parameter were determined; four typical formulae were used to compare the accuracy of the proposed formulae. The experimental results show that the momentum boundary-layer thickness, hydraulic radius, and resistance coefficient for the flow in different regimes correlate well with the bedform dimensions. The calculation results show that the dimensionless particle size should not be ignored in the calculation of bedform dimensions. The bedform dimensions have an obvious trend of rapid increase with an increase in the ratio of flow depth to sand size (H/d). The bedform dimensions obtained using the van Rijn method and the Engelund and Hansen method did not represent the variation trend of the bedform length in the upper flow regime with an increase in H/d when H/d was greater than 103. The calculations using the proposed formulae are more accurate and reasonable than those in previous studies predicting the bedform height and length on an alluvial bed in a unidirectional flow.

In recent years, accidents of gantry cranes caused by strong winds have occurred from time to time. Therefore, it is of practical engineering significance to study the wind load of gantry cranes. Aiming at the two gantry cranes wind load characteristics, the computational fluid dynamics (CFD) method was adopted to carry out simulation research on two gantry cranes. Firstly, the Pro/E software was used to establish a three-dimensional model of the gantry crane; the ANSYS software was used to establish the outflow field of the crane; the grid division and grid independence of the computational domain were carried out by ANSYS. Then, the numerical simulation of a single gantry crane was carried out by Fluent software to analyze the aerodynamic coefficients of a single gantry crane under different wind direction angles. At the same time, the difference between the wind load in Design Rules for Cranes and the simulation was compared. Finally, considering only the influence of inflow wind load, the numerical simulation of two gantry cranes was carried out. Meanwhile, the influence of wind direction angles and two gantry cranes spacing S to the drag coefficient, the wind reduction factor of gantry crane, the velocity change cloud diagram and the pressure distribution of gantry crane were studied. The results show that the maximum wind load on the gantry crane appears in the 45° wind direction. In 90° wind direction, the wind proof effect is the best with about 52% wind reduction when the distance between the two gantry cranes S =15 m. Critical spacing of two gantry cranes S=35 m. When S ＞35 m, two gantry cranes shielding effect is weakened until it disappears. The maximum pressure on headwind of main girder of gantry crane is close to the both ends of the girder. [ABSTRACT FROM AUTHOR]

Copyright of Special Oil & Gas Reservoirs is the property of Special Oil & Gas Reservoirs Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Natural gas control ball valves are fluid control devices that regulate the flow and direction of the medium in a natural gas transportation system, and nowadays the requirements for valve intelligence are increasing. To implement the intelligent control of the valve system, the precise acquisition of the operating parameters of the control ball valve was studied in this paper. A numerical simulation of the internal flow field of a V-shaped ball valve was conducted based on a finite volume method and an renormalization group (RNG) k–ε turbulence model. A valve performance test bench was established, and the pressures at the inlet and outlet of the valve at various relative openings were measured, in which the accuracy of the numerical model was verified. Through numerical simulations, the internal flow characteristics at various relative openings and spool cone angles were studied. By comparing the influence of three different relative openings on the valve internal flow field, it was found that the valve showed better flow characteristics under the relative opening of 80%, and the increase of the cone angle effectively improved the unstable flow in the valve. An accurate expression between the external parameters of the valve operating condition and the internal flow was established, and the expression is the theoretical basis to implement intelligent control. This study provides strong technical support for an efficient operation of natural gas pipelines. [ABSTRACT FROM AUTHOR]

At present, China's high-speed rail is in a period of rapid development. Most of the refrigerants used in Chinese motor train units at this stage are still R134a and R407c, which have an impact on the environment. In response to the environmental protection concept of green travel, it is of great significance to study the air conditioning system of motor train units using CO2 refrigerant. Using CFD simulation analysis technology, the heat transfer performance of the air side of the CO2 finned tube evaporator used in the air conditioning system of the motor train unit is studied. We select the air outlet temperature, pressure drop, heat transfer factor, and resistance factor as the objective function, in addition, monitoring points are set up in the air flow channel to monitor the turbulent flow field and pipe wall pressure. Our research shows that the cooling capacity of the CO2 evaporator can reach up to 29.76 kW, which can meet the heat exchange required in the air conditioning system of the motor train unit. In order to obtain a better structure and the conditions of the heat transfer effect, structural optimization was conducted. The simulation results demonstrate several trends: (i) With the augment of the air inlet velocity, the cooling capacity of the evaporator increases and the heat exchange effect improves; when the air inlet ve > 2.2 m/s, the effect of continuing to augment ve on heat exchange is weak. (ii) Following appropriate reduction of the diameter of the heat exchange tube, the wind resistance is reduced and the cooling capacity of the evaporator is improved. (iii) With the enlargement of the fin spacing, the turbulent motion in the flow channel can be fully developed, there is a peak in the change in the heat exchange tube area optimization factor, and the optimal fin spacing is between 1.6 mm and 1.7 mm; at this time, the average turbulent kinetic energy of the air side is larger and the turbulent dissipation rate is smaller. These results provide a reference for the practical application of CO2 refrigerant in the motor train unit. [ABSTRACT FROM AUTHOR]

Copyright of Advanced Engineering Science / Gongcheng Kexue Yu Jishu is the property of Advanced Engineering Science Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Resistance of the bare hull of the tourist submarine with spherical heads, moving in forward and transverse directions is analyzed in OpenFOAM using Computational Fluid Dynamics. The resistance coefficients of the submarine are estimated for different length-to-diameter ratios and Reynolds numbers. The Artificial Neural Network with the optimum number of neurons is then trained to predict the resistance coefficients. Two simplified Artificial Neural Network models and Nonlinear Least Squares Marquardt-Levenberg algorithm are employed to fit the results in the form of equations that may be used in the initial design of this type of submarines. The comparative analysis of different prediction models is performed and guidelines for their practical application are given. [ABSTRACT FROM AUTHOR]

Vegetation plays a significant role in preventing desertification, conservation of soil and water. However, nowadays, there is still uncertainty regarding the mechanisms of flow resistance caused by dissimilar vegetation covers. To address this gap, a series of these was conducted in this study to investigate the influence of synthetic grass and stems on the variation of resistance on overland flows. Thirty vegetation configurations were selected (combining five synthetic grass coverage options and six synthetic stem coverage ones), and tested against five unit discharges (flow range = 0.28–2.22 L m−1 s−1) and four slope gradients (3.49%–20.78%). The results obtained showed that the unit discharge is the key driving factor for the transition from laminar to transitional flow. Furthermore, the relationship between the resistance coefficient (f) and the Reynolds number (Re) was not monotonically increasing or decreasing, but behaviours observed were specifically linked to each vegetation coverage. However, a critical coverage threshold was identified, and it corresponded to 2.72% when the slope gradient tested was 3.49%. This threshold decreased with the increase of the slope gradient. In addition, when the vegetation coverage was less than the critical threshold, the f was negatively correlated with Re, otherwise if the vegetation coverage was higher than the critical threshold identified the f–Re relation was positively correlated. The total flow resistance under synthetic grass and stem cover was unequal to the linear superposition of grain resistance and form resistance caused by synthetic stem and grass, which meant that the linear superposition approach is not applicable to overland flows. Finally, a model was developed to predict the flow resistance by applying the π‐theorem and the multiple nonlinear regression analysis and it has been validated against the experimental results confirming its accuracy and high performance (adj.R2 = 0.99, NSE = 0.94). [ABSTRACT FROM AUTHOR]

Uniform ventilation is important for the safety of long tunnel in underground buildings, it is difficult to install the large size air duct to ensure the centerline of each cross-section of the traditional variable cross-section ventilation system(VCVS) superimposed on the same horizontal axis, which is significant to the ventilation uniformity, energy consumption and installation convenience of the VCVS. On the contrary, each cross-section of the Equal Cross-section Ventilation System (ECVS) has the same horizontal axis, therefore, it is more convenient to manufacture and install the large size air duct in the underground long tunnel and achieve uniform ventilation. This study proposes an ECVS, using computational fluid dynamics(CFD) numerical simulation analyzed the influences of main duct velocity, aspect ratio, and outlet numbers on uniformity and energy consumption per unit air volume(ECPV). It revealed that when each ventilation equalizer's valve Angle β is given, uniformity of air supply decreases slightly with an increase in the inlet velocity. When the air supply main duct aspect ratio increases, the outlet velocity standard deviation range is from 0.22 to 0.34. When outlet numbers N=7~12 and β are constant, air supply uniformity and resistance coefficient ξ also decrease with the decrease of outlet numbers. The outlet number has a significant influence on the uniformity of system air supply, main duct velocity, and aspect ratio are relatively small. ECPV is positively correlated with the main duct velocity and outlet number, and is negatively correlated with aspect ratio.

This paper presents and patents new profiled- and annular-channel tangential swirlers with 1.8–3 times less hydraulic drag coefficient compared to swirlers with straight channel walls at the same flow rate, respectively. The results of numerical simulation of the gas velocity and pressure profiles for tangential swirler channels of different structures are presented. The modelling was carried out with the help of OpenFOAM software using the k-ε turbulence model. It is found that the shape of the velocity profile at the channel inlet has a decisive influence on the swirler drag coefficient. The greatest contribution to the total drag coefficient of the tangential swirler is made by the pressure drop at the channel inlet compared to the pressure drop at the channel wall and the channel outlet. The experimental dependencies of the tangential swirlers' drag coefficient on the Reynolds number with a gas criterion of 2000–20,000 and the following structural channel parameters: width 1, 2–9 mm, height 1, 5–10 mm, number 5–45 units, inclination angle 0–45° are presented. The experimental data were compared with the modelling calculations and the convergence of data was achieved. The generalized dependence for the measurement of the hydraulic drag coefficient of three types of tangential swirlers considering the effect made by the geometric parameters (flow rate, width and height of the channel, wall inclination angle) on the pressure drop has been determined; it can be useful at the unit design stage as it allows for reducing the calculation time of the swirler parameters. [ABSTRACT FROM AUTHOR]

3D mats are environmentally friendly and ecological materials for protecting river and waterway banks. The anti-scour properties of the materials and the erosion resistance of the soil under them can be studied to provide decision support for the selection of slope protection materials and their applicable areas. In this paper, an indoor prototypical scouring experiment with a flume is carried out to study the anti-scour properties of three types of 3D mat materials (vegetation grass mats, Enkamat and reinforced Mike mat) and the erosion resistance of the underlying soil under typical combined conditions of flow rate and water stage. It is concluded that the 3D mats increase the resistance coefficient of the bed surface, and that with the same incoming flow, the average flow velocity is inversely related to the resistance coefficient. There are three scouring modes for 3D mats under the action of water flow: material failure caused by mechanical damage, performance failure caused by serious erosion of the soil mass and non-failure. Of the three mat materials, the reinforced Mike mats are more resistant to scouring than the other two unreinforced materials, and the erosion volume ratios of reinforced Mike mats, vegetation grass mats and Enkamat are 59.24%, 61.81% and 62.17%, respectively, under the same small flow rate and high water stage. The results show that the reinforced Mike mats have the best anti-scour property and soil conservation performance, followed by Enkamat and the vegetation grass mats. In addition, reinforced materials outperform non-reinforced ones in their anti-scour performance and their protection for the underlying soil on the bank slope. [ABSTRACT FROM AUTHOR]

Relevance. The drilling results are influenced by the effectiveness of the rock cutting tool operation at the bottom of the well. The indicators of the mechanical drilling speed, the quality of well construction and sampling are closely related to the correspondence of the selected rock cutting tool and technology of its application to the physical and mechanical properties of the rocks that make up the geological section being opened. With the technology unchanged, the increase in resistance from the bottom hole leads to a change in the intensity of the well deepening. Information about the resistance coefficient allows you to correctly control the process and timely adjust the nature of the impact of the drilling tool on the bottomhole. The purpose of research is to control the power contact of the drilling tool cutters with the bottom of the well; it is necessary to have a methodological apparatus that allows determining the mechanism of rock destruction taking into account the resistance forces. Objects: rock breaking. Methods: experimental, full factorial experiment method, analytical research, analysis. The article presents a method for studying the resistance of rocks to destruction with a diamond cutter, based on the use of the method of a full factorial experiment with obtaining mathematical models of factors and their graphic interpretation, in particular the dependence of deepening in one revolution on drilling modes on the basis of which the resistance coefficient when drilling at a particular moment is determined. Results. Based on the analytical study of the results obtained, the dependence of the tangential force on the axial force, rock properties, and the friction coefficient was determined. The paper presents the analytical research of the possibility of regulating drilling modes in order to achieve the greatest effect from drilling by assessing the drag coefficient as a function of the intensity of destruction or deepening in one revolution. The authors have derived and proved the validity of expression of the drag coefficient dependence on the cutter penetration depth into the rock, the number of cutters at the end of the drilling tool and their size, the depth of the formed fracture groove, the cutter friction coefficient on the rock and the dynamic component of the drilling tool operation.

• The liquid metal flow and heat transfer characteristics in helical bundles is investigated. • The effects of coiling strategy and tube pitch are analyzed. • New correlations for liquid metal crossflow through helical bundles are established. There are currently few friction factor and heat transfer correlations for liquid metal flow in the shell-side of helical-coiled once-through steam generators (H-OTSG). The flow and heat transfer characteristics in H-OTSG are affected by various configuration parameters. Therefore, it is crucial to develop friction factor and Nusselt number correlations for the preliminary design of liquid metal H-OTSG. In this study, a numerical method is proposed to investigate the resistance and heat transfer characteristics of liquid metal crossflow through helical tube bundles. The effects of the coiling strategy and tube pitch on the resistance and heat transfer are analyzed in detail based on the validated numerical method. New correlations for friction factor and Nusselt number are developed based on the numerical results. This study will provide a reference for the design and safety analysis of liquid metal H-OTSG. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ultra-dry C/W foam reduced reservoir permeability and decreased its heterogeneity. • The ability of residual foam to plug cores was stable. • Parallel-core experiment and COMSOL simulation verified good plugging of the foam. For oil recovery in low-permeability oil fields, ultra-dry CO 2 foam flooding possesses the dual advantages of pure CO 2 flooding and surfactant flooding, and is also effective for CO 2 storage. Herein, ultra-dry CO 2 -in-water (C/W) foam with 10 v/v% water content was used for core plugging and to decrease the heterogeneity of oil reservoirs. The resistance coefficient (R f) and residual resistance coefficient (R ff) characterizing the foam-plugged cores were measured at different foam existence times (different times after forming the foam) and for cores with different permeabilities. As the foam existence time increased, the non-uniformity of the foam intensified, resulting in a decrease in its ability to plug cores. Specifically, the resistance coefficient (R f) decreased from 12.179 to 6.802, while the residual resistance coefficient (R ff) decreased from 7.149 to 3.809. With a decrease in the core permeability, R f decreased from 26.525 to 10.398, R ff decreased from 17.313 to 4.230, and the ability of the foam to plug cores decreased, indicating that the ultra-dry C/W foam could effectively plug the high-permeability layer and decreasing the reservoir heterogeneity. Based on the distribution of foam and pore size, three plugging mechanisms were proposed: single-bubble bridge, multi-bubble accumulation and foam compression, deformation and rupture. Additionally, a scale factor I (I = R ff / R f) was introduced to evaluate the stability of the residual foam in the plugged core. After different existence times, the value of I for the foam injected into the core was stable at 0.55–0.6, indicating good stability of the foam. Finally, oil recovery in parallel cores was evaluated and two-phase flow was simulated based on the phase-field method, which further proved that the ultra-dry C/W foam can effectively decrease the reservoir heterogeneity and enhance oil recovery in the low-permeability zone. [ABSTRACT FROM AUTHOR]

At present, China’s high-speed rail is in a period of rapid development. Most of the refrigerants used in Chinese motor train units at this stage are still R134a and R407c, which have an impact on the environment. In response to the environmental protection concept of green travel, it is of great significance to study the air conditioning system of motor train units using CO2 refrigerant. Using CFD simulation analysis technology, the heat transfer performance of the air side of the CO2 finned tube evaporator used in the air conditioning system of the motor train unit is studied. We select the air outlet temperature, pressure drop, heat transfer factor, and resistance factor as the objective function, in addition, monitoring points are set up in the air flow channel to monitor the turbulent flow field and pipe wall pressure. Our research shows that the cooling capacity of the CO2 evaporator can reach up to 29.76 kW, which can meet the heat exchange required in the air conditioning system of the motor train unit. In order to obtain a better structure and the conditions of the heat transfer effect, structural optimization was conducted. The simulation results demonstrate several trends: (i) With the augment of the air inlet velocity, the cooling capacity of the evaporator increases and the heat exchange effect improves; when the air inlet ve > 2.2 m/s, the effect of continuing to augment ve on heat exchange is weak. (ii) Following appropriate reduction of the diameter of the heat exchange tube, the wind resistance is reduced and the cooling capacity of the evaporator is improved. (iii) With the enlargement of the fin spacing, the turbulent motion in the flow channel can be fully developed, there is a peak in the change in the heat exchange tube area optimization factor, and the optimal fin spacing is between 1.6 mm and 1.7 mm; at this time, the average turbulent kinetic energy of the air side is larger and the turbulent dissipation rate is smaller. These results provide a reference for the practical application of CO2 refrigerant in the motor train unit.

• Field experiments are conducted in a vineyard to estimate soil properties. • Three soil conditions are considered: soft soil, firm soil, and wet saturated soil. • Resistance coefficient and sinkage are evaluated by FEM for different wheel sizes. • The results are analyzed through response surfaces. In this study a 2D FEM model was developed to analyze ruts formation, rolling resistance, and power loss for a grape transporting cart aimed to replace the use of heavy tractors while harvesting grape. The model was supported by experiments in a vineyard in South Italy. Cone penetration tests were conducted to estimate frictional and cohesive properties in three soil conditions: firm, soft, and wet saturated. A tractor pulled test rig for a single wheel was developed to measure rolling resistance and sinkage, and complete the selection of the soil parameters. Completed the model, the analysis was conducted for a range of different wheel dimensions, and the outputs analyzed through response surfaces. The results showed the different impacts that width and diameter have on ruts formation and rolling resistance for different soil conditions. Wider wheels determined a main reduction of the sinkage, while the width contribution to the rolling resistance was affected by the total soil volume deformed. Larger diameters led to lower rolling resistance, with a higher impact on more deformable soils. Contact stress was compared with the thresholds recommended in the literature to determine the acceptable designs. This analysis represents a tool to select the running gear dimensions. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) tracking of nano-objects represents a novel pathway for understanding dynamic nanoscale processes within bioanalytics and life science. Here we demonstrate 3D tracking of diffusing 100 nm gold nanosphere within a water-filled optofluidic fiber via elastic light scattering–based position retrieval. Specifically, the correlation between intensity and position inside a region of a fiber-integrated microchannel has been used to decode the axial position from the scattered intensity, while image processing–based tracking was used in the image plane. The 3D trajectory of a diffusing gold nanosphere has been experimentally determined, while the determined diameter analysis matches expectations. Beside key advantages such as homogenous light-line illumination, low-background scattering, long observation time, large number of frames, high temporal and spatial resolution and compatibility with standard microscope, the particular properties of operating with water defines a new bioanalytical platform that is highly relevant for medical and life science applications.

The problem of ensuring a uniform velocity field at the air inlet to the first stage of the gas turbine compressor SGT5-2000E with an angular inlet path, that contains an inlet filter, a silencer and an angular intake flare, is considered. Based on the mathematical modeling of the flow in this flare, it was found that the maximum speed at the compressor inlet is 36% higher than the average flow rate. It leads to the fact that the range of stable operation of the compressor seriously narrows. To solve this problem, it is proposed to change the intake flare design so that a newly developed effective damper of uneven velocity fields is installed in its flow part. Studies have shown that in this way the nonuniformity coefficient was reduced from the above 36% to 6%.

Resistance of the bare hull of the tourist submarine with spherical heads, moving in forward and transverse directions is analyzed in OpenFOAM using Computational Fluid Dynamics. The resistance coefficients of the submarine are estimated for different length-to-diameter ratios and Reynolds numbers. The Artificial Neural Network with the optimum number of neurons is then trained to predict the resistance coefficients. Two simplified Artificial Neural Network models and Nonlinear Least Squares Marquardt-Levenberg algorithm are employed to fit the results in the form of equations that may be used in the initial design of this type of submarines. The comparative analysis of different prediction models is performed and guidelines for their practical application are given.

The results of an experimental study and numerical modeling of the distribution of the gas velocity and pressure in tangential swirlers are presented. The modeling is executed by the finite element method using the k–ε turbulence model in the Comsol Multiphysics program. The resistance coefficient of tangential devices at different design parameters of the swirler is experimentally determined. The effect of the number of channels, their length, and the slope angle on the resistance of the swirler is found after the integrated processing of the data. It is confirmed that the value of the resistance coefficient of a swirler increases with the increase in the width of the channel under otherwise equivalent conditions. Pressure losses associated with factors such as the inlet/outlet of the gas into/from the channel and its length are considered. It is found that the pressure losses determined by the viscous friction forces in the channel have the greatest effect on the value of the resistance coefficient. The dependence for the assessment of the value of the resistance coefficient of a tangential swirler is presented. [ABSTRACT FROM AUTHOR]

Marine reactors are subjected to additional motions due to ocean conditions. These additional motions will cause large fluctuation of flow rate and change the coolant flow field, making the system unstable. Therefore, in order to understand the effect of oscillating motion on the flow characteristics, a numerical simulation of fluid flow is carried out based on a full-scale three-dimensional oscillating marine reactor. In this study, the resistance coefficients of the lattice, rod buddle and steam generator are fitted, and the distribution of flow rate, velocity as well as pressure in different regions is investigated through the standard model. After additional oscillation is introduced, the flow field in an oscillating reactor is presented and the effect of oscillating angle and elevation on the flow rate is investigated. Results show that the oscillating motion can greatly change the flow field in the reactor; most of the coolant circulates in the downcommer and lower head with only a small amount of coolant entering the core; the flow fluctuation period is consistent with the oscillating period, and the flow variation patterns under different oscillating conditions are basically the same; since the flow amplitude is related to oscillating speed, the amplitude of flow rate rises when decreasing the maximum oscillating angle; the oscillating elevation has little effect on the flow rate.

This study provides guidance for the effective application of dendritic hydrophobically associating polymer (DHAP) solutions to establish flow resistance in porous media. The solution properties (viscoelasticity, rheological properties, hydrodynamic size, and static adsorption capacity) of a DHAP were evaluated. The seepage characteristics of the porous medium were also studied. The effects of solution concentration, the permeability of the porous medium, and the injection rate of the polymer solution on the establishment of flow resistance were analyzed. The results showed that the elastic modulus of DHAP was dominant over the viscosity modulus, and the rheological behavior and hydrodynamic size were not greatly affected by the solution concentration. The adsorption characteristics of DHAP on the porous medium indicated multimolecular-layer adsorption. The equilibrium adsorption capacity was approximately 1100 μg/g. When DHAP at a concentration of 2000 mg/L passed through a 2500-mD porous medium at a flow rate of 0.1 mL/min, the injection pressure increased with cumulative injection volume, and it was difficult to achieve injection equilibrium. Increasing the injection rate caused the injection pressure to increase more quickly, making it easier to reach injection equilibrium. As the injection velocity increased, the resistance factor of the polymer solution in the porous medium first decreased and then became stable. Thus, high-speed DHAP injection reduced the resistance factor in the porous medium, while low-speed DHAP injection resulted in higher flow resistance. [ABSTRACT FROM AUTHOR]

In order to analyze the characteristics of vegetation influenceto the water flow resistance and provide a theoretical basis for predicting runoff and hydraulic erosion in slope watersheds, this paper discussed the effects of vegetation on slope flow characteristics from the aspects of vegetation attributes (flexibility and rigidity), slope flow resistance, slope flow structure and numerical simulation. Significance and the law of influence were also discussed. Moreover, the current research methods were analyzed and prospected. Scholars had studied flow resistance and hydrodynamic hydrodynamic through theoretical analysis, field experiments, hydraulic model tests and other research methods. Combined with the current research status, the following problems are existed: the traditional slope flow simulation test is to conduct a generalized study on rigid or flexible vegetation, however, the nature of vegetation on slopes is complex and diverse, and its influence cannot be fully discussed; there is a power function relationship between the drag coefficient and the Reynolds number, but there are few studies on the influence of other flow-related parameters such as Froude number to the drag coefficient; the definition of slope flow pattern is controversial, leading to no unified conclusion on the determination of flow pattern. Therefore, the future research directions are that a) it should study the vegetation closer to the actual situation; b) a new inference and judgment standards suitable for the flow pattern of the slope surface needs to be generated; c) the applicable conditions and scope of the open channel flow resistance formula should be clarified and; d) breakthrough a new type of research method to study the influence mechanism of vegetation. [ABSTRACT FROM AUTHOR]

In the present study turbulent flow in a circular cross-sectioned 90° smooth-walled pipe bend has been investigated numerically. The geometry of the model consisted of three sections: a straight inlet pipe of length 52 diameters, a 90° bend with radius of curvature 1 diameter, and a straight downstream pipe of length 52 diameters. Reynolds numbers from 5,000 to 120,000 were considered. The numerical model was developed using COMSOL Multiphysics and all turbulent flow simulations were performed using the standard k - ε turbulence model. The main objective of this work was to estimate the resistance coefficient of pipe bends using not only pressure drop but also information of the flow behavior far downstream in the outlet pipe. Wall static pressure and velocity fields of the secondary flow were illustrated to provide information of the flow behavior in the bend and downstream of the pipe bend. Furthermore, swirl intensity of secondary flow was presented in order to describe its behavior as the flow develops in the outlet pipe. Estimations of resistance coefficient were calculated and compared to other studies. It was found that the procedure used in this study is a viable method for a more accurate estimation of resistance coefficient values for turbulent pipe flows containing 90° bends. For best accuracy in either experimental or computational analyses, it is recommended that pressure in the downstream tangent be measured at no less than fifty diameters downstream of the bend to avoid influence of the secondary flow. [ABSTRACT FROM AUTHOR]

Between 2004 and 2017, multiple studies on the herbicide resistance of weeds were conducted by the Institute of Plant Protection – National Research Institute in Poland. Weed seeds, collected from fields located in various regions of Poland where herbicide use was ineffective, were used in studies conducted under greenhouse conditions. A total of 261 loose silky bent (Apera spica-venti L.) samples were found to be herbicide resistant, which translates to 52.4% of the fields under study. Nearly 50% of the analyzed samples exhibited resistance to sulfonylurea herbicides. Resistance to acetyl CoA carboxylase (ACCase) inhibitors was found in 18 fields, whereas resistance to photosystem II (PSII) inhibitors (isoproturon) was found in 12 fields. Herbicide resistance of blackgrass (Alopecurus myosuroides Huds.) occurred in 26 of the fields under study. In addition, resistance of wild oat (Avena fatua L.) to acetyl CoA carboxylase inhibitors occurred in 10 spring cereal crops. In the case of winter wheat, resistance of cornflower (Centaurea cyanus L.) to tribenuron-methyl occurred in 23 fields. Scentless chamomile (Matricaria inodora L.) and field poppy (Papaver rhoeas L.) were resistant to tribenuron-methyl in four and three fields, respectively, of winter wheat. In the case of sugar beet, three biotypes of fat hen (Chenopodium album L.) and two biotypes of redroot amaranth (Amaranthus retroflexus L.) were resistant to metamitron. Horseweed (Conyza canadensis L.), which grows on railway tracks, exhibited resistance to glyphosate. This paper reviews all studies conducted in Poland on weed resistance. Based on the results, maps of weed resistance in Poland were created.

[Objectives]Fragment is the key object of vessel liquid tank protection, and the study on the water-penetrating velocity attenuation characteristic of the high-speed "pie" fragment can provide theoretical reference for the protection analysis and optimization of the vessel liquid tank.[Methods]First to consider the change in resistance coefficient during water-penetrating process of fragment,the classical theoretical formula is modified by introducing the empirical coefficient a and b. Then, numerical simulation method is used to simulate the water-penetrating process of fragment,and the simulation results are compared with the calculation results from classical theoretical formula and improved formula. Finally,the influences of the initial velocity and slenderness ratio on the fragment penetration velocity attenuation are studied by the empirical coefficient a and b.[Results] The improved formula is more suitable than the classical formula to study the attenuation characteristics of the water-penetrating velocity of the "pie" fragment. The resistance coefficient is related to the slenderness ratio:when the slenderness ratio is less than 0.5,the resistance coefficient is greatly affected by the change of the penetration distance;when the slenderness ratio is greater than 0.5,the resistance coefficient is less affected by the change of the penetration distance, and the resistance coefficient can be treated as a constant.[Conclusions]The protective effect of vessel liquid tank on "pie" fragment can be calculated simply by using the improved theoretical formula in this paper.

The relevance. Polymer flooding is widely used in practice in the development of oil fields. The high-concentration polymer solution has strong viscoelasticity, but with the increase in mass concentration of the polymer, the compatibility problem occurs between polymer molecules aggregate size and reservoir rock pore size during its practical application. Cr3 + polymer gel based on intramolecular cross-linking has a smaller aggregate size and good compatibility with the reservoir, so it is relevant to study the effect of gel formation of Cr3 + polymer gel and its influence factors. The main aim of the research is to study filtration and rheological properties of polyacrylamide-based aqueous gel with chromium acetate to enhance oil recovery. Methods: physical simulation of oil displacement and fluid filtration under reservoir conditions on a filtration unit, determination of viscosity of cross-linked polymer gel using the Brookfield DV-II viscometer, measuring the size of the molecular coil Dh in a Brookhaven BI-200SM light scattering system (Brookhaven Instruments Cop., USA), determination of viscoelasticity using the Harke10 rheometer. Results. Regulating the concentration of polymer, water solution salinity and the ratio of the polymer content and chromium (w(П/Cr3+)), one can obtain the Cr3+ polymer gel system based on intramolecular cross-linking with a smaller molecular aggregate and higher resistance confidence. After the reaction of intramolecular cross-linking of the polymer solution, on the one hand the viscoelasticity of the system is significantly improved and the oil displacement coefficient increased. On the other hand, the intramolecular crosslinking reaction reduces the flexibility of the polymer molecule aggregates, increases their rigidity, weaken their deformability in the process of passing through the pores, and enhance the retention ability in the high permeability layer. Cr3 + polymer gel system not only has good injectability, it can also gradually reach a higher injection pressure, so it enlarges sweep volume effectively. In total, it is shown that the oil recovery coefficient of the polymer gel system is higher than the polymer solution.

Relevance. In recent years, polymer flooding technologies have been widely used in exploitation of oil and gas fields, especially in the later stages of field development. However, when operating reservoirs with elevated temperature of more than 70–80 °C and a high degree of salinity of formation water, many polymeric oil-displacing agents undergo rapid degradation, which leads to decrease in the level of hydrocarbon production. In this regard, one of the important problems is the creation and development of thermo- and salt-resistant polymeric materials and compositions based on them to increase the production of hydrocarbons in the oil and gas fields. The main aim of the research is to investigate the effect of formation water salinity on the physicochemical and filtration characteristics of polymer solutions and gels to enhance oil recovery. Methods. Viscosity of the polymer solutions and polymer gel were determined on Brookfield DV-II viscometer; shape and size of the polymer particles and polymer gel were studied on Hitachi S-400N scanning electron microscope; polymer size of molecular tangle Dh was measured on a wide-angle dynamic/static light scattering system Brookhaven BI-200SM (Brookhaven Instruments Cop., USA); physical modeling of fluid filtration at reservoir conditions was carried out on the filtration unit; determination of viscoelasticity and rheological properties of polymer solutions and gels was studied using a rheometer Harke 10. Results. The degree of mineralization of formation water has a significant effect on the viscosity of polymer solutions. Due to the fact that calcium and magnesium ions were preliminarily removed in partially demineralized water, the polymers have good solubility and the ability to increase the viscosity of the solutions. With increasing concentration of displacing agent, the viscosity of the solutions increases. Destructive effects of salts of formation water on polymers cause a significant decrease in viscosity of solutions of displacing agents. Due to the high degree of mineralization of partially demineralized water, a large amount of sodium chloride ions surround the molecular skeleton of the polymer of the displacing agent. The macromolecules of polymer P-1 have a predominantly two-dimensional network structure. The macromolecules of polymers P-2 and P-3 have a predominantly spatial three-dimensional network structure, in which some polymer molecular chains are broken and the network structure of polymers is defective. Compared with polymer P-3, the three-dimensional network structure of the polymer molecular aggregate P-4 has a clearer spatial structure. Comparing the physico-chemical properties of polymers P-1, P-2 and P-3, it follows that the coefficient of resistance and the coefficient of residual resistance for polymer P-1 are greater than for polymers P-2 and P-3. This is due to the fact that the salt-resistant polymer P-1 forms aggregates of the network structure due to intermolecular association, which leads to poor compatibility with core pores, and the resistance coefficient and residual resistance coefficient for polymer P-4 are the greatest the polymer mixture underwent reactions of intramolecular crosslinking of polymer molecules and Cr3+ cations, which led to a significant increase in the retention of the polymer solution, filtration resistance, injection pressure and to enhance oil recovery.

This paper presents and patents new profiled- and annular-channel tangential swirlers with 1.8–3 times less hydraulic drag coefficient compared to swirlers with straight channel walls at the same flow rate, respectively. The results of numerical simulation of the gas velocity and pressure profiles for tangential swirler channels of different structures are presented. The modelling was carried out with the help of OpenFOAM software using the k-ε turbulence model. It is found that the shape of the velocity profile at the channel inlet has a decisive influence on the swirler drag coefficient. The greatest contribution to the total drag coefficient of the tangential swirler is made by the pressure drop at the channel inlet compared to the pressure drop at the channel wall and the channel outlet. The experimental dependencies of the tangential swirlers’ drag coefficient on the Reynolds number with a gas criterion of 2000–20,000 and the following structural channel parameters: width 1, 2–9 mm, height 1, 5–10 mm, number 5–45 units, inclination angle 0–45° are presented. The experimental data were compared with the modelling calculations and the convergence of data was achieved. The generalized dependence for the measurement of the hydraulic drag coefficient of three types of tangential swirlers considering the effect made by the geometric parameters (flow rate, width and height of the channel, wall inclination angle) on the pressure drop has been determined; it can be useful at the unit design stage as it allows for reducing the calculation time of the swirler parameters.