Central Jet Research Articles

Design and investigation of a central air jet flameless combustor

Due to strict regulations on harmful emissions such as NOx and CO, many novel combustion techniques have been investigated in order to decrease emissions from gas turbines. One of these novel techniques is colorless distributed combustion (CDC) or flameless combustion (FC). CDC has been examined under reacting conditions using ANSYS Fluent at 27 different operating cases for the aim of developing design equations and a 3D flameless combustion map that includes the effect of air diameter, confinement size and excess air ratio on recirculation ratio to allocate flameless combustion regions. A simple lab scale combustor with central air jet arrangement is employed for the analysis. Eddy dissipation concept (EDC) either global or with detailed mechanism (DRM19) fails to predict the effect of excess air ratio in flameless combustion. A numerical approach for calculating the recirculation ratio is presented. As the air jet diameter decrease 40% there is about 54% increase in the recirculation ratio and about 90% decrease in the NOx emissions. It is found that above a recirculation ratio of 3 there is an insignificant effect on NOx emissions. Reducing the combustor diameter by a constant value for a given air diameter is found to result in a decrease in the recirculation ratio and the percentage of decrease is higher at high thermal intensities combustors. Moreover, it is observed that as the combustor diameter decrease to half of its value at constant air jet diameter and constant excess air ratio, there is an 80–90% increase in the NOx emissions inside the combustor. Furthermore, design equation is obtained to predict the appropriate air diameter that if combined with the available combustor diameter achieves a minimum recirculation ratio suitable to sustain flameless combustion.

Double droplet splashing on a thin liquid film with a pseudopotential lattice Boltzmann method

This paper studies the interaction of two droplets splashing on a stationary film. A source term is included in the large-density-ratio pseudopotential lattice Boltzmann method to achieve tuneable surface tension. This model offers excellent numerical accuracy and stability for droplet impacts on liquid films. The influence of the Reynolds number, Weber number, film thickness, and horizontal/vertical distance between the droplets on the crown geometry evolution is investigated. The energy loss during the impact process and the velocity discontinuity in the liquid film are the two key factors affecting the stability and evolution process of the crown. A smaller Reynolds number or thicker liquid film enhances the energy loss and decreases the velocity discontinuity, leading to more stable side and central jets. An increase in the horizontal distance between the droplets reduces the velocity discontinuity, causing the central jet height to decrease. An increase in the Weber number does not affect the energy loss or velocity discontinuity, but the lower surface tension leads to a dramatic deformation in both the central and side jets. A vertical distance between the two droplets causes an asymmetrical evolution of the crown geometry, and postpones the breakup time of the central jet .

Study of spray structure under flash boiling conditions using 2phase-SLIPI

In gasoline engines, including conventional gasoline direct injection (GDI) engines and newly developed gasoline compression ignition (GCI) engines, flash boiling of the spray occurs during throttling or low load operations. Superheated fuel that is injected into the cylinder, where the gas pressure is lower than the fuel’s saturation vapor pressure, experiences a fast phase change. Plume interaction and spray collapse can occur as a consequence of flash boiling. The structure of flashing spray has not been well elucidated experimentally because of strong multiple-scattering effects in conventional laser sheet imaging due to illumination of out-of-laser-plane droplets. Here, the structured laser illumination planar imaging (SLIPI) is implemented for the first time to study flash boiling sprays. Both front-view and side-view cross-sections are examined to reveal spray behaviors during collapsing events. A comparison of the reconstructed 3D spray volume by SLIPI and conventional laser sheet imaging clearly shows the advantage of SLIPI in resolving the inner structure of the collapsed spray. The near-nozzle region on the injector axis is found to be hollow, indicating that spray collapsing occurs a bit downstream of the nozzle instead of immediately at the nozzle. This observation could not be obtained by conventional laser sheet imaging nor by diffused back illumination (DBI) techniques. In this work, the central tip observed in the 2D DBI image at Rp = 0.1 case has been proven to be not a ’central jet on injector axis’ formed due to radial collapse, but a longer projection on the image caused by stronger adjacent plume circumferential interactions.

Benefit of Mach number and expansion level on the flow development in a cylindrical tube diameter of 18 mm

In this paper, experiments are performed at high Mach numbers to examine the flow control effect located in the separated region at 6.5 mm from the central jet. A circular orifice is placed in the wake region to manipulate the base flow to boost the wake area's pressure and ultimately reduce the base drag. The study also investigates the impact of micro-jets on the stream of the tube. Accordingly, tests are conducted using C-D nozzles fabricated at Mach 1.87, 2.2, and 2.58. Flow generated from these nozzles is exhausted in a duct whose diameter is 18 mm. The results show that for duct length 6D and above, the flow field inside the duct becomes oscillatory, whereas such fluctuations are not noticed when duct size less than 4D. Dynamic control shows mixed trends when jets are operating at design NPR or under the impact of favorable pressure. And within reattachment length, active flow control is not able to impact the flow pattern. When nozzles are running underneath, over-expansion and flow control are initiated; it decreases the duct's pressure. The smallest duct size essential for the stream to continue connected appears to be 1D for Mach 1.87 and Mach 2.2 and 2.58; this requirement is 2D.

Impact of expansion level on flow field of a circular duct at high Mach numbers

The study discusses the impact of different nozzle pressure ratios and the duct sizes on the duct’s flow field. The duct diameter was 16 mm, and the inertia levels at which the experiments were done are M = 1.87, 2.2, and 2.58. Dynamic regulators as an orifice stationed in the wake region at 6.5 mm from the central jet axis. At M = 1.87, when the jets are operated at NPR = 3, the duct size 1D and 2D, the wall pressure assumes high, and control is not helpful. There is no impact on the flow control management at Mach 2.2 for duct length 1D and 2D at NPR = 3, 5, and 7. But for this Mach, this trend is limited at NPR = 3 and 5. When the Mach value is 2.58, the wall pressure assumes ambient condition, and control has minimal impact on the duct’s flow pattern. When the duct length is 10D, the stream field turns oscillatory for Mach investigated. The control device does not impact the inside flow negatively.

Tricuspid Regurgitation in Hypoplastic Left Heart Syndrome: Three-Dimensional Echocardiography Provides Additional Information in Describing Jet Location

Twenty-five percent of patients with hypoplastic left heart syndrome (HLHS) require tricuspid valve (TV) repair. The location of tricuspid regurgitation (TR) is important in determining the type of repair performed. Studies using three-dimensional echocardiography (3DE) have reported a high incidence of error on two-dimensional echocardiography (2DE) for the identification of TV leaflets. The aim of this study was to compare assessment of TR on 3DE and 2DE in patients with HLHS (jet location, TR grade, and reproducibility). A retrospective, single-center review was performed. Fifty-six patients with HLHS with available two-dimensional and three-dimensional echocardiograms, and mild or greater TR, were included. TR location, grade, vena contracta area, and TV annular diameter were measured on 2DE and 3DE. Reproducibility was assessed by blinded reviewers. Three-dimensional echocardiography identified the primary jet location as central (57%) followed by anteroseptal (36%). There was poor agreement between findings on 3DE and 2DE for jet location (κ=0.05; 95 CI, -0.08 to 0.19). Interobserver reproducibility for location on 3DE was excellent (κ=0.8), whereas reproducibility for 2DE was poor (κ=0.32). The most common jet location pre-Norwood and pre-Glenn was central (70%), whereas pre-Fontan and post-Fontan, jet location was central (45%) and anteroseptal (48%). Vena contracta area on 2DE correlated moderately with vena contracta area on 3DE (r=0.60, P<.0001). TV annular diameters on 2DE and 3DE for lateral (r=0.85, P<.0001) and anteroposterior (r=0.74, P=.001) dimensions were strongly correlated. In children with HLHS, assessment of TR location on 2DE had poor agreement with assessment on 3DE and was poorly reproducible. In contrast, TR jet location on 3DE was highly reproducible. Pre-Glenn, a central TR jet was the most common, while post-Glenn, central and anteroseptal locations were equal, highlighting the importance of preoperative identification of TR jet location in patients with HLHS.

Baffled tubes with superimposed oscillatory flow: Experimental study of the fluid mixing and heat transfer at low net Reynolds numbers

Experimental results of flow pattern and heat transfer in circular-orifice baffled tubes under pure oscillatory flow and compound flow conditions are presented. The hydrogen bubble visualization technique is employed for describing the unsteady flow structure, and particle image velocimetry is used in order to measure the velocity field during eight different phases of the oscillation cycle. The existence of a central jet and the cyclic dispersion of vortices upstream and downstream of the baffles is analyzed. The loss of the flow axisymmetry for Reosc>130 is clearly identified. Heat transfer measurements under uniform heat flux (UHF) conditions are obtained in a thermal-hydraulic rig, allowing for the description of the influence of net and oscillatory Reynolds numbers on the Nusselt number, using propylene-glycol as working fluid (Pr=150). The impact of chaotic mixing, for Reosc>150, results in a uniform local heat transfer distribution along the reactor cell, as well as in thermal uniformity in the transverse plane of the tube.

Topological imaging of turbulent premixed, prevaporized liquid fuel jet flames using CH (C-X) band PLIF

New imaging capabilities for topology in prevaporized, liquid-fuel flames are presented with the application of CH-radical planar laser-induced fluorescence (PLIF) using the C2Σ+-X2Π (v′=0, v″=0) band. Imaging of turbulent flame structure for ethanol, n-heptane, n-dodecane, and kerosene (JP-8) fuels has been conducted in jet flames using a piloted McKenna burner with a central jet tube. This work presents the first application of CH PLIF for the study of full flame structure and curvature effects with prevaporized liquid fuels, particularly n-dodecane and kerosene. Liquid fuel structure is also compared to results with methane and ethylene. Results show that good signal-to-noise ratio (SNR) is achieved for all fuels, and the method is feasible in the presence of a dilute droplet field, despite the resonant nature of the technique. Reaction-zone structures clearly depict evidence of nonequidiffusive (Le ≠ 1) effects: strong variation in CH fluorescence is observed in regions of high curvature. Simultaneous excitation of the OH radical is also possible with prevaporized liquid fuels, for combined imaging of the reaction and heat-release zones. In kerosene flames, with aromatic species, fuel fluorescence may also be simultaneously captured, in addition to that from CH and OH, providing information on vapor localization.

Receding Dynamics of Droplet Deposition on a Smooth Surface from a Central Jet to Secondary Droplet Emission.

A droplet impacting a solid surface undergoes deposition, splashing, or rebounding, depending on the properties of the droplet and impacted surface. The deposition pattern attracts lots of attention for the reasons of its predictable behavior on wetting and dewetting. The phenomenon of the central jet, even breaking up into a secondary droplet, is observed during gentle deposition on partially wettable surfaces. The mechanism behind the central jet is addressed by the dual role of the inertia force. In this paper, the dynamic characteristics of droplet deposition are analyzed with a focus on the receding process from jetting to secondary droplet emission. The jet is pinched off into a small secondary droplet when the impacting Weber (We) number is within the range of approximately 26-54. The secondary droplet is then ejected because of the collision with the upward jet. The convergence of capillary waves on the liquid film is employed to explain the two-stage upward jet. The jet tip is pinched off because of Rayleigh-Plateau instability, leading to the generation of the secondary droplet. A geometric model of a two-floor cylinder is further proposed to describe the equivalent recession of the capillary wave. The equivalent radius of the receding wave is linear with time, and the jet height exhibits a scaling law of Djet ∼ (t - 0.8)1/2 with normalized time. Additionally, the dynamic characteristics are investigated from time and size views. With various Weber numbers, the normalized receding, jetting, and tip times are found to remain almost constant. A piecewise relationship with the Weber number is revealed for the normalized receding wave and the tip height. The wave recedes at the characteristic velocity of 0.23 m/s. Moreover, the normalized jet height and tip diameter, as well as secondary droplet diameter, are independent of the inertia force. The emission velocity and kinetic energy of the secondary droplet are found to reach the maximum at We ∼ 41.6.

Statistical Characteristics of Flow Field through Open and Semi-Closed Bileaflet Mechanical Heart Valve

The formation of thrombi on the streamlined surface of the bileaflet mechanical heart valves is one of the main disadvantages of such valves. Thrombi block the valve leaflets and disrupt the cardiovascular system. Diagnosis of thrombosis of the bileaflet mechanical heart valves is relevant and requires the creation of effective diagnostic tools. Hydroacoustic registration of the heart noise is one of the methods for diagnosing the operation of a mechanical heart valve. The purpose of the research is to determine the statistical characteristics of the vortex and jet flow through the open and semi-closed bileaflet mechanical heart valve, to identify hydroacoustic differences and diagnostic signs to determine the operating conditions of the valve. Experimental studies were conducted in laboratory conditions on a model of the left atrium and left ventricle of the heart between which there was the bileaflet mechanical heart valve. Hydrodynamic noise was recorded by miniature pressure sensors, which were located downstream of the valve. The vortex and jet flow behind the prosthetic heart valve were non-linear, random processes and were analyzed using the methods of mathematical statistics and probability theory. The integral and spectral characteristics of the pressure field were obtained and the differences in the noise levels and their spectral components near the central and side jets for the open and semi-closed mitral valve were established. It was shown that hydroacoustic measurements could be an effective basis for developing diagnostic equipment for monitoring the bileaflet mechanical heart valve operation. Doi: 10.28991/SciMedJ-2020-0204-1 Full Text: PDF

Large-eddy simulation of a swirling flow in a model combustion chamber

Large-eddy simulations of the swirling annular jet flow are performed in a model of a combustion chamber at two different flow regimes with and without the central jet at Re = 5000. The mesh convergence study provides well-described time-averaged statistics even for a coarse mesh, while small-scale features are only resolved after a proper refinement. The central jet is shown to significantly modify the recirculation bubble and partially suppress the precessing vortex core.

Effect of flash boiling injection on combustion and PN emissions of DISI optical engine fueled with butanol isomers/TPRF blends

Direct injection spark ignition (DISI) engines have been widely used in passenger cars due to their lower fuel consumption, better controllability, and high efficiency. However, DISI engines are suffering from wall wetting, imperfect mixture formation, excess soot emissions, and cyclic variations. Applying a new fuel atomization technique and using biofuels with their distinctive properties can potentially aid in improving DISI engines. In this research, the effects of isobutanol and 2-butanol and their blends with Toluene Primary Reference Fuel (TPRF) on spray characteristics, DISI engine combustion, and particle number (PN) emissions are investigated for conditions with and without flash boiling of the injected fuel. Spray characteristics are investigated using a constant volume chamber. Then, the combustion, flame propagation, and PN emissions are examined using an optical DISI engine. The fuel temperature is set to 298 K and 453 K for liquid injection and flash boiling injection, respectively. The tested blending ratio is 30 vol% butanol isomers and 70 vol% TPRF. The results of the spray test reveal that liquid fuel plumes are distinctly observed, and butanol blends show a slightly wider spray angle with lower penetration length compared to TPRF. However, under flash boiling injection, the sprays collapse towards the injector axis, forming a more extended single central vapor jet due to the plumes' interaction. Meanwhile, butanol blends yield a narrow spray angle with more extended penetration compared to TPRF. The flame visualization test shows that the flash boiling injection reduced yellow flames compared to liquid fuel injection, reflecting the improvements in mixture formation. Thus, improvements were noted in the heat release and PN emissions. Butanol addition reduced the PN emissions by 43% under regular liquid injection. Flash boiling injection provided an additional 25% reduction in PN emissions.

Film levitation and central jet of droplet impact on nanotube surface at superheated conditions.

Influences of surface nanotubes at high temperatures are investigated on droplet impact dynamics and Leidenfrost effect. Five distinct regimes of impact droplets are found on the nanotube surface, including contact boiling, film levitation, central jet levitation, central jet, and Leidenfrost phenomenon. The regimes of film levitation, central jet levitation, and central jet are characterized by either film levitation and/or liquid central jet. The regime of Leidenfrost phenomenon is characterized by droplet bounce-off behavior free of any liquid jets. Film levitation is driven by the vaporization of two parts of the droplet, with one as the droplet bottom layer over the contact area above the nanotube structure, and the other as the hemiwicking liquid in nanotubes. Both the vaporization is impaired by increasing the surface temperature, which is attributed to the reduced contact time and less extent of spread of the droplet at a higher surface temperature. The central jet phenomenon is driven by the vapor stream produced by hemiwicking liquid in the central area upon impact. It is enhanced and then suppressed by elevating the surface temperature, resulting from the collective effects of the vapor pressure in nanotubes which increases with the surface temperature, and the cross-sectional area of the vapor stream, which increases and then decreases with the surface temperature. At a high Weber number, the Leidenfrost temperature can be increased by 125^{∘}C on the nanotube surface, implying a great potential in heat transfer enhancement for droplet-based applications.

Simulation of pellet coating in Wurster coaters.

A combination of computational fluid dynamics (CFD), discrete element method (DEM), and discrete droplet method (DDM), i.e., a CFD-DEM-DDM model, was developed to simulate coating of pellets in a Wurster coater. The model equations were implemented in parallel using an approach that uses the computational resources of both CPU and GPU. Effects of the gas flow pattern, inlet gas temperature, partition gap, and spray characteristics were studied on the process. Decreasing the peripheral gas velocity, increasing the central jet velocity, and reducing the partition gap caused more uniform distributions of the circulation time and draft tube time, while the inlet gas temperature had negligible effect on them. Very high jet velocity caused a wider distribution of the circulation time. The dynamics of the spray and its interaction with pellets had significant effects on the coating mass distribution. Widening the spray angle while maintaining the droplet size constant caused the most uniform coating mass distribution and the highest deposition rate. Heat and mass transfer conditions as well as the deposition pattern changed the distributions of the solvent content and temperature of the pellets.

LES of a lifted methanol spray flame series using the sparse Lagrangian MMC approach

Two-phase multiple mapping conditioning / large eddy simulation (MMC-LES) is applied for the first time to lifted spray flames on a vitiated coflow burner. Three flames with different inlet fuel mass loading are investigated. MMC-LES uses a hybrid Eulerian-Lagrangian-Lagrangian approach for the evolution of gas-phase flow, stochastic particles, and liquid fuel droplets, respectively. Due to the benefits of localizing mixing in a reference mixture fraction space, a sparse-Lagrangian distribution of particles is able to be used, permitting computationally efficient simulations of the flame series using gas-phase chemical kinetics that includes 32 species and 167 reactions. Heat and mass transfer between the stochastic particles and evaporative fuel droplets are also local in the reference mixture fraction space. Analysis of the gas-phase temperature fields reveals two distinct flame base stabilization phenomena. The first, which is observed for the low and intermediate fuel loading cases, produces a flat flame base spreading across the central region of the jet. The second, observed for the highest fuel loading case, produces an annular flame base in the shear layer that surrounds a cold central jet region, which is characteristic of autoignition due to entrainment of hot oxidizer from the co-flow. Except for a few axial locations, predicted radial profiles of temperature and liquid-phase velocity/size statistics yield a reasonable agreement with experimental measurements for all three flames. Furthermore, the trend of decreasing lift-off height with an increase in fuel loading is captured well.

Time-averaged flow characteristics and mixing properties of double-concentric jets

We examined the flow behaviors and mixing characteristics of double-concentric jets using laser-assisted smoke flow visualization method to analyze typical flow patterns and binary boundary detection technique to investigate jet spread width. Time-averaged velocity vectors, streamline patterns, velocity distributions, turbulence properties, and vorticity contours were analyzed using Particle Image Velocimetry (PIV). Topological flow patterns were analyzed to interpret the vortical flow structures. Mixing properties were investigated using a tracer-gas concentration detection method. Four characteristic modes were observed: annular flow dominated mode, transition mode, central jet dominated mode-low shear, and central jet dominated mode-high shear. The jets’ mixing properties were enhanced by two major phenomena: the merging of annular flow and central jet at the centerline and the large turbulence fluctuations produced in the flow field. The merging of the jets induced stagnation points on the central axis in the annular flow dominated mode, which caused reverse flow on the central axis and drastic turbulence fluctuations of the near field region. When the central jet penetrated the recirculation region in the other three modes, the stagnation points on the central axis and the reverse flow vanished. Therefore, the mixing behaviors were prominently enhanced in the annular flow dominated mode.

GAS BURNER DEVICES OF JET DIFFUSION TYPE AND JET BURNERS, CREATED BY TUBULAR TECHNOLOGY

The article discusses the design and operation features of two-wire gas burners developed at the Gas Institute of the National Academy of Sciences of Ukraine. These are jet-diffusion type burners and jet burners, the creation of which is based on the concept of burning gaseous fuels using a highly efficient unified tubular technology developed in conjunction with specialists from the National Technical University of Ukraine «Igor Sikorsky Kyiv Polytechnic Institute». A description of burners and burner devices of the jet diffusion type of the SG and SGL series is provided. The design of the SGL series burners provides for the possibility of interconnecting individual modules, which ensures the creation of heat generators of almost unlimited power. It is shown that such heat generators can operate in a wide range of excess air, this allows to get a coolant of any required temperature. Heat generators of this type operate in many industries. In jet burners created by tubular technology, as a result of the interaction of gas jets and air jets, diffuse gas flames are formed, which provide high reliability of the burners with possible fluctuations in the gas-air ratio. Also shown are the designs of burners created as a combination of these combustion technologies. The design of turbulent vortex burners, which provides a high degree of stabilization of the flame through the use of a central jet diffusion burner, is described. These burners are equipped with steam and hot water boilers, as well as melting furnaces. When operating these burners, it is possible to achieve 10 % of the natural gas consumption of the nominal load, which allows the operation of heating furnaces in the hot reserve with short-term shutdowns of technological equipment. Библ. 15, рис. 12.

Effect of co-flow velocity ratio on evolution of poly-disperse particles in coaxial turbulent jets: A large-eddy simulation study

In the present work, the particle-laden coaxial turbulent jet flow is studied using large-eddy simulation (LES). An Eulerian–Lagrangian framework is used to study the interaction between the continuous phase (air) and the discrete phase (glass bead particles). The solver is validated, using single-phase and particle-laden simulations, with reference data from experiments. A good match is observed between the present results and the reference data, for centerline velocity decay and radial profiles of axial velocity. Simulations are performed for three co-flow velocity ratios of 0, 1, and 1.5. The results pertaining to particle characteristics are presented for three different particle size-classes. The effect of the co-flow velocity ratio on the particle size–velocity correlation and velocity statistics of both phases are studied with an emphasis on understanding the differences in the particle dispersion due to co-flow around the central jet. It is observed that the particle size–velocity correlation is negative in the potential core region, and it becomes positive as one moves downstream. For heavy particles, the axial distance required to attain the same velocity as that of air increases with an increase in the co-flow velocity ratio. The size-conditioned particle number density profiles along the axial and radial directions of coaxial jets showed some interesting trends that could be explained based on the particle Stokes number effect. Significant radial dispersion of particles is realized when the corresponding Stokes number (StL), defined based on large-scale turbulent eddies, is of the order of one. The axial evolution of the characteristic particle size exhibited non-monotonic trends for all co-flow ratios. Overall, the present work demonstrates potential application of LES for an in-depth study of dispersion of poly-disperse particles in turbulent coaxial jets.

Resummation of non-global logarithms in cross sections with massive particles

A factorization formalism for jet processes involving massive colored particles such as the top quark is developed, extending earlier results for the massless case. The factorization of soft emissions from the underlying hard process is implemented in an effective field theory framework, which forms the basis for the resummation of large logarithms. The renormalization group evolution giving rise to non-global logarithms is implemented into a parton shower code in the large-Nc limit. After a comparison of the massive and massless radiation patterns, the cross section for toverline{t} production with a veto on additional central jet activity is computed, taking into account radiation both from the production and the decay of the top quarks. The resummation of the leading logarithms leads to an improved description of ATLAS measurements at sqrt{s} = 7 TeV.

Determination of the influence area of a bridge crossing in a river stream

The object of research is the formation of the influence zone of the bridge crossing in the river flow. The method for determining the length of the zone of influence of the bridge crossing provides for the calculation of such parameters as the specific discharge of floodplains, the length of the zones of compression and spreading, and the full backwater in front of the bridge section. The proposed approach is based on changing the properties of the central stream of the river flow in the zone of artificial influence of the bridge structure. Determination of the flow depth and the inclined free surface is carried out according to the corresponding finite-difference analogs of differential equations describing the change in these quantities. All calculations are made, respectively, for each branch of a flood or flood, for a certain day. Calculations start with a full spreading alignment, where all hydraulic characteristics of the flow have natural values. The paper presents the calculation of the zone of influence of the bridge crossing on the river Seversky Donets on the T-05-14 highway within the Donetsk region (Ukraine). It has been established that the development of general channel deformations in the channel and on the floodplains occurs in a section from 1195 m to 2144 m long. The distribution of the river flow depth is obtained, which increases from 0.58 m to 2.17 m in the alignment of the bridge crossing after the flood. With an increase in the flow rate of the river flow, the parameters of the compression zone also increase from 246 m to 1382 m, and the spreading zones decrease from 949 m to 762 m. The change in the parameter of the central jet occurs in accordance with the distribution of the compression and spreading zones during the course of the flood. The obtained results are the initial conditions for conducting research on predicting eroded processes in a river flow, taking into account artificial compression in the zone of influence of the bridge crossing.