Flow Velocity Characteristics Research Articles

Numerical Simulation and Computational Flow Characterization Analyses of Centrifugal Pump Operating as Turbine

Using a pump in reverse mode as a hydraulic turbine remains an alternative for hydropower generation in meeting energy needs, especially for the provision of electricity to remote and rural settlements. The primary challenge with small hydroelectric systems is attributed to the high price of smaller size hydraulic turbines. A specific commercial pump model, with a flow rate of 12.5 m3/h, head 32 m, pressure side diameter of 50 mm, impeller out, and inlet diameters of 160 mm and 6 mm, respectively, was chosen for this research. This research aimed to investigate a pump’s flow characteristics as a turbine to help select a suitable pump to be used as a turbine for micro- or small hydropower construction. Numerical methodologies have been adopted to contribute to the thoughtful knowledge of pressure and velocity distribution in the pump turbine performance. In this study, the unsteady flow relations amongst the rotating impeller and stationary volute of the centrifugal pump made up four blades and four splitters. Intermittent simulation results of pressure and velocity flow characteristics were studied considering diverse impeller suction angles. The study was conducted by considering a wide range of rotational speeds starting from 750 rpm to 3250 rpm. From the results, it was found that PAT operation was improved when operated at low speeds compared to high-speed operation. Thus, speeds between 1500 rpm and 2000 rpm were suitable for PAT performance. This research helps to realize the unsteady flow physiognomies, which provide information for future research on PAT. This study makes useful facts available which could be helpful for the pump turbine development. Future studies should focus on cost analysis and emission generation in energy generation.

Laboratory Analysis of Debris Flow Characteristics and Berm Performance

In this study, laboratory tests were used to determine the deposition characteristics (runout distance, lateral width, and deposition area) of debris flow and their relationships with the flow characteristics (flow velocity and flow depth) according to the presence of a berm. An experimental flume 1.3 to 1.9 m long, 0.15 m wide, and 0.3 m high was employed to investigate the effects of channel slope and volumetric concentration of sediment with and without the berm. The runout distance (0.201–1.423 m), lateral width (0.045–0.519 m), and deposition area (0.008–0.519 m2) increased as the channel slope increased and as the volumetric concentration of sediment decreased. These quantities also increased with the flow velocity and flow depth. In addition, the maximum reductions in the runout distance, lateral width, and deposition area were 69.1%, 65.9%, and 93%, respectively, upon berm installation. The results of this study illustrate general debris flow characteristics according to berm installation; the reported relationship magnitudes are specific to the experimental conditions described herein. However, the results of this study contribute to the design of site-specific berms in the future by providing data describing the utility and function of berms in mitigating debris flow.

Study on the Influence of Geometric Characteristics of Grain Membranes on Permeability Properties in Porous Sandstone.

Studying the influence of grain characteristics on fluid flow in complex porous rock is one of the most important premises to reveal the permeability mechanism. Previous studies have mainly investigated the fluid flow laws in complex rock structures using an uncontrollable one single parameter of natural rock models or oversimplified control group models. In order to solve these problems, this paper proposes a novel method to reconstruct models that can independently control one single parameter of rock grain membranes based on mapping and reverse-mapping ideas. The lattice Boltzmann method is used to analyze the influence of grain parameters (grain radius, space, roundness, orientation, and model resolution) on the permeability characteristics (porosity, connectivity, permeability, flow path, and flow velocity). Results show that the grain radius and space have highly positive and negative correlations with permeability properties. The effect of grain roundness and resolution on permeability properties shows a strong regularity, while grain orientation on permeability properties shows strong randomness. This study is of great significance to reveal the fluid flow laws of natural rock structures.

Experimental Study on Flow Structure around Spur Dikes of Different Types

As water damage phenomenon of spur dike exists generally, spur dike must be maintained in order to ensure its regulation function, but its structure changed in the process of maintenance. In order to find out flow structure around the spur dike of different pattens, through generalized flume model tests, variation characteristics of water surface profile and flow velocity around the spur dike of five different pattens were analysed. The results show that the straight head had a greater influence than hook head spur dike on the water surface profile, circular cross-section had smaller effects than trapezoidal cross-section spur dike on the water surface profile; Velocity of Choke area and contraction order from large to small is trapezoidal cross-section and fan straight head dike, trapezoidal cross-section and arc straight head dike, arc section and arc straight head dam, trapezoidal cross-section and fan hook head dike, trapezoidal cross-section arc hook head dike; Cross section vertical velocity distribution from large to small is trapezoidal cross-section and fan hook head dam, trapezoidal cross-section and circular straight head dike, arc cross-section and circular straight head dam, trapezoidal cross-section and circular hook head dike.

Scale law analysis of the curved boundary layer evolving around a horizontal cylinder at Pr > 1

The convective boundary layer flow on the external surface of an isothermally heated horizontal cylinder is investigated in this study. Numerical simulations are first carried out for a wide range of flow parameters, i.e., Rayleigh and Prandtl numbers, and scale relations quantifying the boundary layer flow are then determined from the simulation data. The numerical results suggest that the curved boundary layer experiences an initial growth state, a transitional state, and a developed state, which are essentially identical to the extensively studied flat boundary layers. Scale relations quantifying the local flow variables are obtained, and the proposed scale laws indicate that during the initial growth, the present curved boundary layer flow follows a two-dimensional growth rather than the well-known one-dimensional startup of flat boundary layers. It is further demonstrated that the characteristic velocity of the boundary layer flow maximizes at π/2, but its thickness is circumferential location independent. In the steady state, however, the maximum streamwise velocity of the boundary layer shifts to approximately 7π/9 and the thickness consistently increases with the circumferential location. It is also shown that the thickness of the inner viscous boundary layer could be obtained by properly considering the Prandtl number effect, i.e., by the term (1 + Pr−1/2)−1. The proposed scale relations could reasonably describe the curved boundary layer flow, and all regression constants are above 0.99.

Characteristics of Plasma Flow for Microwave Plasma Assisted Aerosol Deposition.

To validate the possibility of the developed microwave plasma source with a novel structure for plasma aerosol deposition, the characteristics of the plasma flow velocity generated from the microwave plasma source were investigated by a Mach probe with pressure variation. Simulation with the turbulent model was introduced to deduce calibration factor of the Mach probe and to compare experimental measurements for analyses of collisional plasma conditions. The results show calibration factor does not seem to be a constant parameter and highly dependent on the collision parameter. The measured plasma flow velocity, which witnessed fluctuations produced by a shock flow, was between 400 and 700 m/s. The optimized conditions for microwave plasma assisted aerosol deposition were derived by the results obtained from analyses of the parameters of microwave plasma jet. Under the optimized conditions, Y2O3 coatings deposited on an aluminum substrate were investigated using scanning electron microscope. The results presented in this study show the microwave plasma assisted aerosol deposition with the developed microwave plasma source is highly feasible for thick films with >50 μm.

Prandtl\u2019s Secondary Flows of the Second Kind. Problems of Description, Prediction, and Simulation

—The occurrence of turbulent pulsations in straight pipes of noncircular cross-section leads to the situation, when the average velocity field includes not only the longitudinal component but also transverse components that form a secondary flow. This hydrodynamic phenomenon discovered at the twenties of the last century (J. Nikuradse, L. Prandtl) has been the object of active research to the present day. The intensity of the turbulent secondary flows is not high; usually, it is not greater than 2–3% of the characteristic flow velocity. Nevertheless, their contribution to the processes of transverse transfer of momentum and heat is comparable to that of turbulent pulsations. In this paper, a review of experimental, theoretical, and numerical studies of secondary flows in straight pipes and channels is given. Emphasis is placed on the issues of revealing the physical mechanisms of secondary flow formation and developing the models of the apriori assessment of their forms. The specific features of the secondary flow development in open channels and channels with inhomogeneously rough walls are touched upon. The approaches of semiempirical simulation of turbulent flows in the presence of secondary flows are discussed.

Wave overtopping flow striking a human body on the crest of an impermeable sloped seawall. Part II: Numerical modelling

The present paper is the second of two companion papers on the investigations of wave overtopping flow striking a cylinder, which is the schematisation of a human body, on the crest of an impermeable sloped seawall with a deep foreshore. This paper numerically examines the detailed characteristics of the overtopping flow and the force on the cylinder in-line with the flow direction by using a volume-of-fluid (VOF) based Reynolds-Averaged Navier-Stokes (RANS) model. The numerical model is successfully validated against the experimental data on the wave overtopping flow depth and the inline force on the cylinder. The characteristics of the overtopping flow velocity are analysed using the validated numerical model. It is observed that the maximum depth-averaged flow velocity usually occurs before the maximum flow depth during an overtopping event, and decay of the overtopping velocity is much slower than the flow depth along the seawall crest. For plunging-breaker cases, the overtopping force on the cylinder usually comprises a cycle of a first impact peak, a main peak and a secondary peak. However, for surging-breaker cases, it is largely dominated by the main peak. The first impact peak is due to the impact of the tip of the overtopping flow on the cylinder, which usually has a higher flow velocity than the main stream. The main peak is generated by the asymmetric pressure distribution around the cylinder, which co-occurs with the maximum local momentum flux of the overtopping flow. As the force decreases after the main peak, there sometimes exists a secondary peak, which is formed by the complex free surface motion locally behind the cylinder. Additional numerical experiments are presented to demonstrate the applicability of a simple maximum force predictor developed in Part I. A prototype-scale simulation of irregular waves overtopping a sloped seawall is conducted to obtain the maximum force. The predictor also gives the maximum force in a wave-by-wave manner using the incident wave condition. These two approaches produce very similar estimates, suggesting that the predictor can be used for engineering applications.

Mixed convection stagnation point flow of the blood based hybrid nanofluid around a rotating sphere

In this new world of fluid technologies, hybrid nanofluid has become a productive subject of research among scientists for its potential thermal features and abilities, which provides an excellent result as compared to nanofluids in growing the rate of heat transport. Our purpose here is to introduce the substantial influences of magnetic field on 2D, time-dependent and stagnation point inviscid flow of couple stress hybrid nanofluid around a rotating sphere with base fluid is pure blood, {text{TiO}}_{2} ,,{text{and}},,{text{Ag}} as the nanoparticles. To translate the governing system of partial differential equations and the boundary conditions relevant for computation, some suitable transformations are implemented. To obtain the analytical estimations for the corresponding system of differential expression, the innovative Optimal Homotopy Analysis Method is used. The characteristics of hybrid nanofluid flow patterns, including temperature, velocity and concentration profiles are simulated and analyzed in detail due to the variation in the evolving variables. Detailed research is also performed to investigate the influences of relevant constraints on the rates, momentum and heat transport for both {text{TiO}}_{2} + {text{Ag}} + Blood and {text{TiO}}_{2} + Blood. One of the many outcomes of this analysis, it is observed that increasing the magnetic factor will decelerate the hybrid nanofluid flow velocity and improve the temperature profile. It may also be demonstrated that by increasing the Brownian motion factor, significant improvement can be made in the concentration field of hybrid nanofluid. The increase in the nanoparticle volume fraction from 0.01 to 0.02 in the case of the hybrid nanofluid enhances the thermal conductivity from 5.8 to 11.947% and for the same value of the nanoparticle volume fraction in the case of nanofluid enhance the thermal conductivity from 2.576 to 5.197%.

The Influence of Venous Characteristics on Peripherally Inserted Central Catheter-Related Symptomatic Venous Thrombosis in Cancer Patients.

BackgroundWith increasing use, peripherally inserted central catheters (PICCs) are associated with the risk of venous thrombosis. Few studies have focused on the relationships between venous thrombosis and venous characteristics. This study aimed to identify effects of venous characteristics on symptomatic PICC-related venous thrombosis in cancer patients and explore the relationship between venous characteristics and blood flow velocity.MethodsThe data of patients who underwent placement of PICC were retrospectively studied between January 2015 and September 2017. Symptomatic PICC-related venous thrombosis was confirmed by ultrasound. Univariable, multivariable logistic regression analyses were performed to identify the risk factors associated with PICC-related venous thrombosis. In October 2017, 169 patients with PICCs were enrolled prospectively, and the relationships between blood flow velocity and venous characteristics were recorded and analyzed.ResultsA total of 2933 cancer patients were enrolled in this study; of these patients, 68 experienced symptomatic venous thrombosis. In the bivariate analysis, body mass index (BMI), history of venous thrombosis, triglycerides, tumor category, vessel diameter, vessel depth and arm circumference were associated with thrombosis. The multivariable analyses showed that arm circumference, vascular diameter, triglyceride level and tumor category were independent risk factors for thrombosis. Blood flow velocity was positively correlated with vessel depth and arm circumference but not with vessel diameter.ConclusionDifferent venous characteristics can lead to different blood flow rates, which can affect the incidence of thrombosis. A vein depth of greater than 1.07cm or less than 0.57cm was associated with a higher incidence of PICC-related venous thrombosis, and the greater the arm circumference and vessel diameter, the greater the risk of venous thrombosis.

Coupling one-dimensional user code and STAR-CCM+ for simulation of rolling conditions in a rod bundle channel

The numerical simulation of the one-dimensional user code and the three-dimensional software STAR-CCM + coupling is performed on a natural circulation loop of a 3 × 3 rod bundle channel under rolling conditions. The coupling simulation method in this paper utilizes our one-dimensional user code, which is compiled and linked to generate a dynamic link library (DLL). The DLL is then imported into STAR-CCM+, so as to realize the coupling simulation of the one-dimensional user code and the three-dimensional Computerized Fluid Dynamics (CFD) code. In the one-dimensional user code, the mathematical model under rolling conditions is established to simulate the natural circulation loop except for the rod bundle channel. Adding a rotational motion to the STAR-CCM + enables a rolling simulation of the rod bundle channel. In order to compare the rationality of the coupled simulation, this paper also reports on the results carried out in an uncoupled simulation to study the rod bundle channel under the rolling conditions. The coupled simulation is a simulation that can be performed independently of an experiment, but the uncoupled simulation is not. That fact further demonstrates the wide applicability of the coupled simulation. The flow velocity and pressure drop characteristics in the 3 × 3 rod bundle channel are investigated. The results show that the coupled simulation method can predict the flow characteristics of the rolling rod bundle channel in the natural circulation loop well. The paper describes the coupling method in detail, which can make a foundation for future coupling research.

Measurement of the flow behavior index of Newtonian and shear-thinning fluids via analysis of the flow velocity characteristics in a mini-channel

An in-situ measurement technique to determine the rheology of a fluid based on the experimentally measured velocity profile of a flow in a mini-channel is introduced. The velocity profiles of a Newtonian and different shear-thinning fluids along a rectangular channel were measured using shadowgraph particle image velocimetry (PIV). Deionized water and different concentrations of a polyacrylamide solution were used as Newtonian and shear-thinning fluids, respectively and were studied at different Reynolds numbers. The flow indices of the fluids were determined by comparing the experimental velocity profile measurements with developed theory that takes into account the non-Newtonian nature of the fluids rheology. The results indicated that the non-Newtonian behavior of the shear-thinning fluid intensified at lower Reynolds numbers and it behaved more as a Newtonian fluid as the Reynolds number increased. A comparison between the power law index determined from experimental monitoring of the velocity profile at different Reynolds numbers and measurements from a rheometer reflected good agreement. The results from the study validate the new approach of the rheology measurement of Newtonian and non-Newtonian flows through straight, rectangular cross-section channels. The proposed approach can be further utilized using other methods such as X-ray PIV to characterize the rheology of non-transparent fluids and in general, for all non-Newtonian fluids.

Flow behaviours and velocity fields of non-oscillating and transversely oscillating jets

The near-field flow characteristics and jet fluid dispersion properties of non-oscillating and transversely oscillating jets issued from a fluidic oscillator were studied experimentally. A V-shaped fluidic oscillator was designed to induce transverse jet oscillations by merging two bifurcated alternatively issuing side jets. The characteristic flow patterns, evolution processes, velocities, vorticities, turbulence intensities and jet fluid dispersion capabilities in the median plane of the jets were examined. The characteristic flow patterns were obtained using laser-light-sheet-assisted smoke flow visualization method. The flow velocities were measured using particle image velocimetry. The jet fluid dispersion properties were analysed using tracer gas detection method. The non-oscillating jet was axial momentum-dominated—the axial momentum of the jet was limited within a narrow region around the central axis and was significantly larger than the transverse momentum. Therefore, the transverse velocities and vorticities were small and the dispersion of the jet fluid was relatively low. The transversely oscillating jets meandered in the near-field so the flow patterns presented a violent breakup of vortical flow structures and large transverse widths. The streamlines expanded transversely outwards and caused a part of the axial momentum to transfer towards the transverse direction. The vorticities and transverse velocities were increased and the axial velocities were decreased, so the dispersion of jet fluid was augmented in the transversely oscillating jets.

ANFIS grid partition framework with difference between two sigmoidal membership functions structure for validation of nanofluid flow

In this study, a square cavity is modeled using Computational Fluid Dynamics (CFD) as well as artificial intelligence (AI) approach. In the square cavity, copper (Cu) nanoparticle is the nanofluid and the flow velocity characteristics in the x-direction and y-direction, and the fluid temperature inside the cavity at different times are considered as CFD outputs. CFD outputs have been assessed using one of the artificial intelligence algorithms, such as a combination of neural network and fuzzy logic (ANFIS). As in the ANFIS method, we have a non-dimension procedure in the learning step, and there is no issue in combining other characteristics of the flow and thermal distribution beside the x and y coordinates, we combine two coordinate parameters and one flow parameter. This ability of method can be considered as a meshless learning step that there is no instability of the numerical method or limitation of boundary conditions. The data were classified using the grid partition method and the MF (membership function) type was dsigmf (difference between two sigmoidal membership functions). By achieving the appropriate intelligence in the ANFIS method, output prediction was performed at the points of cavity which were not included in the learning process and were compared to the existing data (the results of the CFD method) and were validated by them. This new combination of CFD and the ANFIS method enables us to learn flow and temperature distribution throughout the domain thoroughly, and eventually predict the flow characteristics in short computational time. The results from AI in the ANFIS method were compared to the ant colony and fuzzy logic methods. The data from CFD results were inserted into the ant colony system for the training process, and we predicted the data in the fuzzy logic system. Then, we compare the data with the ANFIS method. The results indicate that the ANFIS method has a high potentiality compared to the ant colony method because the amount of R in the ANIFS system is higher than R in the ant colony method. In the ANFIS method, R is equal to 0.99, and in the ant colony method, R is equal to 0.91. This shows that the ant colony needs more time for both the prediction and training of the system. Also, comparing the pattern recognition in the two systems, we can obviously see that by using the ANFIS method, the predictions completely match the target points. But the other method cannot match the flow pattern and velocity distribution with the CFD method.

Taylor Dispersion in Nanopores during Miscible CO2 Flooding: Molecular Dynamics Study

The miscible process between carbon dioxide (CO2) and oil in nanopore multiphase flow is essential for CO2-enhanced oil recovery (CO2-EOR) techniques, especially in low permeability oil reservoirs. The interplay between diffusion and convection dominates the miscible process in CO2-EOR. The Taylor dispersion model supposes that the shear flow smears the concentration distribution in the flow direction, thus enhancing the diffusion and convection in the capillary tube. However, the nanoscale applicability of this assumption is unclear. This work simulated the multiphase flows of CO2 and dodecane in nanopores at different flow velocities by using molecular dynamics (MD) simulations to investigate the process. Mass fraction profiles along the flow direction are overestimated using the Taylor dispersion model. Fluid velocity profiles from the MD results confirm the presence of the slippage phenomenon. A comparison between miscible flow and single-phase flow shows that the slip length of miscible flow might be the average of two single-phase flows of a specific component. A modified Taylor dispersion model considering slip boundary condition is obtained using the characteristic flow velocities modified by the slip length. The modified model-produced predictions correlated with the MD results and thus can predict the miscible process of nanoscale multiphase flow in CO2-EOR techniques.

Cavitation erosion characteristics at various flow velocities in NaCl medium of carbide-based cermet coatings prepared by HVOF spraying

This study aims to investigate the correlation between flow velocity and cavitation erosion (CE) characteristics of high-velocity oxygen-fuel (HVOF) sprayed Cr3C2-NiCr (CN) and WC-Cr3C2-Ni (WCN) coatings in 3.5 wt% NaCl medium, except for the microstructures, mechanical properties and electrochemical behaviors. In comparison with the CN coating, the WCN coating shows higher values of elastic modulus (E), hardness (H), H/E and H3/E2 as well as lower porosity, resulting in lower volume loss rate (VLR) and enhanced CE resistance in NaCl medium at each value of flow velocity. The VLR values of both coatings increase as the flow velocity increases. The change of the CE progresses in NaCl medium of the CN coating is the formation of cavitation pinholes, pits, craters and oxidation films coupled with the exfoliation of chromium carbide particles when the flow velocity is 23.4 and 33.5 m s−1 as well as the brittle fracture structure with layers delamination accompanied by the oxidation films when the flow velocity is 41.9 m s−1. In a wide flow velocity range, the formation of cavitation pinholes, pits and micro-cracks along with the oxidation films are addressed as the dominant CE mechanism in NaCl medium of the WCN coating.

Flow velocity characteristics at a confluent channel with and without flexible vegetation

The interaction between confluence and vegetation is important for understanding the rules of flood control and ecological restoration. To this end, artificial flexible plastic grass was used in a 90° confluent open channel to simulate the ambient conditions of the natural state, and three-dimensional velocities were measured by an acoustic Doppler velocimeter. The velocities of different spatial distribution in different conditions were analysed. The results showed that the existence of vegetation will change the velocity's horizontal distribution and the velocity decreases greatly because of the vegetation. The vegetation reduces the deflection angle of the 90° confluence flow intersection. Under the influence of the vegetation, the flow direction can be restored to the main flow direction more quickly after confluence. Vegetation is the main factor causing the flow velocity reduction in the upstream, whereas in the vicinity of the confluence the influence of vegetation on the velocity will change with the intensity of the turbulence in the region. The influence range of the vegetation on the vertical velocity was found to be double the average height of the vegetation. The vertical velocities changes greatly near the average height of the vegetation.

Integrated assessment of cerebral blood flow and cerebrovascular reactivity based on functional tests data in patients with Parkinson’s disease and vascular pathology

Objective. To evaluate cerebral blood flow parameters and cerebrovascular reactivity indices based on data of functional tests in patients with Parkinson’s disease (PD) and vascular pathology.Material and Methods. A total of 148 people were examined, divided into 4 groups: (1) main group comprised 24 patients with idiopathic PD; (2) comparison group 1 included 21 patients with vascular parkinsonism; (3) comparison group 2 included 26 patients with a diagnosis of chronic cerebral ischemia of severity degree 2 with no signs of parkinsonism; and (4) comparison group 3 included 77 patients with PD and cerebrovascular disease. All patients received transcranial duplex scanning of cerebral blood vessels (TCD) through the temporal window (Toshiba Aplio 500, Japan, 2–2.5 MHz sector probe) using standard protocols for the assessment of blood flow velocity characteristics. An assessment of cerebrovascular reactivity (reserve) was performed using the diagnostic and treatment complex “Carbonic”. The range of cerebrovascular and vasomotor hypercapnia reactivity to hypercapnia was evaluated in the “Testing of cerebrovascular reactivity” mode.Results. A comprehensive study of cerebral blood flow parameters using functional tests suggested that the absence of changes in the cerebrovascular reactivity index (VRhyperCO2 ) observed in patients with idiopathic PD may be considered a differential diagnostic criterion for Parkinson’s disease and cerebrovascular pathology with Parkinson’s symptoms.

Spawning flow velocity demand for representative fish species in the upper Yangtze River

To mitigate possible negative impacts of cascade dams on spawning of rare and endemic fish species in the national nature reserve downstream of these dams, spawning flow velocity demand for fish need to be considered in the cascade dams operation. Based on the cascade dams constructed in the upper Yangtze River, Coreius Heterodon was selected as the representative fish species. According to the drifting distance of fish eggs, the flow velocity characteristics at the spawning location of Coreius Heterodon were analysed with the unsteady flow mathematical model. The results show that a large flow velocity increase process is good for Coreius Heterodon spawning, and the process of velocity fluctuation is similar before spawning. The cumulative velocity amplitude, the cumulative number of fluctuations and the maximum velocity amplitude are closely correlation with the spawning number. The velocity in spawning period is affected by the dams operation, and the suitable range of velocity is changed from [0.8m/s, 1.2m/s] to [1.1m/s, 1.4m/s]. The results can provide the basis for future ecological operation based on flow velocity index of the cascade dams.

Experimental study on radial evolution of droplets in vertical gas-liquid two-phase annular flow

In vertical gas-liquid two-phase annular flow, the radial evolution of droplets in the gas core plays a key role in affecting the characteristic of gas carrying liquids. In this paper, the droplets size and velocity at 11 radial positions were measured with the phase Doppler anemometry and then analyzed based on the recognition method of droplet role to figure out the radial evolution characteristics of droplets flow rate, size, velocity, and momentum. The results show that the droplet quantity flow rate decreases with the entrained droplets moving from the liquid film-gas core interface to the centerline, due to the fact that the droplet coalescence has a greater effect than the droplet breakup. The proportion of small droplets decreases while the proportion of relatively large droplets increases. The overall distribution characteristics of droplet diameter remain unchanged. The overall distribution characteristics of droplet axial velocity, radial velocity, and velocity size remain unchanged, although the droplets undergo the process of axial acceleration and radial deceleration during the radial migration. The distribution of droplet momentum varies greatly in the process of droplet radial migration. The contribution of small droplets to the total droplet momentum gradually decreases, while the contribution of large droplets to the total droplet momentum gradually increases. Although the number of large droplets is small, their contribution to the total droplet momentum cannot be neglected.