Axial Direction Research Articles

Supercritical n-decane heat transfer in a vertical tube subjected to high-temperature crossflow air

The study presents a numerical investigation of high-temperature supercritical n-decane flowing upward in a tube subjected to non-uniform heating. The aim of the study is to evaluate the heat transfer mechanisms due to the non-uniform heating condition where it can be observed that the radial inner wall temperatures exhibit a typical pendulum-type distribution. In particular, between 140° < θ < 220° (near the cold side of the tube), the temperature at the inner wall is at the lowest and remains essentially constant, which indicates that the n-decane between the hot and cold sides in the tube exhibits poor mixing. Also, the higher the inlet temperature, the more likely heat transfer deterioration (HTD) will occur closer to the tube inlet. Moreover, detailed information on wall temperatures, velocity, and secondary flow of the supercritical n-decane are evaluated and discussed. The results show that Re is affected by the density and kinetic viscosity of n-decane near the pseudocritical temperature so that Re near the wall fluctuates and has an influence on the wall heat transfer in the HTD region. The Pr at the center of the fluid decreases along the axial direction and the fluid boundary layer becomes thinner, resulting in a more pronounced non-uniformity of Pr in the radial direction. Meanwhile, the stability of the turbulent kinetic energy (TKE) distribution and the high intensity of TKE favor the heat transfer of n-decane in the tube.

Impact of heat transfer in a duct composed of anisotropic porous material: A non-linear Brinkman-Forchheimer extended Darcy's model: A computational study

Forced convective heat transport in a rectangular porous channel with anisotropic permeability is investigated in this study. A fully developed flow field is assumed, and the Brinkman-Forchheimer extended Darcy's equation is adopted to model the fluid flow. The thermal field is developing. A weak formulation of the momentum equation has been obtained. The existence and uniqueness of the solution for the weak momentum equation are proved using the Browder-Minty theorem. The finite difference approach has been utilized to solve these coupled differential equations. Non-equidistant grids are implemented in the axial direction to reduce computational time and space. The effect of anisotropic parameters, such as permeability ratio and orientation angle, on the hydrodynamic and thermal characteristics of the flow has been discussed. An increase in the permeability ratio (K) causes an increase in the local Nusselt number. Anisotropy has been identified as crucial in heat transmission for the Darcy numbers less than0.75. The anisotropic phenomenon of the channel contributed to a more than 13 % increase in the heat transmission rate compared to the isotropic scenario. Also, as the anisotropic parameters increase, the amount of heat transferred from the walls to the fluid up to any desired axial distance increases. Validation of numerical solutions is done using existing literature.

Multiple-point ignition as a driver of flame acceleration at the early stage of burning in channels

In the present study, flame acceleration driven by an array of multiple ignition kernels, equally spaced in the axial direction of a channel closed at one end, is studied numerically. In order to demonstrate the effects of the proposed ignition configuration on the flow dynamics, free-slip wall boundary condition is adopted. It is demonstrated that the burning of multiple flame kernels generates a powerful upstream flow, propelling the flame kernels, with the leading kernel’s tip undergoing a strong exponential acceleration. In a channel with smooth walls, such a powerful acceleration process is limited in time. The present study is mainly focused on the dynamics of the flame during the exponential stage of acceleration. The dependence of the acceleration rate, total acceleration time, and the maximum flame velocity on the initial distance between the kernels, the number of ignition kernels, and the thermal gas expansion coefficient, is quantified. Remarkably, the initial distance between the kernels has a weak influence on the above mentioned characteristics of flame dynamics as long as it is sufficiently large. It is observed that the acceleration rate increases with the kernel number. Notably, a significantly large maximum flame tip velocity can be achieved using the multi-kernel configuration as compared to the single-point ignition scenario. The acceleration rate demonstrates a nearly linear dependence on the thermal expansion coefficient, thus, the increase in thermal expansion results in a considerably stronger flame acceleration process.Novelty and Significance StatementFor the first time, the flame acceleration process upon simultaneous ignition of a multi-point array of hot kernels equally spaced at the centerline of a channel was systematically studied. The work emphasizes the potential for achieving an extremely high flame speed within a very short time as compared to the single-ignition method. The acceleration rate, total acceleration time, and maximum achievable flame velocity were quantified. In a multi-point ignition scenario, we demonstrate that the burning of the fresh mixture between the kernels increases an overall cumulative gas expansion, propelling the leading tip. This result suggests a method for creating a powerful flame acceleration, which is an essential step in deflagration-to-detonation transition. Notably, the powerful acceleration is achieved in channels with smooth walls, which is important for DDT applications, in which using obstructed channels may be associated with a range of operational problems. The simplicity of the setup is also emphasized.

Photothermally‐Engineered Crystallization of GAP‐Se Bulk Chalcogenide Nanocomposites toward the Realization of 3D Gradient Refractive Index Profiles

AbstractTailorability of a medium's optical properties, specifically refractive index and dispersion, is key to enabling compact optical designs. Chalcogenide glasses (ChGs) are widely used for infrared (IR) imaging applications, and the development of gradient refractive index (GRIN) optics. This work extends efforts to create and characterize 3D GRIN profiles in bulk multi‐component Ge‐As‐Pb‐Se (GAP‐Se) ChGs through spatially selective conversion of commercial glass to glass ceramic. This work extends prior efforts on bulk and film lab‐scale glass media, to that of a commercially produced material with improved optical homogeneity. Laser‐induced crystallization upon heat treatment results in the formation of high index Pb‐containing crystals that contribute to an increase in the nanocomposite's resulting effective refractive index, neff. The material's induced crystallinity imparted via laser exposure and heat treatment using metrology tools such as refractometry, X‐ray diffraction, FTIR, and TEM are studied. The resulting material response is quantified which is shown to be modulated via laser dose in both lateral and for the first time, axial directions enabling the first demonstration of a true, 3D GRIN profile. By comparing these outcomes to prior radial GRIN structures, the promise of these media as candidate materials for infrared systems.

Swirling instability of viscous liquid jets with axial shear effect in gas surroundings

Linear instability analysis of a viscous swirling liquid jet surrounded by ambient gas is carried out by considering the significant influence of axial shear effect. The jet azimuthal flow is assumed as a Rankine vortex, and the non-uniform velocity distribution in the jet axial direction is approximated by parabolic and error functions. The enhancement of jet rotation is found to promote the predominant mode with larger azimuthal wavenumbers, and the mode transition is decided by the competition between centrifugal force and axial shear stress. Subsequently, the influence of the axial shear effect is examined through changing the degree of shear stress and the thickness of the gas velocity boundary layer. It is found that an increase of jet average velocity or surface velocity in the axial direction leads to the predominant mode transition to smaller azimuthal wavenumbers, due to the combined effects of shear stress and gas pressure perturbation. A larger velocity difference between ambient gas and liquid jet also promotes the predominant modes with smaller azimuthal wavenumbers, and the physical mechanism is attributed to gas pressure perturbation. Phase diagrams of different azimuthal modes are given and compared with the study of Kubitschek &amp; Weidman (J. Fluid Mech., vol. 572, 2007, pp. 261–286), where a static swirling column without axial shear stress was considered. The strengthened axial shear effect is found to delay the transition of predominant modes with the increase of angular velocity. Experimental studies considering the swirling jets with different axial velocities are further carried out, which validate the theoretical findings. Different instability mechanisms and their transition rules are also identified through energy budget analysis. This study is expected to give scientific guidance on understanding the instability mechanisms of the swirling jets that widely exist in natural phenomena and engineering applications.

Refined speckle contrast estimation in OCT based on compensation of scattering-related distortions of speckle pattern parameters

Abstract Speckle contrast (SC) parameters in optical coherence tomography (OCT) scans are formed by the interplay of several factors—local level of optical wave backscattering by the material inhomogeneities, parameters of spatial distribution of the latter and the degree of cumulative optical wave attenuation during its fourth-and-back propagation. For the optical wavelengths used in OCT, this attenuation is usually dominated by the influence of scattering in the visualized turbid tissues rather than by absorption. For sufficiently high concentrations of scatterers (at least a few scatterers in the coherence volume) characterized by comparable scattering strengths and a fairly homogeneous distribution in space, the interference of locally scattered waves should be characterized by a Rayleigh distribution of speckle amplitudes, for which the local SC tends to 0.52. Equivalently, in terms of speckle intensities, the local SC tends to unity. Local spatial inhomogeneities or strongly uneven scattering strengths lead to the appearance of increased values of SC, which may serve as a diagnostic feature of some tissue components in OCT images. At the same time, in comparison to surface speckles formed by coherent-light scattering from rough surfaces, OCT-beam attenuation during its fourth-and-back propagation may introduce intensity inhomogeneities in OCT scans even for homogeneous tissue areas. This effect results in artefactual distortion of the visible SC in comparison with the above-mentioned expected value. Moreover, the presence of individual strong scatterers may additionally non-locally distort SC values due to the appearance of elongated shadows below such scatterers, which causes lateral inhomogeneities in OCT scans. Here, we propose a refined SC parameter, which is cleaned from distorting scattering-related effects in both axial and lateral directions. Depth-resolved estimation of the optical attenuation coefficient is used to restore attenuation-free OCT scans, for which the refined SC is estimated. The efficiency of the proposed approach is demonstrated using both digital OCT phantoms with highly controlled properties and experimental OCT data.

Large room-temperature elastocaloric effect and enhanced specific adiabatic temperature change of Ni–Mn-based shape memory microwire

Continuous miniaturization of electronic components puts higher demands on the heat dissipation of the micro-systems, which requires environmental friendliness, good heat exchange capability, and high-performance micro-refrigeration materials. Here, we developed a Ni–Mn–Fe–In microwire fabricated by the Taylor–Ulitovsky method, showing ⟨001⟩A orientation close to the axial direction of microwire. Due to the large volume change ΔV/V (−1.24%), the large entropy change ΔStr of 43.6 J kg−1 K−1 was achieved in the microwire. Owing to the low driving force of the microwire with a single crystalline of ⟨001⟩A orientation close to the axial direction of microwire, large adiabatic temperature change of −5.7 K was achieved at room temperature after removing a low stress of 120 MPa. Thus, high specific adiabatic temperature change of 47.5 K/GPa was obtained in the microwire, which is the highest value among all the reported low-dimension elastocaloric materials, including thin films/foils, microwires/wires, and ribbons. The outstanding comprehensive properties give this microwire a great application potential in miniaturization and compactness of refrigeration devices.

Nonlinear Oxidation Behavior at Interfaces in Coated Steam Dual-Pipe with Initial Waviness and Cooling Temperature

A numerical simulation method is proposed to investigate the nonlinear growth of thermally grown oxide (TGO) on a novel coated steam dual-pipe system operating at 700 °C. Utilizing oxidation kinetics data from high-temperature water vapor experiments, the study examines interface stresses and morphology evolution, considering initial surface waviness and cooling temperature effects. The findings indicate that the parabolic law accurately describes the nonlinear growth of TGO during high-temperature water vapor oxidation, with the TGO growth oxidation rate constant being 4.5×10−4μm2/h. The growth rate of TGO thickness decreases with increasing oxidation duration. Stress concentrations are found to develop at TGO interfaces, particularly in regions with high curvature, and those with elevated wavy amplitudes. The primary factor influencing stress redistribution and morphology evolution is the wavy amplitude of the TGO. Additionally, variations in cooling temperature affect interface stresses along the axial direction of the pipe system during nonlinear oxidation, resulting in relatively minor changes in morphology.

Cephalopod-inspired jetting devices for gastrointestinal drug delivery.

Needle-based injections currently enable the administration of a wide range of biomacromolecule therapies across the body, including the gastrointestinal tract1-3, through recent developments in ingestible robotic devices4-7. However, needles generally require training, sharps management and disposal, and pose challenges for autonomous ingestible systems. Here, inspired by the jetting systems of cephalopods, we have developed and evaluated microjet delivery systems that can deliver jets in axial and radial directions into tissue, making them suitable for tubular and globular segments of the gastrointestinal tract. Furthermore, they are implemented in both tethered and ingestible formats, facilitating endoscopic applications or patient self-dosing. Our study identified suitable pressure and nozzle dimensions for different segments of the gastrointestinal tract and applied microjets in a variety of devices that support delivery across the various anatomic segments of the gastrointestinal tract. We characterized the ability of these systems to administer macromolecules, including insulin, a glucagon-like peptide-1 (GLP1) analogue and a small interfering RNA (siRNA)in large animal models, achieving exposure levels similar to those achieved with subcutaneous delivery. This research provides key insights into jetting design parameters for gastrointestinal administration, substantially broadening the possibilities for future endoscopic and ingestible drug delivery devices.

Temporal variation in utilisation distribution and direction distribution of dugong feeding trails in intertidal seagrass beds in Talibong Island, Thailand: an insight into dugong feeding routes

Context A better understanding of animal habitat use informs fundamental ecology and can provide underpinnings for effective management. Aims This study explored the temporal variation in feeding ground utilisation by dugongs (Dugong dugon) in two intertidal seagrass beds in Talibong Island, Thailand (Sites A and B), focusing on the distribution and direction of dugong feeding trails. Methods Drone-based aerial photography was conducted quarterly over 1 year and daily over 2 weeks to observe feeding trails and behaviour. Key results During five and seven separate photography periods over 1 year, 0.04 ± 0.01% (range: 0.03–0.06%) of Site A (200,000 m2) was covered with new feeding trails daily, while 0.35 ± 0.31% (range: 0.07–0.96%) of Site B (278,000 m2) was covered daily. This temporal variation in the feeding trail area corresponded to that in seagrass coverage. Daily observations over 2 weeks during six separate photography periods revealed a significant decrease in overlapping rates (intersection over union) of the core areas (50% kernel density estimation [KDE]) as time elapsed. The 1-year observation highlighted relatively higher overlapping rates of home ranges (95% KDE) (Site A: 0.27 ± 0.09; Site B: 0.49 ± 0.08) and low overlapping rates of core areas (Site A: 0.02 ± 0.03; Site B: 0.09 ± 0.09). The relative frequencies of the feeding trail direction remained consistent across survey seasons, and the most and least dominant directions were common across all survey seasons and sites. The circular correlation coefficient between the directions of dugong body axis and the estimated tidal current was 0.45, suggesting that feeding generally occurred in the upstream direction. The direction and spatial range of dugong feeding may be affected by temporally consistent factors. One factor that can affect the feeding direction is the tidal current. Conclusions Overall, dugongs may feed and move within seagrass beds in a temporally consistent manner, even when there are shifts in feeding hotspots. Implications This research enhances our understanding of how dugongs utilise their feeding grounds and highlights the importance of not only identifying feeding hotspots but also predicting their feeding routes by considering the direction and distribution of feeding trails.

Research on Typical Decay-like Fracture Defects of Composite Insulators Based on Electro-Thermal Coupling

In response to the typical decay and fracture defects of composite insulators, a three-dimensional electrically and thermally coupled simulation physical model was constructed based on the finite element method, and the local electric field distortion and temperature rise were analyzed. The study confirms that the insulator interface’s axial electric and thermal fields show a U-shaped curve; the interface field strength is the largest. There is an electric field gradient difference between the mandrel and the sheath, and the thermal field is concentrated at the mandrel and the interface. The field strength at the edge of the defect is the largest, the aberrant electric field at the defect shows a sawtooth shape, and the temperature rise is concentrated in the defect area. The degradation is fast in the air gap, the etching hole diameter direction, and the carbonation channel axial direction. The larger the defect volume, the larger the aberration in the electric field and temperature rise. Water vapor air gaps, breakdown holes, and carbonized channels have the most pronounced electric field and temperature changes. The functional relationship between electric field aberration, temperature rise, and defect volume is established. The results provide a basis for the protection of insulator decay-like fracture.

Entanglement and iSWAP gate between molecular qubits.

Quantum computation and simulation rely on long-lived qubits with controllable interactions. Trapped polar molecules have been proposed as a promising quantum computing platform, offering scalability and single-particle addressability while still leveraging inherent complexity and strong couplings of molecules1-5. Recent progress in the single quantum state preparation and coherence of the hyperfine-rotational states of individually trapped molecules allows them to serve as promising qubits6-11, with intermolecular dipolar interactions creating entanglement12,13. However, universal two-qubit gates have not been demonstrated with molecules. Here we harness intrinsic molecular resources to implement a two-qubit iSWAP gate using individually trapped X1Σ+ NaCs molecules. By allowing the molecules to interact for 664 μs at a distance of 1.9 μm, we create a maximally entangled Bell state with a fidelity of 94(3)% in trials in which both molecules are present. Using motion-rotation coupling, we measure residual excitation of the lowest few motional states along the axial trapping direction and find them to be the primary source of decoherence. Finally, we identify two non-interacting hyperfine states within the ground rotational level in which we encode a qubit. The interaction is toggled by transferring between interacting and non-interacting states to realize an iSWAP gate. We verify the gate performance by measuring its logical truth table.

Experimental and numerical studies of the open hole tensile strength of drilled‐ and molded‐hole unidirectional laminates

AbstractIn this paper, we created a new molded‐hole process to manufacture holes instead of drilling in unidirectional (UD) carbon fiber reinforced plastics avoid fiber discontinuity. Several open hole tensile (OHT) tests were carried out on specimens with Cross ply (CP) and Quasi‐isotropic (QI) stacking sequence with drilled holes and molded holes. At the same time, we established finite element analysis (FEA) models of drilled‐hole laminate and molded‐hole laminate to characterize the stress field around the hole. The numerical analysis results reveals that the max principal strain distribution around the molded hole has much higher coincidence with fiber axial direction than that in drilled‐hole laminate. Moreover, the OHT strength results of QI specimens indicate that the plates with molded holes were more 50% higher than those with drilled holes. This process will provide reference for molded UD CFRP structure holes. And the numerical model can help engineering designer make OHT strength prediction.Highlights A new molded‐hole process for unidirectional prepreg was created. Molded‐hole specimens have higher open hole tensile strength than drilled‐hole pieces. The simulation results were close to the experimental results.

Mechanical properties and vibration characteristics of multiaxial carbon/glass hybrid fiber composites

AbstractIn this paper, the mechanical properties and vibration characteristics of Carbon‐Glass Hybrid Fiber Composites (CGHFC) are experimentally investigated with varying axial directions and blending ratios. The experimental results demonstrate a significant increase in the tensile strength of the CGHFC with an increasing content of carbon fibers. The biaxially CGHFC exhibits a maximum static tensile strength of 413.27 MPa in the 0° direction and 466.33 MPa in the 90° direction, surpassing both the quadratic and uniaxial directions. Notably, compared to biaxially oriented glass fiber material, the tensile strength of CGHFC is enhanced by 44.36%, thereby significantly improving its overall performance, making them particularly suitable for blade structures subjected to simultaneous tensile and vibratory loads. By optimizing the fiber orientation and blend ratio, the CGHFC provides good vibration control and fatigue resistance while ensuring high strength, thus maximizing the overall performance and service life of the blades. The results of this paper provide important data and theoretical support for the selection and design of wind turbine blade materials and help to promote the development of composite materials in wind turbine blade structure and design.Highlights CGHFCs show enhanced tensile strength with more carbon fibers. Biaxial CGHFCs have max tensile strength at 0° and 90° directions. CGHFCs' strength improves by 44.36% over glass fiber materials. Optimized CGHFCs offer superior vibration control and fatigue resistance. Research supports wind turbine blade material innovation.

Pore-Scale Visualized Transport and Retention of Fibrous and Fragmental Microplastics in Porous Media under Various Surfactant Conditions.

For advancing current knowledge on the transport of microplastics (MPs) in the environment, this study used a real-time pore-scale visualization and quantitative system to examine the motions and mobility of fibrous and fragmental MPs under various surfactant (AEO, CTAC, and AES) and electrolyte conditions. The videos showed that fibrous MPs formed tangles through entanglement, which moved in an axial direction aligned with the flow streamline. Both fibrous and fragmental MPs showed suspended movement as well as surface movement (e.g., sliding, rolling, and saltating) in the porous media. Some deposited fibrous MPs showed flexible deformation due to shear flow. Compared to fragmental MPs, fibrous MPs showed lower mobility due to the tendency to deposit and clog the porous media. The mobility of fragmental MPs was enhanced in the presence of AEO but remained relatively unchanged with AES. In the presence of CTAC, the mobility of fragmental MPs was slightly inhibited under low ionic strength (IS) conditions but remarkably enhanced under high IS conditions. However, the mobility of fibrous MPs was largely unaffected by the surfactants. Both the numerical model and FDLVO calculations effectively described the transport and deposition of MPs in porous media.

Combing mobile electrical capacitance tomography with Fourier neural operator for 3D fluidized beds measurement

AbstractDespite the practical importance, 3D measurements of gas–solid distribution in fluidized beds calls for further breakthroughs. Here an approach combing a recently developed mobile electrical capacitance tomography (ECT) sensor with Fourier Neural Operator (FNO) is developed, in which the fluidized bed is divided into a series of cross‐sectional slices along axial direction. At any given instant, the gas–solid distribution in one slice is measured by mobile ECT and the others, meantime, are predicted by FNO pre‐trained using experimental data. We verified this approach via computational fluid dynamics (CFD) simulations and experimental measurement of static object (i.e., cone, cylinder, and sphere) in fluidized bed. Following we applied this approach to direct measure 3D gas–solid distribution in a bubbling fluidized bed, and found that satisfactory image correlation coefficients and solid concentration average absolute deviation could be obtained, which indicates the proposed approach is promising for 3D fluidized bed measurements.

The simplest transformation model of deformation of a rod-strip fixed on a double-sided support element through elastic interlayers

An extremely simplified transformation model of dynamic deformation of a rod-strip consisting of two sections along its length is constructed. It is based on the classical geometrically nonlinear Kirchhoff-Love model on an unfixed section, and the fixed section of finite length is considered to be connected to a rigid and fixed support element through elastic layers. On the fixed section, the deflections of the rod and interlayers are considered zero, and for displacements in the axial direction within the thicknesses of the rod and interlayers, approximations are adopted according to the shear model of S.P. Timoshenko, subject to the conditions of continuity at the points of their connection with each other and immobility at the points of connection of the interlayers with the support element. The conditions for the kinematic coupling of the unfixed and fixed sections of the rod are formulated, and based on these, using the d’Alembert-Lagrange variational principle, the corresponding equations of motion and boundary conditions, as well as the force conditions for coupling of the sections, are derived for the sections introduced into consideration.

Study on eccentric compressive performance of circular double skin concrete filled steel tube connected by thread through inside lining tube

Connection method of lengthening the steel tube of circular hollow sandwich concrete-filled steel tube by inside lining tube and thread is proposed. Twelve circular hollow sandwich concrete filled steel tubular beam-column connected by thread through inside lining tube are designed and fabricated using the length of the thread along the axial direction, the working height of the thread, and the position of the thread as parameters; In addition, one unconnected specimen and two welded specimens also are designed and fabricated to conduct controlled experimental research. The test phenomena and failure modes, axial compressive load-compression curve, axial compressive load-lateral deflection curve, and axial compressive load-strain in steel tube curve, as well as bearing capacity, strength reservation, deflection curve shape, lateral stiffness, ductility and plane section assumption are analyzed. The research results indicate that, within the parameter range studied, the thread connection through inside lining tube is reliable before tripping, and the experimental phenomenon of specimens connected by thread is basically consistent with that of the unconnected specimens. The axial compressive load-compression curve and axial compressive load-lateral deflection curve of all specimens can be approximately divided into elastic stage, elasto-plastic stage, and descending stage. The peak load of all specimens is relatively close, while although experiencing almost the same loading process, the strength reserve of the specimens connected by thread is insufficient. During the entire loading process, the shape of the deflection curve of all specimens is close to the sine half wave curve, and the distribution of longitudinal strain in the steel tube along the height of the middle cross-section basically conforms to the plane section assumption. Calculation method for bearing capacity of circular hollow sandwich concrete filled steel tubular beam-column connected by thread through inside lining tube is suggested.

INCREASING THE EFFICIENCY OF THE SEED SHAFT TURBER OF THE LINTER MACHINE

It is noted that the main factor in reducing the quality of the lint is its contamination caused by the increased content of crushed seeds. The latter is explained by the mechanical impact on the seed roller from the rigid elements of the working bodies of the linter machine, such as saws, grates and agitator. The magnitude of this impact largely depends on the density of the seed roller itself. In addition, its high density is the cause of additional energy costs for its rotation. To reduce the dynamic loads on the seeds in the roller, an original design of agitator with elastic inclined blades separated by elastic bushings is proposed. The proposed agitator provides intensive mixing of seeds in the seed roller both in the axial direction and in the direction of its rotation. It is shown that agitator with elastic blades allows to reduce energy costs by 20 % and reduce seed damage by 0.3 %

Comparative Analyses of Dynamic Characteristics of Gas Phase Flow Field Within Different Structural Cyclone Separators

The gas phase flow field inside a cyclone separator is crucial to the particle separation process. Previous studies have paid attention to the steady-state characteristics of the gas phase flow field, while research on its dynamic characteristics remains insufficient. Meanwhile, cyclone separators often adopt different structural forms according to the process requirements, the evolution laws of the dynamic characteristics flow field within them are still not well understood. Therefore, in this study, a hot-wire anemometer (HWA) was employed to measure the instantaneous tangential velocity of the gas phase flow fields within different structural cyclone separators (cylinder type, cylinder–cone (no hopper), and cylinder–cone (with hopper)). Comparative analyses and discussions were conducted regarding the dynamic characteristic distribution rules of the flow field in the time domain and the frequency domain. The results revealed that the dimensionless tangential velocity distributions of different types of cyclone separators all conformed to the Rankine vortex structure. The instantaneous tangential velocity fluctuated with low frequency and high amplitude, and the low-frequency velocity fluctuation exhibited a transfer behavior along the radial direction. Compared with the cylinder–cone-type cyclone separator, the tangential velocity in the cylinder-type cyclone separator fluctuated more greatly, and its quasi-periodic behavior was also more obvious. The time-averaged tangential velocity, the tangential velocity fluctuation intensity (Sd), and the dominant fluctuation frequency all had obvious attenuation along the axial direction in the cylinder-type cyclone separator, while the above-mentioned parameters had no attenuation along the axial direction in cylinder–cone-type cyclone separators. Additionally, the backflow from the hopper of the cylinder–cone-type cyclone separator (with hopper) led to an increase in the instantaneous tangential velocity fluctuation intensity of the local flow field near the dust outlet, as well as the occurrence of the “double dominant frequencies” phenomenon.