Particle Image Research Articles

Soil-Pipeline interaction under localized soil Subsidence: Experimental Investigation

Localized soil subsidence can cause pipeline failures, yet relevant studies remain limited. This research uses 1 g scaling tests to explore granular soil behavior over a subsiding area with a crossing pipeline, employing Particle Image Velocimetry (PIV) and pressure sensors beneath trapdoors. Results reveal various failure mechanisms impacting load on pipelines, especially due to water-drop-shaped slip surfaces above the pipeline. The long side of the rectangular subsidence zone exhibited stronger load transfer compared to the short side. Neglecting the three-dimensional soil arching effect risks underestimating the pipeline load, particularly when the pipeline axis aligns with the long side of the subsidence. Greater distances between the subsidence zone and pipeline improve protection, though very close proximity can also be beneficial. The study suggests that inducing controlled soil failure above the pipeline may help reduce additional load, providing insights into mitigating pipeline damage from subsidence.

Measuring River Surface Velocity Using UAS‐Borne Doppler Radar

AbstractUsing Unoccupied Aerial Systems (UAS) equipped with optical RGB cameras and Doppler radar, surface velocity can be efficiently measured at high spatial resolution. UAS‐borne Doppler radar is particularly attractive because it is suitable for real‐time velocity determination, because the measurement is contactless, and because it has fewer limitations than image velocimetry techniques. In this paper, five cross‐sections (XSs) were surveyed within a 10 km stretch of Rönne River in Sweden. Ground‐truth surface velocity observations were retrieved with an electromagnetic velocity sensor (OTT MF Pro) along the XS at one m spacing. Videos from a UAS RGB camera were analyzed using both Particle Image Velocimetry (PIV) and Space‐Time Image Velocimetry (STIV) techniques. Furthermore, we recorded full waveform signal data using a Doppler radar at multiple waypoints across the river. An algorithm fits two alternative models to the average amplitude curve to derive the correct river surface velocity based on Gaussian models with: (a) one peak, and (b) two peaks. Results indicate that river flow velocity and propwash velocity caused by the drone can be found in XS where the flow velocity is low, while the drone‐induced propwash velocity can be neglected in fast and highly turbulent flows. To verify the river flow velocity derived from Doppler radar, a mean PIV value within the footprint of the Doppler radar at each waypoint was calculated. Finally, quantitative comparisons of OTT MF Pro data with STIV, mean PIV and Doppler radar revealed that UAS‐borne Doppler radar could reliably measure the river surface velocity.

Characterization of droplet clusters in a turbulent multiphase gas cloud using a model cough simulator

This study aims to investigate the transport of droplets ejected from an artificial cough simulator, which releases a turbulent puff of droplets into the surrounding air, closely resembling the human coughing process. The focus is on understanding droplet clustering within the multiphase gas cloud across various operating conditions that emulate the wide variation in the spray characteristics in actual human subjects owing to infection severity, age, and gender. Time-resolved particle image velocimetry (PIV) technique was employed to measure the velocity of both droplet and gas phases. It also facilitates the identification and characterization of droplet clusters through Voronoi analysis of the PIV images. The area and length scale of individual droplet clusters were measured, and the degree of droplet clustering was quantified using the clustering index and relative droplet number density within the clusters. Additionally, the interferometric laser imaging for droplet sizing technique was utilized for planar measurement of individual droplet sizes. The range of Stokes number indicated partial to poor response of the droplets to the turbulent eddies. The results reported, for the first time, the presence of droplet clusters in the simulated coughing process. The wide spectrum of cluster size and self-similar evolution of droplet clusters unveil a multi-scale clustering phenomenon, shedding light on the intricate dynamics of the respiratory droplet dispersion process. The study comprehensively investigates the role of injection pressure on droplet clustering and the spatial development of the clusters, revealing some interesting findings, which are discussed.

An experimental and numerical study on the behavior of finite-length column vortex

This paper explores experimental and numerical investigation of the spatiotemporal dynamics of a finite-length vortex column in three dimensions using particle image velocimetry and large eddy simulation. The research examines the combined impact of bending, buckling, and core-splitting on a finite-length vortex column. More precisely, the work centers on the fundamental motions, evolutions in flow along the axis, how the shape of the vortex core changes over time, the instability caused by the long waves on the vortex column, and the division of the vortex core. A novel prototype is developed that utilizes piston-driven inflow and produces a vortex column through the principles of flow separation and Biot–Savart induction, which is studied for predicting an ex situ cyclonic line vortex. The present study discusses the complete three-dimensional overview of the same columnar vortex. The meridional swirl and the axial transport of vorticity deform the shape of the core cross sections in different lengths of the column. The jump in the axial velocity at the core boundary allows for the occurrence of bending instabilities with a left-handed helical structure. These instabilities have a long wavelength, similar to the length of the vortex column, and belong to the m = +1 mode. The vortex column experiences a non-uniform curvature and torsion caused by the intricate shape of the laboratory model and varying flow speeds at different heights of the vortex column. The results offer valuable insights into the role of inertia, Coriolis, and viscous forces on the dynamics of the vortex column.

Research PIV-based model on subsidence caused by coal mining

The subsidence caused by coal mining could cause the destruction of roads and houses, and even the failure of infrastructures. Understanding of the mechanism of coal mining subsidence may provide early protecting to infrastructures on coming failure, but dynamic analysis of subsidence due to coal mining is currently needed. In this study we apply particle image velocimetry (PIV) method to reveal strata movement and subsidence according to the prototype and indoor physical model similarity experiment of Henan. Our result shows magnitude of the subsidence of overlying strata during the coal mining at different excavation thickness, that more coal mining thickness may produce more subsidence, and that shallower coal may cause more significant subsidence. Our result suggests that further PIV test combined with field monitoring data may be an effective measure to study subsidence mechanism and pattern helping to predict disaster caused by subsidence.

Suppression of the coffee-ring effect by controlling the solid particle density

Previous studies show that the coffee-ring effect can be suppressed by altering the droplet's evaporation rate, surface tension, surface properties, and shape of particles. This experiment used five types of particles with different densities to analyze their behavior during the droplet evaporation process. The results showed that when the particle density is close to the fluid density, the particles move within the droplet and accumulate at the edges, forming a pronounced coffee-ring effect. Conversely, with the higher difference between the particle density and the fluid density increases, they tended to deposit uniformly at the bottom of the droplet and were less likely to be pushed to the edges by capillary effects, effectively suppressing the coffee-ring effect. We also observed that the movement speed of high-density particles relatively slowed down through particle image velocimetry tracking technology. By analyzing the Peclet number and the timescale between particle sinking speed and particle movement speed due to capillary flow, we explained how particle density influences the critical factors of particle sinking and suspension, thereby inhibiting the formation of the coffee-ring effect.

Spatiotemporal structure of flow field by a dielectric-barrier-discharge plasma actuator using phase-resolved particle image velocimetry

A typical dielectric-barrier-discharge plasma actuator (DBD-PA) operating in continuous mode generates a self-similar starting vortex followed by a quasi-steady wall jet. In the burst mode, it generates periodic vortices, leading to a spatially wider mean flow field. The characteristics of periodic vortices can be controlled by adjusting the duty cycle α and burst frequency fb of the actuation signal. In the present study, the flow field generated by the actuator in burst mode is studied for 50%≥α≤90%, and 10 Hz ≥fb≤90 Hz. The Reynolds number of mean flow based on the maximum induced velocity and jet half-width ranges from 171 to 524. High-speed laser-sheet visualization and time-resolved particle image velocimetry are used for flow field measurements. The flow field generated during burst mode operation shows the strong influence of the burst frequency. Periodic vortices with comparable size and convection speed of starting vortex are generated at low fb. Dipoles and small-scale vortices are formed at moderate fb similar to the behavior of a transitional wall jet. Kelvin–Helmholtz instability is observed at higher burst frequency. An ornamental vortex consisting of several small periodic vortices is formed at high values of fb during the starting period. Based on the temporal evolution of momentum, the flow field generated by the DBD-PA can be classified into (i) starting flow regime, (ii) transitional flow regime, and (iii) periodic flow regime. The self-similarity of the mean flow field generated by the DBD-PA is verified by comparing the mean velocity profile at multiple downstream locations with the self-similar solutions of laminar and turbulent wall jets. The entrainment coefficient of the mean flow field is similar to that of an axisymmetric turbulent wall jet. The bi-orthogonal analysis shows that both coherent mode energy content and the entropy are minimum (about 5% only) for the continuous mode actuation. For the burst mode actuation, both the coherent mode energy content and the entropy are higher in magnitude compared to that of continuous mode and decrease with increasing burst frequency. The vortices in the periodic flow regime are locked in with fb. The distance between subsequent vortices, λx and flow frequency, f follow a power-law relationship, λx=cf−n, where c is a constant and n can be approximated as 2/3.

Streaming flows within ultrasonic levitators

The streaming flows inside a single-axis ultrasonic levitator are experimentally investigated using particle imaging velocimetry (PIV). Detailed quantification of the flow motion within the levitator is provided for both scenarios, with and without a suspended droplet. In the case of suspended droplets, both water and ethanol are studied to investigate the varying external streaming around droplets with different volatilities. The quantified PIV results reveal two acoustically induced jet flows, originating from the transducer and reflector, within the empty levitator in the absence of a suspended droplet. These flows, identified as Eckart streaming, dominate the external streaming around less-volatile water droplets by directly interacting with their surfaces. For highly volatile ethanol droplets, the Stefan flow, which carries ethanol vapor away from the droplet surface, is clearly observed. This flow counteracts the motion of Eckart streaming within the levitator, preventing it from reaching the surface of the ethanol droplet. This observation confirms the presence of Stefan flow around a highly volatile droplet in the ultrasonic levitator. The interaction between Stefan flow and Eckart streaming determines the external streaming patterns of the ethanol droplet, which significantly differ from those around water droplets. Additionally, boundary-driven acoustic streaming near the droplet surface, also known as Rayleigh–Schlichting streaming, can only develop in the presence of a strong Stefan flow leaving from the highly volatile ethanol droplets. In contrast, without the “protection” of this robust Stefan flow, the boundary-driven streaming around less volatile water droplets are swept away by Eckart streaming within the levitator. This study emphasizes the importance of considering both Eckart streaming and Stefan flow when modeling the transport phenomena of droplets suspended in single-axis ultrasonic levitators. The differences in external streaming patterns between less volatile and highly volatile droplets may influence their corresponding heat and mass transfer processes in the levitator.

Remote sensing of wave-orbital velocities in the surfzone

Wave-orbital velocities are estimated with particle image velocimetry (PIV) applied to rapid sequences of images of the surfzone surface obtained with a low-cost camera mounted on an amphibious tripod. Time series and spectra of the remotely sensed cross-shore wave-orbital velocities are converted to the depth of colocated acoustic Doppler velocimeters (ADVs), using linear finite depth theory. These converted velocities are similar to the velocities measured in situ (mean nRMSE for time series=16% and for spectra=10%). Small discrepancies between depth-attenuated surface and in situ currents may be owing to errors in the surface velocity measurements, uncertainties in the water depth, the vertical elevation of the ADVs, and the neglect of nonlinear effects when using linear finite depth theory. These results show the potential to obtain spatially dense estimates of wave velocities using optical near-field remote methods during field campaigns and continuous monitoring operations.

Microparticle sorting in microfluidic Taylor–Couette flows

In this experimental study, we demonstrate that settling polymethyl methacrylate (PMMA) microparticles with diameters ranging from 6 to 60 µm segregate into distinct bands according to their size when subjected to a rotating laminar annular gap flow with a diverging gap width in the axial direction. Different gap widths ranging from 130 to 1200 µm have been investigated in the fully laminar flow regime. Distinct, spatially separated particle bands of different particle sizes have been observed for nine different geometric configurations, including non-conical, conical, double conical, and variously inclined conical inner cylinder shapes. The study considers different rotation rates, geometric combinations, particle volume fractions, and particle size combinations. Particle size separation was achieved at volume fractions ranging from 2.2% to 11% for rotating inner cylinders. In contrast, no separation occurs during the experimental run when both the outer and inner cylinders are perfectly cylindrical, with no significant variation in the annular gap height. Our experiments also show that rotation of the inner cylinder results in more pronounced particle separation than rotation of the outer cylinder. Microscopic particle image velocimetry (µPIV) measurements show that the presence of particles induces an axial velocity component, which acts as a key transport mechanism. In addition, a significant variation in shear rate is observed across particle bands, which may explain size segregation by shear-induced migration. Furthermore, single particle simulations show that particle trajectories and velocities vary significantly with particle size.

Effect of settling vortex of coal slime flocs with different sizes on the settlement of microfine particles

This article explores the flow field changes and micro vortex formation mechanisms caused by coagulation and sedimentation of coal slurry flocs of different sizes. The collision adhesion rate, motion trajectory and force analysis of fine particles under micro vortex disturbance. Particle image velocimetry (PIV) and high-speed camera were used to capture deposition process of coal slime flocs, the changes of flow field and fine particles were analyzed by numerical simulation. The smaller flocs form a single vortex ane larger flocs show periodic vortex shedding, resulting in increase fluid velocity and larger interference area. The collision adhesion rate of fine particles in the 3.4 mm floc settling disturbance area is the largest, 9.45 %;Particles<0.3 mm are easily sucked into vortices, while particles>0.3 mm are disturbed by vortices and change their motion trajectory towards the vortex center. It is mainly affected by gravity, pressure gradient force, flow field resistance, and centrifugal force.

Effect of solid loading and particle size on bubble behavior and flow field structure in slurry bubble column

The complexity of fluid dynamics in a slurry bubble column reactor introduces significant uncertainty in reactor design and scale-up. This paper investigates the hydrodynamic performance of the gas–liquid–solid system within the reactor by employing computational fluid dynamics-population balance modeling numerical simulations alongside particle image velocimetry (PIV) experiments. The effect of superficial gas velocity and particle conditions on the overall gas holdup were analyzed, focusing on the effects of particle size and solid concentration on bubble size, bubble behavior, flow field structure, and local gas holdup distribution at high superficial gas velocities. Bubble size was evaluated using calibrated image measurements, and the impact of varying solid conditions was thoroughly explored. The results revealed that an increase in solid size correlated with higher gas holdup and smaller bubble sizes, whereas a greater solid concentration resulted in decreased gas holdup and larger bubble sizes. PIV experiments indicated that bubbles exhibited a tendency to migrate toward the central region of the reactor, leading to the formation of larger bubbles that accelerated the rise of surrounding bubbles, while smaller bubbles near the wall moved downward. As the slurry bed height increased, the range of local gas holdup distribution expanded, resulting in a symmetrical distribution of radial local gas holdup in the fully developed stage at a height of 0.16 m.

Study on the impact of grouting reinforcement on the mechanical behavior of non-penetrating fracture sandstone

The grouting reinforcement technology is an essential method to enhance the mechanical performance of fractured rock masses and the effectiveness of reinforcement varies with different grouting materials. To further understand the mechanical improvement capabilities of each grout and the reinforcement mechanisms at the grout-rock interface, this study prepared samples with different grouting materials (sulphoaluminate cement (SAC), ultra-fine cement (UFC), and epoxy resin (EPR)) and the uniaxial compression tests were conducted. Based on these tests, the macro and micro mechanical characteristics of different grouting samples were revealed using particle image velocimetry (PIV), acoustic emission (AE), scanning electron microscopy (SEM), and nuclear magnetic resonance (NMR). The results indicate that grouting helps improve the mechanical performance and deformation resistance of fractured rock masses. It effectively limited lateral displacement of the samples, reduced stress concentration at fracture tips, enhanced shear effects during sample fracture, and altered the crack propagation process and failure modes. Compared to the fractured samples, the peak strength of SAC, UFC, and EPR samples increased by 17.8 %, 23.4 %, and 28.3 %, and the elastic modulus increased by 14.3 %, 7.9 %, and 24.8 %, respectively. Among these, the EPR samples exhibited a similarity in parameter indicators to intact samples of over 85 %, making EPR the optimal grouting material. The degree of grout-rock fusion is the primary factor influencing grouting reinforcement effectiveness. SAC is covering-type cement, UFC is embedded cement, EPR is a fusion material, and the fusion-type materials are more beneficial for improving the mechanical performance of fractured rocks.

Effect of a perforation on the flow characteristics of corrugated wall

The flow characteristics on a corrugated wall and the variations caused by a perforation are investigated experimentally based on two-dimensional particle image velocimetry (PIV), and the passive control mechanism of the perforation on the corrugated wall is studied. The corrugated wall has an amplitude-to-wavelength ratio 2a/λ = 0.1, with the wavelength Reynolds number Reλ = 14400 and bulk Reynolds number Reb = 17500. The perforation is located on the eleventh cycle of the corrugated wall. The results show that perforation increases the area of the recirculation zone, reduces the effect of frictional resistance, weakens the turbulence intensity and the Reynolds normal stress on the corrugated wall, but enhances the Reynolds shear stress. The POD and the Finite-Time Lyapunov Exponent(FTLE) are used to analyze the vortex structures. From the FTLE result, it can be seen that the perforation disturbs the original shear layer and redistributes the vortex structure of the flow field. The instantaneous fluctuating flow field of the first 50 % and the last 50 % of the energy content after POD mode decomposition is reconstructed to study the effect of perforation on on large and small scale structures in the flow field. It is found that the impact of perforation on small-scale structures is greater than that on large-scale structures.

The effect of aspect ratio and mass ratio on the flow-induced flutter of a thin flexible sheet

This study experimentally investigates the flow-induced flutter of a thin flexible sheet, focusing on how the sheet's aspect ratio and mass ratio affect its stability and flutter characteristics in the post-critical regime. The flutter frequency of the sheet was obtained using hotwire measurements, while flutter amplitude and mode shape were acquired through high-speed imaging. The flowfield around the flapping sheet was analyzed using particle image velocimetry (PIV). Based on experimental observations, we report the onset of flutter as a subcritical bifurcation with hysteresis. The dynamic characteristics of the sheet play a significant role in its flutter instability, with the onset and cessation of flutter occurring at a frequency close to the sheet's second-mode natural frequency. The results show that both aspect ratio and mass ratio significantly affect the critical wind speed and flutter characteristics in the post-critical regime. Both flutter frequency and amplitude decrease as the aspect ratio decreases. PIV measurements in various planes reveal the highly three-dimensional nature of the flow. Results from off-axis PIV show a pair of counter-rotating spiral vortices in the wake that oscillate and change orientation with the sheet's movement. Additionally, a theoretical analysis was conducted to derive an approximate analytical relationship between the aspect ratio and critical wind speed. Experimental results aligned well with theoretical predictions for sheets with low aspect ratios (aspect ratio ≤1) but deviated for sheets with higher aspect ratios (aspect ratio &amp;gt;1). The relevant scaling parameters have also been explored to represent the experimental data in a non-dimensional form.

Bimagnetic Core/Shell Nanoprobes with Tunable Exchange Coupling for High Resolution and Sensitive Magnetic Particle Imaging

Magnetic particle imaging (MPI) has demonstrated versatile applications in biomedicine, including tumor imaging, cell tracking, and image‐guided hyperthermia. Despite these advancements, the prevalent use of clinically approved tracers has posed limitations on MPI's resolution and sensitivity. In this study, we engineered a bimagnetic core/shell nanocrystals (BMCS) tailored for MPI by optimizing the heterostructure and modulating the exchange coupling effect between the two magnetic components. The resulting BMCS exhibited remarkably heightened susceptibility and magnetization while maintaining low coercivity, thereby substantially improved both MPI resolution and sensitivity compared to conventional tracers such as VivoTrax. At an equivalent mass concentration, BMCS demonstrated a notable 5.08‐fold increase in signal intensity and achieved an unprecedentedly high resolution down to 1 mm. The excellent MPI performance contributes to high resolution MPI and the sensitive detection of orthotopic colorectal cancer in mice. The design strategy employed in BMCS, centered on the exchange coupling effect, introduces an efficacious approach for the development of high performance MPI tracers.

Bimagnetic Core/Shell Nanoprobes with Tunable Exchange Coupling for High Resolution and Sensitive Magnetic Particle Imaging.

Magnetic particle imaging (MPI) has demonstrated versatile applications in biomedicine, including tumor imaging, cell tracking, and image-guided hyperthermia. Despite these advancements, the prevalent use of clinically approved tracers has posed limitations on MPI's resolution and sensitivity. In this study, we engineered a bimagnetic core/shell nanocrystals (BMCS) tailored for MPI by optimizing the heterostructure and modulating the exchange coupling effect between the two magnetic components. The resulting BMCS exhibited remarkably heightened susceptibility and magnetization while maintaining low coercivity, thereby substantially improved both MPI resolution and sensitivity compared to conventional tracers such as VivoTrax. At an equivalent mass concentration, BMCS demonstrated a notable 5.08-fold increase in signal intensity and achieved an unprecedentedly high resolution down to 1 mm. The excellent MPI performance contributes to high resolution MPI and the sensitive detection of orthotopic colorectal cancer in mice. The design strategy employed in BMCS, centered on the exchange coupling effect, introduces an efficacious approach for the development of high performance MPI tracers.

Vesicle Picker: A tool for efficient identification of membrane protein complexes in vesicles

Electron cryomicroscopy (cryo-EM) has recently allowed determination of near-atomic resolution structures of membrane proteins and protein complexes embedded in lipid vesicles. However, particle selection from electron micrographs of these vesicles can be challenging due to the strong signal contributed from the lipid bilayer. This challenge often requires iterative and laborious particle selection workflows to generate a dataset of high-quality particle images for subsequent analysis. Here we present Vesicle Picker, an open-source program built on the Segment Anything model. Vesicle Picker enables automatic identification of vesicles in cryo-EM micrographs with high recall and precision. It then exhaustively selects all potential particle locations, either at the perimeter or uniformly over the surface of the projection of the vesicle. The program is designed to interface with cryoSPARC, which performs both upstream micrograph processing and downstream single particle image analysis. We demonstrate Vesicle Picker’s utility by determining a high-resolution map of the vacuolar-type ATPase from micrographs of native synaptic vesicles (SVs) and identifying an additional protein or protein complex in the SV membrane.

Experimental evaluation and simulation of myoblast cell alignment on the UV-irradiated liquid crystalline elastomers as a versatile tissue-engineered Scaffolding material

Efforts to develop versatile tissue-engineered scaffolds mimicking the functions of extracellular matrices (ECMs) have led to the emergence of liquid crystalline elastomers (LCEs) as promising materials. Here, thiol-acrylate-based LCEs forming a nematic phase upon UV irradiation were synthesized, and their biological compatibility was evaluated using C2C12 myoblast cells. Prior to UV exposure, some characteristics, e.g., phase transition temperature (TNI), order parameter, and reaction time, of the as-synthesized LCEs are characterized for property optimization. Fourier-transform infrared spectroscopy revealed that thiol-acrylate Michael addition polymerization was successful, judged by the disappearance of the characteristic peaks of thiol and acrylate groups. Differential scanning calorimetry thermograms and dynamic mechanical thermal analysis curves showed TNI values at ca. 49 °C, at which point the nematic phase is the dominant morphology. Moreover, the cross-linking density, the fixing, and the recovery ratios for the sample with optimal properties (i.e., LCE3) were determined to be 10.3 mol/cm3, 97.2 % and 91 %, respectively. Assessment of mesomorphism and roughness demonstrated the suitability of LCE3 for cell culture. Subsequent studies on adhesion, viability, differentiation, and proliferation of cultured myoblast cells, coupled with particle image velocimetry simulation, highlighted the potential of UV-irradiated LCE3 as a promising scaffold material for inducing surface morphology-induced cellular alignment and interactions.

Revealing the flame inhibition effect of phytic acid (PA) by PIV measurements and detailed chemical kinetic modeling of counterflow CH4/PA/air flames

As industrialization continues to deepen, polymers have become ubiquitous in daily life. However, their flammable characteristics pose significant safety risks. Therefore, supporting the global goal of sustainable development necessitates the development of high-performance, environmentally friendly flame retardants. Biomass phytic acid (PA) has emerged as a promising option because of its high phosphorus content and excellent biocompatibility. However, its combustion behaviors and chemical kinetic mechanisms remain unclear. In this study, quantum chemical calculation methods were used to construct a detailed PA chemical reaction kinetic model. A series of experiments were conducted to validate the model and evaluate PA's flame suppression effect. Utilizing a counterflow flame burner and particle image velocimetry (PIV), the inhibitory effect of various PA concentrations was examined based on the laminar flame speed of CH4/PA/Air mixture. The results revealed that a merely 0.2 % addition of PA could reduce the laminar flame speed by 38.9 %, demonstrating its significant flame suppression effect. Building on the foundational GRI-Mech 3.0 and integrating PA's pyrolysis and reaction mechanism, this study developed for the first time a detailed chemical model of CH4/PA/Air combustion. This model integrated PA's thermal decomposition module and thermodynamic data via ab-initio quantum chemical calculations, thereby accurately predicting global kinetic indicators such as laminar flame speed. Results suggested that the key reactions, such as PO2+H + M→HOPO + M, HOPO2+H→PO2+H2O, and HOPO + OH→PO2+H2O primarily influenced the laminar flame speed. Moreover, the CFD simulation elucidated the complex interaction between PA and flame structures. A detailed analysis of the spatial distribution of key parameters such as temperature, combustion radicals, and effective inhibition radicals unveiled the PA's flame suppression mechanism in support of the practical application of this eco-friendly flame retardant.