Three-dimensional Unsteady Flow Field Research Articles

Spectral feature extraction of rocket exhaust plume using spectral proper orthogonal decomposition

The spectral characterization of flow-field parameters provides a new perspective for understanding the spatiotemporal evolution of unsteady supersonic exhaust plumes and for extracting typical structures. In this study, a large-eddy simulation is performed to calculate the three-dimensional unsteady supersonic plume flow field of rocket engines, and a spectral proper orthogonal decomposition (SPOD) method with a spatiotemporal separation is established. This approach is used to extract the coherent structural features of the unsteady exhaust plume flow field and analyze the mode space structure at different frequencies. The three-dimensional reconstruction and denoising of the exhaust plume flow-field parameters can be achieved via the frequency- and time-domain reconstructions of the SPOD algorithm and oblique projection method, respectively. The ground rocket exhaust plume of ballistic evaluation motor-II is analyzed. The results indicate that the SPOD method can effectively extract the single-frequency mode structure of the reactive supersonic flow field, and that low-order behavior appears in the m = 0 and m = 1 azimuth modes. The potential core exhibits a high-frequency wave-packet structure that is affected by shock waves and shear layers. Time-domain reconstruction based on the oblique projection method facilitates the capture of the dynamic characteristics of the flow field. For the first-order SPOD mode, the frequency- and time-domain reconstruction errors are 3.3% and 1.5%, respectively. The frequency-domain reconstruction method exhibits a 4% improvement in denoising ability compared to low-pass filters. This study provides a novel method for the spectral characterization and spatiotemporal feature extraction of supersonic exhaust plume flow fields.

Forecasting three-dimensional unsteady multi-phase flow fields in the coal-supercritical water fluidized bed reactor via graph neural networks

The study of three-dimensional unsteady multi-phase flows inside the coal-supercritical water fluidized bed (SCWFB) reactor coupled with fluid dynamics, heat transfer and chemical reactions usually relies on time-consuming numerical simulation. Recently, to provide quick spatio-temporal estimation of the SCWFB reactor, the data-driven deep learning techniques have been adopted to build a digital yet fast reactor forecasting model. However, due to the irregular 3D geometry, it usually uses unstructured meshes to discrete the domain of reactor and builds the corresponding simulation model, which poses difficulties for the convolutional neural networks based deep learning models. Hence, this article develops a 3D unstructured spatio-temporal forecasting model, named GraphReactorNet, via graph neural networks for learning the dynamics under multi-phase flow fields inside the SCWFB reactor. It utilizes an efficient strategy to tackle large-scale 3D transient flow graphs and proposes an effective unstructured spatio-temporal learning module to extract the underlying flow dynamics. This model is trained on data collected from the transient simulator at different conditions. Numerical experiments reveal that in comparison to the counterparts, the GraphReactorNet not only achieves accurate multi-step-ahead predictions of the multi-phase flow fields at unseen conditions, but also performs thousands of times faster than the numerical simulator.

Numerical analysis of the internal biased flow mechanism of the siphon outlet pipe under the action of axial flow pump

One of the often employed flow structures in vertical pumping stations is the siphon outlet pipe. It has a complicated geometric structure and internal flow field, which directly affects how effectively, safely, and steadily pumping stations operate. The entire flow conduit of the vertical axial flow pump device was adopted as the study object in order to elucidate the mechanism of the internal biased flow of the siphon outlet pipe caused by the axial flow pump under different flow conditions, and the three-dimensional unsteady flow field of the vertical axial flow pump device was numerically solved using the numerical simulation technique. Physical model tests were used to confirm the results of the numerical simulation. The findings demonstrate that there is a horizontal bias in the flow of the inlet surface and outlet surface of the elbow pipe of the siphon outlet pipe, and that when the flow rate rises, the degree of the horizontal bias in the flow gradually diminishes, and the ratio of biased flow gradually decreases. The flow in hump segment presents up-and-down flow, and when the flow rate increases, the ratios of biased flow first rises before falling. The major causes of the production of biased flow in the outlet pipe are residual velocity circulation at the guide vane's outlet, wall constraint at the elbow pipe, and flow inertia; Under various flow conditions, the morphologies of the vortex structures in the outlet pipe vary; the characteristics of the energy conversion of each part of the pump device are disclosed, with the inlet pipe having the lowest proportion of energy conversion. Under the optimal flow condition, the elbow-inlet pipe's proportion of energy conversion is only around 1.04%, and the proportions of the guide vane, 60° elbow pipe, and siphon outlet pipe's energy conversion are significant and fluctuate with time. The proportion of energy conversion in the elbow-inlet pipe and siphon outlet pipe steadily increases as flow rate rises, but the proportion in the guide vane and 60° elbow pipe drops initially before increasing.

Effect of Aspect Ratio on Swept-Wing Dynamic Stall

The role of aspect ratio on the dynamic stall process of swept finite wings is investigated using high-fidelity implicit large-eddy simulations. Two aspect ratios ( and 8) are explored for a 30 deg swept wing (NACA 0012) pitching sinusoidally from an initial incidence of 4 deg to a maximum angle of attack of 22 deg with a reduced frequency of over one pitching cycle. The flow is simulated at a chord Reynolds number of and a freestream Mach number of . The unsteady three-dimensional flowfield for the higher-aspect-ratio wing showed similarity with the lower-aspect-ratio wing through the initial flow separation at the leading edge. Motion-induced effects promoted earlier initiation of the unsteady vortical structures at higher aspect ratios. The vortex tube at the larger span underwent significant distortion, which contrasted with the vortex observed at the lower span. The vortical structure eventually interacted with the trailing-edge vortex, which was not observed at . Examination of the unsteady loads detailed a larger lift slope, mean values, peak values, and earlier stall as the aspect ratio increased. Analysis of the aerodynamic pitch damping suggests the wing is less susceptible to local torsional instabilities than the wing.

Analysis of pressure pulsation and energy characteristics of guide vane for axial flow pump based on Hilbert-Huang transform considering impeller-guide vane interaction.

In order to explore the characteristics of pressure pulsation signals and energy distribution of water flow at the guide vane considering impeller-guide vane interaction. The numerical simulation of the vertical axial flow pump device's steady and unsteady three-dimensional flow fields was carried out. The Hilbert-Huang method was used to conduct empirical mode decomposition decomposition and Hilbert spectrum analysis of pressure pulsation signal at each monitoring point in the inlet and outlet regions of the guide vane. The results show: Under the condition of 0.3Qbep, the internal pressure of the guide vane is obviously affected by the impeller, and there are large block-shaped vortex structures in the guide vane. Under the operating conditions of 1.0Qbep and 1.2Qbep, the size of the pressure area in the guide vane is basically not affected by the impeller, and the vortex structures in the guide vane are concentrated near the outlet of the guide vanes, and there are long strip-shaped vortex structures at the edge of the guide vane. The size and number of vortex structures decrease with the increase in flow rate. The pressure pulsation signal at the inlet of the guide vane is affected by the rotation of the impeller and exhibits good periodicity, with the main frequency centered around 146 Hz, and the energy ratio of the main frequency is up to 97.7%. There are low-frequency signals below 100 Hz and high-frequency signals fluctuating around 146 Hz in all three flow conditions. When the flow rate increases, the fluctuation amplitude of the high-frequency signal increases. The flow rate has a significant impact on the water flow at the outlet of the guide vane. At 0.3Qbep, its frequency is distributed in the range of 0-500 Hz, mainly concentrated in the area below 400 Hz. At 1.0Qbep, the frequency of pressure pulsation is distributed below 250 Hz after the guiding function of the guide vane. At 1.2Qbep, the water flow is mainly controlled by the rotation of the impeller, and after the energy recovery of the guide vane, its main frequency is still concentrated around 150 Hz, which is 337.2% and 268.5% of 0.3Qbep and 1.0Qbep. Under the working condition of 0.3Qbep, the proportion of intrinsic mode function energy corresponding to the dominant frequency at the center of the guide vane inlet is as high as 95.9%, and the proportion of intrinsic mode function energy corresponding to the dominant frequency at the shroud side and hub side of the guide vane is rather low. If the flow rate rises from 0.3Qbep to 1.2Qbep, the proportion of intrinsic mode function energy increases by more than 42%. Under the working conditions of 0.3Qbep and 1.0Qbep, the main frequency of pressure pulsation signal of water flow at the guide vane outlet is less affected by the impeller and the corresponding energy proportion is low. Under the working condition of 1.2Qbep, the main frequency of pressure pulsation signal is 4 times the rotational frequency and the corresponding energy proportion is higher than 60%.

Leakage Flow Characteristics in Blade Tip of Shaft Tubular Pump

The shaft tubular pump device is widely used in various water diversion projects because of its ultra-low head and large flow characteristics. Due to the tip clearance between the blade and the shroud, it is easy to cause hydraulic mechanical performance changes, induced vibration, and noise, which seriously affects the safe and stable operation of the pump. Steady and unsteady three-dimensional flow field numerical simulations of a shaft tubular pump device were carried out using computational fluid dynamics to investigate the impeller flow properties of the device under various flow conditions, including the tip clearance leakage flow (TCLF) and change rule of pressure pulsation. The TCLF, vortex morphology evolution, and pressure pulsation properties of the impeller tip clearance were analyzed. The results show that with an increase in the flow rate, the influence of the tip clearance size on the tip clearance flow decreases, the TCLF decreases, and the axial velocity of the water flow at the tip clearance increases. When the flow rate increases, the swirling strength of the tip leakage vortex decreases, and the distance between the tip leakage vortex and the suction surface of the blade increases. With the increase in flow rate, the pressure pulsation amplitude at the tip clearance increases first and then decreases. The focus of this study is to analyze the variation of tip clearance flow field and pressure pulsation under multiple working conditions, aiming to provide some help for improving the performance of the pump device and ensuring its safe operation.

Effect of Aspect Ratio on Finite-Wing Dynamic Stall

The role of aspect ratio on the dynamic stall process of an unswept finite wing is investigated using high-fidelity large-eddy simulations. Three aspect ratios (, 8, and 16) are explored for wings (NACA 0012 cross section) at chord Reynolds number and freestream Mach number . The wings pitch sinusoidally from initial incidence of 4° to a maximum angle of attack of 22° with reduced frequency over one pitching cycle. The three-dimensional unsteady flowfields show similarity among the three wings through laminar separation bubble formation/bursting. The flow topology during dynamic stall exhibits distinctly different evolutions at the higher aspect ratio relative to the lower, baseline aspect ratio. Rather than evolving into a vortex (), the higher-aspect-ratio wings show dramatic three-dimensional deformation of the vortex tube that resembles cellular structures. The vortical structure eventually interacts with the trailing-edge vortex, which contrasts with the lower aspect ratio. Examination of the unsteady loads shows an increase in lift slope, average loads, peak loads, and earlier stall with aspect ratio.

Parallel Numerical Simulation of Complex Unsteady Multi-Component Three-Dimensional Flow Field of Nonequilibrium Chemical Reaction

Parallel Numerical Simulation of Complex Unsteady Multi-Component Three-Dimensional Flow Field of Nonequilibrium Chemical Reaction

Unsteady flow simulations in two-stage turbines of a rocket turbopump to estimate blade structural soundness for fatigue

Abstract This study first aims at detailed investigations of three-dimensional unsteady flow field in the reference and optimized rocket turbine stages by performing time-accurate flow simulations based on Transient Blade Row (TBR) method or Time Transformation (TT) method in a commercial software ANSYS CFX. Although TT method is believed to enable relatively low-cost unsteady flow simulation, detailed comparisons between TT method-based and conventional unsteady flow simulations are made before TT method application to Fluid-Structural Interaction (FSI) problem. This study then makes an attempt to conduct structural analyses of the 1st and 2nd stage turbine blades under the influence of unsteady fluid forces caused by rotor-stator interaction predicted by TT method-based flow simulations. The structural analyses are executed by use of MSC Nastran. In this study, two materials are adopted as blade material. After the Fourier-series decomposition of the calculated unsteady pressure distributions, the unsteady pressure information is mapped onto the FEM (Finite Element Method)-modeled turbine blade surface as exciting aerodynamic loading. The frequency response analyses are then performed to calculate alternating stresses of the blade, from which the maximum magnitudes of alternating stress are obtained so as to discuss the rotor blade fatigue life.

Simulation and experimental research on aerodynamic noise of gas turbine 1.5-stage axial compressor

The aerodynamic noise of the axial compressor is one of the significant noise sources of gas turbines, and it has gradually attracted the attention of the majority of researchers. In this paper, the aerodynamic noise characteristics of a 1.5-stage axial compressor were studied through simulations and experiments. A full-channel calculation of a three-dimensional unsteady flow field was computed using the Reynolds-averaged Navier Stokes (RANS) method. Spectral analysis of the static pressure in the tip clearance area was in good agreement with experimental data, which verifies the accuracy of the calculations. The volume and surface sound sources were extracted from computational fluid dynamics calculations to estimate the far-field acoustic characteristics of the compressor. The simulated results of the sound field were verified by a comparison with experimental data. The results show that the sound source intensity of the compressor’s guide vanes is much lower than that originating in the rotor and stator, which indicates that the interaction between the rotor and stator is much stronger than that of the guide vane and rotor. This conclusion is consistent with the unsteady flow field analysis. To investigate the influence of complex geometric structures on sound propagation, three sets of finite element grids were employed for noise prediction. The calculations considering all structures are in the best agreement with the experimental data, which shows that complex structures cannot be ignored when calculating aeroacoustic predictions.

Numerical Investigation of the Performance, Hydrodynamics, and Free-Surface Effects in Unsteady Flow of a Horizontal Axis Hydrokinetic Turbine

This paper presents computational fluid dynamics (CFD) simulations of the flow around a horizontal axis hydrokinetic turbine (HAHT) found in the literature. The volume of fluid (VOF) model implemented in a commercial CFD package (ANSYS-Fluent) is used to track the air-water interface. The URANS SST k-ω and the four-equation Transition SST turbulence models are employed to compute the unsteady three-dimensional flow field. The sliding mesh technique is used to rotate the subdomain that includes the turbine rotor. The effect of grid resolution, time-step size, and turbulence model on the computed performance coefficients is analyzed in detail, and the results are compared against experimental data at various tip speed ratios (TSRs). Simulation results at the analyzed rotor immersions confirm that the power and thrust coefficients decrease when the rotor is closer to the free surface. The combined effect of rotor and support structure on the free surface evolution and downstream velocities is also studied. The results show that a maximum velocity deficit is found in the near wake region above the rotor centerline. A slow wake recovery is also observed at the shallow rotor immersion due to the free-surface proximity, which in turn reduces the power extraction.

Quantitative analysis of position setting effect on magnetohydrodynamics angular vibration sensor response

Magnetohydrodynamics angular vibration sensor (MHD AVS) has been widely used in stabilization servo subsystem to measure angular motions with extremely low noise in relatively broad range of bandwidth. In practical, MHD AVS is usually affixed to the housing equipment with its angular axis of sensitivity possibly not coincident with the rotation axis. This work presents quantitative analysis of the position setting effect on MHD AVS performance including frequency response, linearity and measurement noise. A theoretical model that correlates physical and positional parameters with the sensor’s output is established on the basis of Navier-Stokes equation in the non-inertial system. Finite element analysis (FEA) is conducted to investigate mechanical resonant characteristics of the current sensor. The interaction between three-dimensional unsteady flow and non-uniform radial magnetic field, as well as error sources varying with frequency and positional parameters within MHD AVS are analyzed through numerical simulations. Experiments are finally carried out to verify the established theoretical model and numerical simulations under a variety of conditions. Conclusions drawn from the theoretical model, numerical simulations and experiments are found to be basically consistent, which indicate that MHD AVS is nearly no sense to the eccentricity and is essentially cosine to the output of pure rotation when its measuring axis is not parallel to the rotation axis.

Dynamic characteristics analysis of a hydraulic valve by FEM and CFD method

The dynamic characteristic of the flood valve is an important index to ensure its safety and reliability. In this paper, CFD computational fluid dynamics (CFD) method is used to model and simulate the three-dimensional unsteady internal flow field of the valve during its working process, so as to obtain the dynamic distribution of the internal flow field parameters of the valve under specific working conditions. The modal analysis of the valve body is carried out to provide a calculation method and data support for the evaluation of the vibration and noise level during the operation of the valve.

An Additively Manufactured Four-Sensor Fast Response Aerodynamic Probe

Abstract This study describes the design, development, and testing of a miniature fast response aerodynamic probe (FRAP) with four sensors (4S), which are able to perform measurements in the unsteady three-dimensional flow field. Moreover, the calibration and first results with the newly developed probe are provided. The miniature FRAP-4S demonstrates a 3 mm tip diameter, offering a 25% reduction in diameter size, in comparison to a first-generation FRAP-4S, without any loss in terms of measurement bandwidth. The 3 mm outer casing of the probe is additively manufactured with a high-precision binder jetting technique. In terms of aerodynamic performance, the probe demonstrates high angular sensitivity up to ± 18 deg incidence angle in both directions. To evaluate the measurement accuracy of the newly developed FRAP-4S, measurements are performed at the Laboratory for Energy Conversion (LEC) in both a round axisymmetric jet and an one-and-a-half stage, unshrouded and highly loaded axial turbine configuration. Turbulence measurements performed with the miniature FRAP-4S are compared against hot-wire studies in round free-jets found in the literature. Good agreement in both trends but also absolute values is demonstrated. Moreover, the performance of the probe is compared against traditional instrumentation developed at LEC, namely, miniature pneumatic and FRAP-2S probes. The results indicate that the FRAP-4S, despite its larger size in comparison to the other probes tested, can resolve the main flow patterns, with the highest deviations occuring in the presence of highly skewed and sheared flow. Furthermore, the additively manufactured probe was proven to be robust after more than 50 hours of testing in the representative turbine environment configuration. Finally, it should be highlighted that the newly developed FRAP reduces measurement time by a factor of three in comparison to FRAP-2S, which directly translates to reduced development time and thus cost during the turbomachinery development phase.

Analysis of Unsteady Pressure Fluctuation in a Semi-Open Cutting Pump

In order to understand the pressure fluctuation characteristics of a semi-open cutting pump, the three-dimensional unsteady flow fields were calculated. External and internal flow characteristics of four schemes with different relative angles between the rotary cutter and the impeller were studied. The pressure fluctuations in the lower plate, the upper plate, the clearance between the rotary cutter and the fixed cutter, the first section in volute and nearby parts of the tongue were all analyzed, which are all the places that pressure distributions are greatly affected by the static and dynamic interaction, and at the same time, the force on the impeller was also analyzed. The results show that the fluctuations at different positions change periodically; the main frequency is blade frequency. The amplitude of pressure fluctuation decreases from near the rotating part to far away, from near the tongue to far from the tongue. Due to the influence of both impeller and rotary cutter, the pressure fluctuation on the lower plate is the largest. The pressure fluctuation is affected by flow rate, the larger the flow rate, the greater the pressure fluctuation. The radial and axial forces of the impeller change periodically with time, and the number of wave peaks and wave valleys is the same as the number of blades.

Research on Calculation of Thermal Resistance of Water-Cooling Radiator of Cooling Tower of Thermal Power Plant Based on Fluid Software Fluent

This paper introduces the method of calculating the thermal resistance and thermal resistance of high-power water-cooled radiators in cooling towers of thermal power plants using computational fluid software (CDF) Fluent. By solving the three-dimensional unsteady flow field and thermal field, the thermal resistance and thermal resistance value of the water cooling radiator of the cooling tower of the thermal power plant under different flow rates are calculated, which provides the temperature calculation for the steady state and dynamic process of the high-power inverter in accordance with.

Numerical investigation of energy loss in a centrifugal pump through kinetic energy dissipation theory

In this study, energy loss within a centrifugal pump is investigated by post-processing three-dimensional unsteady flow field through kinetic energy dissipation theory. The three-dimensional unsteady flow field is predicted by solving unsteady Reynolds-averaged Navier–Stokes equations. The kinetic energy dissipation consists of three parts: averaged kinetic energy dissipation, turbulent kinetic energy dissipation, and near-wall revised kinetic energy dissipation. The total value variations of three kinetic energy dissipations in the centrifugal pump with flowrate are investigated and compared. Results show that with the increase in flowrate, the total near-wall revised kinetic energy dissipation gradually increases, the total turbulent kinetic energy dissipation first gradually decreases and then gradually increases, and reaches the minimum value at the design flowrate. The total averaged kinetic energy dissipation is less than the total turbulent and the total near-wall revised kinetic energy dissipations, and the total near-wall revised kinetic energy dissipation is larger than the total turbulent kinetic energy dissipation when the flowrate is larger than 0.75 Qdes. The space variation of the near-wall revised kinetic energy dissipation with flowrate shows that large near-wall revised kinetic energy dissipation mainly occurs at the volute and transfers from the small cross-section casing to large cross-section casing and discharge pipe with the increase in flowrate. The space variations of the turbulent kinetic energy dissipation with time for three flowrates are also discussed. Results indicate that large turbulent kinetic energy dissipation near the volute tongue evidently changes with the rotation of the impeller, particularly in 0.5 Qdes. The large turbulent kinetic energy dissipation gradually expands to the pressure side of the blade when the volute tongue gradually approaches the middle of the impeller blade passage. The large turbulent kinetic energy dissipation transfers from the impeller inlet and outlet to the volute tongue and discharge pipe with the increase in flowrate. The findings of this study can serve as guide to improve the design of centrifugal pumps.

Spray drying experiments and CFD simulation of guava juice formulation

This paper presents a computational fluid dynamics (CFD) approach to model the spray-drying of a formulation of guava juice. The computational model incorporates the characteristic drying rate curve (CDC) of the formulation. The CDC is derived from the drying history of single droplets suspended on a thin glass filament. The computational domain is based on the geometry of a small production spray-dryer with a capacity of 10 kg/h. A two-phase Eulerian-Lagrangian model implemented in a commercial CFD package (ANSYS-FLUENT) is used to simulate the gas-particle interaction in the dryer. Hot-wire anemometry (HWA) measurements of the air flow in the drying chamber are used to calibrate the CFD model. The URANS k-ω SST and the Scale-Adapted Simulation turbulence models are employed to compute the unsteady three-dimensional flow field. Model calibration suggests that the swirl number of the air flow entering the dryer is about 0.61. Simulations predict high axial velocities along the center-line and a narrow jet core in the upper part of the dryer. Lagrangian particle tracking is used to calculate the particle trajectories starting from the perimeter of the rotary disk atomizer and ending at the dryer walls and bottom outlet. Simulation results of particle size distribution, time-average temperature and humidity profiles are presented in order to analyze the overall drying performance. The procedure shown in this work emphasizes the need of implementing drying kinetics with experimental support, and suitable inlet flow conditions to perform detailed CFD simulations of the spray-drying of fruit juices.

Study into the Improvement of Dynamic Stress Characteristics and Prototype Test of an Impeller Blade of an Axial-Flow Pump Based on Bidirectional Fluid–Structure Interaction

This paper performed a numerical study into the dynamic stress improvement of an axial-flow pump and validated the simulation results with a prototype test. To further analyze the dynamic stress characteristics of impeller blades of axial-flow pumps, a bidirectional fluid–structure interaction (FSI) was applied to numerical simulations of the unsteady three-dimensional (3-D) flow field of the whole flow system of an axial-flow pump, and the gravity effect was also taken into account. In addition, real-structure-based single-blade finite element model was established. By using the finite element method, a calculation of the blade’s dynamic characteristics was conducted, and its dynamic stress distribution was determined based on the fourth strength theory. The numerical results were consistent with the prototype tests. In a rotation cycle, the dynamic stress of the blade showed a tendency of first increasing, and then decreasing, where the maximum value appeared in the third quadrant and the minimum appeared in the first quadrant in view of the gravity effect. A method for reducing the stress concentration near the root of impeller blades was presented, which would effectively alleviate the possibility of cracking in the unreliable region of blades. Simultaneously, an experimental method for the underwater measurement of the dynamic stress of prototypical hydraulic machinery was put forward, which could realize the underwater sealing of data acquisition instruments on rotating machinery and the offline collection of measured data, finally effectively measuring the stress of underwater moving objects.

Numerical investigation of external radiation noise induced by dipole and quadrupole sources in an axial piston pump

Extensive research has been performed on the reduction of flow ripple and pressure fluctuation in axial piston pumps. However, the acoustic characteristics and sound sources of the external radiation noise induced by the fluid within an axial piston pump body have been rarely studied. In this study, a hybrid method combining computational fluid dynamics (CFD) with computational acoustics (CA) based on the Lighthill's acoustic analogy (LAA) theory was adopted to calculate the external radiation noise. First, a three-dimensional unsteady flow field was calculated by using CFD model, and the consistency between the computed results and experimental test data was verified. Then, the quadrupole and dipole sound sources were obtained based on the LAA theory. After that, the finite element method (FEM) was adopted to numerically analyze the natural modes of the axial piston pump shell, and it had been verified by the experimental modal test. Finally, the external radiation noise induced by the different fluid sound sources was calculated based on FEM/AML (automatically matched layer) vibro-acoustic coupling method. The results show that the quadrupole sound source is the main contributor of external radiation noise. Subsequently, the effects of different triangular groove structural parameters on external radiation noise were studied. This research can provide guidance for engineers in the design of low noise axial piston pumps.