Flow Measurement and Instrumentation最新文献

{"title":"Deep learning model for flow regime identification in mixing tanks from pressure signals","authors":"Carlos Avilés-Cruz ,&nbsp;Miguel Magos-Rivera ,&nbsp;Robert Jäckel ,&nbsp;Héctor Puebla ,&nbsp;Jorge Ramírez-Muñoz","doi":"10.1016/j.flowmeasinst.2025.102958","DOIUrl":"10.1016/j.flowmeasinst.2025.102958","url":null,"abstract":"<div><div>Identifying the flow regime (laminar, transition, or turbulent) is crucial in stirred tank mixing processes, affecting mixing efficiency and overall performance. Pressure is often the dominant driving force acting on fluid elements, and its fluctuations provide valuable information for classifying different flow regimes. This paper introduces a data-driven method based on a Convolutional Deep Learning (CDL) neural network to identify flow regimes in a baffled stirred tank. The algorithm was trained on time-pressure signals from force sensors placed in the baffles and flow regime predictions derived from the Newtonian power number, serving as training labels. Once trained, direct measurements of Reynolds number parameters, such as temperature-dependent density and fluid viscosity, which can vary significantly in industrial mixing tanks, are not required to determine the flow regime. The dataset was split into two subsets to implement and validate the CDL model, with 57.14% used for training and validation and 42.86% reserved for testing. The results show that the model successfully classifies pressure signals across all three flow regimes. The proposed non-invasive method provides reliable, fast, and low-cost in-line monitoring of tank mixing, enabling precise flow regime identification without measuring the fluid’s viscosity or density.</div></div>","PeriodicalId":50440,"journal":{"name":"Flow Measurement and Instrumentation","volume":"106 ","pages":"Article 102958"},"PeriodicalIF":2.3,"publicationDate":"2025-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144501659","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Research on loaded contact characteristics of planetary gear train for high-order elliptic non-circular gear hydraulic motor","authors":"Juan Wang ,&nbsp;Changbin Dong ,&nbsp;Yongping Liu ,&nbsp;Fuqiang Wang ,&nbsp;Zhiwei Zhao ,&nbsp;Hao Liu","doi":"10.1016/j.flowmeasinst.2025.102982","DOIUrl":"10.1016/j.flowmeasinst.2025.102982","url":null,"abstract":"<div><div>Non-circular planetary gear train is the core component of non-circular gear hydraulic motor. The non-circular planetary gear train exhibits significant nonlinear and time-varying characteristics due to the dynamic changes of the pitch curve, which makes its loaded contact analysis face a series of challenges. In this paper, based on the finite element analysis method, the actual meshing behavior of the non-circular planetary gear train is simulated, and the whole tooth contact model of the non-circular planetary gear train is established. By introducing the meshing stiffness of the tooth surface mesh node, the variation law of the contact trajectory, the normal contact force, the comprehensive elastic deformation, meshing stiffness and loaded transmission error in the meshing process are analyzed. The influence of load and rotational speed on the loaded contact characteristics of gears is studied, and the variation law of loaded contact behavior of non-circular planetary gear train is revealed. The research results have certain guiding significance for the dynamic contact analysis of non-circular planetary gear train.</div></div>","PeriodicalId":50440,"journal":{"name":"Flow Measurement and Instrumentation","volume":"106 ","pages":"Article 102982"},"PeriodicalIF":2.3,"publicationDate":"2025-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144513556","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fractal feature map construction and validation for the gas-solid two-phase flow","authors":"Feifei Fu ,&nbsp;Xiuyun Zheng","doi":"10.1016/j.flowmeasinst.2025.102981","DOIUrl":"10.1016/j.flowmeasinst.2025.102981","url":null,"abstract":"<div><div>Feature maps have shown significant potential in gas-solid two-phase flow research. However, traditional feature maps, such as chaotic attractors and recurrence plots, suffer from issues like dependence on subjective parameter selection or structural folding. This study proposes a novel method for constructing a fractal feature map of the gas-solid two-phase flow that effectively captures its fractal properties. Using phase space reconstruction, the electrostatic signal is transformed into a phase space trajectory, and then an inter-point distance matrix is calculated to generate the map. This map exhibits a unique texture structure composed of horizontal and vertical stripes, with a construction process that is nearly independent of parameter selection and free from structural folding. To validate the effectiveness of the fractal feature map, this study simultaneously employs detrended fluctuation analysis (DFA) to examine from a time perspective, and a new method based on the power-law relationship between periodic intensity and spatial scale to examine from a spatial perspective. Results show that the power-law curves obtained from both methods exhibit consistent trends, revealing the fractal properties of gas-solid two-phase flow and confirming the effectiveness of the fractal feature map in capturing such dynamics. This map provides a new tool for flow feature visualization, offering a new perspective for analyzing the behavior of gas-solid two-phase flow, and provides a reference for future exploration of combining deep learning techniques with fractal feature maps to enhance flow pattern recognition and prediction capabilities.</div></div>","PeriodicalId":50440,"journal":{"name":"Flow Measurement and Instrumentation","volume":"106 ","pages":"Article 102981"},"PeriodicalIF":2.3,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144490802","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geometric shape characterization-based algorithm for electrical impedance tomography reconstruction","authors":"Zekun Chen,&nbsp;Leilei Shi,&nbsp;Xiupeng Qiao,&nbsp;Bowen Li,&nbsp;Shili Liang","doi":"10.1016/j.flowmeasinst.2025.102973","DOIUrl":"10.1016/j.flowmeasinst.2025.102973","url":null,"abstract":"<div><div>Due to the advantages of B-spline curves in geometric modeling, this paper proposes an electrical impedance tomography (EIT) reconstruction algorithm based on geometric shape characterization (GSC). First, the method uses Density-Based Spatial Clustering of Applications with Noise (DBSCAN) to estimate the number and location of unknown inclusions within the measurement field. Based on this information, the conductivity reconstruction is formulated as an optimization problem involving the adjustment of B-spline curve control points, which is then solved iteratively using the Gauss–Newton (GN) and Levenberg–Marquardt (LM) algorithms. Both simulation and experimental results demonstrate that, compared to traditional image reconstruction methods, the B-spline-based approach enhances reconstructed image quality while preserving detail features of inclusions. Additionally, it achieves better reconstruction performance and noise robustness, with quantitative metrics such as the Spearman correlation coefficient, SSIM, and overlap rate consistently exceeding 0.9. The introduction of B-spline curves to construct regularization terms or to provide prior information reduces the ill-posedness and uncertainty of the inversion, thereby improving the quality and stability of the results. The code is available at <span><span>GitHub</span><svg><path></path></svg></span>.</div></div>","PeriodicalId":50440,"journal":{"name":"Flow Measurement and Instrumentation","volume":"106 ","pages":"Article 102973"},"PeriodicalIF":2.3,"publicationDate":"2025-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144366912","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Back to basics: On the proper determination of free-surface slope (FSS) in gradually varied open channel flows","authors":"Emma House ,&nbsp;Kyeongdong Kim ,&nbsp;Marian Muste ,&nbsp;Ehab Meselhe ,&nbsp;Ibrahim Demir","doi":"10.1016/j.flowmeasinst.2025.102979","DOIUrl":"10.1016/j.flowmeasinst.2025.102979","url":null,"abstract":"<div><div>This study is a fundamental evaluation of the fluvial wave propagation in river reaches affected by hysteresis, one of the most complex open-channel topics, materialized in loops and lags among hydraulic variables. Hysteresis processes are still understudied as measurements in natural streams for the whole wave propagation duration are hardly available, while the data from existing gaging sites (almost exclusively relying on stage-discharge relationships) can deviate up to 65 % from the actual flows. A better understanding of hysteresis in general and its impact on streamflow monitoring in unsteady flows can be obtained if the free-surface slope (FSS) is determined and analyzed for its variation during wave propagation. Reliable FSS replication in such flows requires a robust understanding of the spatial-temporal sampling constraints. The study addresses the basic, but still weakly resolved, issue of tracing the FSS for waves of different magnitudes and durations. We do so by translating theoretical concepts on oscillatory waves to fluvial counterparts and observing rules for sampling continuous-time signals with discrete-time measurements. The conceptual understanding is verified with numerical simulations and experimental data represented in Eulerian and Lagrangian observation frameworks. We demonstrate that sampling stream stages with spatial and temporal resolutions (expressed in terms of fractions of the wavelength, <em>dx</em>_<em>i</em><em>/λ</em>_<em>R,</em> and duration, <span><math><mrow><msub><mrow><mo>Δ</mo><mi>T</mi></mrow><mi>i</mi></msub><mo>/</mo><msub><mi>T</mi><mi>R</mi></msub></mrow></math></span> for the flood wave to reach its peak) between approximately<span><math><mrow><msub><mrow><mspace></mspace><msub><mrow><mspace></mspace><mn>0.0075</mn><mo>≤</mo><mi>d</mi><mi>x</mi></mrow><mi>i</mi></msub><mo>/</mo><mi>λ</mi></mrow><mi>R</mi></msub><mo>≤</mo><mn>0.01</mn></mrow></math></span> and, 0.004 <span><math><mrow><mo>≤</mo><msub><mrow><mo>Δ</mo><mi>T</mi></mrow><mi>i</mi></msub><mo>/</mo><msub><mi>T</mi><mi>R</mi></msub><mo>≤</mo><mn>0.06</mn></mrow></math></span>, respectively, are required to properly trace FSS for subsequent usage in experimental or numerical simulation contexts.</div></div>","PeriodicalId":50440,"journal":{"name":"Flow Measurement and Instrumentation","volume":"106 ","pages":"Article 102979"},"PeriodicalIF":2.3,"publicationDate":"2025-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144322123","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimization of micro-texture in thermo plastic elasto-hydrodynamic lubrication for improving the start-up behavior of the piston/cylinder pair in axial piston pump","authors":"Hao Zhang ,&nbsp;Yan Lu ,&nbsp;Junzhi Long ,&nbsp;Zhuoyuan Liu ,&nbsp;Fuquan Tu","doi":"10.1016/j.flowmeasinst.2025.102976","DOIUrl":"10.1016/j.flowmeasinst.2025.102976","url":null,"abstract":"<div><div>The piston/cylinder pair is a critical friction pair that serves to achieve suction and pressure oil functions, significantly influencing the performance of axial piston pumps and representing a major vulnerable point affecting their reliability and service life. This article presents an experimental study of axial piston pump internal leakage, revealing an abnormal increase in leakage during start-up condition. A thermo-fluid-solid oil film properties model is constructed for the start-up condition with plastic cumulative damage in the eccentric attitude of the piston/cylinder pair, and the oil film properties and wear leakage of the axial piston pump are analyzed in comparison under the start-up condition and steady condition, and the validity of the model is verified with the experimental leakage law. The results indicate that under start-up condition, the plastic accumulation of damage in the piston/cylinder pair and the leakage are significantly more severe, which is approximately 1.9 times of the leakage in the steady condition. Thus, a textured surface was developed on the piston. textured design induces a micro-dynamic pressure effect within the oil film throughout the oil suction process. This improvement enhances its load-bearing capacity, leading to a 20 % reduction in wear and a 22 % decrease in leakage. This design effectively enhances the tribological performance of the piston/cylinder pair.</div></div>","PeriodicalId":50440,"journal":{"name":"Flow Measurement and Instrumentation","volume":"106 ","pages":"Article 102976"},"PeriodicalIF":2.3,"publicationDate":"2025-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144338476","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental investigation of leakage flow measurement and surface morphology in small-scale liquid mechanical seals","authors":"Shaolin Liu,&nbsp;Amine Ben-Abdelwahed,&nbsp;Alain Sommier,&nbsp;David Reungoat,&nbsp;Philippe Darnis","doi":"10.1016/j.flowmeasinst.2025.102957","DOIUrl":"10.1016/j.flowmeasinst.2025.102957","url":null,"abstract":"<div><div>This study presents an experimental investigation into the fluid leakage behavior of small-scale liquid mechanical seals, with a focus on precise leakage flow characterization under controlled conditions. An advanced experimental platform was developed to simulate realistic operating conditions, including varying pressures and rotational speeds, enabling accurate assessment of fluid transport mechanisms in mechanical seals. The investigation involved detailed leakage flow rate measurements and surface roughness characterization for two types of seals: a worn seal (3000 h of industrial use) and a new, unused seal. Leakage flow rates were measured using a volumetric collection method to capture flow variations under controlled pressure (up to 12 bars) and rotational speed conditions (up to 6000 rpm). Non-contact surface roughness analysis was conducted using the AltiSurf 500 profilometer, providing 1D, 2D roughness profiles, and 3D surface reconstructions. Results indicate that the worn seal exhibited a lower average roughness (Ra = 0.08928–0.1397 <span><math><mi>μ</mi></math></span>m) compared to the new seal (Ra = 0.1203–0.2023 <span><math><mi>μ</mi></math></span>m). Despite this smoother surface, kurtosis (Rku) analysis revealed higher peak sharpness in the worn seal (Rku = 13.7611) versus the new seal (Rku = 6.5860), indicating localized surface peaks induced by prolonged operational wear. Leakage flow rate measurements revealed distinct trends. At a constant differential pressure of 4 bars, the worn seal exhibited unstable leakage flow at rotational speeds below 3000 rpm but stabilized at 12.0 mL/h (±0.5 mL/h) above this threshold. Under constant speed conditions (4000 rpm), leakage remained minimal at low pressure differentials (<span><math><mo>&lt;</mo></math></span>1 bar) but increased significantly beyond 5 bars, marking a transition in leakage mechanisms. The new seal exhibited minimal leakage under all conditions, highlighting the strong correlation between surface evolution and leakage characteristics. These findings provide valuable insights into leakage flow measurement techniques and reveal the influence of surface morphology changes on fluid transport in mechanical seals. The results contribute to improved measurement methodologies and provide guidance for optimizing seal design in aerospace applications.</div></div>","PeriodicalId":50440,"journal":{"name":"Flow Measurement and Instrumentation","volume":"106 ","pages":"Article 102957"},"PeriodicalIF":2.3,"publicationDate":"2025-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144280837","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Research on hydraulic characteristics and discharge calculation methods for top-hinge trapezoidal gates","authors":"Wanshang Meng ,&nbsp;Lin Li ,&nbsp;Wenming Zhang","doi":"10.1016/j.flowmeasinst.2025.102978","DOIUrl":"10.1016/j.flowmeasinst.2025.102978","url":null,"abstract":"<div><div>This study proposes a novel type of flat sluice gate – top-hinge trapezoidal gate, which is suitable for integrated flow measurement and control in canal systems at various levels in irrigation districts or for medium and small-scale water diversion canals. This paper investigates the hydraulic characteristics of the top-hinge trapezoidal gate under free-flow and submerged-flow through both theoretical and experimental methods. A total of 192 groups of free-flow tests and 384 groups of submerged-flow tests were conducted. Based on the experimental data and theoretical analysis, threshold condition formulas were proposed, achieving accuracy rates of 100 % for free flow and 98 % for submerged flow. Discharge equations for the top-hinge trapezoidal gate were established and evaluated. The average relative errors were 2.05 % for free-flow and 2.21 % for submerged-flow when derived from dimensional analysis, and 3.04 % and 3.39 %, respectively, when using the equations derived from the energy conservation method. The dimensional analysis method yielded slightly higher accuracy than the energy conservation method. The research findings provide important theoretical and practical guidance for the application of top-hinge trapezoidal gates.</div></div>","PeriodicalId":50440,"journal":{"name":"Flow Measurement and Instrumentation","volume":"106 ","pages":"Article 102978"},"PeriodicalIF":2.3,"publicationDate":"2025-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144306470","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Developing the next generation of dual-tip phase-detection probes for air–water flow experiments","authors":"Matthias Kramer","doi":"10.1016/j.flowmeasinst.2025.102949","DOIUrl":"10.1016/j.flowmeasinst.2025.102949","url":null,"abstract":"<div><div>Self-aeration is a fascinating phenomenon that commonly occurs in high Froude-number flows in natural or human made environments. The most common air–water flow measurement instrument to characterise such flows is the intrusive dual-tip phase-detection needle probe, which identifies phase changes around the needle tips due to a change of resistivity (phase-detection conductivity probe) or light refraction (phase-detection fibre optical probe). Phase-detection conductivity probes are typically custom made for research purposes, with current design dating back to the 1980ies. In the present study, the next generation of dual-tip conductivity probes is developed and validated against a state-of-the-art system. The novel probe design comprises two main features, including (1) a printed circuit board of the sensor’s electrodes and (2) a detachable sensor head. These features offer many advantages over the classical needle-type design. For example, the circuit boards can be manufactured with high precision and the sensor head can be easily replaced in case of damage or deterioration. As such, it is anticipated that this relatively cheap and robust design will enable a better repeatability of air–water flow experiments, combined with an enhanced accessibility for the air–water flow research community.</div></div>","PeriodicalId":50440,"journal":{"name":"Flow Measurement and Instrumentation","volume":"106 ","pages":"Article 102949"},"PeriodicalIF":2.3,"publicationDate":"2025-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144312795","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Time series identification, classification, and display methods for periodic flow patterns","authors":"Jie Fang ,&nbsp;Rui Li ,&nbsp;Tongyang Zhang ,&nbsp;Jiaxin Zhang ,&nbsp;Kang Zheng ,&nbsp;Jinfan Liu ,&nbsp;Guobiao Cai","doi":"10.1016/j.flowmeasinst.2025.102977","DOIUrl":"10.1016/j.flowmeasinst.2025.102977","url":null,"abstract":"<div><div>In the oxygen turbopump of a LOX/kerosene rocket engine, low-temperature gas-liquid flow and phase change processes occur, representing a typical case of direct contact condensation (DCC). DCC exhibits periodic flow characteristics under certain operating conditions, which are crucial for the normal operation of the rocket engine. This study aims to propose a temporal identification method for flow patterns with periodic characteristics and introduce a new method for displaying flow pattern diagrams to enhance the accuracy of flow pattern identification and description. Through experimental observations, the flow conditions are classified into three main flow patterns: crawling, chugging, and condensation oscillation. This study used You Only Look Once (YOLO) to extract single frame image features and Long Short-Term Memory (LSTM) to extract time series features. After evaluating the confidence of the model, the average accuracy of YOLO and LSTM were 99.33 % and 88.33 %, respectively. Furthermore, the flow pattern diagram proposed in this study effectively integrates temporal information of flow pattern variations with the proportions of different flow patterns. Based on the new flow pattern diagram, the variation rules of flow patterns under low mixing pressure and low mass flow rate were discussed. The trends of flow pattern proportion changes at non-operating points were effectively predicted, and the results align closely with traditional flow pattern diagrams. These findings provide an analytical basis for the mixing process of oxygen-rich gas and liquid oxygen in the inter-pump tubing of LOX/kerosene engines and can support future research.</div></div>","PeriodicalId":50440,"journal":{"name":"Flow Measurement and Instrumentation","volume":"106 ","pages":"Article 102977"},"PeriodicalIF":2.3,"publicationDate":"2025-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144298339","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}