Search Results (3,046)

Reliable detection of faults in centrifugal pump systems is challenging in industrial environments due to harsh operating conditions, limited sensor access, and the need for fast, explainable decisions. We developed PumpSpectra, an industrial Motor Current Signature Analysis (MCSA) platform that processes uploaded stator-current CSV files using FFT/STFT with transparent, rule-based models designed to identify mechanical faults including misalignment, bearing defects, and impeller anomalies; field validation demonstrated misalignment detection. In a case study at the El Oued desalination plant (Algeria; $n=40$ operating points), PumpSpectra achieved 91.2% diagnostic accuracy with a 95% reduction in analysis time compared to manual MCSA post-processing, and a false-positive rate of 3.8% at 0.1 Hz resolution. These results suggest that current-only, explainable analytics can support predictive maintenance programs by accelerating fault triage, improving traceability of decisions, and reducing avoided maintenance costs in pump-driven industrial assets. Full article

This study presents a reduced-order modeling framework for the shape optimization of a centrifugal pump. A database of CFD solutions is generated using Latin Hypercube Sampling over five design parameters to construct a reduced-order model based on proper orthogonal decomposition with radial basis function interpolation. The model predicts the flow field at the impeller–diffuser interface and pump outlet, enabling the estimation of impeller torque and total pressure rise. The active subspaces method is applied to reduce the dimensionality of the input space from five to four modified parameters. The sensitivity of the ROM is assessed with respect to further dimensionality reductions in the parameter space, POD mode truncation, and adaptive sampling. The model is then used to perform pump shape optimization via a quasi-Newton method, identifying the combination of the parameters that minimizes the impeller torque while satisfying a constraint on the head. The optimal result is validated through CFD analysis and compared against the Pareto front generated by a genetic algorithm. The work highlights the potential of model-order reduction techniques in centrifugal pump optimization. Full article

This study presents a streamlined and accurate approach for modeling the performance of hermetic reciprocating compressors under variable-speed conditions. Traditional compressor models often neglect the influence of motor frequency, leading to considerable deviations at low-speed operation. To address these limitations, a frequency-dependent numerical framework was developed using one-dimensional (1-D) and two-dimensional (2-D) polynomial regressions to represent volumetric efficiency (${\eta }_v$) and isentropic efficiency (${\eta }_{isentr}$) as functions of compression ratio (r) and motor speed frequency (f). The proposed model integrates manufacturer data and thermodynamic property databases to predict compressor behavior across a wide range of operating conditions. Validation using the Bitzer 4HTE-20K CO₂ compressor demonstrated strong agreement with experimental data, maintaining prediction errors within ±10% for both power input and discharge temperature. Moreover, the model enhanced accuracy by up to 19.4% in the low-frequency range below 40 Hz, where conventional models typically fail. The proposed method provides a practical and computationally efficient tool for accurately simulating the performance of hermetic reciprocating compressors that support improved design, optimization, and control of refrigeration and heat pump systems. Full article

Electric Submersible Pumps (ESPs) are widely deployed in high-flowrate wells but are constrained by frequent failures and the need for rig-based interventions. This study presents the development and field validation of a rigless cable-deployed ESP (CDESP) system designed to enhance operational uptime and reduce intervention costs. The system features a corrosion-resistant metal-jacketed power cable, an inverted ESP configuration that eliminates the motor lead extension (MLE), and a vertical cable hanger spool (VCHS) for surface integration without removing the production tree. A field trial in a high-H₂S well demonstrated successful rigless deployment using coiled tubing (CT), achieving over two years of continuous runtime. Post-retrieval inspection revealed minimal wear, validating the system’s mechanical durability and reusability. Operational performance demonstrated reduced non-productive time (NPT), enhanced safety, and cost savings, with deployment completed in under 24 h, compared to the typical 10–14 days for rig-based methods. The CDESP system’s compatibility with digital monitoring and its potential for redeployment across wells positions it as a transformative solution for offshore and mature field operations. These findings support the broader adoption of CDESP as a scalable, efficient, and safer alternative to conventional ESP systems. Full article

The elbow suction conduit plays a decisive role in determining inflow conditions, thereby influencing a pump’s efficiency and cavitation characteristics. The complex three-dimensional swirling and separating flow makes pinpointing the sources and mechanisms of energy dissipation challenging. This study aims to accurately diagnose the sources of hydraulic losses within the elbow suction conduit and conduct effective geometric optimization to enhance overall pump performance. Entropy production theory was integrated with three-dimensional Reynolds-averaged Navier-Stokes simulations to quantitatively analyze the irreversible energy dissipation in different parts of the conduit. Results reveal that energy dissipation is predominantly concentrated at the inlet section, wall surfaces, outer curvature of the bend, and the inner conical diffuser. Key geometric parameters were systematically optimized. Compared to the baseline design, the optimized configuration not only reduced entropy generation induced by wall shear and turbulent fluctuations but also improved the spatio-temporal uniformity of the outflow. Consequently, this translated directly into enhanced overall pump performance: the optimized design shows a 0.34% increase in efficiency and a 3.6% reduction in the inception cavitation coefficient at the rated condition, leading to lower energy consumption and enhanced operational reliability. The effectiveness of entropy production analysis for the hydraulic optimization of pumps was demonstrated. Full article

The advancement of miniaturized liquid chromatography (M-LC) systems has drawn considerable attention for their ability to enhance sensitivity, expedite analysis, and minimize the environmental impact of chemical usage in various analytical processes. This review explores the fundamental principles and recent innovations in M-LC technology, including diverse pump designs, advanced column techniques, and the reduction in connection devices. Emphasizing the need for components that operate efficiently at the capillary or nanoscale with minimal dead volumes, we also discuss the development of benchtop instruments and mass spectrometry integrations. The review further highlights the growing applications of M-LC in food, environmental, and biological analyses, highlighting its potential as a powerful and emerging tool in separation science. Looking forward, addressing problems such as limited robustness, fabrication complexity, and integration with sensitive detectors will be instrumental to advancing M-LC technology. Modern innovation in microfabrication, materials science, and hyphenated methods holds great promise for allowing real-time, high-throughput, and portable analytical solutions in the near future. Full article

Traditional zero-compensation techniques employed to improve sub-sampling phase-locked loop (SSPLL) stability often exacerbate spur degradation or incur excessive area overhead, rendering them unsuitable for high-resolution image sensor applications. This paper proposes a novel SSPLL based on capacitor multiplication technology. This capacitor multiplication technology employs dual charge pumps (CP1 and CP2) in a coordinated operational scheme where their charge/discharge states are inversely synchronized. The effective capacitance of the loop filter is thereby amplified without expanding the physical layout area dedicated to capacitive components. Meanwhile, the continued use of zero-compensation technology ensures the stability of the SSPLL. The proposed SSPLL is designed and verified in a 55 nm CMOS process. At a 1.2 GHz output frequency, simulation results show a spot phase noise of −131.5 dBc/Hz at 1 MHz offset, accompanied by an integrated RMS jitter of 549 fs across the 10 kHz to 40 MHz spectrum, spurs suppressed to −51.3 dB, while maintaining a power efficiency of 3.81 mW and a compact layout area of 0.064 mm². All the above results show that by introducing the novel dual-CP charge multiplication technology, the SSPLL can achieve low jitter and low power consumption performance while reducing the layout area, providing a new technical approach for its application in high-resolution image sensors. Full article

A coupled CFD-DEM model was adopted to investigate the floating ice accumulation mechanism and its disturbance to the flow field in the pump house of coastal nuclear power plants in cold regions. Based on numerical simulations, the motion, accumulation, and flow interaction characteristics of floating ice under various release positions and heights were analyzed. The results indicate that the release height significantly governs the accumulation morphology and hydraulic response. The release height critically determines ice accumulation patterns and hydraulic responses. For inlet scenarios, lower heights induce a dense, wedge-shaped accumulation at the coarse trash rack, increasing thickness by 57.69% and shifting the accumulation 38.16% inlet-ward compared to higher releases. Conversely, higher releases enhance dispersion, expanding disturbances to the central pump house and intensifying flow heterogeneity. In bottom release cases, lower heights form wall-adhering accumulations, while higher releases cause ice to rise into mid-upper layers, thereby markedly intensifying local vortices (peak intensity 79.68, approximately 300% higher). Spatial release locations induce 2.7–4.8-fold variations in flow disturbance intensity across monitoring points. These findings clarify the combined impact of the release height and location on the ice accumulation and flow field dynamics, offering critical insights for the anti-ice design and flow safety assessment of pump houses. Full article

Dy³⁺:InF₃ fiber shows promise for 4.4 μm mid-infrared lasing, but the much shorter lifetime of its upper laser level compared to the lower level causes inevitable self-termination. While cascade 4.4 μm/3 μm lasing has been proposed as a potential solution, this method faces complex configuration and an extremely high pump threshold (>30 W under continuous-wave operation), rendering it impractical for high-power use, especially given InF₃’s soft-glass nature. To address the self-termination challenge and enable the low-threshold, high-efficiency lasing, this study proposes, for the first time to our knowledge, a dual-wavelength cascade-pumping scheme utilizing 2.8 μm and 2.4 μm pumps. Numerical simulations demonstrate that the dual-wavelength cascade-pumped Dy³⁺:InF₃ fiber laser exhibits an optical-to-optical efficiency of up to 18.4% and a maximum slope efficiency of 38.5%. The total pump threshold is as low as 5.4 W, remarkably lower than that required by the cascade lasing approach. This work provides a viable solution and design guidelines for the development of 4 μm-class mid-infrared fiber lasers. Full article

To address the problem of the proton exchange membrane fuel cell (PEMFC) temperature management under stochastic disturbances, this paper integrates a PEMFC thermal model with a water pump model and establishes a nonlinear stochastic model for temperature regulation. The objective is to maintain the stack temperature at its optimal value. Due to the inherent complexity of the PEMFC electrochemical reactions, the thermal dynamics exhibit strong nonlinear characteristics. To tackle this issue, a control strategy based on the stochastic backstepping method is proposed. Furthermore, to cope with variations in membrane water content and ambient temperature during operation, we design stochastic estimator-based adaptive laws. Simulation results, considering both stochastic disturbances driven by tracking error and those driven by stack temperature and load current, indicate that the proposed control strategy effectively maintains the stack temperature at 343 K under various operating conditions, with a maximum deviation of 0.2 K, thereby confirming its effectiveness and robustness. Full article

The present paper provides a general overview of the state of the art of steam generating heat pumps (SGHPs) technology employed in the industrial field. Recommended best practices and optimization procedures for overall performance improvement of compression closed-loop-based systems are described in detail, as well as the main modifications of the thermodynamic heat pump cycle. Once the main configurations of SGHPs are described, the different concepts are compared in terms of supply temperature ranges; cases of comparison among different concepts are reviewed, and techno-economic barriers are also discussed. The working fluids (including natural refrigerants) commonly selected for these steam generating systems are presented along with their uses. Moreover, zeotropic refrigerant mixtures and new potentially usable mixtures are mentioned. After that, refrigerant selection criteria for high temperature heat pumps are also discussed. Then, using an internal heat exchanger, refrigerant injection technique and super heating in lubricated compressors are herein presented as best practices for general performance improvement. Regarding thermodynamic cycle modifications, basic auto-cascade and quasi-two-stage compression cycles are discussed along with further improvements suggested in the specialized literature. Lastly, optimization strategies useful to enhance the heat pumps’ design and based on TOPSIS method, advanced exergy analysis, exergy-based cost minimization and combined design are analyzed. Full article

The paper presents an automatic frequency calibration (AFC) technique for a charge pump-based phase-locked loop (CPPLL) with 5–6 μsec correction time. The architecture detects frequency offset in real time while keeping the loop active and performs a variable gain calibration that increases the correction gain at large frequency offsets to accelerate lock acquisition and gradually reduce the gain near locking frequency to suppress residual oscillation and overshoot. The implemented synthesizer rapidly re-acquires the lock within several adjacent coarse-tuning codes after frequency drift and maintains continuous operation without interruption. It demonstrates that the designed AFC achieves seamless frequency recovery in dynamically varying environments. Fabricated in a 65 nm CMOS process, the prototype fractional-N synthesizer occupies an active area of 0.603 mm² and operates over a 5.3–6.2 GHz tuning range. At 5.8 GHz, the design achieves a phase noise of −107 dBc/Hz at 1 MHz offset and consumes 21.5 mW from a 1.2 V supply. Full article

In real-world industrial settings, obtaining class-balanced fault data is often difficult. Imbalanced data across categories can degrade diagnostic accuracy. Time-series Generative Adversarial Network (TimeGAN) is an effective tool for addressing one-dimensional data imbalance; however, when dealing with multiple fault categories, it faces issues such as unstable training processes and uncontrollable generation states. To address this issue, from the perspective of data augmentation and classification, a gradient-penalized Conditional Time-series Generative Adversarial Network with a Multi-Scale Importance-aware Network (CTGAN-MSIN) is proposed in this paper. Firstly, a gradient-penalized Conditional Time-Series Generative Adversarial Network (CTGAN) is designed to alleviate data imbalance by controllably generating high-quality fault samples. Secondly, a Multi-scale Importance-aware Network (MSIN) is constructed for fault classification. The MSIN consists of the Multi-scale Depthwise Separable Residual (MDSR) and Scale Enhanced Local Attention (SELA): the MDSR network can efficiently extract multi-scale features, while the SELA network is capable of screening out the most discriminative scale features from them. Finally, the proposed method is validated using the HUST bearing dataset and the axial piston pump dataset. The results show that under the data imbalance ratio of 15:1, the CTGAN-MSIN achieves diagnostic accuracies of 98.75% and 96.50%, respectively, on the two datasets and outperforms the comparison methods under different imbalance ratios. Full article

This study introduces a sensorless fault diagnosis method for efficiently detecting bearing faults in induction motors. The proposed method eliminates the need for torque sensors, frequency sensors, thermal cameras, or real-time Fast Fourier Transform (FFT) tools. Induction motors are commonly utilized in a variety of industrial applications, including fans, pumps, and home appliances, due to their straightforward construction, affordability, and robust reliability. Traditional bearing fault diagnosis methods often rely on additional hardware such as vibration or thermal sensors. Additionally, approaches employing Artificial Intelligence (AI) and real-time FFT processing require advanced and expensive hardware capabilities. However, many V/f control systems are primarily intended for cost-effective and simple implementations, making resource-intensive approaches undesirable. Therefore, such methods present limitations for these use cases. To address these challenges, this paper presents a sensorless detection technique that estimates torque via a flux observer, removing the dependence on external sensors. The estimated torque is processed using an offline FFT to identify amplitude changes within bearing fault frequency bands. Here, the FFT-based frequency analysis is performed offline and is used to design a targeted band-pass filter (BPF). The torque signal, after passing through the BPF, undergoes a straightforward threshold-based logic to assess the existence of faults. Compared to AI- or data-driven approaches, the proposed method provides a lightweight, interpretable, and sensorless solution without the need for additional training or high-end processors. Despite its straightforward approach, the technique achieves effective detection of bearing faults across various components and speeds, making it ideal for embedded and economically constrained motor applications. Full article

As the core component of pumped storage stations (PSS), pumped storage units (PSU) require a scientific and comprehensive evaluation method to guide the selection of optimal units and support the development of the new-type power system (NPS). This paper aims to address the symmetry issues in PSU evaluation methods by proposing an innovative approach based on evolutionary combination weighting and cloud model theory, thereby adapting to the long-term asymmetric evolution of the power system. First, the subjective and objective weights of indicators at all levels for PSU are obtained using the analytic hierarchy process (AHP) and the entropy weight method (EWM). Then, the optimal combination coefficients for subjective and objective weights are determined through game theory, achieving symmetry and balance between the subjective and objective weights. Subsequently, dynamic correction of the indicator weights is realized using a designed evolutionary response function, enabling the weights to evolve dynamically in response to the asymmetric development of the power system. Finally, the cloud model is employed to characterize the randomness and fuzziness of evaluation boundaries, which enhances the adaptability of the evaluation process and the interpretability of results. The simulation results show that, when considering the long-term asymmetric evolution of the power system, the expected score deviations of secondary indicators are approximately 4.7%, 1.3%, 3.5%, and 7.7%, respectively, with an overall score deviation of about 6.4%. The proposed method not only achieves symmetry and balance between subjective and objective factors in traditional evaluation but also accommodates the asymmetric evolution requirements of the power system. Full article