Self-reactive lubricating graphite-like coating for low-friction hydraulic energy converters

Performance enhancement of a new hybrid hydrogen compression system via hydraulic accumulator-mediated pressure energy recovery

When pumped from one production unit to another, molten cheese spread is a highly viscous liquid, which inevitably affects all hydraulic calculations for optimal pipeline characteristics. However, such calculations often miss out the effect of the viscosity on the pump efficiency. This article introduces a new method for determining the optimal pipe diameter to transport liquid media during food production. It takes into account the viscosity of the liquid and the technical characteristics of the rotary lobe pump. The research featured a lobe-pump hydraulic system for transporting highly viscous cheese spreads. The calculations involved the technical parameters of the lobe pump and pipelines, as well as electricity tariffs. To determine the annual electricity costs, we used electricity tariffs for small businesses as of June 2024 in three random regions of the Russian Federation. The parameters of different cheese spreads (55–95°C) came from scientific publications in the public domain. Among the various factors that affected the optimal pipe diameter, the greatest impact belonged to the temperature-related changes in viscosity. As the operation time of the lobe pump increased, so did the share of electrical energy costs. As a result, the optimal diameter of the pipeline increased significantly to compensate for the hydraulic pressure losses and energy costs. The optimal diameter also depended on the investment parameters. Bigger Life-Cycle values correlated with larger optimal pipe diameters, i. e., the reduced costs went down. Higher interest rates, on the other hand, correlated with smaller optimal pipe diameters, i. e., the reduced costs went up. In general, the overall efficiency of the pumping station depended quite strongly on all the factors featured in this research. The new method made it possible to determine the optimal pipe diameter for inter-operational transportation of cheese spreads in particular and highly viscous laminar fluids in general. It relied on viscosity values and lobe pump specifications. Numerically, it was based on a step-by-step calculation of economic and hydraulic parameters. The method demonstrated good prospects for food pipeline design.

Pumps as turbines (PATs) are widely applied in micro-hydropower stations and chemical industries as economical and efficient energy recovery devices. This study used numerical simulations and entropy dissipation theory to investigate the influence of four draft tube diffusion angles (β0, β1, β2, and β3) on the hydraulic performance and energy losses of a double-suction centrifugal PAT. The results show that the diffusion angle exhibits a complex nonlinear effect on head, efficiency, and shaft power across different flow rates. Under low-flow conditions (0.6Qd), β2 reduces efficiency by 9.27%, whereas under high-flow conditions (1.4Qd), β3 improves efficiency by 1.01%. Entropy analysis reveals that total entropy generation follows an approximately parabolic trend with flow rate, reaching its minimum near the design condition. Among the schemes, β1 and β3 effectively reduce total entropy generation, with β3 achieving a 5.51% reduction under high-flow conditions. The impeller is identified as the dominant source of energy loss (approximately 53% of entropy production), followed by the draft chamber (approximately 30%). Further analysis indicates that entropy generation in the draft chamber primarily arises from turbulent dissipation and wall friction and is highly sensitive to the diffusion angle. Under high-flow conditions, β3 reduces draft chamber entropy production by 7.44%, whereas under low-flow conditions, larger diffusion angles increase entropy production. Thus, optimizing the diffusion angle not only improves impeller flow conditions but also effectively reduces system energy losses, particularly under high-flow and off-design operating conditions. This work provides theoretical insights and engineering guidance for the optimized design of PAT draft tubes.

Premise plumbing systems (PPS) are essential for delivering safe, efficient, and sustainable water services in buildings. However, current design practices rely on outdated assumptions, including static demand curves and prescriptive codes, which contribute to oversizing, stagnation, water quality degradation, and energy-health trade-offs. This review offers the first integrated synthesis of recent advances across five interrelated domains: (i) hydraulic design, (ii) water conservation, (iii) water quality, (iv) energy efficiency, and (v) socio-economic factors. Each domain influences PPS performance but is often treated in isolation. Drawing on empirical evidence, international standards, and emerging modelling frameworks, the paper frames PPS design as the alignment of hydraulic, thermal, water quality (including microbial and chemical), and economic processes across the system life cycle. It identifies persistent barriers such as fragmented workforce training, economic constraints, and misaligned conservation strategies, while also highlighting emerging enablers, including digitalization, policy support, and industrialized construction. Future research priorities are outlined for dynamic sizing, water quality risk modelling, and life-cycle cost analysis. This review provides a roadmap for transforming PPS into adaptive, health-protective systems aligned with global sustainability targets.

Wave-focusing smart structure with pressure-adaptive enhancement for hydraulic energy harvesting

Non-thermal plasma-driven advanced oxidation is a promising method for treating organic wastewater, which exhibits rapid reaction kinetics and high pollutant removal and does not need chemical reagents. However, its practical application is often limited by high specific energy consumption and the inefficient mass transfer of short-lived reactive species across the gas–liquid interface. This review summarizes the fundamentals of non-thermal plasma chemistry and the process intensification of plasma multiphase reactors by mass transfer enhancement and waste energy-driven conversion. This review focus on four coupling approaches: microbubble-assisted plasma to expand the reactive interfacial area; plasma coupled with hydraulic cavitation to enhance convection and radical formation; plasma–piezoelectric catalysis coupling to harvest hydraulic energy and promote charge-driven reactions; and plasma-assisted Fenton oxidation to improve the utilization of weakly oxidizing species (H2O2). The energy efficiency of various plasma-based oxidation systems is compared and discussed clearly. Key remaining challenges are also discussed, including standardized energy efficiency assessment, scale-up and hydrodynamic control, catalyst stability and fouling, by-product formation and toxicity, and long-term operational reliability. Overall, this review aims to provide guidance for developing efficient plasma-based wastewater treatment systems for large-scale applications.

Although peristaltic pumps are common in biomedical, complex fluid-structure interactions within small flexible tubes are often oversimplified by standard hydraulic theories. This study experimentally investigates the hemodynamic performance of a peristaltic pump using flexible silicone tubes with different inner diameters (6-10 mm) and wall thicknesses. Unlike traditional parametric studies, a comprehensive dimensionless analysis was conducted using the Buckingham Pi theorem to evaluate the Flow Coefficient, Head Coefficient, and Power Coefficient as functions of the Reynolds number. Additionally, Wall Shear Stress was analyzed to assess hemocompatibility. While the 10 mm tube exhibited stable hydraulic behavior, the 6 mm tube suffered from significant volumetric loss and pressure fluctuations due to radial expansion. Most critically, the dimensionless Power Coefficient in the 6 mm tube was approximately 30 times higher than in the 10 mm tube, indicating that a massive portion of hydraulic energy is dissipated to overcome wall deformation and high frictional resistance. Furthermore, WSS analysis showed that the 6 mm tube generated shear stresses reaching 90 Pa, far exceeding the physiological safety limit for hemolysis (15 Pa), whereas the 10 mm tube remained within the safe range (4–14 Pa). Pressure generation requires optimizing trade-offs with efficiency and hemocompatibility.

Transient hydraulic characteristics and energy loss mechanisms in a variable-speed pumped storage unit operating in pump mode

Experimental study on vertical propagation of hydraulic fracturing in multilayer permeability heterogeneous reservoirs: Based on true triaxial experiment and acoustic emission monitoring

Power Generating Suspension is an innovative vehicle suspension technology that converts mechanical energy produced due to road irregularities into useful electrical energy. In conventional suspension systems, vibrations and shocks caused by uneven road surfaces are dissipated as heat, resulting in energy loss. The power generating suspension system utilizes mechanisms such as electromagnetic, hydraulic, or piezoelectric energy harvesting to transform this wasted mechanical energy into electrical power. The generated energy can be stored in batteries or super capacitors and used to power on board electronic devices, sensors, lighting systems, or to support auxiliary loads in electric and hybrid vehicles. This system not only improves overall energy efficiency but also contributes to reduced fuel consumption and lower environmental impact. Despite challenges such as increased system complexity and initial cost, power generating suspension systems offers promising solution for sustainable and energy-efficient transportation in modern vehicles.

A 2.4 kWp Solar Water Pumping System (SWPS) was installed in Kadaghu Tana, South West Sumba, to provide clean water from a total head of 115 m. The site receives 4.8-6.0 kWh/m2/day of solar irradiation. The system uses Photovoltaic (PV) modules connected to a Lorentz DC pump through an MPPT controller. Performance was evaluated through simulation and field monitoring. Key parameters assessed were flowrate, hydraulic energy, wire-to-water efficiency, motor efficiency, and daily pump operating hours. The pump operated 07.00–16.00 WITA, slightly earlier than the simulated 08.00 start time. The average monitored flowrate (1.07 m³/h) closely matched the simulated value (1.08 m³/h). Monthly average output was 10.75 m³ (monitoring) versus 10.83 m³ (simulation). The PV system produced 7.34 kWh/day, yielding a yield factor of 3.06 kWh/kWp/day. Hydraulic energy output was 3.31 kWh/day, resulting in overall system efficiency of 26–30%, consistent with typical Lorentz DC pump performance. System performance aligns well with simulation predictions. Operation is strongly influenced by irradiance, ambient temperature, total dynamic head, and well characteristics. The SWPS demonstrates reliable performance for remote clean-water supply in Sumba.

This study presents the first ichnological analysis of the Upper Devonian Imperial Formation in the Mackenzie Mountains (Northwest Territories, Canada), a siliciclastic succession deposited during the Ellesmerian orogeny. By integrating sedimentological and ichnological data from four measured sections, seven sedimentary facies were grouped into four facies associations that record a transition from wave-dominated delta front and storm-dominated lower shoreface deposits to storm-influenced prodelta, and ultimately to slope. Nineteen ichnotaxa were identified, with the highest ichnodiversity and bioturbation intensities occurring in wave-dominated shallow-marine and ramp settings. The trace-fossil assemblages in these settings reflect a typical Cruziana Ichnofacies and comprise tiered communities dominated by deposit- and detritus-feeders. In contrast, turbidite deposits of deeper slope settings contain sparse, diminutive trace fossils, reflecting rapid sedimentation rates and high hydraulic energy conditions. In contrast to the underlying Canol Formation, which was deposited under anoxic conditions, the Imperial Formation reflects more oxygenated conditions, as indicated by the higher diversity of trace-fossil assemblages. These ichnological patterns are interpreted as responses to evolving depositional environments and benthic food availability during foreland basin development. This work contributes a rare data point for Devonian shallow to deep-marine ichnology in western North America and enhances our understanding of post-Frasnian-Famennian recovery faunas in clastic foreland basin settings.

Hydraulic conveying of aquaculture feed pellets through pipes has recently been adopted in offshore fish farms, but design guidelines for safe and energy-efficient operation are still lacking. In this study. In this study, the hydraulic conveying characteristics of floating aquaculture feed pellets within horizontal pipelines were investigated based on the CFD-DEM coupling method. In this study, a two-way coupled CFD-DEM framework is used to investigate the hydraulic conveying characteristics of floating feed pellets in a horizontal pipe with an inner diameter of 0.10 m and a total length of 3.0 m. Water with an inlet velocity of 2.0 m·s−1 and a pellet mass flow rate of 0.3 kg·s−1 is considered. The feed pellets are modeled as cylinders with diameter-to-length ratio ϕ in the range 0.4–1.6 and pellet size ratio ζ in the range 0.06–0.12. After validating the CFD-DEM model against classic experimental data for coarse spherical particles, the effects of ϕ and ζ on conveying velocity, cross-sectional distribution, collision frequency, energy loss and fluid pressure drop are systematically analyzed under statistically steady conditions. The results show that pellet shape strongly affects conveying behavior: increasing ϕ reduces pellet-wall collision frequency and associated energy loss, whereas increasing ζ enhances energy loss and significantly increases pressure drop. In all cases, pellet-pellet collisions are more frequent than pellet-wall collisions, but pellet-wall impacts dominate the collisional energy dissipation. The pressure drop along the pipe is nearly linear in the fully developed region, consistent with a constant friction factor. Within the investigated parameter space, designing pellets with moderately large ϕ and relatively small ζ improves conveying safety and reduces hydraulic energy consumption, providing practical guidance for feed pellet and pipeline design in marine aquaculture.

Abstract Forecasting is an essential part of risk mitigation, where the mitigation efficacy depends strongly on the quality of forecasts. We explore the neural temporal point process as a deep learning framework to forecast induced earthquakes. We train our deep learning model using numerous enhanced geothermal systems and hydraulic fracturing test cases. We find that our model's performance is comparable to that of a modified Epidemic Type Aftershock Sequence; the “winning” model varies, depending on the test case in question. The addition of supplementary input data (e.g., seismic moment release, cumulative volume, injection pressure, hydraulic energy) tends to reduce model performance, as compared to simply using traditional metrics (i.e., magnitudes and injection rates). Our model's architecture allows for a flexible and data‐driven inference of the inter‐event time distribution and the injection forcing function. We find that the inter‐event time distribution is compatible with an Omori‐like decay of seismicity rates. On the other hand, our model does not recover a linear proportionality between injection and seismicity rates—instead preferring a simple on/off relationship. Finally, we discuss the statistical/physical implications of these results for and suggest future improvements. Overall, this model will likely be an important part of an ensemble of forecasting approaches that constrain seismicity risks.

Hydraulic compressed gas energy storage in salt caverns - system design and energy efficiency analysis

Making waves: Electric-field-programmable membrane interfaces for fouling control.

Mineralized faults—fractures that have accommodated displacement and were subsequently filled or coated with mineral precipitates—are commonly found in hydrothermal regions. Precipitation from circulating fluids or magmatic intrusions can substantially alter fault structure, reduce permeability, and influence frictional stability. Despite their geological importance, the slip behavior and frictional evolution of mineralized faults during fluid injection remain poorly constrained. To address this knowledge gap, we conduct triaxial shear-flow experiments on critically stressed mineralized faults in granite to examine their hydro-mechanical response to fluid pressurization. Deionized water is injected at a constant rate of 0.6 mL·min −1 under different confining pressures of 20 and 30 MPa. Fault slip occurs in two distinct stages: an initial unstable stick-slip phase followed by stable slip, with higher confining pressure promoting the transition. The effective friction coefficient fluctuates during stick-slip but increases progressively during stable slip. Greater hydraulic energy input does not necessarily induce earlier fault reactivation, but it results in greater deformation moment accumulation and higher energy release. Microstructural analysis reveals distinct deformation mechanisms: foliation-like microfractures develop near the fault surface at 20 MPa, while 30 MPa conditions lead to grain crushing and the formation of interconnected fracture networks. These findings advance our understanding of injection-induced slip in mineralized faults and provide insights relevant to geothermal energy extraction, energy storage, and waste disposal. • Injection-induced slip on mineralized faults is investigated by triaxial shear-flow experiment. • Injection induces two-stage slip on mineralized faults: stick-slip then stable slip. • Higher confining pressure delays reactivation and promotes stable slip. • Effective friction rises during injection and keeps increasing in stable slip. • Microstructures: 20 MPa—foliation-like cracks; 30 MPa—grain crushing, networks.

ABSTRACT Enhancing heat‐transfer efficiency in compact heat exchangers is essential for reducing energy consumption and improving overall system performance. This research investigates the behavior of an innovatively designed thermal and hydraulic energy promoter (EP), mounted on the inner wall of a circular tube, to improve heat transfer and minimize pressure loss. Water was used as the simulation fluid at Reynolds numbers between 4000 and 20,000, employing the Shear Tension Transmission k – ω perturbation model in ANSYS Fluent. The EP generates strong vortices that intensify the fluid mixing near the tube wall. Compared with a smooth tube, the Nusselt number increased by 1.9–3.4, while the coefficient of friction increased by 2.9–4.8. This further indicates an improvement in overall efficiency, exceeding the Performance Evaluation Criterion value of 1 in all cases (1.1–2.6). The promoter height of 1 mm achieved the best performance in terms of both increased heat transfer and reduced pressure. The flow analysis revealed the formation of secondary vortices and high‐kinetic‐energy regions, which are key optimization mechanisms. Compared with traditional passive methods, such as ribs and grooves, the proposed catalyst concept offers an effective solution for improving thermal performance without inducing excessive mechanical stress.

While climate impacts on hydropower output are well-documented, plant efficiency, the critical ratio of electrical energy generated to hydraulic energy input, remains an underexplored metric, particularly in data-limited regions. This study analyzes the efficiency dynamics of the Ruzizi I plant (29.8 MW) from 2000 to 2023 to unravel the interplay between hydrological drivers and operational constraints. Building on the established context of a hydraulic trade-off between water volume and head, we employed machine learning (Multiple Linear Regression, Random Forest, Gradient Boosting) and operational analysis to diagnose efficiency drivers. Results reveal that plant efficiency increased significantly (+ 3.6%-points/decade) and is overwhelmingly governed by discharge (r = 0.998), with machine learning models confirming the negligible role of head and seasonality. This indicates that efficiency gains are almost entirely flow-dependent, masking the potential negative impact of head loss. The system exhibits strong buffering from Lake Kivu, with efficiency remaining stable during drought but surging by 17–18% during wet years. Crucially, operational analysis identified an optimal load factor range (78–82%) that could improve efficiency by ~ 4% points compared to historical operation. However, a concurrent decline in available capacity factor (− 5.5%/decade) signals emerging non-hydrological constraints. These findings underscore that while water volume currently dominates efficiency gains, long-term sustainability requires managing sediment-induced head loss and optimizing operations within the identified optimal range to mitigate the underlying vulnerabilities in the energy conversion process.