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This study aims to explore how the seal face structure affects the gas flow and film performance, focusing on compliant foil face gas seal with an upstream pumping spiral gap. The research is done to reveal the leakage control mechanism and obtain the optimal parameters of structure.

A gas-elastic coupling lubrication model for compliant foil face gas seal is developed using gas lubrication and elastic mechanics theories. The finite difference method is applied to calculate film pressure, deformation and flow rate variations under varying gap spiral angles. What’s more, the impacts of equilibrium film thickness, rotational speed and medium pressure on sealing performances are researched, and the flexibility coefficients α₁ (dynamic pressure area) and α₂ (sealing area) are optimized.

This design significantly reduces leakage rates while maintaining the adaptive operation capability of compliant foil face gas seals. When α₁ takes values from 0.10 to 0.15, α₂ takes values from 0.5 to 0.6 and φ (gap spiral angle) is equal to 30°, the comprehensive performance of sealing in steady and transient states is better.

Integrating the design concept of upstream pumping dry gas seals and the adaptive structure of compliant foil face gas seals, a novel foil face gas seal structure with upstream pumping function is proposed.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-11-2024-0434/

This study aims to evaluate the effects of the downhole environment and auxiliary rubber bellows on the contact mechanical characteristics and sealing performance of rubber-bellows mechanical seals (RBMS) in electric submersible pumps (ESPs), considering the elastic support of the rubber bellows, multi-field coupling effect and actual operating conditions.

A thermal-fluid-solid multi-field coupling numerical model for RBMS in ESPs is developed using the finite element analysis and influence coefficient method. Based on the contact mechanical characteristics of RBMS, the interactions of multiple physical fields between the sealing rings and lubricating oil are accounted for to assess the liquid lubrication state and sealing performance of RBMS in ESPs.

The findings indicate the anti-leakage effects of rubber bellows, the transition of lubrication state of the sealing end face and the evolution law of sealing performance with environmental pressure, axial compression amount and contact widths of rubber bellows.

This study innovatively proposes a multi-field numerical research method to reveal the impact of the downhole environment and rubber bellows on RBMS in ESPs. These findings contribute to a more comprehensive understanding of the sealing mechanism of RBMS and optimize the sealing design for ESPs in high-pressure environments.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-10-2024-0369/

This study aims to develop a large gap nanomagnetic liquid sealing technology to address the problems of significant deformation, vibration, and radial oscillation caused by harsh working conditions such as low assembly and processing accuracy, heavy load, and high speed in mechanical equipment.

Based on the principle of magnetic liquid sealing structure, a large gap magnetic fluid sealing scheme based on axial and radial distribution was proposed, equipped with self-made silicone oil–based magnetic fluid. Taking the common roller in mining equipment as an example, sealing performance tests were conducted using a mining roller running resistance test bench in the simulated underground environment.

In routine environmental tests, the running resistance of the new magnetic liquid sealing roller is reduced by an average of 7.6% and 34.3% compared to the labyrinth sealing roller, respectively; In long-term environmental tests, the running resistance of the new magnetic liquid sealing roller decreased by an average of 16.2% compared to the labyrinth sealing roller, it is recommended to equip it with self-made silicone oil–based magnetic fluid; In vibration environmental tests, the running resistance of the new magnetic liquid sealing roller is more stable compared to the magnetic liquid sealing roller with only axial distribution.

The research results have important theoretical and practical value in compensating for the shortcomings of magnetic fluid sealing structure and expanding the application fields of magnetic fluid.

The purpose of this study is to evaluate the corrosion retardation properties of methylene blue on carbon steel in hydrochloric acid solutions.

The corrosion inhibition property of methylene blue on carbon steel was investigated by hydrogen evolution technique (gasometric technique) and weight loss measurements at 303 K and 333 K in hydrochloric acid solutions.

The results revealed that methylene blue inhibited the corrosion carbon steel, and the inhibition efficiency was temperature dependent. The maximum inhibition efficiencies were 88% at 303 K and 79.2% at 333 K. The corrosion data was consistent with the Langmuir adsorption isotherm which posits that the methylene blue molecules adhered to the metal substrate. The corrosion kinetics followed the first-order kinetic reaction equation. The activation energy (Ea) values ranged from 45.6 to 81.7 kJ/mol and indicated physical adsorption.

This paper provides new information on the possible application of methylene blue as corrosion inhibitor for carbon steel.

This paper aims to investigate the lubrication characteristics of siliconized graphite with a wavy-tilt-dam (WTD) pattern applied to the hydrodynamic face seals.

It focuses on two friction pairs, carbon graphite versus tungsten carbide (CG-TC) and siliconized graphite versus siliconized graphite (SG-SG), through a three-dimensional elastic hydrodynamic lubrication numerical model that integrates finite difference method and finite element method. The consequence of axial elastic deformation of sealing pair materials on film thickness, film pressure, cavitation and sealing performance for a WTD mechanical face seal under full working conditions of ΔP = 0.8, 5.3 and 15.8 MPa are analyzed theoretically.

The nuclear hydrodynamic WTD face seal generates a convergent gap and exhibits a dual-characteristic behavior of hydrodynamic and hydrostatic effects under various ΔP. Compared to the CG-TC, the SG-SG shows a lower minimum film thickness, decreasing by 3.9%, 17.3% and 35.1%. The flow leakage rate decreases by 47.8%, 52.1% and 75.4%. In addition, the film stiffness increases by 46.8%, 49.8% and 97.8%. Thus, the SG-SG better deals with the dynamic tracking problem, and the sealing performance is stable. The strength and hardness of siliconized graphite enhance WTD sealing performance and improve cavitation control in high-pressure applications.

The lubrication characteristics of the siliconized graphite with a WTD pattern could inform the future design of hydrodynamic shallow groove wavy seals in boiler feedwater engineering implements under high-pressure conditions for the nuclear power industry.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-10-2024-0382/

This study aims to investigate the behavior of the green biomass-derived copper (lignin/silica/fatty acids) complex, copper lignin/silica/fatty acids (Cu-LSF) complex, when incorporated into the nonpolar ethylene propylene diene (EPDFM) rubber matrix, focusing on its reinforcing and antioxidant effect on the resulting EPDM composites.

The structure of the prepared EPDM composites was confirmed by Fourier-transform infrared spectroscopy, and the dispersion of the additive fillers and antioxidants in the EPDM matrix was investigated using scanning electron microscopy. Also, the rheometric characteristics, mechanical properties, swelling behavior and thermal gravimetric analysis of all the prepared EPDM composites were explored as well.

Results revealed that the Cu-LSF complex dispersed well in the nonpolar EPDM rubber matrix, in thepresence of coupling system, with enhanced Cu-LSF-rubber interactions and increased cross-linking density, which reflected on the improved rheological and mechanical properties of the resulting EPDM composites. From the various investigations performed in the current study, the authors can suggest 7–11 phr is the optimal effective concentration of Cu-LSF complex loading. Interestingly, EPDM composites containing Cu-LSF complex showed better antiaging performance, thermal stability and fluid resistance, when compared with those containing the commercial antioxidants (2,2,4-trimethyl-1,2-dihydroquinoline and N-isopropyl-N’-phenyl-p-phenylenediamine). These findings are in good agreement with our previous study on polar nitrile butadiene rubber.

The current study suggests the green biomass-derived Cu-LSF complex to be a promising low-cost and environmentally safe alternative filler and antioxidant to the hazardous commercial ones.

The restoration and strengthening of QT600 is an industry bottleneck challenge. The Co-12 cladding layer has great wear and corrosion resistance. The purpose of this paper is to quantitatively reveal the transient evolution law of the corrosion process of Co-12 cladding layer on QT600 surface.

In this paper, a three-dimensional numerical model of the corrosion process of Co-12 cladding layer by QT600 laser cladding is established. The interaction between pitting pits and corrosion medium is considered to reveal the transient evolution of ion concentration, electrode potential, pH and corrosion rate at different locations.

The calculation shows that the ion concentration in pitting pit changes Cl⁻>Co²⁺>Na⁺, pH value decreases from top to bottom and corrosion rate at bottom is greater than that at top. The electrochemical corrosion test of Co-12 cladding layer was carried out. It is shown that the current density of QT600 increases by an order of magnitude compared to the Co-12 cladding layer, and the corrosion rate is 4.862 times higher than that of the cladding layer.

The results show that Co-12 cladding layer has great corrosion resistance, which provides an effective way for QT600 protection.

This research aims to provide a innovative class of shape-memory-responsive cellulosic composites (RCC) for 4D printing, enabling self-activated, reversible shape morphing. By integrating experimental, theoretical, and computational modeling, the study optimizes material behavior, offering precise curvature predictions for advanced biomedical and pharmaceutical applications.

This study presents an innovative class of shape–memory–responsive cellulosic composites (RCC), with a unique combination of starch and Affnisol^TM. RCC-mediated filaments were used to print single-layer strips using fused deposition modeling 3D printing technology. The printed single-layer strip exhibited reversible, contactless and self-activated shape morphing in response to swelling and heat. The programming stage involves the swelling and heating of the composite strip and subsequent shape recovery through heating. The shape deformation during the self-activated programming stage was both estimated and predicted using simple experimental, theoretical and computational tools. The study was conducted at different thicknesses (1.5, 2.0 and 2.5 mm) and temperatures (25°C and 37°C) to validate the performance of the developed model in predicting bending curvature.

The developed model showed less than a 13.96 % difference in curvature predicted using theoretical and experimental modeling at studied temperatures. At lower thicknesses, the model can predict the bending curvature with less than a 2.0 % difference in curvature. These RCC materials exhibited potential reversible 4D printing capacity and satisfied the adopted approaches and modeling to forecast the bending curvature for reversible 4D printing.

This study introduces a new class of composite materials for potential 4D applications and provides simple predictive models to forecast bending curvature in reversible 4D printing.

This paper aims to develop an innovative 3D printer based on material extrusion to expand applied material field and shorten the production cycle. The developed 3D printer can fabricate products directly using various powders, including polymers and fillers. In addition, the influence of extrusion on the orientation of thermal conductive filler is also investigated.

To ensure the plasticizing effect and the mixing ability, the printing head is a conical twin-screw extruder, which have a smaller volume. PA12 and h-BN powders were selected for printing as matrix and filler, respectively. The properties of printing products were characterized.

The results show that the new printer can fabricate products directly using polymer powders because of the mixing ability of the twin-screw. The h-BN filler orient in the PA12 matrix and form thermal conduction paths due to the extrusion process, which make the printed samples have an anisotropic thermal conductivity.

The innovative 3D printer provides a method of printing products directly using powders, which can expand material field and shorten the production cycle. For composites, the extrusion process can make fillers orient in the matrix to fabricate products with anisotropic characteristics.