Sign in to use this feature.

Years

Between: -

Subjects

remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline

Journals

Article Types

Countries / Regions

Search Results (44)

Search Parameters:
Keywords = thermal-capillary force

Order results
Result details
Results per page
Select all
Export citation of selected articles as:
21 pages, 5750 KiB  
Article
Numerical Simulations of Coupled Vapor, Water, and Heat Flow in Unsaturated Deformable Soils During Freezing and Thawing
by Sara Soltanpour and Adolfo Foriero
Geotechnics 2025, 5(3), 51; https://doi.org/10.3390/geotechnics5030051 (registering DOI) - 4 Aug 2025
Abstract
Freezing and thawing cycles significantly affect the mechanical and hydraulic behavior of soils, posing detrimental challenges for infrastructures in cold climates. This study develops and validates a coupled Thermal–Hydraulic–Mechanical (THM) model using COMSOL Multiphysics (Version 6.3) to demonstrate the complexities of vapor and [...] Read more.
Freezing and thawing cycles significantly affect the mechanical and hydraulic behavior of soils, posing detrimental challenges for infrastructures in cold climates. This study develops and validates a coupled Thermal–Hydraulic–Mechanical (THM) model using COMSOL Multiphysics (Version 6.3) to demonstrate the complexities of vapor and water flux, heat transport, frost heave, and vertical stress build-up in unsaturated soils. The analysis focuses on fine sand, sandy clay, and silty clay by examining their varying susceptibilities to frost action. Silty clay generated the highest amount of frost heave and steepest vertical stress gradients due to its high-water retention and strong capillary forces. Fine sand, on the other hand, produced a minimal amount of frost heave and a polarized vertical stress distribution. The study also revealed that vapor flux is more noticeable in freezing fine sand, while silty clay produces the greatest water flux between the frozen and unfrozen zones. The study also assesses the impact of soil properties including the saturated hydraulic conductivity, the particle thermal conductivity, and particle heat capacity on the frost-induced phenomena. Findings show that reducing the saturated hydraulic conductivity has a greater impact on mitigating frost heave than other variations in thermal properties. Silty clay is most affected by these changes, particularly near the soil surface, while fine sand shows less noticeable responses. Full article
Show Figures

Figure 1

27 pages, 10150 KiB  
Article
Numerical Simulation and Experimental Study of the Thermal Wick-Debinding Used in Low-Pressure Powder Injection Molding
by Mohamed Amine Turki, Dorian Delbergue, Gabriel Marcil-St-Onge and Vincent Demers
Powders 2025, 4(3), 22; https://doi.org/10.3390/powders4030022 - 1 Aug 2025
Viewed by 91
Abstract
Thermal wick-debinding, commonly used in low-pressure injection molding, remains challenging due to complex interactions between binder transport, capillary forces, and thermal effects. This study presents a numerical simulation of binder removal kinetics by coupling Darcy’s law with the Phase Transport in Porous Media [...] Read more.
Thermal wick-debinding, commonly used in low-pressure injection molding, remains challenging due to complex interactions between binder transport, capillary forces, and thermal effects. This study presents a numerical simulation of binder removal kinetics by coupling Darcy’s law with the Phase Transport in Porous Media interface in COMSOL Multiphysics. The model was validated and subsequently used to study the influence of key debinding parameters. Contrary to the Level Set method, which predicts isolated binder clusters, the Multiphase Flow in Porous Media method proposed in this work more accurately reflects the physical behavior of the process, capturing a continuous binder extraction throughout the green part and a uniform binder distribution within the wicking medium. The model successfully predicted the experimentally observed decrease in binder saturation with increasing debinding temperature or time, with deviation limited 3–10 vol. % (attributed to a mandatory brushing operation, which may underestimate the residual binder mass). The model was then used to optimize the debinding process: for a temperature of 100 °C and an inter-part gap distance of 5 mm, the debinding time was minimized to 7 h. These findings highlight the model’s practical utility for process design, offering a valuable tool for determining optimal debinding parameters and improving productivity. Full article
Show Figures

Graphical abstract

20 pages, 3007 KiB  
Article
Hydrophobic Collagen/Polyvinyl Alcohol/V2CTx Composite Aerogel for Efficient Oil Adsorption
by Erhui Ren, Jiatong Yan, Fan Yang, Hongyan Xiao, Biyu Peng, Ronghui Guo and Mi Zhou
Polymers 2025, 17(14), 1949; https://doi.org/10.3390/polym17141949 - 16 Jul 2025
Viewed by 342
Abstract
The development of effective oil adsorbents has attracted a great deal of attention due to the increasingly serious problem of oil pollution. A light and porous collagen (COL)/polyvinyl alcohol (PVA)/vanadium carbide (V2CTx) composite aerogel was synthesized using a simple [...] Read more.
The development of effective oil adsorbents has attracted a great deal of attention due to the increasingly serious problem of oil pollution. A light and porous collagen (COL)/polyvinyl alcohol (PVA)/vanadium carbide (V2CTx) composite aerogel was synthesized using a simple method of blending, directional freezing, and drying. After modification with methyltriethoxysilane (MTMS) via chemical vapor deposition, the aerogel possessed an excellent hydrophobicity and its water contact angle reached 135°. The hydrophobic COL/PVA/V2CTx composite aerogel exhibits a porous structure with a specific surface area of 49 m2/g. It also possesses prominent mechanical properties with an 80.5 kPa compressive stress at 70% strain, a low density (about 28 mg/cm3), and outstanding thermal stability, demonstrating a 61.02% weight loss from 208 °C to 550 °C. Importantly, the hydrophobic COL/PVA/V2CTx aerogel exhibits a higher oil absorption capacity and stability, as well as a faster absorption rate, than the COL/PVA aerogel when tested with various oils. The hydrophobic COL/PVA/V2CTx aerogel has the capacity to adsorb 80 times its own weight of methylene chloride, with help from hydrophobic interactions, Van der Waals forces, intermolecular interactions, and capillary action. Compared with the pseudo first-order model, the pseudo second-order model is more suitable for oil adsorption kinetics. Therefore, the hydrophobic COL/PVA/V2CTx aerogel can be used as an environmentally friendly and efficient oil adsorbent. Full article
(This article belongs to the Section Polymer Applications)
Show Figures

Graphical abstract

20 pages, 5699 KiB  
Article
Upcycling of Agro-Waste: Research on Performance of a Novel Super-Hygroscopic Material Prepared by Exploiting the Porous Structure of Steam-Exploded Modified Corn Stalk Pith
by Nan Wang, Chuntao Xia, Tingting Liu and Dawei Wang
Polymers 2025, 17(13), 1779; https://doi.org/10.3390/polym17131779 - 27 Jun 2025
Viewed by 281
Abstract
Herein, a novel super-hygroscopic material, steam-exploded modified corn stalk pith (SE-CSP), was developed from corn stalk pith (CSP) via the steam explosion (SE) method, and its hygroscopic properties and mechanisms were evaluated. The results confirmed that SE effectively removed lignin and hemicellulose, disrupted [...] Read more.
Herein, a novel super-hygroscopic material, steam-exploded modified corn stalk pith (SE-CSP), was developed from corn stalk pith (CSP) via the steam explosion (SE) method, and its hygroscopic properties and mechanisms were evaluated. The results confirmed that SE effectively removed lignin and hemicellulose, disrupted the thin cell walls of natural CSP, and formed an aligned porous structure with capillary channels. SE changed the bonding distribution and surface morphology, and enhanced the crystallinity and thermal stability of CSP. The equilibrium hygroscopic percentage of SE-CSP (62.50%) was higher than that of CSP (44.01%) at 25 °C and 80% relative humidity (RH), indicating significantly greater hygroscopicity. The hygroscopic process of SE-CSP followed a Type III isotherm and fitted the Guggenheim–Anderson–de Boer (GAB), Peleg, and pseudo-first-order kinetic models. This process exhibited multi-layer adsorption with enthalpy-driven, exothermic behavior, primarily through physical adsorption involving hydrogen bonds and van der Waals forces. This work offered a new approach for advancing sorption dehumidification technology. Full article
(This article belongs to the Special Issue Applications of Polymer-Based Absorbent Materials)
Show Figures

Graphical abstract

18 pages, 3144 KiB  
Article
Comparative Forced Degradation Study of Anticomplement C5 Biosimilar and Originator Monoclonal Antibodies
by Merve Celik Yamaci, Ceren Pamukcu, Yigit Erdemgil, Ahmet Emin Atik, Zeynep Zulfiye Yildirim Keles and Ozge Can
Pharmaceuticals 2025, 18(4), 579; https://doi.org/10.3390/ph18040579 - 16 Apr 2025
Cited by 1 | Viewed by 881
Abstract
Background/Objectives: The stress testing of biotherapeutic products is a critical component of drug development, enabling the assessment of stability, biosimilarity, and degradation pathways. Subjecting biosimilar monoclonal antibodies to controlled stress conditions yields essential insights into their structural and functional integrity, informing formulation [...] Read more.
Background/Objectives: The stress testing of biotherapeutic products is a critical component of drug development, enabling the assessment of stability, biosimilarity, and degradation pathways. Subjecting biosimilar monoclonal antibodies to controlled stress conditions yields essential insights into their structural and functional integrity, informing formulation optimization and mitigating risks before clinical trials. In this study, biosimilar products were comprehensively characterized and compared with originator products under forced degradation. The aim was to expose the products to different stress conditions such as oxidative, pH, thermal, freeze/thaw, and agitation. The products were then tested at defined time points using validated analytical methods. Methods: This study employed size-exclusion chromatography to detect aggregated forms. Isoelectric focusing characterized protein charge variants (e.g., acidic/basic isoforms) from post-translational modifications, while capillary electrophoresis quantified product-related impurities (aggregates and fragments). In addition, a complement assay was used to determine the efficacy and potency under specific stress conditions. Results: Our findings showed that biosimilar and originator products exhibited similar degradation profiles. The biosimilar monoclonal antibody was found to be analytically similar to the originator product in terms of critical parameters related to efficacy and safety under various stress conditions such as aggregation profile, biological activity, and charge variant distribution. Conclusions: Forced degradation studies facilitated the comprehensive and well-validated characterization of the structure and biological activity of biosimilar monoclonal antibody products. Full article
(This article belongs to the Special Issue Biosimilars Development Strategies)
Show Figures

Figure 1

12 pages, 2254 KiB  
Article
Activation Energy of SDS–Protein Complexes in Capillary Electrophoresis with Tetrahydroxyborate Cross-Linked Agarose Gels
by Dániel Sárközy and András Guttman
Gels 2024, 10(12), 805; https://doi.org/10.3390/gels10120805 - 7 Dec 2024
Cited by 1 | Viewed by 1060
Abstract
Hydrogels like agarose have long been used as sieving media for the electrophoresis-based analysis of biopolymers. During gelation, the individual agarose strands tend to form hydrogen-bond mediated double-helical structures, allowing thermal reversibility and adjustable pore sizes for molecular sieving applications. The addition of [...] Read more.
Hydrogels like agarose have long been used as sieving media for the electrophoresis-based analysis of biopolymers. During gelation, the individual agarose strands tend to form hydrogen-bond mediated double-helical structures, allowing thermal reversibility and adjustable pore sizes for molecular sieving applications. The addition of tetrahydroxyborate to the agarose matrix results in transitional chemical cross-linking, offering an additional pore size adjusting option. Separation of SDS-proteins during gel electrophoresis is an activated process defined by the interplay between viscosity, gelation/cross-link formation/distortion, and sample conformation. In this paper, the subunits of a therapeutic monoclonal antibody were separated by capillary SDS agarose gel electrophoresis at different temperatures. The viscosity of the separation matrix was also measured at all temperatures. In both instances, Arrhenius plots were used to obtain the activation energy values. It was counterintuitively found that larger SDS–protein complexes required lower activation energies while their low-molecular-weight counterparts needed higher activation energy for their electromigration through the sieving matrix. As a first approximation, we considered this phenomenon the result of the electric force-driven distortion of the millisecond range lifetime reticulations by the larger and consequently more heavily charged electromigrating molecules. In the meantime, the sieving properties of the gel were still maintained, i.e., they allowed for the size-based separation of the sample components, proving the existence of the reticulations. Information about the activation energy sheds light on the possible deformation of the sieving matrix and the solute molecules. In addition, the activation energy requirement study helped in optimizing the separation temperature, e.g., with our sample mixture, the highest resolution was obtained for the high-molecular-weight fragments, i.e., between the non-glycosylated heavy chain and heavy-chain subunits at 25 °C (lower Ea requirement), while 55 °C was optimal for the lower-molecular-weight light chain and non-glycosylated heavy chain pair (lower Ea requirement). Future research directions and possible applications are also proposed. Full article
(This article belongs to the Section Gel Applications)
Show Figures

Graphical abstract

12 pages, 4539 KiB  
Article
A Flexible Sensing Material with High Force and Thermal Sensitivity Based on GaInSn in Capillary Embedded in PDMS
by Fandou Bao, Fengyao Ni, Qianqian Zhai, Zhizhuang Sun, Xiaolin Song and Yu Lin
Polymers 2024, 16(23), 3426; https://doi.org/10.3390/polym16233426 - 5 Dec 2024
Viewed by 1164
Abstract
Flexible sensing materials have become a hot topic due to their sensitive electrical response to external force or temperature and their promising applications in flexible wear and human–machine interaction. In this study, a PDMS/capillary GaInSn flexible sensing material with high force and thermal [...] Read more.
Flexible sensing materials have become a hot topic due to their sensitive electrical response to external force or temperature and their promising applications in flexible wear and human–machine interaction. In this study, a PDMS/capillary GaInSn flexible sensing material with high force and thermal sensitivity was prepared utilizing liquid metal (LM, GaInSn), flexible silicone capillary, and polydimethylsiloxane (PDMS). The resistance (R) of the flexible sensing materials under the action of different forces and temperatures was recorded in real-time. The electrical performance results confirmed that the R of the sensing material was responsive to temperature changes and increased with the increasing temperature, indicating its ability to transmit temperature signals into electrical signals. The R was also sensitive to the external force, such as cyclic stretching, cyclic compression, cyclic bending, impact and rolling. The ΔR/R0 changed periodically and stably with the cyclic stretching, cyclic compression and cyclic bending when the conductive pathway diameter was 0.5–1.0 mm, the cyclic tensile strain ≤ 20%, the cyclic tensile rate ≤ 2.0 mm/min, the compression ratio ≤ 0.5, and the relative bending curvature ≤ 0.16. Moreover, the material exhibited sensitivity in detecting biological signals, such as the joint movements of the finger, wrist, elbow and the stand up-crouch motion. In conclusion, this work provides a method for preparing a sensing material with the capillary structure, which was confirmed to be sensitive to force and heat, and it produced different types of R signals under different deformations and different temperatures. Full article
(This article belongs to the Section Smart and Functional Polymers)
Show Figures

Figure 1

40 pages, 11424 KiB  
Review
Modeling, Design, and Optimization of Loop Heat Pipes
by Yihang Zhao, Mingshan Wei and Dan Dan
Energies 2024, 17(16), 3971; https://doi.org/10.3390/en17163971 - 10 Aug 2024
Cited by 1 | Viewed by 3686
Abstract
Thermal management technology based on loop heat pipes (LHPs) has broad application prospects in heat transfer control for aerospace and new energy vehicles. LHPs offer excellent heat transfer performance, reliability, and flexibility, making them suitable for high-heat flux density, high-power heat dissipation, and [...] Read more.
Thermal management technology based on loop heat pipes (LHPs) has broad application prospects in heat transfer control for aerospace and new energy vehicles. LHPs offer excellent heat transfer performance, reliability, and flexibility, making them suitable for high-heat flux density, high-power heat dissipation, and complex thermal management scenarios. However, due to limitations in heat source temperature and heat transfer power range, LHP-based thermal management systems still face challenges, especially in thermohydraulic modeling, component design, and optimization. Steady-state models improve computational efficiency and accuracy, while transient models capture dynamic behavior under various conditions, aiding performance evaluation during start-up and non-steady-state scenarios. Designs for single/multi-evaporators, compensation chambers, and wick materials are also reviewed. Single-evaporator designs offer compact and efficient start-up, while multi-evaporator designs handle complex thermal environments with multiple heat sources. Innovations in wick materials, such as porous metals, composites, and 3D printing, enhance capillary driving force and heat transfer performance. A comprehensive summary of working fluid selection criteria is conducted, and the effects of selecting organic, inorganic, and nanofluid working fluids on the performance of LHPs are evaluated. The selection process should consider thermodynamic properties, safety, and environmental friendliness to ensure optimal performance. Additionally, the mechanism and optimization methods of the start-up behavior, temperature oscillation, and non-condensable gas on the operating characteristics of LHPs were summarized. Optimizing vapor/liquid distribution, heat load, and sink temperature enhances start-up efficiency and minimizes temperature overshoot. Improved capillary structures and working fluids reduce temperature oscillations. Addressing non-condensable gases with materials like titanium and thermoelectric coolers ensures long-term stability and reliability. This review comprehensively discusses the development trends and prospects of LHP technology, aiming to guide the design and optimization of LHP. Full article
Show Figures

Figure 1

13 pages, 14379 KiB  
Article
Enhancing Mesopore Volume and Thermal Insulation of Silica Aerogel via Ambient Pressure Drying-Assisted Foaming Method
by Jinjing Guo, Kaiqiang Luo, Wenqi Zou, Jun Xu and Baohua Guo
Materials 2024, 17(11), 2641; https://doi.org/10.3390/ma17112641 - 30 May 2024
Cited by 1 | Viewed by 1376
Abstract
Ambient pressure drying (APD) of silica aerogels has emerged as an attractive method adapting to large-scale production. Spring-back is a unique phenomenon during APD of silica aerogels with volume expansion after its shrinkage under capillary force. We attribute the intense spring-back at elevated [...] Read more.
Ambient pressure drying (APD) of silica aerogels has emerged as an attractive method adapting to large-scale production. Spring-back is a unique phenomenon during APD of silica aerogels with volume expansion after its shrinkage under capillary force. We attribute the intense spring-back at elevated drying temperatures to a dense structure formed on the surface and the formation of positive internal pressure. Furthermore, an APD-assisted foaming method with an in situ introduction of NH4HCO3 was proposed. NH4HCO3 decomposing at drying temperatures hastened the emergence of positive pressure, thereby increasing the expansion volume. Compared to the previous method, the porosity of silica aerogel increased from 82.2% to 92.6%, and mesopore volume from 1.79 cm3 g−1 to 4.54 cm3 g−1. By adjusting the amount of the silicon source, silica aerogels prepared by the APD-assisted foaming method generated higher volume expansion and lower thermal conductivity. After calcination to remove undecomposed ammonium salts, the hydrophobic silica aerogel with a density of 0.112 g cm−3 reached a mesopore volume of 5.07 cm3 g−1 and a thermal conductivity of 18.9 mW m−1·K−1. This strategy not only improves the thermal insulation properties, but also offers a significant advancement in tailoring silica aerogels with specific porosity and mesopore volume for various applications. Full article
Show Figures

Figure 1

16 pages, 4792 KiB  
Article
Anti-Cracking TEOS-Based Hybrid Materials as Reinforcement Agents for Paper Relics
by Mengruo Wu, Le Mu, Zhiyue Zhang, Xiangna Han, Hong Guo and Liuyang Han
Molecules 2024, 29(8), 1834; https://doi.org/10.3390/molecules29081834 - 17 Apr 2024
Cited by 8 | Viewed by 1700
Abstract
Tetraethoxysilane (TEOS) is the most commonly used silicon-based reinforcement agent for conserving art relics due to its cost-effectiveness and commercial maturity. However, the resulting silica gel phase is prone to developing cracks as the gel shrinks during the sol–gel process, potentially causing severe [...] Read more.
Tetraethoxysilane (TEOS) is the most commonly used silicon-based reinforcement agent for conserving art relics due to its cost-effectiveness and commercial maturity. However, the resulting silica gel phase is prone to developing cracks as the gel shrinks during the sol–gel process, potentially causing severe damage to the objects being treated. In this study, dodecyltrimethoxysilane (DTMS) was introduced into TEOS to minimize this shrinkage by adding elastic long chains to weaken the capillary forces. The gel formed from the DTMS/TEOS hybrid material was transparent and crack-free, featuring a dense microstructure without mesopores or micropores. It exhibited excellent thermal stability, with a glass transition temperature of up to 109.64 °C. Evaluation experiments were conducted on artificially aged, handmade bamboo paper. The TEOS-based hybrid material effectively combined with the paper fibers through the sol–gel process, polymerizing into a network structure that enveloped the paper surface or penetrated between the fibers. The surface of the treated paper displayed excellent hydrophobic properties, with no significant changes in appearance, color, or air permeability. The mechanical properties of the treated bamboo paper improved significantly, with longitudinal and transverse tensile strengths increasing by up to 36.63% and 44.25%, respectively. These research findings demonstrate the promising potential for the application of DTMS/TEOS hybrid materials in reinforcing paper relics. Full article
(This article belongs to the Special Issue Chemical Conservation of Paper-Based Cultural Heritage)
Show Figures

Figure 1

17 pages, 14360 KiB  
Article
Heat Transfer Performance of a 3D-Printed Aluminum Flat-Plate Oscillating Heat Pipe Finned Radiator
by Xiu Xiao, Ying He, Qunyi Wang, Yaoguang Yang, Chao Chang and Yulong Ji
Nanomaterials 2024, 14(1), 60; https://doi.org/10.3390/nano14010060 - 25 Dec 2023
Cited by 4 | Viewed by 2497
Abstract
As electronic components progressively downsize and their power intensifies, thermal management has emerged as a paramount challenge. This study presents a novel, high-efficiency finned heat exchanger, termed Flat-Plate Oscillating Heat Pipe Finned Radiator (FOHPFR), which employs arrayed flat-plate oscillating heat pipes (OHP) as [...] Read more.
As electronic components progressively downsize and their power intensifies, thermal management has emerged as a paramount challenge. This study presents a novel, high-efficiency finned heat exchanger, termed Flat-Plate Oscillating Heat Pipe Finned Radiator (FOHPFR), which employs arrayed flat-plate oscillating heat pipes (OHP) as heat dissipation fins. Three-dimensional (3D)-printed techniques allow the internal microchannels of the FOHPFR to become rougher, providing excellent surface wettability and capillary forces, which in turn significantly improves the device’s ability to dissipate heat. In this study, the 3D-printed FOHPFR is compared with traditional solid finned radiators made of identical materials and designs. The impacts of filling ratio, inclination angle, and cold-end conditions on the heat transfer performance of the 3D-printed FOHPFR are investigated. It is demonstrated by the results that compared to solid finned radiators, the FOHPFR exhibits superior transient heat absorption and steady-state heat transfer capabilities. When the heating power is set at 140 W, a decrease in thermal resistance from 0.32 °C/W in the solid type to 0.11 °C/W is observed in the FOHPFR, marking a reduction of 65.6%. Similarly, a drop in the average temperature of the heat source from 160 °C in the solid version to 125 °C, a decrease of 21.8%, is noted. An optimal filling ratio of 50% was identified for the vertical 3D-printed FOHPFR, with the minimal thermal resistance achieving 0.11 °C/W. Moreover, the thermal resistance of the 3D-printed FOHPFR is effectively reduced compared to that of the solid finned radiator at all inclination angles. This indicates that the FOHPFR possessed notable adaptability to various working angles. Full article
(This article belongs to the Special Issue Advances in Nano-Enhanced Thermal Functional Materials)
Show Figures

Figure 1

14 pages, 10173 KiB  
Article
Testing Various Cement Formulations under Temperature Cycles and Drying Shrinkage for Low-Temperature Geothermal Wells
by Hartmut R. Fischer and Al Moghadam
Materials 2023, 16(23), 7281; https://doi.org/10.3390/ma16237281 - 23 Nov 2023
Viewed by 1306
Abstract
Low-enthalpy geothermal wells are considered a sustainable energy source, particularly for district heating in the Netherlands. The cement sheath in these wells experiences thermal cycles. The stability of cement recipes under such conditions is not well understood. In this work, thermal cycling experiments [...] Read more.
Low-enthalpy geothermal wells are considered a sustainable energy source, particularly for district heating in the Netherlands. The cement sheath in these wells experiences thermal cycles. The stability of cement recipes under such conditions is not well understood. In this work, thermal cycling experiments for intermediate- and low-temperature geothermal well cements have been conducted. The samples were cured either under ambient conditions or under realistic pressure and temperature for 7 days. The samples did not show any signs of failure after performing 10 cycles of thermal treatment between 100 °C and 18 °C. We also tested cement formulations under drying conditions. Drying shrinkage is caused by a reduction in the water content of cement, which leads to capillary forces that can damage cement. Such circumstances lead to tensile stresses causing radial cracks. Most samples exhibited cracks under low humidity conditions (drying). Fiber reinforcement, especially using short PP fibers, improved the cement’s resilience to temperature and humidity changes. Such additives can improve the longevity of cement sheaths in geothermal wells. Full article
Show Figures

Figure 1

16 pages, 7882 KiB  
Article
Experimental Investigation on Thermal Performance of Vapor Chambers with Diffident Wick Structures
by Yujuan Xia, Feng Yao and Mengxiang Wang
Energies 2023, 16(18), 6464; https://doi.org/10.3390/en16186464 - 7 Sep 2023
Cited by 5 | Viewed by 2722
Abstract
In this paper, a type of vapor chamber with a gradient pore size wick (VC-G) was developed, and its thermal performance was experimentally tested and compared with two types of VCs with uniform pore size wick (which can be defined as VC-U (200) [...] Read more.
In this paper, a type of vapor chamber with a gradient pore size wick (VC-G) was developed, and its thermal performance was experimentally tested and compared with two types of VCs with uniform pore size wick (which can be defined as VC-U (200) and VC-U (50) as the powder size of the wick is 50-mesh and 200-mesh, respectively) and a VC without a wick (VC-N). In addition, a VC heat transfer ability experiment platform was built, and the thermal resistance, temperature distribution and thermal response time of the VC with different wick structures were experimentally investigated. The experiment results show that the capillary driving force provided by gradient pore size wick increases gradually from outside, which can not only promote the condensation fluid to gather in the central heat source but also facilitate the vapor to spread around. Therefore, compared with VC-U (200), VC-U (50) and VC-N, VC-G shows the best heat transfer performance, temperature uniform performance and start-up performance. Full article
(This article belongs to the Special Issue Heat and Mass Transfer 2023)
Show Figures

Figure 1

13 pages, 2089 KiB  
Article
Experimental Investigation of Temperature Distribution in a Laminar Boundary Layer over a Heated Flat Plate with Localized Transverse Cold Air Injections
by Muhammad Ehtisham Siddiqui, Ammar A. Melaibari and Fahad Sarfraz Butt
Energies 2023, 16(17), 6171; https://doi.org/10.3390/en16176171 - 25 Aug 2023
Viewed by 1993
Abstract
This study presents an experimental investigation focused on the interaction between a transverse injection of cold air (blowing) and the boundary layer over a heated flat plate. The flat plate was equipped with a cylindrical coil heater positioned at its center along the [...] Read more.
This study presents an experimental investigation focused on the interaction between a transverse injection of cold air (blowing) and the boundary layer over a heated flat plate. The flat plate was equipped with a cylindrical coil heater positioned at its center along the flow direction. The constant heat flux was maintained using a variable resistance potentiometer. The flat plate with the heater was mounted inside a subsonic wind tunnel to sustain a constant laminar air flow. The primary objective of this research was to examine the effects of cold air injections through localized holes in the flat plate near the trailing edge on the thermal boundary layer thickness δt(x,Rex,Pr). The thermal boundary layer thickness was measured using K-type thermocouples and PT-100 RTD sensors, which are made to move precise, small distances using a specially constructed traversing mechanism. Cold air was injected using purposefully fabricated metal capillary tubes force-fitted into holes through the hot flat plate. The metal tubes were thermally insulated using class-F insulation, which is used in electric motor windings. The presented work focused on a fixed free-stream velocity and a fixed cold-injection velocity less than the free-stream velocity but for two-variable heat fluxes. The results show that the thermal boundary layer thickness generally increased due to the secondary cold flow. Full article
(This article belongs to the Collection Advances in Heat Transfer Enhancement)
Show Figures

Figure 1

25 pages, 203904 KiB  
Article
Properties and Model of a Lacustrine Shale Oil Reservoir: A Case Study of the Upper Fourth Member and Lower Third Member of the Shahejie Formation in Dongying Sag and Zhanhua Sag, Jiyang Depression
by Cunfei Ma, Xianxu Fang, Xiaonan Ma, Xiantai Liu, Bingkun Xu and Xinmin Ge
J. Mar. Sci. Eng. 2023, 11(7), 1441; https://doi.org/10.3390/jmse11071441 - 19 Jul 2023
Cited by 2 | Viewed by 2115
Abstract
By combining thermal simulation experiments with core data, thin sections, scanning electron microscopy (SEM), source rock, and high-pressure mercury and gas adsorption analysis, this paper evaluates the properties and models of shale reservoirs in the upper fourth member and the lower third member [...] Read more.
By combining thermal simulation experiments with core data, thin sections, scanning electron microscopy (SEM), source rock, and high-pressure mercury and gas adsorption analysis, this paper evaluates the properties and models of shale reservoirs in the upper fourth member and the lower third member of the Shahejie Formation in Dongying Sag and Zhanhua Sag. The results show that the oil shale is a high-quality source rock with petroleum generation potential. Inorganic mineral pores, organic pores, and fractures have developed with petroleum storage capacity. Clay and organic-rich soft shale lithofacies are interbedded with carbonate-rich hard shale lithofacies to form sandwich-type source–reservoir–caprock assemblages with internal sealing properties. Bitumen occurs mostly in the free state, and to a lesser extent is adsorbed, and shows flow characteristics. The migration resistance of the bitumen is displacement pressure, including capillary force and adsorption resistance, and the main force is pore fluid pressure. The migration modes of the bitumen include both subcritical flow and instantaneous flow, which are controlled by pore fluid pressure, displacement pressure, and the rock’s fracture strength. Owing to the multi-scale characteristics of the shale reservoir space, a vein-type model of a multi-scale progressive transport network is developed that obeys Murray’s law with a dominant migration pathway in the shale reservoir. The shale oil reservoir is a special lithologic reservoir controlled by the sedimentary environment and has self-generation, self-storage, and self-sealing characteristics with developed pore fluid overpressure and a multi-scale transport network. Full article
(This article belongs to the Special Issue High-Efficient Exploration and Development of Oil & Gas from Ocean)
Show Figures

Figure 1

Back to TopTop