Article
Construction & Building Technology
Haibo Ding, Azuo Nili, Jiale Chen, Zonghao Yang, Hadis Jemal Muktar, David Connolly, Yanjun Qiu
Summary: To better understand the thermoreversible aging of heavily oxidized asphalt, experiments on six different asphalt samples with various C20H42 proportions were conducted, including extended bending beam rheometer (ExBBR) tests, modulated differential scanning calorimetry (MDSC) tests, and atomic force microscope (AFM) observations. The results demonstrate that heavy oxidation affects both the low temperature properties and thermoreversible aging characteristics of asphalt, with the former being influenced by storage temperature. The increased viscosity due to heavy oxidation hinders C20H42 migration, but higher storage temperature promotes thermoreversible aging by facilitating wax molecule movement. Furthermore, analysis reveals that the grade loss of asphalt blended with C30H62 varies at different storage temperatures and oxidation levels, indicating the importance of selecting multiple storage temperatures for testing heavily oxidized asphalt. Combined with thermal and morphological analysis, heavy oxidation increases wax precipitation, lowers the Tg of asphalt, and forms more perfect crystals during low temperature storage, thereby significantly enhancing thermoreversible aging. Finally, the incorporation of C20H42 intensifies physical hardening of asphalt, highlighting the need to study the effect of asphalt wax content on the degree of thermoreversible aging in heavily oxidized asphalt.
CONSTRUCTION AND BUILDING MATERIALS
(2023)
Article
Construction & Building Technology
Haibo Ding, Simon A. M. Hesp
Summary: Thermoreversible aging of asphalt is an important attribute that affects durability of flexible pavements. The aging process strongly depends on composition and particularly wax content. Binders produced from oil sands-derived crude oil with low wax contents benefit overall life cycle costs and improve the sustainability of the road building industry.
CONSTRUCTION AND BUILDING MATERIALS
(2021)
Article
Food Science & Technology
Ziyu Wang, Jayani Chandrapala, Tuyen Truong, Asgar Farahnaky
Summary: The interactions between ethylcellulose (EC) and natural waxes in structuring edible oil are not well explored. In this study, novel oleogels were prepared using a lower concentration of EC (4%) with beeswax (BW) and carnauba wax (CRW). The addition of EC improved the properties of the wax oleogels, including increased yield stress and flow point. These findings suggest that EC/wax mixtures have potential as solid fat substitutes.
Article
Engineering, Chemical
Yu Zhang, Qiyu Huang, Yamei Liu, Yiran Liu, Rongbin Li, Yijie Wang, Xun Zhang
Summary: In this study, the behavior and differences of wax deposition in polyethylene pipes and stainless steel pipes were compared. It was found that there were differences in weight and content of wax deposition between the two materials. Moreover, important parameters such as diffusivity and temperature gradient played significant roles and had a significant impact on radial mass flux. Higher diffusivity in polyethylene pipes enhanced the diffusion flux of wax in the radial direction, while a larger radial concentration gradient played a decisive role.
Article
Chemistry, Multidisciplinary
Yudou Wang, Xu Zhu, Minghui Gao, Bo Zhang, Lei Zhu
Summary: This paper introduces a degradable glutinous rice/chitosan-phytic acid composite coating that can solve the problem of wax deposition on pipeline surfaces. The coating exhibits excellent antifouling and antiwaxing performance.
Article
Green & Sustainable Science & Technology
Pavel Ilushin, Kirill Vyatkin, Anton Kozlov
Summary: This paper presents a new empirical model for addressing wax deposits in oil production. The model considers oil flow conditions, laboratory data, and product water cut. Industrial operation experience showed a high convergence between calculated and actual deposit profiles, with a standard deviation of maximum wax thickness of 6.0% and a depth with the greatest wax thickness of 3.5%. The use of this technique optimizes well cleaning, heating cable installation, and hot flushing parameters, increasing efficiency and reducing costs.
Article
Energy & Fuels
Charlie van der Geest, Leticia Bizarre, Aline Melchuna, Ivanei F. Pinheiro, Vanessa C. B. Guersoni
Summary: This paper presents evidence that wax deposition is limited by phase transition (heat transfer) and shows that heat transfer equations can accurately predict the thickness of wax deposition. Therefore, the boundary condition in wax deposition simulators needs to be improved.
Article
Energy & Fuels
Fei Yang, Haoran Zhu, Chuanxian Li, Bo Yao, Feng Wang, Jinxiu Chen, Guangyu Sun
Summary: The study focuses on the impacts and mechanisms of asphaltenes and wax inhibitors on the wax deposition characteristics of model waxy oil. It is found that the presence of asphaltenes and wax inhibitors can lead to thinner and harder wax deposits, without significantly affecting the solubility of wax crystals. Additionally, the adsorption of EVA molecules on asphaltene surfaces can improve crude oil rheology at low temperatures and inhibit wax deposition.
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
(2021)
Article
Energy & Fuels
Huiyuan Li, Jinjun Zhang, Qinggong Xu, Yadong Sun, Yiwei Xie, Shanpeng Han, Changchun Wu
Summary: The study found that waxy deposits with less polar asphaltenes have lower mass but higher wax content, affecting the diffusion rates of wax molecules and the internal diffusion coefficient of the deposits. Waxy deposits formed with less polar asphaltenes exhibit higher resistance and structural strength.
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
(2021)
Article
Engineering, Multidisciplinary
Benchun Yao, Zichen He, Na Lu, Shimin Zhang
Summary: This paper introduces a novel PIG and its pigging scheme, highlighting its innovative features and motion control mechanism. Furthermore, an intelligent wax-removal algorithm based on Convolutional Neural Network is proposed and its superiority is demonstrated, laying the foundation for future practical applications.
INTERNATIONAL JOURNAL OF PRESSURE VESSELS AND PIPING
(2022)
Article
Engineering, Chemical
Weigang Du, Yongsheng An, Liyong Guan, Chengchen Xiong, Runshi Huo, Bing Tang
Summary: This study presents a thermal dynamic wax removal method using hot nitrogen gas circulation and develops a temperature calculation model for a wellbore considering different injection parameters. It provides a design method for wax removal and plug removal.
Review
Energy & Fuels
Weidong Li, Wenda Wang, Jirong Ran, Huiyuan Li, Jianxun Liu
Summary: This paper focuses on the issues in flow assurance of crude oil pipeline transportation, particularly on pig stalling and wax blockage. By extensively surveying multiple field pigging operations, it summarizes the experience and lessons obtained from these incidents. The drawn experience and lessons are helpful for scheduling pigging program and enhancing the security of pipelines.
PETROLEUM SCIENCE AND TECHNOLOGY
(2022)
Article
Engineering, Chemical
Rongbin Li, Qiyu Huang, Dongxu Zhang, Xiangrui Zhu, Jinxu Shan, Zhimin Li
Summary: Through comparing the diffusivity of wax, radial thermal gradient, and wax precipitation rate in PE and SS pipes, it was found that these factors have interrelated effects, with the thermal gradient playing a dominant role in the migration of wax from the oil bulk to the deposits. The diffusivity of wax in the PE pipe was higher, while the radial thermal gradient and wax precipitation rate were lower.
Article
Energy & Fuels
Haoran Zhu, Yun Lei, Chuanxian Li, Bo Yao, Fei Yang, Shuangshuang Li, Haoping Peng, Pengfei Yu
Summary: This study used methane as a substitute for dissolved gas in crude oils and developed a series of pressurized laboratory apparatuses to investigate the influence of dissolved methane on the flowability and wax deposition of Changqing waxy crude oil. It was found that dissolved methane improved the flowability of the crude oil and inhibited wax deposition rate. However, it increased the wax appearance temperature, average wax content of deposits, and mass of wax diffused into deposits. These results have significant implications for the design of pipeline networks and calculation of wax deposition.
Review
Materials Science, Multidisciplinary
Xiao Han, Geng Wu, Shuyan Zhao, Jingjing Guo, Muyu Yan, Xun Hong, Dingsheng Wang
Summary: High-entropy alloys (HEAs) are a new type of alloy with multiple elements at equal or near-equal ratios. Their tunable multicomponent structure and potential novel properties have attracted a lot of attention. However, understanding the atomic structure of HEAs and their catalytic performance is challenging due to the complex composition. This review aims to provide insights into HEAs, summarize their structure and catalytic performance, and promote the design of efficient catalysts based on HEAs.
Article
Energy & Fuels
Mohamed F. El-Amin, Budoor Alwated, Hussein A. Hoteit
Summary: This study utilizes machine learning methods to forecast nanoparticle transport with two-phase flow in porous media. Various machine learning techniques, including gradient boosting regression, decision trees, random forests, and artificial neural networks, are employed. The results show that the artificial neural network model performs the best in predicting the transport of nanoparticles in porous media.
Review
Energy & Fuels
Nilanjan Pal, Yara Alzahid, Abdulkareem M. AlSofi, Muhammad Ali, Hussein Hoteit
Summary: The area of conformance improvement technology (CIT) involves the use of various conventional fluids, such as polymers, gels, foams, bacteria, and emulsions. However, these methods have limitations due to degradation, damage, and segregation issues. To overcome these problems, microemulsions, which are stable fluids with tunable properties, can be used by injecting the optimal dosage of surfactants. Microemulsions can plug high permeability pore throats and improve flow stability through molecular interactions. However, more research is needed to validate their design and application for conformance improvement.
Article
Energy & Fuels
Hussein Hoteit, Xupeng He, Bicheng Yan, Volker Vahrenkamp
Summary: This work presents a novel method for estimating thermal recovery and produced-enthalpy rates in geothermal field modeling. It combines uncertainty quantification and optimization, using time-continuous, multi-objective uncertainty quantification technique. The method utilizes a database of 135 geothermal fields to determine uncertainty ranges, and evaluates thermal recovery and produced-enthalpy rates as functions of dimensionless uncertainty parameters. It can be applied to geothermal field modeling with re-injection when detailed subsurface data are not available, quantifying time-continuous uncertainty and global sensitivity.
Article
Energy & Fuels
Amer Alanazi, Ahmed Farid Ibrahim, Saleh Bawazer, Salaheldin Elkatatny, Hussein Hoteit
Summary: For the purpose of carbon capture, utilization, and storage, this study presents a machine-learning framework that predicts CO2 adsorption in coal formations based on various coal properties and testing conditions. The ML techniques used include decision tree regression, random forests, gradient boost regression, K-nearest neighbor, artificial neural network, function network, and adaptive neuro-fuzzy inference system.
INTERNATIONAL JOURNAL OF COAL GEOLOGY
(2023)
Article
Computer Science, Interdisciplinary Applications
Anis Younes, Behshad Koohbor, Marwan Fahs, Hussein Hoteit
Summary: This work introduces a new model for simulating variable density flow in fractured porous media using advanced cell-centered numerical methods. The model utilizes a hybrid mixed finite element method for flow discretization in the matrix and fracture continua, and the discontinuous Galerkin method for advection-dominated transport in fractures. It ensures continuity of various properties at matrix-fracture interfaces and intersection of fractures. The model also uses high-order adaptive time integration techniques for time discretization, improving accuracy and efficiency.
JOURNAL OF COMPUTATIONAL PHYSICS
(2023)
Article
Chemistry, Physical
Nilanjan Pal, Yara Alzahid, Abdulkareem M. AlSofi, Muhammad Ali, Xuan Zhang, Hussein Hoteit
Summary: This article discusses the use of microemulsion-assisted conformance improvement technology (ME-CIT) to decrease the water-to-oil ratio during production operations. Experimental validation is carried out to identify the phase behavior of surfactant-based microemulsions. The results show the presence of different Winsor phases at varying salinity levels and demonstrate the favorable flow attributes of microemulsions.
JOURNAL OF MOLECULAR LIQUIDS
(2023)
Article
Water Resources
Sara Tabrizinejadas, Anis Younes, Hussein Hoteit, Jerome Carrayrou, Marwan Fahs
Summary: Modeling dissolution processes in discrete fracture networks (DFNs) is a challenging task. In this work, an advanced Discontinuous Galerkin (DG) model is developed to simulate transport with dissolution in DFNs. The model successfully captures the nonlinear coupling between flow, mass transport, and reactive processes associated with fracture aperture evolution by dissolution. Numerical examples show that the DG-DFN model avoids unphysical oscillations and reduces numerical diffusion, providing accurate and efficient simulations of flow, transport, and aperture evolution processes in DFNs.
ADVANCES IN WATER RESOURCES
(2023)
Article
Green & Sustainable Science & Technology
Sara Tabrizinejadas, Marwan Fahs, Hussein Hoteit, Anis Younes, Behzad Ataie-Ashtiani, Craig T. Simmons, Jerome Carrayrou
Summary: Geological CO2 sequestration (GCS) is the main solution to mitigate global warming. This study aims to investigate the temperature effect on CO2 transport and dissolution in a field case. A numerical model is developed to simulate the reactive thermohaline convection (RTHC) processes. Results show that including the temperature effect intensifies fingering processes and CO2 dissolution, and neglecting it can significantly impact model predictions.
INTERNATIONAL JOURNAL OF GREENHOUSE GAS CONTROL
(2023)
Article
Biochemical Research Methods
Antonia Sugar, Maged Serag, Ulrich Buttner, Satoshi Habuchi, Hussein Hoteit
Summary: Understanding the dynamic behavior of polymeric fluids in porous media is necessary for various geoscience applications, such as enhanced oil recovery and polymer-enhanced soil washing for soil contamination clean-up. By integrating microfluidics with single-molecule imaging, this study directly visualizes and characterizes the dynamic behavior of polymer molecules in a representative porous medium, revealing their adsorption, entrapment and hydrodynamic retention contribute to their overall retention in porous media. These findings have significant implications for better capturing the behavior of complex fluids in confined environments and can lead to improved models for various applications in geoscience, materials science, and rheology.
Article
Biochemical Research Methods
Antonia Sugar, Maged Serag, Ulrich Buttner, Satoshi Habuchi, Hussein Hoteit
Summary: Understanding the dynamic behavior of polymeric fluids in porous media is crucial for various geoscience applications, such as enhanced oil recovery and soil decontamination. By integrating microfluidics with single-molecule imaging, we directly visualize and characterize the dynamic behavior of polymer molecules in a representative porous medium. Our study reveals the contributions of polymer adsorption, entrapment, and hydrodynamic retention to their overall retention in porous media.
Article
Energy & Fuels
Zeeshan Tariq, Muhammad Ali, Nurudeen Yekeen, Auby Baban, Bicheng Yan, Shuyu Sun, Hussein Hoteit
Summary: The success of geological H2 storage depends on rock-H2-brine interactions and wettability. Experimentally assessing the H2 wettability is difficult due to H2 reactivity and embrittlement damages. Data-driven machine learning (ML) models accurately predict rock-H2-brine wettability and can be conducted under geo-storage conditions that are impossible or hazardous to replicate in the laboratory. These predictions are beneficial for accurately determining H2 geo-storage capacities and assessing containment security for large-scale geo-storage projects.
Article
Energy & Fuels
Amer Alanazi, Auby Baban, Muhammad Ali, Alireza Keshavarz, Stefan Iglauer, Hussein Hoteit
Summary: Carbon capture and sequestration (CCS) in geological formations is an important solution for reducing carbon emissions. A study using nuclear magnetic resonance (NMR) explores the residual saturations of CO2, N2, and a CO2/N2 mixture in an Indiana limestone, demonstrating the reduced hydrophilicity of the limestone due to the interaction with CO2. The study also examines the water displacement process in different pore sizes and provides comprehensive information for CCS and enhanced oil recovery (EOR) applications.
Article
Engineering, Petroleum
Zhen Zhang, Xupeng He, Marwah AlSinan, Hyung Kwak, Hussein Hoteit
Summary: This study proposes a new robust method using Bayesian Markov chain Monte Carlo (MCMC) to perform assisted history matching under uncertainties. The proposed method includes multiresolution low-fidelity models, LSTM network combined with Bayesian optimization, and Bayesian MCMC to obtain accurate predictions with narrow ranges of uncertainties.
Article
Energy & Fuels
Ruben Figueroa Hernandez, Anis Younes, Marwan Fahs, Hussein Hoteit
Summary: Fracture networks can enhance the deliverability of fluids from underground reservoirs, but fractures may lose efficiency due to closure or damage. Current Pressure Transient Analysis (PTA) models do not consider the combined effect of stress-dependent conductivity of fractures and fracture face skin. This study proposes a rigorous PTA model that incorporates fracture closure and skin effects for hydraulic fractures with different geometries. The proposed model is verified extensively and can serve as a diagnostic tool to detect fracture conductivity degradation.
GEOENERGY SCIENCE AND ENGINEERING
(2023)
Article
Energy & Fuels
Fatemah Alhammad, Mujahid Ali, Nurudeen Yekeen, Muhammad Ali, Hussein Rasool Abid, Hussein Hoteit, Stefan Iglauer, Alireza Keshavarz
Summary: Carbon capture and sequestration (CCS) are effective methods for achieving net-zero carbon emissions. This study investigates the impact of methyl orange (MO) on the wettability of organic-acid-contaminated quartz, which represents sandstone geo-storage formations. The results show that the presence of MO can alter the wettability of quartz from hydrophilic to hydrophobic, indicating the potential for enhancing CO2 storage capacity in sandstone formations. Therefore, it is recommended to dispose of MO in deep underground sandstone formations to mitigate CO2 emissions.
Article
Thermodynamics
Mahsa Taghavi, Swapnil Sharma, Vemuri Balakotaiah
Summary: This study investigates the natural convection effects in the insulation layers of spherical storage tanks and their impact on the tanks' performance. The permeability and Rayleigh number of the insulation material are considered as key factors. The results show that as the Rayleigh number increases, new convective cells emerge and cause the cold boundary to approach the external hot boundary. In the case of large temperature differences, multiple solutions may coexist.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Jinyang Xu, Fangjun Hong, Chaoyang Zhang
Summary: This study introduces a self-induced jet impingement device for enhancing pool boiling performance in high power electronic cooling. Through visualization and parametric investigations, the effects of this device on pool boiling performance are studied, revealing the promotion of additional liquid supply and vapor exhausting. The flow rate of the liquid jet is found to positively impact boiling performance.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Wenchao Ke, Yuan Liu, Fissha Biruke Teshome, Zhi Zeng
Summary: Underwater wet laser welding (UWLW) is a promising and labor-saving repair technique. A thermal multi-phase flow model was developed to study the heat transfer, fluid dynamics, and phase transitions during UWLW. The results show that UWLW creates a water keyhole, making the welding environment similar to in air laser welding.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Xingrong Lian, Lin Tian, Zengyao Li, Xinpeng Zhao
Summary: This study investigates the heat transfer mechanisms in natural fiber-derived porous structures and finds that thermal radiation has a significant impact on the thermal conductivity in low-density regions, while natural convection rarely occurs. Insulation materials derived from micron-sized natural fibers can achieve minimum thermal conductivity at specific densities. Strategies to lower the thermal conductivity include increasing porosity and incorporating nanoscale pores using nanosize fibers.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Yasir A. Malik, Kilian Koebschall, Stephan Bansmer, Cameron Tropea, Jeanette Hussong, Philippe Villedieu
Summary: Ice crystal icing is a significant hazard in aviation, and accurate modeling of sticking efficiency is essential. In this study, icing wind tunnel experiments were conducted to quantify the volumetric liquid water fraction, sticking efficiency, and maximum thickness of ice layers. Two measurement techniques, calorimetry and capacitive measurements, were used to measure the liquid water content and distribution in the ice layers. The experiments showed that increasing wet bulb temperatures and substrate heat flux significantly increased sticking efficiency and maximum ice layer thickness.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Jinqi Hu, Tongtong Geng, Kun Wang, Yuanhong Fan, Chunhua Min, Hsien Chin Su
Summary: This study experimentally examined the heat dissipation of vibrating fans and demonstrated its inherent mechanism through numerical simulation. The results showed that the flow fields induced by the vibrating blades exhibited pulsating features and formed large-scale and small-scale vortical structures, significantly improving heat dissipation. The study also identified the impacts of different blade structures and developed a trapezoidal-folding blade, which effectively reduced the maximum temperature of the heat source and alleviated high-temperature failure crisis.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Dan-Dan Su, Xiao-Bin Li, Hong-Na Zhang, Feng-Chen Li
Summary: The boiling heat transfer of low-boiling-point working fluid is a common heat dissipation technology in electronic equipment cooling. This study analyzed the interfacial boiling behavior of R134a under different conditions and found that factors such as the initial thickness of the liquid film, solid-liquid interaction force, and initial temperature significantly affect the boiling mode and thermal resistance.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Jinyi Wu, Dongke Sun, Wei Chen, Zhenhua Chai
Summary: A unified lattice Boltzmann-phase field scheme is proposed to simulate dendrite growth of binary alloys in the presence of melt convection. The effects of various factors on the growth are investigated numerically, and the model is validated through comparisons and examinations.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Shaokun Ge, Ya Ni, Fubao Zhou, Wangzhaonan Shen, Jia Li, Fengqi Guo, Bobo Shi
Summary: This study investigated the temperature distribution of main cables in a suspension bridge during fire scenarios and proposed a prediction model for the maximum temperature of cables in different lane fires. The results showed that vehicle fires in the emergency lane posed a greater thermal threat to the cables.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Shuang-Ying Wu, Shi-Yao Zhou, Lan Xiao, Jia Luo
Summary: This paper investigates the two-phase flow and heat transfer characteristics of low-velocity jet impacting on a cylindrical surface. The study reveals that the heat transfer regimes are non-phase transition and nucleate boiling with the increase of heat transfer rate. The effects of jet impact height and outlet velocity on local surface temperatures are pronounced at the non-phase transition stage. The growth rates of heat transfer rate and liquid loss rate increase significantly from the non-phase transition to nucleate boiling stage.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Emad Hasani Malekshah, Wlodzimierz Wlodzimierz, Miros law Majkut
Summary: Cavitation has significant practical importance and can be controlled by air injection. This study investigates the natural to ventilated cavitation process around a hydrofoil through numerical and experimental methods. The results show that the location and rate of air injection have a meaningful impact on the characteristics of cavitation.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Feriel Yahiat, Pascale Bouvier, Antoine Beauvillier, Serge Russeil, Christophe Andre, Daniel Bougeard
Summary: This study explores the enhancement of mixing performance in laminar flow equipment by investigating the generation of chaotic advection using wall deformations in annular geometries. The findings demonstrate that the combined geometry can achieve perfect mixing at various Reynolds numbers.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Hui He, Ning Lyu, Caihua Liang, Feng Wang, Xiaosong Zhang
Summary: This study investigates the condensation, frosting, and defrosting processes on superhydrophobic surfaces with millimeter-scale structures. The results reveal that the structures can influence the growth and removal of frost crystals, with the bottom grooves creating a frost-free zone and conical edges promoting higher frost crystal heights. Two effective methods for defrosting are observed: hand-lifting the groove and airfoil retraction contraction on protruding structures. This research provides valuable insights into frost formation and defrosting on millimeter-structured superhydrophobic surfaces, with potential applications in anti-frost engineering.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Thiwanka Arepolage, Christophe Verdy, Thibaut Sylvestre, Aymeric Leray, Sebastien Euphrasie
Summary: This study developed two thermal concentrators, one with a 2D design of uniform thickness and another with a 3D design, using the coordinate transformation technique and metamaterials. By structuring the thermal conductor, the desired local density-heat capacity product and anisotropic thermal conductivities were achieved. The homogenized thermal conductivities were obtained from finite element simulations and cylindrical symmetry consideration. A 3D concentrator was fabricated using 3D metal printing and characterized using a thermal camera. Compared to devices that solely consider anisotropic conductivities, the time evolution characteristics of the metadevice designed with coordinate transformation were closer to those of an ideal concentrator.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Liangyuan Cheng, Qingyang Wang, Jinliang Xu
Summary: In this study, we investigated the supercritical heat transfer of CO2 in a horizontal tube with a diameter of 10.0 mm, covering a wide range of pressures, mass fluxes, and heat fluxes. The study revealed a non-monotonic increase in wall temperatures along the flow direction and observed both positive and negative wall temperature differences between the bottom and top tube. The findings were explained by the thermal conduction in the solid wall interacting with the stratified-wavy flow in the tube.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)