Advanced Heat and Mass Transfer Technologies

Journal Name	Impact Factor	CiteScore	Launched Year	First Decision (median)	APC
Applied Sciences applsci	2.7	4.5	2011	16.9 Days	CHF 2400	Submit
Energies energies	3.2	5.5	2008	16.1 Days	CHF 2600	Submit
Materials materials	3.4	5.2	2008	13.9 Days	CHF 2600	Submit
Processes processes	3.5	4.7	2013	13.7 Days	CHF 2400	Submit
Fluids fluids	1.9	2.8	2016	20.7 Days	CHF 1800	Submit

18 pages, 4275 KiB

Open AccessArticle

Conjugate Heat Transfer Advancements and Applications in Aerospace Engine Technology

by Hao Zha, Yaqian Xu, Zhigong Tang, Bin Li and Dongzhi Wang

Appl. Sci. 2024, 14(9), 3556; https://doi.org/10.3390/app14093556 - 23 Apr 2024

Viewed by 180

Over the past few decades, conjugate heat transfer (CHT) technology has been instrumental in predicting temperature fields within aerospace engines, guiding engine design with its predictive capabilities. This paper comprehensively surveys the foundational technologies of CHT and their applications in engine design, backed [...] Read more.

Over the past few decades, conjugate heat transfer (CHT) technology has been instrumental in predicting temperature fields within aerospace engines, guiding engine design with its predictive capabilities. This paper comprehensively surveys the foundational technologies of CHT and their applications in engine design, backed by an extensive literature review. A novel coupling iteration methodology, su-F-TFTB, was proposed. Following this, it introduced grid splicing technology tailored for heat flux conservation, which significantly enhances the adaptability of CHT grids. Ultimately, this study employed the self-developed Aerospace Engine Numerical Simulation (AENS v4.0.1) software to perform CHT analyses on NASA-C3X turbine blades equipped with ten radial cooling systems. A comparative analysis of pressure distributions across various density meshes was undertaken to affirm mesh independence. Furthermore, the impacts of the Spalart–Allmaras (SA) one-equation model and k–ω Shear Stress Transport (SST) two-equation model on the temperature distribution in conjugate heat transfer were investigated. The results indicated that the k–ω SST model exhibited superior performance, aligning closely with NASA experimental data. This validation confirmed the effectiveness of the software. Full article

(This article belongs to the Topic Advanced Heat and Mass Transfer Technologies)

21 pages, 2410 KiB

Open AccessArticle

Darcy–Brinkman Model for Ternary Dusty Nanofluid Flow across Stretching/Shrinking Surface with Suction/Injection

by Sudha Mahanthesh Sachhin, Ulavathi Shettar Mahabaleshwar, David Laroze and Dimitris Drikakis

Fluids 2024, 9(4), 94; https://doi.org/10.3390/fluids9040094 - 18 Apr 2024

Viewed by 297

Abstract

Understanding of dusty fluids for different Brinkman numbers in porous media is limited. This study examines the Darcy–Brinkman model for two-dimensional magneto-hydrodynamic fluid flow across permeable stretching/shrinking surfaces with heat transfer. Water was considered as a conventional base fluid in which the copper [...] Read more.

Understanding of dusty fluids for different Brinkman numbers in porous media is limited. This study examines the Darcy–Brinkman model for two-dimensional magneto-hydrodynamic fluid flow across permeable stretching/shrinking surfaces with heat transfer. Water was considered as a conventional base fluid in which the copper (Cu), silver (Ag), and titanium dioxide (

T i O_{2}

) nanoparticles were submerged in a preparation of a ternary dusty nanofluid. The governing nonlinear partial differential equations are converted to ordinary differential equations through suitable similarity conversions. Under radiation and mass transpiration, analytical solutions for stretching sheets/shrinking sheets are obtained. Several parameters are investigated, including the magnetic field, Darcy–Brinkman model, solution domain, and inverse Darcy number. The outcomes of the present article reveal that increasing the Brinkman number and inverse Darcy number decreases the velocity of the fluid and dusty phase. Increasing the magnetic field decreases the momentum of the boundary layer. Ternary dusty nanofluids have significantly improved the heat transmission process for manufacturing with applications in engineering, and biological and physical sciences. The findings of this study demonstrate that the ternary nanofluid phase’s heat and mass transpiration performance is better than the dusty phase’s performance. Full article

(This article belongs to the Topic Advanced Heat and Mass Transfer Technologies)

► Show Figures

Figure 1

15 pages, 4440 KiB

Open AccessArticle

The Material Balance of Complex Separation Flowsheets

by Anastasia Frolkova, Alla Frolkova, Michael Sibirtsev and Kirill Lysenko

Processes 2024, 12(4), 821; https://doi.org/10.3390/pr12040821 - 18 Apr 2024

Viewed by 250

Abstract

The paper shows the expediency of supplementing the balance simplex method by calculating the number of free variables of separation flowsheets containing recycle flows. The need to determine and set the free variables that provide lower energy consumption when calculating the material balance [...] Read more.

The paper shows the expediency of supplementing the balance simplex method by calculating the number of free variables of separation flowsheets containing recycle flows. The need to determine and set the free variables that provide lower energy consumption when calculating the material balance of flowsheets with recycling is justified. The problem of material balance multivariance is illustrated, and ways to solve it are shown with the example of separation flowsheets for two ternary mixtures: n-butanol + water + toluene and n-butanol + butyl acetate + water. Separation flowsheets containing three distillation columns and a liquid–liquid separator are proposed for both systems. The dependence of the recycle flow values and the energy consumption of distillation columns and separation flowsheets on the selection and setting of values of free variables in solving the balance problem is shown. The dependence of energy consumption on the composition of the original mixture is studied for an n-butanol + butyl acetate + water system. Recommendations for setting free variables for flowsheets of the separation of ternary mixtures with three binary (and one ternary) azeotropes are formulated. The technique of highlighting the region of separation flowsheet operability is illustrated. The column operating parameters that ensure the production of products of a given quality with minimal energy consumption are determined. It is shown that with the incorrect selection and setting of variables (during balance task solvation), the energy consumption for mixture separation can be overestimated by more than 40%. Full article

(This article belongs to the Topic Advanced Heat and Mass Transfer Technologies)

► Show Figures

Figure 1

13 pages, 5011 KiB

Open AccessArticle

Effect of Rotational Angle of Discrete Inclined Ribs on Horizontal Flow and Heat Transfer of Supercritical R134a

by Genxian Yang, Junrui Tang and Zhouhang Li

Energies 2024, 17(7), 1631; https://doi.org/10.3390/en17071631 - 28 Mar 2024

Viewed by 434

Abstract

This work numerically studied the heat transfer and flow characteristics of supercritical R134a in horizontal pipes equipped with DDIR, considering variations in the rotation angle of DDIR. The aim is to improve the effects of the DDIR configuration on the heat transfer of [...] Read more.

This work numerically studied the heat transfer and flow characteristics of supercritical R134a in horizontal pipes equipped with DDIR, considering variations in the rotation angle of DDIR. The aim is to improve the effects of the DDIR configuration on the heat transfer of supercritical flow. After validation with experimental data, the AKN model was employed to examine the effects of four sets of rotation angles (0°, 30°, 45°, and 60°) on the axial and circumferential heat transfer characteristics of DDIR horizontal tubes under the influence of strong (q₁/G₁ = 0.1 kJ/kg) and medium (q₂/G₂ = 0.056 kJ/kg) buoyancy. Results show that variations in the rotation angle do not induce significant alterations in the flow field, thus exerting minimal influence on the axial heat transfer characteristics. Meanwhile, the rotation angle determines the relative positioning of the circumferential inner wall temperatures and heat flux distribution, although the magnitude of this effect remains inconspicuous. The rotational angle parameter can be reasonably neglected in the future design and installation of heat exchangers. Full article

(This article belongs to the Topic Advanced Heat and Mass Transfer Technologies)

► Show Figures

Figure 1

22 pages, 5338 KiB

Open AccessArticle

Multi-Output Regression Algorithm-Based Non-Dominated Sorting Genetic Algorithm II Optimization for L-Shaped Twisted Tape Insertions in Circular Heat Exchange Tubes

by Shijie Li, Zuoqin Qian and Ji Liu

Energies 2024, 17(4), 850; https://doi.org/10.3390/en17040850 - 11 Feb 2024

Viewed by 536

Abstract

In this study, an optimization method using various multi-output regression models as model proxies within the NSGA-II framework was applied to determine the geometric parameters (P, W, D) of L-shaped twisted tape inserts for achieving the optimal overall heat transfer performance in a [...] Read more.

In this study, an optimization method using various multi-output regression models as model proxies within the NSGA-II framework was applied to determine the geometric parameters (P, W, D) of L-shaped twisted tape inserts for achieving the optimal overall heat transfer performance in a circular heat exchange tube. Herein, 4 multi-output regression models, namely, MOLR, MOSVR, MOGPR, and BPNN, were selected as proxy models and trained on a dataset containing 74 groups of data. The training results indicated that the MOGPR model, balancing high accuracy and low error conditions, exhibited moderate training times among the four algorithms. BPNN showed a comparatively lower comprehensive training effect, obtaining training accuracy close to that of the MOGPR algorithm but with approximately twice the training time. The worst fitting performance was gained with the MOSVR algorithm. Due to its fitting performance, the MOSVR algorithm was excluded from the subsequent NSGA-II model proxy. Through multi-objective optimization with NSGA-II, the optimal structural dimensions for three sets of L-shaped twisted tape inserts were obtained to achieve the best overall heat transfer efficiency within the tube. Full article

(This article belongs to the Topic Advanced Heat and Mass Transfer Technologies)

► Show Figures

Figure 1

34 pages, 38064 KiB

Open AccessReview

A Review of Cooling Technologies in Lithium-Ion Power Battery Thermal Management Systems for New Energy Vehicles

by Ping Fu, Lan Zhao, Xuguang Wang, Jian Sun and Zhicheng Xin

Processes 2023, 11(12), 3450; https://doi.org/10.3390/pr11123450 - 18 Dec 2023

Cited by 1 | Viewed by 3238

Abstract

The power battery is an important component of new energy vehicles, and thermal safety is the key issue in its development. During charging and discharging, how to enhance the rapid and uniform heat dissipation of power batteries has become a hotspot. This paper [...] Read more.

The power battery is an important component of new energy vehicles, and thermal safety is the key issue in its development. During charging and discharging, how to enhance the rapid and uniform heat dissipation of power batteries has become a hotspot. This paper briefly introduces the heat generation mechanism and models, and emphatically summarizes the main principle, research focuses, and development trends of cooling technologies in the thermal management of power batteries in new energy vehicles in the past few years. Currently, the commonly used models for battery heat generation are the electrochemical-thermal model and the electrical-thermal model. Scholars have conducted more research based on multidimensional electrochemical-thermal/electrical-thermal models because taking the actual characteristics of the battery into account can provide a more comprehensive and systematic description. Among various cooling technologies, the air-cooling system boasts the most economical manufacturing costs and a compact, reliable structure. The heat transfer coefficient of the liquid-cooling system is very high, while the temperature remains uniform in the PCMs cooling system during the material phase transition process. Against the background of increasing energy density in future batteries, immersion liquid phase change cooling technology has great development prospects, but it needs to overcome limitations such as high cost and heavy weight. Therefore, the current lithium-ion battery thermal management technology that combines multiple cooling systems is the main development direction. Suitable cooling methods can be selected and combined based on the advantages and disadvantages of different cooling technologies to meet the thermal management needs of different users. Full article

(This article belongs to the Topic Advanced Heat and Mass Transfer Technologies)

► Show Figures

Figure 1

21 pages, 5880 KiB

Open AccessArticle

Thermal Diffusivity in the Subsoil: A Case Study in the Asturias (Northern Spain)

by Germán Marcos-Robredo, María Pilar Castro-García, Miguel Ángel Rey-Ronco and Teresa Alonso-Sánchez

Energies 2023, 16(24), 8108; https://doi.org/10.3390/en16248108 - 17 Dec 2023

Viewed by 747

Abstract

This study presents a novel methodology for determining the apparent thermal diffusivity of subsoil in situ, employing two heat transfer models within the subsurface: one method is based on heat conduction caused by air temperature oscillations, while the other considers heat transmission via [...] Read more.

This study presents a novel methodology for determining the apparent thermal diffusivity of subsoil in situ, employing two heat transfer models within the subsurface: one method is based on heat conduction caused by air temperature oscillations, while the other considers heat transmission via both conduction and convection due to groundwater flow. Differential equations were solved, and non-linear regression analysis was employed. This method has direct applications in various engineering and environmental domains, such as underground transmission lines, oil and gas pipelines, radioactive waste management, and geothermal systems, especially in the context of implementing horizontal geothermal collectors (HGC). The apparent thermal diffusivity value of 1.514 × 10⁻⁶ m² s⁻¹, within a 95% confidence interval spanning 1.512 × 10⁻⁶ m² s⁻¹ and 1.516 × 10⁻⁶ m² s⁻¹, was obtained from the section between 1.67 and 3.86 m depth in a research borehole located in Asturias, Northern Spain, using twenty-one temperature sensors. The method allowed for the calculation of the subsoil’s apparent thermal diffusivity up to a depth of 14.55 m. Full article

(This article belongs to the Topic Advanced Heat and Mass Transfer Technologies)

► Show Figures

Figure 1

17 pages, 7141 KiB

Open AccessArticle

Performance Evaluation of a Steam Ejector Considering Non-Equilibrium Condensation in Supersonic Flows

by Youhao Xie, Yu Han, Xiaodong Wang, Chuang Wen and Yan Yang

Energies 2023, 16(23), 7755; https://doi.org/10.3390/en16237755 - 24 Nov 2023

Viewed by 736

Abstract

The present study established an experimental system of steam ejector refrigeration to evaluate the effect of the operating parameters, such as pressure on the diffuser wall and primary and secondary fluid, on the performance and efficiency of the ejector. The model validation of [...] Read more.

The present study established an experimental system of steam ejector refrigeration to evaluate the effect of the operating parameters, such as pressure on the diffuser wall and primary and secondary fluid, on the performance and efficiency of the ejector. The model validation of numerical methods was carried out against the experimental data, while the numerical simulation was conducted by utilizing computational fluid dynamics modeling to analyze the internal flow of the ejector. The results indicated that the escalation of the primary steam pressure in the choking position increased the Mach number and entrainment ratio as the flow area of the secondary fluid remained constant. The optimization studies show that the entrainment ratio was maximum when the primary steam pressure was 0.36 MPa. While the pressure was inordinate, the expansion core increased in size and further compressed the flow area of the secondary fluid, hence reducing the entrainment ratio. Subject to the influence of the normal shockwave, the change in back pressure did not alter the entrainment ratio before the critical back pressure. In contrast, the ejector no longer produces the normal shockwave after the critical back pressure; the entrainment ratio, therefore, was reduced with the increase in back pressure. Full article

(This article belongs to the Topic Advanced Heat and Mass Transfer Technologies)

► Show Figures

Figure 1

17 pages, 6189 KiB

Open AccessArticle

The Impact of Ultrasound Pre-Treatment on Hot-Air-Drying Kinetics and Quality of Carrot Slices Assessed by Simulations and Experiments

by Thi Thu Hang Tran, Thi Thuy Dung Nguyen, Abdolreza Kharaghani and Kieu Hiep Le

Appl. Sci. 2023, 13(21), 11865; https://doi.org/10.3390/app132111865 - 30 Oct 2023

Viewed by 923

Abstract

This study investigated experimentally and numerically the influence of ultrasound pre-treatment on the drying kinetics of sliced carrot samples. Drying experiments were performed under different conditions, including scenarios with and without ultrasound pre-treatment at drying temperatures of 30 °C, 40 °C, and 50 [...] Read more.

This study investigated experimentally and numerically the influence of ultrasound pre-treatment on the drying kinetics of sliced carrot samples. Drying experiments were performed under different conditions, including scenarios with and without ultrasound pre-treatment at drying temperatures of 30 °C, 40 °C, and 50 °C. A diffusion-based-drying model was developed to study the impact of ultrasound pre-treatment on drying kinetics. The effective moisture diffusivity of carrots was expressed as a function of moisture content and temperature. Given the complexity of the dehydration process in carrot slices, which depends on the spatiotemporal variations in moisture content and temperature, and is challenging to monitor experimentally, the effective moisture diffusivity is computed by minimizing the discrepancy between numerical predictions and experimental moisture-content changes over time. This study revealed that ultrasound pre-treatment significantly enhanced the moisture diffusivity of the samples, increasing it by 43% to 90% at drying temperatures of 40 °C and 50 °C, respectively. To apply this analysis of ultrasound pre-treatment in large-scale dryers where thousands of slices may be involved, the proposed diffusion model was simplified to a characteristic drying-curve model. Afterwards, this characteristic drying-curve model was incorporated into a belt-dryer model. The results indicated a 12% reduction in the length of the belt dryer when ultrasound pre-treatment was applied. Additionally, the color of carrot samples was preserved better with ultrasound pre-treatment. On the basis of these results, the application of ultrasound pre-treatment in the hot-air drying of carrot slices was favored, both in terms of improved drying kinetics and quality aspects. Full article

(This article belongs to the Topic Advanced Heat and Mass Transfer Technologies)

► Show Figures

Figure 1

11 pages, 3445 KiB

Open AccessArticle

A Study on Temperature and Pressure Characteristics in a Vessel as Charging Time of Helium Gas Changes

by Jangwoo Park, Junho Choi and Kwonse Kim

Appl. Sci. 2023, 13(20), 11348; https://doi.org/10.3390/app132011348 - 16 Oct 2023

Viewed by 1235

Abstract

The main propose in this research work is to investigate the temperature and pressure increase resulting from the variable valve of a mass flow controller during the charging and discharging of helium gas, which is being used as an alternative to hydrogen gas [...] Read more.

The main propose in this research work is to investigate the temperature and pressure increase resulting from the variable valve of a mass flow controller during the charging and discharging of helium gas, which is being used as an alternative to hydrogen gas in a vessel. In the operation of this experiment, the high-pressure gas stored in the main tank is first reduced to low pressure using an electronic solenoid valve within a regulator to control the flow rate. Subsequently, the flow rate is precisely measured using an MFC (Mass Flow Controller) and supplied to the experimental tank. Throughout this process, temperature and pressure sensors detect changes in physical behavior, collect data using LabVIEW cDAQ, and repeat the process of analyzing and verifying reliable data according to the experiment’s conditions. The mass flow controller valve opening was set at 20%, 60%, and 100% while operating the LabVIEW programming. Also, this experiment was conducted at 20 °C ambient temperature and 0 bar gauge pressure. Both the temperature and pressure increase as the MFC valve opens further because the helium gas flow is accumulating during the valve opening time. Furthermore, in the case of helium temperature, it increases significantly when the gas is charged rapidly, compared to the pressure characteristics. Therefore, one can see that the vessel increases as the valve opening time increases, and the temperature changes; the temperature is more significant when the helium gas is charged rapidly during the valve opening time. Full article

(This article belongs to the Topic Advanced Heat and Mass Transfer Technologies)

► Show Figures

Figure 1

23 pages, 5295 KiB

Open AccessReview

A Review on Cooling Systems for Portable Energy Storage Units

by Alireza Eslami Majd, Fideline Tchuenbou-Magaia, Agnero M. Meless, David S. Adebayo and Nduka Nnamdi Ekere

Energies 2023, 16(18), 6525; https://doi.org/10.3390/en16186525 - 11 Sep 2023

Viewed by 1804

Abstract

Achieving the global electricity demand and meeting the United Nations sustainable development target on reliable and sustainable energy supply by 2050 are crucial. Portable energy storage (PES) units, powered by solid-state battery cells, can offer a sustainable and cost-effective solution for regions with [...] Read more.

Achieving the global electricity demand and meeting the United Nations sustainable development target on reliable and sustainable energy supply by 2050 are crucial. Portable energy storage (PES) units, powered by solid-state battery cells, can offer a sustainable and cost-effective solution for regions with limited power-grid access. However, operating in high-dust and high-temperature environments presents challenges that require effective thermal management solutions. This paper is a comprehensive review of thermal management systems for PES units, with a specific focus on addressing the challenge of overheating in airtight designs. The review of various active and passive cooling systems is conducted through extensive study of the relevant literature, which is significant in providing insights into the operation, performance parameters, and design options for different cooling system technologies. The findings from this review show heat pipe (HP) technologies as key cooling-system solutions for airtight PES units. Specifically, loop and oscillating HPs, as well as the vapour chamber, offer desirable features such as compactness, low cost, and high thermal conductivity that make them superior to other alternatives for the cooling systems in PES. The insights and knowledge generated via this review will help facilitate the design and development of innovative, efficient, and reliable PES units, thereby contributing to the advancement of off-grid renewable energy applications and enabling sustainable power solutions worldwide. Furthermore, an appropriate design of PES units can help in reducing capital and maintenance costs. Full article

(This article belongs to the Topic Advanced Heat and Mass Transfer Technologies)

► Show Figures

Figure 1

24 pages, 3661 KiB

Open AccessArticle

A Tabu-Matching Heuristic Algorithm Based on Temperature Feasibility for Efficient Synthesis of Heat Exchanger Networks

by Xiaohuang Huang, Hao Shen, Wenhao Yue, Huanhuan Duan and Guomin Cui

Processes 2023, 11(9), 2713; https://doi.org/10.3390/pr11092713 - 11 Sep 2023

Viewed by 677

Abstract

The non-structural model of heat exchanger networks (HENs) offers a wide solution space for optimization due to the random matching of hot and cold streams. However, this stochastic matching can sometimes result in infeasible structures, leading to inefficient optimization. To address this issue, [...] Read more.

The non-structural model of heat exchanger networks (HENs) offers a wide solution space for optimization due to the random matching of hot and cold streams. However, this stochastic matching can sometimes result in infeasible structures, leading to inefficient optimization. To address this issue, a tabu matching based on a heuristic algorithm for HENs is proposed. The proposed tabu-matching method involves three main steps: First, the critical temperature levels—high, medium, and low-temperature intervals—are determined based on the inlet and outlet temperatures of streams. Second, the number of nodes is set according to the temperature intervals. Third, the nodes of streams are flexibly matched within the tabu rules: the low-temperature interval of hot streams with the high-temperature interval of cold streams; the streams crossing cannot be matched. The results revealed that by incorporating the tabu rules and adjusting the number of nodes, the ratio of the feasible zone in the whole solution domain increases, and the calculation efficiency is enhanced. To evaluate the effectiveness of the method, three benchmark problems were studied. The obtained total annual costs (TACs) of these case studies exhibited a decrease of USD 4290/yr (case 1), USD 1435/yr (case 2), and USD 11,232/yr (case 3) compared to the best published results. The results demonstrate that the proposed tabu-matching heuristic algorithm is effective and robust. Full article

(This article belongs to the Topic Advanced Heat and Mass Transfer Technologies)

► Show Figures

Figure 1

16 pages, 10257 KiB

Open AccessArticle

Analysis of Flow and Heat Transfer Characteristics and Multi-Objective Optimization for Sinusoidal PCHE

by Qixuan Hu, Zhonglei Fan, Zhe Zhang and Yi Lu

Energies 2023, 16(15), 5763; https://doi.org/10.3390/en16155763 - 02 Aug 2023

Cited by 1 | Viewed by 880

Abstract

A Printed Circuit Heat Exchanger (PCHE) is a compact heat exchanger with high temperature and pressure resistance and is considered one of the best choices for the recuperators in the Supercritical Carbon dioxide (S-CO₂) Brayton cycle. The flow and heat transfer [...] Read more.

A Printed Circuit Heat Exchanger (PCHE) is a compact heat exchanger with high temperature and pressure resistance and is considered one of the best choices for the recuperators in the Supercritical Carbon dioxide (S-CO₂) Brayton cycle. The flow and heat transfer performance of sinusoidal channel PCHE were analyzed and a second-order regression model was established based on the response surface method to improve the performance of the continuous channel PCHE. It was found that reducing the channel diameter, increasing the channel amplitude, and reducing the channel pitch can increase the average value of the heat transfer coefficient and pressure drop per unit length. Moreover, sensitivity coefficient analysis was used to investigate the influence of various structural parameters on flow performance, heat transfer performance, and comprehensive performance. In addition, the structure of the sinusoidal channel PCHE was optimized using a multi-objective genetic algorithm, and three sets of Pareto optimal solutions were obtained. The corresponding optimal channel diameter D, channel amplitude A, and channel pitch Lp were in the range of 1.0–1.7 mm, 2.4–3.0 mm, and 15.1–17.0 mm, respectively, which can provide theoretical basis for the design of PCHE. Full article

(This article belongs to the Topic Advanced Heat and Mass Transfer Technologies)

► Show Figures

Figure 1

14 pages, 4893 KiB

Open AccessArticle

Biomimetic Copper Forest Structural Modification Enhances the Capillary Flow Characteristics of the Copper Mesh Wick

by Jia-Li Luo, Fan-Bin Zhao, Mou Xu, Dong-Chuan Mo and Shu-Shen Lyu

Energies 2023, 16(14), 5348; https://doi.org/10.3390/en16145348 - 13 Jul 2023

Cited by 2 | Viewed by 1071

Abstract

In a two-phase heat transfer device, achieving a high capillarity of the wick while reducing flow resistance within a limited space becomes the key to improving the heat dissipation performance. As a commonly used wick structure, mesh is widely employed because of its [...] Read more.

In a two-phase heat transfer device, achieving a high capillarity of the wick while reducing flow resistance within a limited space becomes the key to improving the heat dissipation performance. As a commonly used wick structure, mesh is widely employed because of its high permeability. However, achieving the desired capillary performance often requires multiple layers to be superimposed to ensure an adequate capillary, resulting in an increased thickness of the wick. In this study, an ultra-thin biomimetic copper forest structural modification of copper mesh was performed using an electrochemical deposition to solve the contradiction between the permeability and the capillary. The experiments were conducted on a copper mesh to investigate the effects of various conditions on their morphology and capillary performance. The results indicate that the capillary performance of the modified copper mesh improves with a longer deposition time. The capillary pressure drops can reach up to 1400 Pa when using ethanol as the working fluid. Furthermore, the modified copper mesh demonstrates a capillary performance value (ΔP_c·K) of 8.44 × 10⁻⁸ N, which is 1.7 times higher than that of the unmodified samples. Notably, this enhanced performance is achieved with a thickness of only 142 μm. The capillary limit can reach up to 45 W when the modified copper mesh is only 180 μm. Microscopic flow analysis reveals that the copper forest modified structure maintains the original high permeability of the copper mesh while providing a greater capillary force, thereby enhancing the overall flow characteristics. Full article

(This article belongs to the Topic Advanced Heat and Mass Transfer Technologies)

► Show Figures

Figure 1

12 pages, 7482 KiB

Open AccessArticle

Organic—Inorganic Hybrid Interfaces Enable the Preparation of Nitrogen-Doped Hollow Carbon Nanospheres as High-Performance Anodes for Lithium and Potassium-Ion Batteries

by Yao Dai, Dong-Chuan Mo, Zong-Tao Qu, Wen-Kang Wang and Shu-Shen Lyu

Materials 2023, 16(14), 4936; https://doi.org/10.3390/ma16144936 - 11 Jul 2023

Cited by 2 | Viewed by 1119

Abstract

An abundant hollow nanostructure is crucial for fast Li⁺ and K⁺ diffusion paths and sufficient electrolyte penetration, which creates a highly conductive network for ionic and electronic transport. In this study, we successfully developed a molecular-bridge-linked, organic–inorganic hybrid interface that enables [...] Read more.

An abundant hollow nanostructure is crucial for fast Li⁺ and K⁺ diffusion paths and sufficient electrolyte penetration, which creates a highly conductive network for ionic and electronic transport. In this study, we successfully developed a molecular-bridge-linked, organic–inorganic hybrid interface that enables the preparation of in situ nitrogen-doped hollow carbon nanospheres. Moreover, the prepared HCNSs, with high nitrogen content of up to 10.4%, feature homogeneous and regular morphologies. The resulting HCNSs exhibit excellent lithium and potassium storage properties when used as electrode materials. Specifically, the HCNS-800 electrode demonstrates a stable reversible discharge capacity of 642 mA h g⁻¹ at 1000 mA g⁻¹ after 500 cycles for LIBs. Similarly, the electrode maintains a discharge capacity of 205 mA h g⁻¹ at 100 mA g⁻¹ after 500 cycles for KIBs. Moreover, when coupled with a high-mass-loading LiFePO₄ cathode to design full cells, the HCNS-800‖LiFePO₄ cells provide a specific discharge capacity of 139 mA h g⁻¹ at 0.1 C. These results indicate that the HCNS electrode has promising potential for use in high-energy and environmentally sustainable lithium-based and potassium-based batteries. Full article

(This article belongs to the Topic Advanced Heat and Mass Transfer Technologies)

► Show Figures

Graphical abstract

28 pages, 3000 KiB

Open AccessReview

Review of Developments in Plate Heat Exchanger Heat Transfer Enhancement for Single-Phase Applications in Process Industries

by Olga Arsenyeva, Leonid Tovazhnyanskyy, Petro Kapustenko, Jiří Jaromír Klemeš and Petar Sabev Varbanov

Energies 2023, 16(13), 4976; https://doi.org/10.3390/en16134976 - 27 Jun 2023

Cited by 9 | Viewed by 3611

Abstract

A plate heat exchanger (PHE) is a modern, effective type of heat transfer equipment capable of increasing heat recuperation and energy efficiency. For PHEs, enhanced methods of heat transfer intensification can be further applied using the analysis and knowledge already available in the [...] Read more.

A plate heat exchanger (PHE) is a modern, effective type of heat transfer equipment capable of increasing heat recuperation and energy efficiency. For PHEs, enhanced methods of heat transfer intensification can be further applied using the analysis and knowledge already available in the literature. A review of the main developments in the construction and exploration of PHEs and in the methods of heat transfer intensification is presented in this paper with an analysis of the main construction modifications, such as plate-and-frame, brazed and welded PHEs. The differences between these construction modifications and their influences on the thermal and hydraulic performance of PHEs are discussed. Most modern PHEs have plates with inclined corrugations on their surface that create a strong, rigid construction with multiple contact points between the plates. The methods of PHE exploration are mostly experimental studies and/or CFD modelling. The main corrugation parameters influencing PHE performance are the corrugation inclination angle in relation to the main flow direction and the corrugation aspect ratio. Optimisation of these parameters is one way to enhance PHE performance. Other methods of heat transfer enhancement, including improving the form of the plate corrugations, use of nanofluids and active methods, are considered. Future research directions are proposed, such as improving fundamental understanding, developing new corrugation shapes and optimisation methods and area and cost estimations. Full article

(This article belongs to the Topic Advanced Heat and Mass Transfer Technologies)

► Show Figures

Figure 1

23 pages, 5770 KiB

Open AccessReview

Insights into Induction Heating Processes for Polymeric Materials: An Overview of the Mechanisms and Current Applications

by Alberto Mariani and Giulio Malucelli

Energies 2023, 16(11), 4535; https://doi.org/10.3390/en16114535 - 05 Jun 2023

Viewed by 1619

Abstract

In polymer systems, induction heating (IH) is the physical outcome that results from the exposure of selected polymer composites embedding electrically-conductive and/or ferromagnetic fillers to an alternating electromagnetic field (frequency range: from kHz to MHz). The interaction of the applied electromagnetic field with [...] Read more.

In polymer systems, induction heating (IH) is the physical outcome that results from the exposure of selected polymer composites embedding electrically-conductive and/or ferromagnetic fillers to an alternating electromagnetic field (frequency range: from kHz to MHz). The interaction of the applied electromagnetic field with the material accounts for the creation of magnetic polarization effects (i.e., magnetic hysteresis losses) and/or eddy currents (i.e., Joule losses, upon the formation of closed electrical loops), which, in turn, cause the heating up of the material itself. The heat involved can be exploited for different uses, ranging from the curing of thermosetting systems, the welding of thermoplastics, and the processing of temperature-sensitive materials (through selective IH) up to the activation of special effects in polymer systems (such as self-healing and shape-memory effects). This review aims at summarizing the current state-of-the-art of IH processes for polymers, providing readers with the current limitations and challenges, and further discussing some possible developments for the following years. Full article

(This article belongs to the Topic Advanced Heat and Mass Transfer Technologies)

► Show Figures

Figure 1

14 pages, 6565 KiB

Open AccessArticle

Fabrication and Experimental Study of Micro/Sub-Micro Porous Copper Coating for Anti-Icing Application

by Jingxiang Chen, Cheng Fu, Junye Li, Weiyu Tang, Xinglong Gao and Jingzhi Zhang

Materials 2023, 16(10), 3774; https://doi.org/10.3390/ma16103774 - 16 May 2023

Cited by 1 | Viewed by 1276

Abstract

Micro and sub-micro-spherical copper powder slurries were elaborately prepared to fabricate different types of porous coating surfaces. These surfaces were further treated with low surface energy modification to obtain the superhydrophobic and slippery capacity. The surface wettability and chemical component were measured. The [...] Read more.

Micro and sub-micro-spherical copper powder slurries were elaborately prepared to fabricate different types of porous coating surfaces. These surfaces were further treated with low surface energy modification to obtain the superhydrophobic and slippery capacity. The surface wettability and chemical component were measured. The results showed that both the micro and sub-micro porous coating layer greatly increased the water-repellence capability of the substrate compared with the bare copper plate. Notably, the PFDTES-fluorinated coating surfaces yielded superhydrophobic ability against water under 0 °C with a contact angle of ~150° and a contact angle of hysteresis of ~7°. The contact angle results showed that the water repellency of the coating surface deteriorated with decreasing temperature from 10 °C to −20 °C, and the reason was probably recognized as the vapor condensation in the sub-cooled porous layer. The anti-icing test showed that the ice adhesion strengths of the micro and sub-micro-coated surfaces were 38.5 kPa and 30.2 kPa, producing a 62.8% and 72.7% decrease compared to the bare plate. The PFDTES-fluorinated and slippery liquid-infused porous coating surfaces both produced ultra-low ice adhesion strengths of 11.5–15.7 kPa compared with the other non-treated surfaces, which showed prominent properties for anti-icing and deicing requirement of the metallic surface. Full article

(This article belongs to the Topic Advanced Heat and Mass Transfer Technologies)

► Show Figures

Figure 1

21 pages, 3936 KiB

Open AccessArticle

Numerical Study of Steam–CO₂ Mixture Condensation over a Flat Plate Based on the Solubility of CO₂

by Bingran Jiang, Yi’ao Jiang, Huaduo Gu, Yaping Chen and Jiafeng Wu

Appl. Sci. 2023, 13(9), 5747; https://doi.org/10.3390/app13095747 - 06 May 2023

Viewed by 1180

Abstract

In order to successfully study the condensation and separation of a steam–CO₂ mixture, a boundary layer model was applied to the mixture condensation of steam and CO₂ on horizontal and vertical plates. The modified condensation boundary layer model of steam and [...] Read more.

In order to successfully study the condensation and separation of a steam–CO₂ mixture, a boundary layer model was applied to the mixture condensation of steam and CO₂ on horizontal and vertical plates. The modified condensation boundary layer model of steam and CO₂, given the CO₂ solubility in the condensate, was established, numerically solved, and verified with existing experimental data. Different condensation data of steam–air and steam–CO₂ mixtures were compared, and the effect of CO₂ solubility on the mixed gas condensation was analyzed under multiple pressure conditions (1 atm–10 MPa). The simulation data show that the presence of CO₂ will deteriorate the condensation heat transfer, just like air. Given that CO₂ is slightly soluble, some CO₂ can pass through the gas–liquid interface to enter the condensate film and reduce the accumulated CO₂ on the gas–liquid interface, which improves the condensation. However, the solubility of CO₂ is only significant under high-pressure conditions, inducing its effects on condensation. A comparison of the condensation coefficients of the steam–CO₂ mixture shows the lower impact of CO₂ condensation on the horizontal plate compared to that on the vertical plate. For most conditions, the steam–CO₂ mixture gas condensation heat transfer coefficient on the vertical plate surface is still larger than that on the horizontal plate surface, and the improvement in the condensation heat transfer coefficient caused by low CO₂ solubility (2 or 10%) at 10 MPa on the vertical plate is also larger than that of the horizontal plate. Full article

(This article belongs to the Topic Advanced Heat and Mass Transfer Technologies)

► Show Figures

Figure 1

Topic Menu

Topic Editors

Advanced Heat and Mass Transfer Technologies

Topic Information

Keywords

Participating Journals

Published Papers (19 papers)

Further Information

Guidelines

MDPI Initiatives

Follow MDPI