Advanced Heat and Mass Transfer Techniques in Power and Energy Systems

A special issue of Applied Sciences (ISSN 2076-3417). This special issue belongs to the section "Fluid Science and Technology".

Deadline for manuscript submissions: 30 September 2024 | Viewed by 5031

Special Issue Editors

School of Energy Science and Engineering, Harbin Institute of Technology, Harbin 150001, China
Interests: convection heat transfer; vortex flow; compact heat exchanger; entropy generation; heat pipe; phase-change heat transfer
Special Issues, Collections and Topics in MDPI journals
Key Laboratory of Aerospace Thermophysics, School of Energy Science and Engineering, Harbin Institute of Technology, Harbin 150001, China
Interests: electromagnetic flow and heat transfer; phase-change heat transfer; Lattice–Boltzmann simulation
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

We wish to invite you to submit a paper for publication in the Applied Sciences journal Special Issue titled “Advanced Heat and Mass Transfer Techniques in Power and Energy Systems”. Heat and mass transfer is a key process in energy systems, especially more recently developed energy systems, such as solar energy systems, compact nuclear power systems, energy storage systems, biomass energy utilization systems, new energy vehicles, advanced aerospace engines, etc. The heat and mass transfer process functions in extreme working conditions, and it is coupled with multiphysical fields and various design-based demands. Many advanced heat and mass transfer techniques, such as micro/nanoscale heat and mass transfer, supercritical flow heat transfer, compact heat exchanger, electromagnetic coupling heat and mass transfer, multi-objective design, etc., will be developed and investigated in this Special Issue.

We will also discuss the advanced heat and mass transfer theoreticals and techniques involved in power and energy systems in recent decades. This Special Issue’s scope will not be limited to conduction, convection, and radiation heat transfers. We also desire papers related to heat and mass transfers occurring at the micro/nanoscale, via multiphysical field coupling, in extreme working conditions, via new design methods, etc.

This Special Issue aims to enable the exchange in research data and ideas related to heat transfer-related subjects. Potential topics of interest include, but are not limited to, the following subjects:

  • Convection heat transfer;
  • Radiation heat transfer;
  • Heat conduction;
  • Condensation, boiling, and evaporation;
  • The development of numerical models;
  • Enhanced heat transfer technique;
  • Micro/nanoscale heat and mass transfer;
  • Supercritical flow heat transfer;
  • Compact heat exchanger;
  • Electromagnetic coupling heat and mass transfer;
  • Solar energy system;
  • Nuclear system;
  • Energy storage system;
  • New energy vehicles;
  • Advanced aerospace engines.

Dr. Wei Wang
Dr. Kang Luo
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Applied Sciences is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • convection heat transfer
  • thermal fluid dynamics
  • turbulent flow
  • phase-change heat transfer
  • multiphase flow
  • numerical methods
  • heat exchangers
  • porous medium
  • energy conversion
  • micro/nano scale
  • supercritical flow
  • electromagnetic flow
  • energy and power system

Published Papers (6 papers)

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Research

18 pages, 11485 KiB  
Article
Gas–Liquid Two-Phase Flow Measurement Based on Optical Flow Method with Machine Learning Optimization Model
by Junxian Wang, Zhenwei Huang, Ya Xu and Dailiang Xie
Appl. Sci. 2024, 14(9), 3717; https://doi.org/10.3390/app14093717 - 26 Apr 2024
Viewed by 461
Abstract
Gas–Liquid two-phase flows are a common flow in industrial production processes. Since these flows inherently consist of discrete phases, it is challenging to accurately measure the flow parameters. In this context, a novel approach is proposed that combines the pyramidal Lucas-Kanade (L–K) optical [...] Read more.
Gas–Liquid two-phase flows are a common flow in industrial production processes. Since these flows inherently consist of discrete phases, it is challenging to accurately measure the flow parameters. In this context, a novel approach is proposed that combines the pyramidal Lucas-Kanade (L–K) optical flow method with the Split Comparison (SC) model measurement method. In the proposed approach, videos of gas–liquid two-phase flows are captured using a camera, and optical flow data are acquired from the flow videos using the pyramid L–K optical flow detection method. To address the issue of data clutter in optical flow extraction, a dynamic median value screening method is introduced to optimize the corner point for optical flow calculations. Machine learning algorithms are employed for the prediction model, yielding high flow prediction accuracy in experimental tests. Results demonstrate that the gradient boosted regression (GBR) model is the most effective among the five preset models, and the optimized SC model significantly improves measurement accuracy compared to the GBR model, achieving an R2 value of 0.97, RMSE of 0.74 m3/h, MAE of 0.52 m3/h, and MAPE of 8.0%. This method offers a new approach for monitoring flows in industrial production processes such as oil and gas. Full article
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16 pages, 5535 KiB  
Article
Enhancing Heat Transfer Efficiency in Permanent Magnet Machines through Innovative Thermal Design of Stator Windings
by Xiang Shen, Xu Deng, Barrie Mecrow, Rafal Wrobel and Richard Whalley
Appl. Sci. 2024, 14(6), 2658; https://doi.org/10.3390/app14062658 - 21 Mar 2024
Viewed by 650
Abstract
This paper investigates innovative methods for enhancing heat transfer efficiency in high-power permanent magnet electrical machines. The objectives are to quantify the effects of increasing the air speed, increasing the turbulence intensity, and introducing the spacing between windings on cooling performance. The cooling [...] Read more.
This paper investigates innovative methods for enhancing heat transfer efficiency in high-power permanent magnet electrical machines. The objectives are to quantify the effects of increasing the air speed, increasing the turbulence intensity, and introducing the spacing between windings on cooling performance. The cooling of stator windings is studied through experimental wind tunnel testing and Computational Fluid Dynamics (CFD) modelling. The CFD model is validated against wind tunnel measurements to within 4 Kelvin (K). The results demonstrate that each enhancement method significantly improves the cooling capability. Increasing the air speed from 10 m/s to 40 m/s reduces the winding hotspot temperature by 34%. Introducing a high turbulence intensity of 40% leads to a 21% lower hotspot temperature compared to 0.5% turbulence intensity. Creating a 1.5 mm spacing between coils also substantially improves convection and conduction heat transfer. Overall, combining these optimised design parameters yields over a 40% reduction in hotspot temperature compared to the original design. This research provides practical guidance for maximising heat transfer efficiency in high-power permanent magnet machines, without increasing complexity. The findings will lead to higher machine efficiency, reliability, and longevity for aerospace and other applications. Full article
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24 pages, 2029 KiB  
Article
Study on Urea Crystallization Risk Assessment and Influencing Factors in After-Treatment System of Diesel Engines
by Ke Sun, Gecheng Zhang, Kui Zhao, Wen Sun, Guoxiang Li, Shuzhan Bai, Chunjin Lin and Hao Cheng
Appl. Sci. 2024, 14(2), 684; https://doi.org/10.3390/app14020684 - 13 Jan 2024
Viewed by 881
Abstract
In order to meet the increasing pollutants discharge standard, the selective catalytic reduction (SCR) module in the diesel engine after-treatment system is an important means to reduce nitrogen oxide (NOx) emissions. SCR systems are prone to urea crystallization at lower temperatures, especially during [...] Read more.
In order to meet the increasing pollutants discharge standard, the selective catalytic reduction (SCR) module in the diesel engine after-treatment system is an important means to reduce nitrogen oxide (NOx) emissions. SCR systems are prone to urea crystallization at lower temperatures, especially during the cold-start conditions of diesel engines. In this study, we use the diesel engine after-treatment system test bench to obtain the boundary parameter of the simulation modules, and the urea crystallization risk assessment model of the diesel SCR system is established. Comparing the computational fluid dynamics (CFD) results with the test bench results, it is shown that the predicted urea film distribution of the assessment model is in good agreement with the experimental results. In order to clarify the various factors that affect the urea crystallization risk, this paper conducts a simulation analysis on a nozzle and mixer structure and operating parameters. The CFD results indicate that the increase in urea spray time will increase the maximum urea film thickness on the SCR system mixer surface. Exhaust temperature is the most important influencing factor. When the diesel engine exhaust temperature increases from 190 °C to 300 °C, the maximum urea film thickness decreases by 32 and the urea film mass accumulation decreases by 5%. Exhaust flow has a small impact on urea crystallization risk. When the exhaust flow increases from 300 kg/h to 600 kg/h, the maximum urea film thickness decreases by 39% and the urea film mass accumulation decreases by about 1%. In addition, urea spray rate, nozzle numbers, spray angle, and spray cone angle are also factors that affect urea crystallization risk. Full article
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19 pages, 6890 KiB  
Article
Improvement of Blocked Long-Straight Flow Channels in Proton Exchange Membrane Fuel Cells Using CFD Modeling, Artificial Neural Network, and Genetic Algorithm
by Guodong Zhang, Changjiang Wang, Shuzhan Bai, Guoxiang Li, Ke Sun and Hao Cheng
Appl. Sci. 2024, 14(1), 428; https://doi.org/10.3390/app14010428 - 3 Jan 2024
Viewed by 920
Abstract
To further improve the performance of the Proton Exchange Membrane Fuel Cell (PEMFC), in this paper, we designed a blocked flow channel with trapezoidal baffles, and geometric parameters of the baffle were optimized based on CFD simulation, Artificial Neural Network (ANN), and single-objective [...] Read more.
To further improve the performance of the Proton Exchange Membrane Fuel Cell (PEMFC), in this paper, we designed a blocked flow channel with trapezoidal baffles, and geometric parameters of the baffle were optimized based on CFD simulation, Artificial Neural Network (ANN), and single-objective optimization methods. The analysis of velocity, pressure, and oxygen distribution in the cathode flow channel shows that the optimized trapezoidal baffle can improve oxygen transport during the reaction. The comparison of the optimization model with the straight flow channel model and the rectangular baffle model shows that the power density of the optimized model is 4.0% higher than that of the straight flow channel model at a voltage of 0.3 V, and the pressure drop is only 37.83% of that of the rectangular baffle model. For on-road PEMFC with a voltage of 0.6 V, the influence of pump power is significant, and the optimized trapezoidal baffle model has a net power increase of 1.47% compared to the rectangular baffle model at 50% pump efficiency and 3.94% at 30% pump efficiency. Full article
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15 pages, 10494 KiB  
Article
Thermal Management of Diesel Engine Aftertreatment System Based on Ultra-Low Nitrogen Oxides Emission
by Ke Sun, Gecheng Zhang, Zhengyong Wang, Da Li, Guoxiang Li, Shuzhan Bai, Chunjin Lin and Hao Cheng
Appl. Sci. 2024, 14(1), 237; https://doi.org/10.3390/app14010237 - 27 Dec 2023
Viewed by 691
Abstract
To achieve diesel engine ultra-low nitrogen oxide emission, light-off selective catalyst reduction (LO-SCR) has been suggested for better performance with lower exhaust temperature. An electric heater upstream of the exhaust aftertreatment system was applied to significantly decrease the NOx emission at a [...] Read more.
To achieve diesel engine ultra-low nitrogen oxide emission, light-off selective catalyst reduction (LO-SCR) has been suggested for better performance with lower exhaust temperature. An electric heater upstream of the exhaust aftertreatment system was applied to significantly decrease the NOx emission at a low exhaust temperature. With a 7.2 kW electric heater coupled with LO-SCR, the NOx emission during 200~500 s of the world harmonized transient cycle (WHTC) decreased from 282.6 ppm to 61.5 ppm, which is a decrease of 45%. Application of an upstream diesel oxidation catalyst (DOC) decreased the NOx emission by 63% at the same interval at the cost of worse cold-start performance. The urea input was also adjusted to avoid NOx emission during the latter part of the WHTC. Full article
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17 pages, 11530 KiB  
Article
Construction of a Numerical Model for Flow Flash Evaporation with Non-Condensable Gas
by Wei Wang, Bingrui Li, Xin Wang, Bingxi Li and Yong Shuai
Appl. Sci. 2023, 13(21), 11638; https://doi.org/10.3390/app132111638 - 24 Oct 2023
Viewed by 996
Abstract
Flash evaporation processes are widely used in petroleum, food, chemical, power, and other industries to separate products or extract heat. The liquid is often entrained by non-condensing gas components. This study develops a multiphase, multicomponent, and pressure-driven phase-change-coupled model to numerically study water [...] Read more.
Flash evaporation processes are widely used in petroleum, food, chemical, power, and other industries to separate products or extract heat. The liquid is often entrained by non-condensing gas components. This study develops a multiphase, multicomponent, and pressure-driven phase-change-coupled model to numerically study water flash evaporation with non-condensing CO2. The model includes the mass, momentum, energy, volume of fluid (VOF), species transport, turbulence (RNG k-ε), modified phase-change Lee, and non-condensing CO2 release governing equations. The steam generation rate and mechanism for pure water and different concentrations of CO2 are considered. The results show that the numerical model can accurately predict the flash evaporation process and has high accuracy compared with the experimental data. Both the dissolved and entrained CO2 that are released can severely disturb the flow field, leading to an increase in the steam generation rate. Under a 1–10% volume concentration of dissolved CO2 and 0.0661–0.1688% mass concentration of entrained CO2, the maximum increase ratio of steam generation can reach 20%. Full article
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