Efficient Thermal Management System Research Articles

Machine learning-based model for the intelligent estimation of critical heat flux in nanofluids

The rising demand for advanced energy systems requires enhanced thermal management strategies to maximize resource utilization and productivity. This is quite an important industrial and academic trend as the efficiency of energy systems depends on the cooling systems. This study intends to address the critical need for efficient heat transfer mechanisms in industrial energy systems, particularly those relying on pool boiling conditions, by mainly focusing on Critical Heat Flux (CHF). In fact, CHF keeps a limit in thermal system design, beyond which the efficiency of the system drops. Recent research materials have highlighted nanofluids’ superior heat transfer properties over conventional pure fluids, like water, which makes them a considerable substitution for improving CHF in cooling systems. However, the broad variability in experimental outcomes challenges the development of a unified predictive model. Besides, Machine Learning (ML) based prediction has shown great accuracy for modeling of the designing parameters, including CHF. Utilizing ML algorithms—Cascade Forward Neural Network (CFNN), Extreme Gradient Boosting (XGBoost), Extra Tree, and Light Gradient Boosting Method (LightGBM)— four predictive models have been developed and the benchmark shows CFNN’s superior accuracy with an average goodness of fit of 89.32%, significantly higher than any available model in the literature. Also, the iterative stability analysis demonstrated that this model with a 0.0348 standard deviation and 0.0268 mean absolute deviation is the most stable and robust method that its performance minorly changes with input data. The novelty of the work mainly lies in the prediction of CHF with these advanced algorithm models to enhance the reliability and accuracy of CHF prediction for designing purposes, which are capable of considering many effective parameters into account with much higher accuracy than mathematical fittings. This study not only explains the complex interplay of nanofluid parameters affecting CHF but also offers practical implications for the design of more efficient thermal management systems, thereby contributing to the broader field of energy system enhancement through innovative cooling solutions.

Improving heat transfer in indirect liquid-based battery thermal management systems through turbulator-equipped conical flow paths

To guarantee the safe operation of Li-Ion Cells (LICs) in various applications, such as electric vehicles, an efficient Battery Thermal Management System (BTMS) is necessary. The design of BTMSs, as documented in the literature, typically involves the use of cooling channels with uniform and smooth configurations. However, these configurations encounter the challenge of temperature non-uniformity in the battery module, which stems from elevated coolant temperatures along the flow direction. In this study, a 3D numerical analysis is conducted to develop a novel indirect liquid-based cooling system for the BTMS of a module with cylindrical LICs. The study explores the effects of conical cooling channels, both with and without twisted turbulators, across various coolant mass flows during a 2C discharge process of LICs. Within the studied ranges, diverging cooling channels improve the overall thermal and hydraulic performance of the BTMS by an average of 40%, increasing the heat transfer coefficient by a maximum of 32.6%, and decreasing pressure drop by up to 35.1%. The application of turbulators proves effective in reducing the maximum temperature difference within the LICs, demonstrating a decrease of approximately 34.2% at the minimum mass flow rate and 74.4% at the maximum mass flow rate. This emphasizes the more substantial impact of turbulator utilization at higher coolant mass flow rates. An increased coolant flow rate leads to a significant enhancement of the heat transfer coefficient, ranging from 70.5% to 79.0% for the BTMS incorporating turbulators. Moreover, the study highlights a more pronounced impact of increasing mass flow rates in the BTMS designed with converging cooling channels compared to those designed with diverging channels. Finally, the results of this analysis demonstrate that the proposed system is capable of efficiently regulating the temperature of the entire battery module, ensuring that it consistently maintains a normal and safe operational range suitable for vehicular applications (below 40 °C).

Multifunctional double cold source system using temperature-sensitive hydrogel for cooling extravehicular spacesuits

The development of future space missions aimed at extended distances has challenged the thermal protection performance of extravehicular spacesuits. The use of more efficient and lightweight cooling systems in spacesuits can reduce costs and promote the advancement of human spaceflight. This study applies the temperature-sensitive hydrogel to the cooling system of the spacesuit, which combined with a water sublimator constitutes a double cooling source that dissipates heat simultaneously. As shown by modeling and simulation, the novel system effectively dissipates heat, with an 11.42% increase in total heat dissipation over the conventional method. Furthermore, the hydrogel can store water, and the water released during heat dissipation is provided to the sublimator for backup, reducing water consumption by 31.2% and lowering consumable demand. We defined the sublimation water release heat dissipation ratio, and it ranges from 1.5 to 3.5 in different operating modes, with the water sublimator serving as the primary cooling source. The research results suggest that the novel double cold source system can deploy heat dissipation capacity according to heat load distribution and flexibly meet the requirements of various tasks. The double cold source system is a highly efficient thermal management system that provides a novel approach to optimizing spacesuits.

Recent advancements and performance implications of hybrid battery thermal management systems for Electric Vehicles

Electric Vehicles (EVs) can contribute significantly toward the reduction of environmental emissions caused by traditional Internal Combustion Engines (ICEs), as well as it reduces the reliance on conventional fossil fuels. Lithium-ion batteries (LiBs) are generally preferred for EVs due to their superior energy density, specific power output, and longer lifespan. LiBs are most effective and achieve optimal performance within a specific temperature range of 15-35 °C. An efficient Battery Thermal Management System (BTMS) is necessary to dissipate the heat produced in the battery during continuous charging and discharging process, which ultimately determines the operating range and life cycle of the battery. The hybrid battery thermal management system is becoming increasingly popular as it tackles the downsides and capitalizes on the upsides of individual conventional battery thermal management systems. Although hybrid Battery Management Systems are often mentioned in review articles, there is a lack of detailed or specialized discussions specifically on hybrid BTMS for electric vehicles. This article summarizes the current state-of-the-art and recent advancements in hybrid battery thermal management of LiBs and discusses the performance implications of a hybrid battery thermal management system. The study extensively examines hybrid BTMSs, designed to enhance the thermal performance of traditional BTMSs to cope with the stringent thermal requirements in high ambient temperatures and fast charging conditions. Lastly, the article critically evaluates and discusses the different BTMSs, emphasizing the future prospects, challenges, and recommendations in the BTMS field. The review's findings will assist researchers in determining the future direction of next-generation LiB thermal management systems for high-power electric vehicles.

Performance analysis of a battery thermal management system based on phase change materials with micro heat pipe arrays

Lithium-ion battery packs generate high-level heat under harsh and rigorous conditions. The inadequate heat dissipation results in high pack temperature above the safe operating range. This study investigates an efficient and cost-effective battery thermal management system based on phase change materials and a micro heat pipe array. The battery is treated as a single domain. A battery pack with six series stacked batteries is analyzed using the Newman-Tiedemann-Gu-Kim model. The thermal performance of a battery thermal management system is analyzed using phase change materials with various melting temperature values, ambient temperature, and convective heat transfer coefficients of micro heat pipe arrays. Results show that the maximum temperature of the cooling system with micro heat pipe arrays and phase change materials is 33.8 °C, which is reduced by 22.3 % and 7.8 % compared to the air-cooled and cooling system with micro heat pipe arrays. At forced convection of 50 W·m−2·K−1, the maximum battery temperature values for the phase change material RT31, RT35, and RT42 are reduced by 11.8 %, 8.9 %, and 5.4 % compared to those at forced convection of 5 W·m−2·K−1. Under short-circuit conditions, the cooling system with micro heat pipe arrays and cooling system with micro heat pipe arrays − phase change materials reduce the maximum battery temperature by 12.4 % and 29.9 % compared to the air-cooled system. Results show that the developed model for the battery thermal management system provides a reference for designing phase change materials with micro heat pipe arrays.

Effects of the cold plate with airfoil fins on the cooling performance enhancement of the prismatic LiFePO4 battery pack

To maintain the optimal battery performance, it is essential to develop an efficient battery thermal management system for keeping the battery operation temperature within the appropriate range. In this work, a novel design of cold plate featuring airfoil fin channel is developed as a highly effective cooling module of a prismatic LiFePO4 battery pack. The thermal performance of battery and the thermo-hydraulic performance of the cooling module for the cold plate featuring airfoil fin channel, U-type channel and serpentine channel are numerically investigated and compared to reveal the superiority of the novel cold plate. The results indicate that compared with the U-type channel and the serpentine channel, the airfoil fin channel can enhance the total heat dissipation amount by 3.47% and 4.64%, respectively. Besides, the airfoil fin channel can provide the smallest battery maximum temperature and temperature difference under the same coolant flow rate. The airfoil fin channel provides the smallest pressure loss and heat transfer coefficient but the largest overall thermo-hydraulic performance indictor in terms of j/f factor. Under the same requirement of battery cooling performance, the remarkably smaller power consumption is required for the airfoil fin channel compared with the U-type channel and serpentine channel.

Study on the effect of immersion thermal management for high-current rate fast charging of 21700 Li-ion batteries

During high-rate fast charging, power batteries will generate significant heat. Therefore, it is more necessary to have an efficient thermal management system. This paper presents a thermal behavior simulation model for a 21700 NCM Li-ion ternary battery module, obtaining the onset temperature of each stage of the overheating decomposition reaction. On this basis, we developed an immersion cooling model for the battery module. And its cooling effect at different spacing (5-20 mm) and two different flow rate ranges (5-20 mm/s and 40-200 mm/s) in the fast charging process is simulated and analyzed. The results show that a 5 mm spacing exhibits a good heat transfer effect at low flow rates, while a flow rate of at least 20 mm/s is required for stable boiling heat transfer. In the high flow rate range, decreasing spacing or increasing flow rate will both reduce the temperature and temperature difference of batteries. Compared to 20 mm spacing and 40 mm/s flow rate, 5 mm spacing and 200 mm/s flow rate reduce temperature and temperature difference of batteries by 9.3 °C and 14.9 °C, respectively. Finally, the addition of the disturbing structure enhances coolant flow uniformity while minimally increasing flow pressure drop, and increases the heat flux by 157 W/m2, thereby further optimizing the cooling effectiveness.

Experimental study on the thermal management performance of lithium-ion battery with PCM combined with 3-D finned tube

As an important intermediary between the green energy and human society, the lithium-ion battery has promising prospects in the new energy vehicles, energy storage, and green development fields. However, lithium-ion batteries can generate a large amount of heat during operation. In addition, excess temperature or big temperature difference of the surface of the lithium-ion battery can reduce its performance, which also results in reducing its operational life and even triggers incidents such as fires and explosions. Therefore, studying efficient thermal management methods for lithium-ion batteries is crucial for increasing their application range. This paper proposes a novel thermal management method by combining 3-D finned tubes with PCM. The thermal management system maintains a battery operating temperature less than 45 °C and a maximum temperature difference less than 2.4 °C. The influence of different fin structure parameters on the melting dynamics of PCM and the heat transfer performance is then discussed. The obtained results show that under each solid–liquid ratio of PCM, the heat transfer performance increases with the increases of the fin height, while it initially decreases and then increases with the increase of the width and axial spacing. Moreover, the heat transfer performance of the 3-D finned tube with different PCM liquid–solid ratios is investigated. The obtained results demonstrate that for constant fin parameters, the heat transfer reaches its highest performance for a PCM liquid–solid ratio greater than 2:2. The findings of this study lay a foundation for the design of efficient thermal management systems incorporating PCM applications.

Heat dissipation performance research of battery modules based on composite phase change materials cooling and electrochemical thermal coupling model

In order to improve electric vehicle lithium-ion batteries (LIBs) performance and increase cycle life, it is crucial to design a reliable and efficient battery thermal management system (BTMS). Compared with other active battery cooling methods, passive phase change material (PCM) cooling has the advantages of simple structure, good temperature control uniformity, strong reliability, and no additional energy consumption. This article uses a series of experimental procedures to add expanded graphite to traditional paraffin wax PCM and obtain composite phase change materials (CPCM) with different mixing ratios. A control experiment is created to compare the cooling performance of the CPCM cooling with natural convection cooling, research shows that the cooling performance of CPCM can well meet the cooling demand which maximum temperature and maximum temperature difference of battery modules. In addition, to study the performance of thermal properties parameters related to CPCM, a COMSOL numerical calculation model of battery module based on CPCM cooling and electrochemical thermal coupling model is established. The effectiveness and accuracy of the model are verified through heat generation experiments at different rates (0.5 C, 1 C, 1.5 C), with a maximum temperature error of 1.6 K and an error accuracy of less than 0.6%. Subsequently, the performance of phase change temperature, thermal conductivity and phase change latent heat is studied and reasonable value ranges are obtained, which are 312 K∼318 K, 2.5 W /(m·K), and 175 J/g∼200 J/g, respectively.

Investigation of multifactorial effects on the thermal performance of battery pack inserted with multi-layer phase change materials

The safe and efficient power battery thermal management system (BTMS) is a prerequisite for the effectiveness and long service life of electric vehicles. So, a BTMS with inserted multi-layer phase change materials (PCMs) is proposed to enhance the safety and working performance of battery pack. Effects of PCM settings and operating conditions on the thermal performance of battery pack are discussed and analyzed. The results reveal that PCM cooling plays a significant role in the thermal management of battery pack, where the maximum temperature value and temperature difference of BTMS with multi-layer PCM #C are respectively reduced by 13.61 °C and 2.54 °C compared to battery pack without PCM. Besides, the coupling effects of multiple factors, that is, PCM permutation, the thickness and height of PCMs, and ambient temperature, on the heat dissipation of battery pack are discussed via orthogonal results analysis. The optimized multi-layer PCMs are obtained for the BTMS, i.e., Ps = 121, h1 = 5 mm and L = 6 mm, which achieves the lowest values of Tmax = 43.02 °C and ΔT = 3.37 °C at Tamb = 20 °C. It provides insights for optimizing thermal control strategies for the advancement of thermal management in electric vehicles, ultimately enhancing safety, performance, and longevity.

Study on an energy-saving thermal management system in outdoor base stations

In order to solve the poor heat dissipation in the outdoor mobile communication base station, especially in summer, high temperature alarm phenomenon occurs frequently, affecting the normal operation of building base band unite, this paper designs an energy-saving and efficient integrated thermal management system, which has achieved good results by applying the combined operation of heat pipe cooling and air conditioning system using the outdoor temperature switching mode. A mobile communication base station in Zhengzhou City was chosen for a pilot application. The measured results showed that the system ran stably, the temperature inside the cabinet was controlled between 12?C and 39?C with no high temperature alarm, the compressor running time was significantly reduced, the power consumption of the air conditioner was significantly reduced, and the annual power saving rate was as high as 58.63%.

Enhancing buoyancy-driven convection transport between two vertical parallel plates with symmetric and asymmetric heating using additively manufactured lattice structures

In this paper, we report the findings of our investigation on achieving enhanced heat dissipation through buoyancy-induced flow between two vertically oriented heated plates by packing additively manufactured porous media between them. Lattice structures comprising five different unit cell topologies: Octet, FD-Cube, FD-Cube paired, TKD, and Cube were selected as the chosen porous media. They were separated from the vertical plates by a finite distance for two values of aspect ratio (plate separation distance-to-height ratio) of ∼0.5 and 2. The vertical walls were subjected to a constant heat flux (symmetric and asymmetric). Among the five topologies explored, the Cube lattice structure provided the highest heat dissipation for a wide range of investigated Rayleigh numbers, under different aspect ratios and heating conditions. This superiority can be attributed to the inherent characteristics of the Cube structure, which exhibited the highest permeability, consequently offering the least resistance to the fluid motion. In contrast, the Octet lattice structure, despite its high surface area-to-volume ratio, had the lowest permeability as compared to other topologies and provided the weakest thermal performance. Thermal performance of the remaining topologies—TKD, FD-Cube paired, and FD-Cube—fell between that of the Cube and the Octet. The results clearly indicate that the resultant thermal performance is a complex interplay between the permeability, surface-area-to-volume ratio, and local fluid dynamics. The insights gained from this investigation can offer guidance for designing efficient thermal management systems across various applications involving buoyancy-induced flows.

Analysis of hybrid active-passive prismatic Li-ion battery thermal management system using phase change materials with porous-filled mini-channels

The rapid expansion of electric vehicles (EVs) has created a significant demand for lithium-ion batteries (LIBs). However, ensuring safety and preventing thermal degradation of LIBs pose challenges to their overall performance and lifespan. Efficient battery thermal management systems (BTMS) are crucial in achieving long-lasting batteries with high energy density. Thermal management procedures are categorized into active and passive approaches. While active cooling methods are crucial, they consume power. Instead, passive cooling methods are not as influential in fulfilling all roles. This study examines a combination of active (mini-channel) and passive (PCM heat sink) techniques. The effects of employing a porous medium inside the mini-channel are also analyzed to enhance the heat exchange. Influences of different factors, including Darcy number, material, the thickness of porous media, and inlet velocity of mini-channel flow in multiple discharge rates (1C, 2C, 3C), are examined. Outcomes show the PCM heat sink itself can lessen the maximum temperature by about 4.2 to 5 K in different inlet velocities. The hybrid porous-filled channel and PCM heat sink can mitigate the maximum temperature by about 13 K in different inlet velocities and at the maximum discharge rate (3C) at the expense of about 14 % higher pumping power in different conditions.

3D Electrothermal Model for Internal Temperature Distribution in Lithium-Ion Battery Cell and Module

In recent years, lithium-ion batteries (LIBs) have been massively developed in many applications as they provide high energy and power densities, high efficiency and long lifespan compared to other battery technologies. Despite remarkable improvements, Li-ion batteries still face thermal issues, which cause performance drop, limited calendar life, safety concerns and temperature-caused degradation. Therefore, proper thermal management for a LIB is necessary to control its temperature and to extend its lifetime. Internal temperature measurement remains very challenging for LIB. So, electrothermal LIB models, developed to forecast both electrical performances and temperature distributions, seems to be a powerful and complementary tool to experiments, in particular to obtain battery temperatures in use. Most of models, assume simplified approach considering that heat sources are either located in the center of the cell or uniformly distributed in the volume of the cell and so do not consider the real internal geometry of the cells.In this work, a 3D electrothermal model of a large commercial prismatic NMC-type lithium-ion cell (25 Ah) is developed based on the internal geometry reconstructed from tomography. The electrothermal model, developed with the COMSOL Multiphysics® software with the real internal geometry as well as the anisotropy of the thermal properties, accounts for irreversible and reversible heat sources. The entropy variation profiles were estimated by Entroview™ using their patented method. The validation of the model is performed thank to temperature measurement during charge and discharge at several currents in a climatic chamber at 25°C. Simulation results highlight exothermal and endothermal behaviors related to the entropy change along with the charge and discharge stages. Moreover, the internal temperature distribution is thoroughly impacted by the internal geometry of the cell and the anisotropy of the thermal properties.Finally, the 3D electrothermal model is extended to a module of 12 cells in series (12S) to evaluate the heterogeneities of internal temperatures considering the real geometry of each cell. Once validated, simulation (as shown of figure 1) underline the heterogeneous temperature distribution at the module scale and the importance of having an efficient battery thermal management system to limit an excessive increase of the temperatures which can cause performance drops until irreversible degradations. Figure 1

Unsteady conjugate heat transfer simulation of wall heat loads for rotating detonation combustor

Rotating detonation engines (RDEs) are the most promising pressure-gain combustion devices, but their long-duration operations are hindered by the harsh thermal environment inside the chamber. This study analyzes the instantaneous and average heat loads on chamber walls of RDEs based on the newly developed unsteady conjugate heat transfer (CHT) OpenFOAM solver named multiRegionBYRFoam. To enhance accuracy in predicting heat transfer characteristics compared to decoupled simulations focusing solely on fluid or solid behavior, three-dimensional CHT simulations are conducted for a premixed H2/air annular RDE coupling the detonation simulation with heat conduction in both inner and outer chamber walls. The transient time evolutions of wall heat flux in RDEs are numerically captured for the first time and agree well with experiments. The calculated peak wall heat flux is 1.98 MW/m2 at the inner wall and 2.63 MW/m2 at the outer wall when a single detonation wave propagates with a mass flow rate of 0.227 kg/s. By investigating the influence of inlet flow conditions and detonation modes, valuable guidelines on designing efficient thermal management systems for RDEs are obtained: larger mass flow rates and multi-wave modes result in higher average wall heat flux; the heat flux at the outer wall exceeds that at the inner wall while both walls require effective cooling for gas turbine engines with a rotating detonation combustor. Furthermore, a novel heat transfer model for RDEs is proposed based on a thermal operation map depicting total heat transfer rates to describe the nonlinear impact of mass flow rate and number of detonation waves, which can be employed to predict total wall heat loads under specific operation conditions of RDE.

Numerical investigation of a battery thermal management system integrated with vapor chamber and thermoelectric refrigeration

An efficient battery thermal management system is crucial for ensuring the working temperature environment of batteries and extending their lifespan. In this paper, a novel battery thermal management system combining vapor chambers and thermoelectric coolers is proposed to improve the battery's thermal behavior. Also, a complete fluid-thermal-electric multiphysics numerical model for the proposed system is built to predict its thermal performance under different cooling parameters. Results show that the use of thermoelectric coolers and vapor chambers can greatly lower the maximum temperature and temperature difference of batteries. Although the maximum temperature decreases with the increase of air convection heat transfer coefficient and coolant flow rate, the temperature difference increases at the same time. Under the given optimal air and water cooling parameters, it is noticed that as the input current of thermoelectric coolers increases, the maximum temperature and temperature difference show a pattern of decreasing first and then increasing. The optimal air convective heat transfer coefficient, coolant flow rate, and input current of 50 W/(m2·K), 0.04 m/s, and 1.5 A, respectively, are suggested, which corresponds to the maximum temperature of 39.83°C and temperature difference of 5.97°C. The present research introduces a fresh perspective on efficient battery thermal management, offering detailed insights into the utilization of thermoelectric cooling for this purpose.

Development of a Computational Fluid Dynamics Simulation Framework for Aerothermal Analyses of Electric Vehicle Battery Packs

Abstract The rise of electric vehicles has driven the extensive adoption of lithium-ion batteries (LIBs) due to their favorable attributes—compactness, low resistance, high power density, and minimal self-discharge. To enhance LIB reliability, an efficient battery thermal management system is imperative. This paper introduces a finite volume-based aerothermal analysis framework for a 32-cell high-energy density LIB pack. We also explore the effectiveness of various turbulence models in capturing local hotspots, discharge rates, and current levels across different geometries and inlet velocities. Our approach involves modeling the battery using Simcenter Battery Design Studio and importing it into Simcenter star-ccm+ for aerothermal simulations in which temperature distribution, discharge rates, current levels, and maximum temperature across are monitored for aligned, cross, and staggered configurations of the battery pack under varying inlet velocities. Our findings highlight the significant impact of boundary condition modeling on simulation stability. Also we observed that the standard k–ε model provides the most accurate predictions, with prediction accuracy within 3–10% of experimental data. Moreover, we identify substantial dependencies between heat generation and discharge current, as well as thermal gradients and inlet velocity. Finally, we conclude that the aligned cell arrangement offers the best thermal uniformity and cooling efficiency.

Experimental research on pipeless power battery cooling system using shape-stabilized phase change materials (SSPCM) coupled with seawater

With the implementation of zero carbon strategy, electric ships based on lithium-ion power batteries have become development mainstream. Compared with vehicle power batteries, the heat generated by the larger size of ship power batteries is more difficult to be discharged. Therefore, efficient ship power battery thermal management (BTM) systems are urgently needed. Herein, a pipeless cooling system based on shape-stabilized phase change materials (SSPCM) as the seawater channel was proposed and experimentally studied. Firstly, the excellent seawater corrosion resistance of SSPCM channel was proven. Then, the cooling performance of SSPCM channel was compared with the metal channel and SSPCM coupled with metal channel. The results demonstrated that the maximum temperature and maximum temperature difference of the SSPCM channel system were 8.3 °C lower and 1.1 °C lower, respectively than the metal channel system. Although the cooling performance of SSPCM and SSPCM coupled with metal channel was similar, SSPCM had a lighter weight and avoided seawater corrosion. Furthermore, the effects of different factors on the SSPCM channel system were investigated and the key factors were identified by orthogonal experiment. The innovative use of SSPCM channel and seawater provides a new idea for the cooling of the ship power batteries.

Study of the enhanced heat transfer characteristics of wavy-walled tube heat exchangers under pulsating flow fields

Heat exchangers have a very wide range of applications in many industrial fields, so the rational design and the performance are to improve the heat exchanger energy efficiency and reduce the production cost of an important means. In this paper, the heat transfer mechanism of pulsation is revealed by simulating and analyzing the effects of three pulsation parameters: volumetric flow rate, pulsation frequency, and pulsation amplitude on the flow and heat transfer of a wavy-walled tube heat exchanger, with the study focusing on the instability behavior that affects the heat transfer mechanism. The results reveal that the combined heat transfer performance of the wavy-walled tube heat exchanger is about 8.2% higher than that of the straight-walled tube heat exchanger. The flow field of the heat exchanger is more fully developed under the pulsating flow field, and its performance evaluation coefficients (PECs) are all greater than 1. It is also found that with the increase in the volume flow rate Qv, the heat transfer enhancement coefficient and PEC first increase and then decrease, and reach the maximum value near Qv = 2.0 m3/h; with the increase in the amplitude A, the vortex and heat transfer enhancement coefficient inside the heat exchanger increase, but the integrated heat transfer performance of the heat exchanger is gradually weakened; with the increase in the frequency fT, the heat transfer enhancement coefficient and PEC first increase gradually, but the increase gradually decreases and levels off in the later stages, reaching a maximum value near fT = 0.5 Hz. Meanwhile, the field coefficients of the wavy-walled tube heat exchanger were analyzed and found to be much smaller than 1, with an order of magnitude of 10−4, and the results also showed that the field coefficients were inversely proportional to the volume flow rate and directly proportional to the amplitude of pulsation and that the field coefficients showed a tendency of increasing and then decreasing with the change of pulsation frequency and reached a maximum value near fT = 0.5 Hz. This work provides an important reference for current manufacturing industries to optimize heat exchanger sizing and develop efficient thermal management systems.

An investigation into a semi-porous channel's forced convection of nano fluid in the presence of a magnetic field as a result of heat radiation

This study investigates the impact of heat radiation on magnetically-induced forced convection of nanofluid in a semi-porous channel. The research employs Akbari-Ganji's and Homotopy perturbation methods to analyze the effects of multiple parameters, including Hartmann number, Reynolds number, Eckert number, radiation parameter, and suction parameter, on the flow and heat transfer characteristics. The results demonstrate that increasing Reynolds number, suction, and radiation parameters increases temperature gradient, providing valuable insights into improving heat transfer in semi-porous channels. The study validates the proposed methods by comparing the results with those obtained from other established methods in the literature. The main focus of this work is to understand the behavior of nanofluids in semi-porous channels under the influence of magnetic fields and heat radiation, which is essential for various industrial and engineering applications. The future direction of this research includes exploring the effects of different nanoparticle shapes and materials on heat transfer performance and investigating the influence of other parameters, such as buoyancy forces and variable properties, on the flow and heat transfer characteristics. The findings of this study are expected to contribute to the development of more efficient thermal management systems in the future.