Browse Topic: Heat transfer

Items (3,316)
Wankel rotary engines are renowned for having lower efficiency than classic reciprocating engines. One of the factors affecting the efficiency is an unfavourable surface area-to-volume ratio given by the particular geometry of the engine, which increases the heat loss during the combustion phase. A novel and specific study on this aspect was carried out in this work by implementing a general parametric routine in Octave/Matlab. It was able to compute the surface area-to-volume ratio and execute a sensitivity analysis on specific engine geometrical parameters (e.g. housing width “b”) in order to determine the geometrical configuration with the minimum surface area-to-volume ratio for a given swept volume, compression ratio and K factor (i.e. the ratio between generating radius and eccentricity). The aforementioned procedure was then applied considering the geometry of the Advanced Innovative Engineering 225CS rotary engine. Three virtual geometrical configurations with the same
Vorraro, GiovanniTurner, James
Electric vehicles (EVs) are gaining popularity due to their zero tailpipe emissions, superior energy efficiency, and sustainable nature. EVs have various limitations, and crucial one is the occurrence of thermal runaway in the battery pack. During charging or discharging condition of battery pack may result in thermal runaway condition. This promotes the requirement of effective cooling arrangement in and around the battery pack to avoid localized peak temperature. In the present work, thermal management of a 26650 Lithium iron phosphate (LFP) cell using natural convection air cooling, composite biobased phase change material (CBPCM) and its combination with copper fins is numerically investigated using multi-scale multi dimension - Newman, Tiedenann, Gu and Kim (MSMD-NTGK) battery model in Ansys Fluent at an ambient temperature of 306 K. Natural convection air cooling was found effective at discharge rates of 1C to 3C, maintaining cell temperature below the safe limit of 318 K for 80
Srivastav, DurgeshPatil, Nagesh DevidasShukla, Pravesh Chandra
Thermal runaway in battery cells presents a critical safety concern, emphasizing the need for a thorough understanding of thermal behavior to enhance battery safety and performance. This study introduces a newly developed AutoLion 3D thermal runaway model, which builds on the earlier AutoLion 1D framework and offers significantly faster computational performance compared to traditional CFD models. The model is validated through simulations of the heat-wait-search mode of the Accelerating Rate Calorimeter (ARC), accurately predicting thermal runaway by matching experimental temperature profiles from peer-reviewed studies. Once validated, the model is employed to investigate the thermal behavior of 3D LFPO cells under controlled heating conditions, applying heat to one or more surfaces at a time while modeling heat transfer from non-heated surfaces. The primary objective is to understand how these localized heating patterns impact temperature profiles, including average core temperatures
Hariharan, DeivanayagamGundlapally, Santhosh
Detailed modeling of battery thermal runaway and propagation often requires a source term that represents the chemical heat release of the cell as a function of temperature. The shape of this heat release trend typically comes from cell testing data. Accelerating rate calorimetry (ARC) tests provide concise information on cell self-heating, since the cell is kept nearly isothermal and adiabatic. Also, compared to differential scanning calorimetry (DSC) tests of battery component materials, it contains all interactions between components. Converting the temperature rise rate data to heat release rate is theoretically very simple, only requiring the heat capacity of the cell. Practically, however, careful analysis is required to avoid artifacts arising from limitations of the test setup. This study uses a simple one-dimensional transient heat transfer model to illustrate the runaway process inside a cell and describe two error sources present in many ARC tests. As the cell temperature
Vanderwege, BradPetersen, Ben
A method for performance calculation and experimental method of a high voltage heater system in electric vehicles is proposed. Firstly, heater outlet temperature and pressure drop of the heater are used as metrics to compare simulation results with experimental data, thereby validating the established model. Then, simulations are performed on two heater flow channel configurations: a cavity flow channel and a cooling fin flow channel. It is observed that the latter significantly reduces the heating plate temperature. This reduction enhances the protection of heating elements and extends their operational lifespan, demonstrating the advantages of incorporating cooling fins into the flow channel structure. The optimization variables for multi-objective optimization include the fin unit length, fin height, fin thickness, fin width, and spacing between two adjacent rows of fins. The optimization objectives include pressure drop, heat transfer efficiency, and heating plate temperature
Gong, MingWang, XihuiWang, DongdongShangguan, Wen-Bin
Plastic waste, in the past few years, has risen to be one of the most concerning and endangering pollutants to environment and life, making its effective management and reduction a major domain of focus among researchers and industrialists. This comparative study is an attempt to utilize recycled Polyethylene Terephthalate (rPET) fibres combined with Epoxy Resin in various combinations, to provide effective and low-cost insulation in moderate to low requirements. The above-mentioned components serve as viable insulators. Moisture resistance of both materials and temperature resistance of Epoxy resins ranging from 120°C to 150°C (depending upon the grade of Epoxy used) indicate a good stability in harsh external operating environment. While Epoxy resins are not inherently flame retardants, additives are introduced for this purpose in order to render the composite safer to use. Owing to the excellent adhesive properties of the Epoxy resin, the rPET fibres are allowed to bond together
Purihella, Sri Sai KrishnaPali, Harveer SinghKumar, PiyushSharma, Ved Prakash
Urea-based selective catalytic reduction (SCR) systems are widely used to meet stringent NOx emission standards in industrial diesel engines. However, suboptimal design of the urea-water solution (UWS) mixing pipes in SCR systems can lead to the formation of urea-derived solid deposits, which may adversely affect the system performance and reliability. Although recent advancements in deposit simulation technology using three-dimensional Computational Fluid Dynamics (3D CFD) have significantly improved the performance and compactness of mixing pipes, assessing deposit formation across all operating and environmental conditions remains challenging due to high simulation costs. This study introduces a novel computational method for predicting the formation and temperature of permanent liquid films from UWS injection which are closely related to deposit formation, along with new deposit evaluation criteria based on them. This proposed method integrates a one-dimensional heat transfer model
Sugimoto, KazumaKawabe, Ken
The heat transfer processes occurring in a compression ignition engine are complex, especially considering flame-wall interaction on the piston crown from impinging jets. To study the heat flux occurring on the piston in a heavy-duty diesel engine, a piston was instrumented with fifteen thermocouples and a wireless telemetry system. Eight of the thermocouples are high speed surface thermocouples placed primarily in regions with significant flame-wall interaction, providing crank-resolved surface temperature data. This work presents the first experimental datasets collected with this instrumented piston, describing in detail the thermocouple location selection process as well as data processing and uncertainty quantification for the high-speed surface thermocouples with a particular emphasis on cyclic variability and sensor-to-sensor variability. With this methodology established, data from this piston can be used for modeling and simulation studies as well as for studying the impact of
Gainey, BrianDatar, AdityaRavikumar, AvinashBhatt, AnkurVedpathak, KunalKumar, MohitGingrich, EricTess, MichaelKorivi, VamshiLawler, Benjamin
Hydrogen is a viable option to power high-performance internal combustion engines while reducing pollutant emissions thanks to its high lower heating value (LHV) and fast combustion rate. Furthermore, if compared to gasoline, hydrogen is characterized by a higher ignition delay time, which makes it more knock-resistant under the same thermodynamic conditions. In this paper, hydrogen potential as a fuel in a high-performance PFI naturally aspirated engine under stoichiometric conditions and high load regimes is investigated through zero and three-dimensional simulations. The analyses show that a stoichiometric hydrogen mixture reaches higher pressure and temperature values during compression than iso-octane at the same operating conditions, hence limiting the maximum engine compression ratio to avoid undesired ignitions throughout the combustion process. Additionally, hydrogen low density causes a reduction in terms of trapped energy inside the cylinder. Thus, despite its LHV is almost
Madia, ManuelVaccari, MarcoDalseno, LucaCicalese, GiuseppeCorrigan, DaireVilla, DavideFontanesi, StefanoBreda, Sebastiano
The improvement of heat dissipation performance of ventilated brake discs is vital to braking safety. Usually, the technical approaches shall be material optimization or structural improvement. In this paper, a simulation model of the heat transfer of brake discs is established using STAR-CCM+ software. Cast iron, aluminum metal matrix composite (Al-MMC), and carbon-ceramic composite materials (C-SiC) are compared. The results show that: Al-MMC has better thermal conductivity so that a more uniform temperature gradient distribution shall be formed; C-SiC has poorer heat capacity yet, according to previous studies, it has better thermal stability, which is the ability to ensure its friction factor under high-temperature condition; cast iron performs better with convective heat transfer rate, which enhances the heat transfer between the surface and surrounding flow field. Based on the results, this paper proposes four types of material combined brake discs using different friction
Wang, JiaruiJia, QingZhao, WentaoXia, ChaoYang, Zhigang
A specific thick film heater (TFH) for electric vehicles is investigaed in this study, and its three dimensional heat tansfer analysis model is estab-lished. The heat transfer and fluid performance of the TFH is analyzed using a computational fluid dynamics soft-ware. The performance of TFH is measured on a test bench, and the measured data is used to validate the developed model. Using the established model, the heating efficiency of TFH is studied for different inlet temperatures and flow rates, and the influence of the fin spoiler structure on TFH heating efficiency and the heating board temperature is investigated. The result indicates that the spoiler structure has a large effect on the board heating temperature, but has little effect on the heating efficiency. An orthogonal experimental design method is used to optimize the design of the fins and water channels, and the purpose is to reduce the board heating temperature for preventing over burning. Under the 25°C inlet
Guan, WenzheGuo, YimingWu, XiaoyongWang, DongdongShangguan, Wen-Bin
Alpha Engineered Composites’ thin profile textile composite heat shields provide thermal protection through several thermodynamic mechanisms including: radiation reflection; heat spreading; and finally heat transfer resistance. Typical under the hood automotive applications require heat shield average operational temperature up to 225°C, but newer internal combustion engines are being designed for higher operational temperatures to: increase efficiency through higher compression cycle ratios and lean burning; boost power through turbocharging; increase energy density; and support advanced emissions controls like EGR that can increase average operational temperature up to 300°C. Unfortunately, thermo-oxidative degradation mechanisms negatively impact the polymer structural adhesive within a heat shield textile composite and degrade thermal protection mechanisms. High average operational temperature degradation of traditional versus next generation textile composite heat shields is
Vazquez, Mark
In driving condition, the electric drive system of electric vehicles generates significant heat, which increases temperature of the motor, leading to reduced performance and energy loss. To manage the motor temperature and recover energy, a plate-fin heat exchanger (PFHE) is used to facilitate heat exchange between the electric drive system and the vehicle's thermal management system. In this study, Computational Fluid Dynamics (CFD) method was used to investigate the fin structure on thermal flow performance within the PFHE. The mathematical models of pressure drop and heat transfer of plate-fin heat exchanger are established in this paper, and an empirical formula for the friction factor was derived by using test data. The NTU method was applied to fit the formula of convective heat transfer coefficient, enabling the derivation of an empirical formula for the Colburn factor. A CFD simulation model was developed for a local heat exchange unit, considering the generic boundary
Yin, JintaiYin, ZhihongLu, XuanWang, MengmengLiu, Qian
This study investigates the impact of various notch geometries on the outer surface of the rotor of an interior permanent magnet synchronous motor intended for traction applications, focusing on improving both its thermal and electromagnetic performances. Traditional motor cooling methods, such as water jackets or oil spray/impingement, typically target the stator and/or end windings, neglecting rotor cooling. As a result, the dissipation of the heat from the rotor is dependent on the heat transfer across the air gap surrounding the rotor, despite air’s poor thermal conductivity, which causes it to act as an insulator. Rotor notches are used to limit the higher order harmonics from air gap flux density which results in decreased torque ripple, cogging torque, noise, and vibration of the machine. While the effect of rotor notches on electromagnetic performance is analyzed, their impact on the thermal management of the motor, particularly the heat transfer coefficient in the air gap
Zajac, ArthurDe Silva, BuddhikaLee, SunMistry, JigarNasirizarandi, RezaJianu, OfeliaKar, Narayan
High-octane fuel presents significant potential for enhancing the efficient and clean combustion of small GCI engines. To achieve both efficient and stable combustion during low load scenarios, this study employs the combination of simulation and experimental methodologies. By coordinating the mixing rate and chemical reaction rate, as well as optimizing the equivalent ratio, temperature inhomogeneity and other parameters, introduces a control strategy termed ‘gasoline-air’ control coupling quasi-homogeneous mixture multi-pulse charge activity control. The research indicates that a quasi-homogeneous mixture can be formed through pilot injection of gasoline during the intake stroke, with low injection pressure can enhance charge activity and promoting clean combustion. The optimal injection timing is identified at approximately -315 CA ATDC, where appears peak value of indicated thermal efficiency. The multi-pulse charge activity control strategy can effectively control the combustion
Nie, JinLongYi, Yucheng
The drive unit of electric vehicles is a complex system consisting of an electric motor and a gear train, which work together to provide the necessary power for vehicle propulsion. One essential component within this system is the ball bearing, which supports the rotating components such as gears and shafts. This study focuses on the thermal simulation of a ball bearing within the drive unit conducted using the Volume of Fluid (VOF) method coupled with mixed timescale Conjugate Heat Transfer (CHT) in Simerics-MP+ to reduce the computational time while ensuring accuracy in the analysis. The Computational Fluid Dynamics (CFD) approach considers the geometrical details and clearances of the inner race, outer race, cage, and ball within the ball bearing. By accounting for the relative motions between these components, it can accurately model the film formation of the lubricating oil and its impact on heat removal from the bearing. The simulations are conducted at two different shaft speeds
Ballani, AbhishekMotin, AbdulDhar, SujanGanamet, AlainMaiti, DipakRanganathan, RajPandey, Ashutosh
The U.S. DRIVE Electrical and Electronics Technical Team has set a goal for 2025 to achieve a power density of 33 kW/L for electric vehicle (EV) motors [1]. The increase in motor power density is highly dependent on effective thermal management within the system, making active cooling techniques like oil-jet impingement essential for continued advancements. Due to the time and expense of physical experimentation, numerical simulations have become a preferred method for design testing and optimization. These simulations often simplify the motor-winding surface into a smooth cylinder, overlooking the actual corrugated surface due to windings, thus reducing computational resources and mesh complexity. However, the coil's corrugated surface affects flow turbulence and heat transfer rates. This study utilizes three-dimensional Computational Fluid Dynamics (CFD) simulations to investigate the impingement-cooling of an Automatic Transmission Fluid (ATF) jet on a corrugated surface that
Mutyal, Jayesh RameshHaghnegahdar, AhmadGurunadhan, MohanaKonangi, SantoshChamphekar, Omkar
To investigate the static and dynamic mechanical properties of air springs and their influencing factors, two models were established in this paper to calculate the static and dynamic mechanical properties of air springs, including a simulation model based on the finite element method and a mathematical calculation model based on thermodynamic theory. First, a performance calculation model for rolling lobe air springs with aluminum tubes was established, which considered the thickness of the bellow and the impact of the inflation and assembly process on the state of the bellow. The static and dynamic mechanical properties of air springs were calculated using this model, including static load-bearing capacity and static/dynamic stiffness. The calculation results showed that both the static characteristics of the air spring under isothermal conditions and the dynamic characteristics under adiabatic conditions were able to be calculated accurately. However, the changes in dynamic
Wang, SiruiKang, YingziXia, ZhaoYu, ChaoLi, JianxiangShangguan, Wen-Bin
The rapid expansion of the global electric vehicle (EV) market has significantly increased the demand for advanced thermal management solutions. Among these, the battery cold plate is a critical component, essential for maintaining optimal battery temperatures and ensuring efficient operation. As EV batteries increase in size, the thermal management requirements become more complex, necessitating the development of new alloys with enhanced strength and thermal conductivity. These advancements are crucial for the effective dissipation of heat and the ability to withstand the mechanical stresses associated with larger and more powerful batteries. The evolving performance demands of EVs are driving material innovation within the thermal management sector. This study aims to explore the global heat exchanger market trends from a material perspective, focusing on the evolution of the mechanical and thermal properties. Specifically, we investigated the transition from the traditional AA3003
Jalili, MehdiWang, XuRazm-poosh, Hadi
Series hybrid vehicles with internal combustion range extenders are a promising solution for sustainable transportation. In this application, net zero carbon emissions can be achieved using renewable fuels. Fischer-Tropsch-derived e-gasolines/naptha allow for high energy density and safe liquid fuels. However, Fischer-Tropsch naptha fuel derivatives must undergo several processing stages to reach current engine-grade octane ratings, negatively affecting the synthesis's profitability and energy efficiency. Gasoline engine technologies capable of operating with low-octane fuels could allow the adoption of unprocessed Fischer-Tropsch gasoline. The rotary Wankel engine design suits range extenders thanks to its high power-to-size ratio. In this study, the knocking tendency of homogenous charge spark-ignition rotary Wankel engines is numerically assessed through Chemkin-Pro spark-ignition engine zonal model for knock assessment. Rotary Wankel engines are modeled by providing the
Brunialti, SirioVorraro, GiovanniTurner, JamesSarathy, Mani
Airborne compression ignition engines operating with aviation fuels are a promising option for reducing fuel consumption and increasing the range of hybrid-electric aircraft. However, the consistent ignition of Jet fuels at high-altitude conditions can be challenging. A potential solution to this problem is to ignite the fuel sprays by means of a glow-plug-based ignition assistant (IA) device. The interaction between the IA and the spray, and the subsequent combustion event result in thermal cycles that can significantly affect the IA’s durability. Therefore, designing an efficient and durable IA requires detailed understanding of the influence that the IA temperature and insertion depth have on the complex physics of fuel-air mixture ignition and flame propagation. The objective of this study is to design a conjugate heat transfer (CHT) modeling framework that can numerically replicate F-24 Jet fuel spray ignition using a glow-plug-based IA device in a rapid compression machine (RCM
Oruganti, Surya KaundinyaLien, Hao-PinTorelli, RobertoMotily, AustenLee, TonghunKim, KennethMayhew, EricKweon, Chol-Bum
Conjugate heat transfer (CHT) analysis of electric motor cooling was performed, simulating both the standard and paperless stator designs, using the CFD software Simerics-MP+ to assess the predictive accuracy of the numerical simulations. The condition investigated involved the motor operating at 14,000 RPM. This high rotor speed was modeled using a novel hybrid approach for mesh rotation to make the problem more tractable. Oil and air, the two immiscible fluids, were modeled using the explicit interface-capturing Volume of Fluid (VOF) method. The traditional CHT approach is computationally expensive for electric motor cooling applications due to the heat transfer time scale differences between the fluid and the solid. Temperature changes in solids occur over a much slower time scale owning to their higher thermal inertia compared to fluids. Therefore, we model the fluid and solid domains separately and use a mixed-time scale approach to exchange the heat transfer data between them
Varghese, JoelSchlautman, JeffChen, YaweiBhunia, SrijohnSrinivasan, Chiranth
Triply Periodic Minimal Surface (TPMS) structures offer the possibility of reinventing structural parts and heat exchangers to obtain higher efficiency and lighter or even multi-functional components. The crescent global climate concern has led to increasingly stringent emissions regulations and the adoption of TPMS represents a resourceful tool for OEMs to downsize and lighten mechanical parts, thereby reducing the overall vehicle weight and the fuel consumption. In particular, TPMS structures are gaining growing interest in the heat exchanger field as their morphology allows them to naturally house two separate fluids, thus ensuring heat transfer without mixing. Moreover, TPMS-based heat exchangers can offer countless possible design configurations. These structures are obtained by periodic repetitions in the three spatial dimensions of a specific unit cell with defined dimensions and wall thickness. By tuning their characteristic parameters, the structure can be tailored to obtain
Torri, FedericoBerni, FabioMartoccia, LorenzoMarini, AlessandroMerulla, AndreaGiacalone, MauroColombini, Giulia
Conversion to hydrogen of automobile internal combustion engines powered by fuels of petroleum origin is the most important direction for solving environmental, energy and climate problems of modern civilization. A number of researchers, based on experimental studies, note the presence of a phenomenon of a significant increase in heat losses in hydrogen engines compared to gasoline engines. This phenomenon is explained by an increase in temperature and speed of movement of the working fluid. In this paper, it is shown that the main reason for the increase in thermal losses is the ability of the hydrogen flame to penetrate into the narrow gap between the piston and the engine sleeve. This problem has not been discussed in engine theory before. D mathematical modeling of flame penetration and extinguishing processes in the specified gap of a hydrogen engine (D/S=86/86 mm/mm, Ne=60 kW, n=5500 min-1) was carried out. Critical gap sizes for various fuels have been established, heat transfer
Kavtaradze, RevazNatriashvili, TamazGladyshev, Sergey
Phase change energy storage devices are extensively utilized in latent heat thermal energy storage and hold significant potential for application in the thermal management of automotive batteries. By harnessing the high-density energy storage capabilities of phase change materials to absorb heat released by the batteries, followed by timely release and utilization, there is a substantial improvement in energy efficiency. However, the thermal conductivity of medium and low temperature phase change materials is poor, leading to its inefficient utilization. This paper focuses on optimizing the structure of a phase change heat exchanger in a phase change energy storage device to improve its performance. A basic design of the phase change heat exchanger is used as an example, and fin structure is added to enhance its heat exchange capabilities. A predictive surrogate model is built using numerical simulation, with the dimension and number of fins as design variables, and heat flow density
Zhang, HaonanSun, MingzheZheng, HaoyunZhang, Tianming
A tested method of data presentation and use is described herein. The method shown is a useful guide, to be used with care and to be improved with use.
S-12 Powered Lift Propulsion Committee
Temperature segregation significantly affects the compaction of asphalt mixtures and the durability of the asphalt pavement layer. Uneven cooling of the mixture during transportation is a key factor contributing to temperature segregation. This study uses finite element simulations to analyze the temporal and spatial temperature evolution during the transportation of asphalt mixtures. A temperature segregation evaluation index (TSIv) is proposed to assess the significance of various factors affecting segregation. Support vector regression (SVR), random forest regression (RFR), and extreme gradient boosting (XGBoost) models are employed to predict temperature changes during transportation and optimize the predictive models. The results indicate that the proportion of areas with a temperature difference of less than 10°C is consistently the highest, followed by areas with a temperature difference greater than 25°C, and then those with temperature differences in the ranges of 10-16°C and
Cheng, HaoMa, TaoTang, FanlongFan, Jianwei
This study investigates the heat transfer properties of graphene nanoplatelets (GnPs) blended with distilled water-ethylene glycol (DW-EG) mixtures, focusing on their potential application in battery thermal management systems (BTMS). Compared to other nanoparticles, carbon nanostructures exhibit higher thermal conductivity due to their low density and integrated thermal conductivity. The experimental findings are relevant in that compared with the base fluid, nanofluid samples had heat transfer capability. The physicochemical characteristics of investigated GNP were characterized using a Scanning Electron Microscope (SEM), pH and UV–Vis spectrophotometry. The thermal conductivity and physical properties of graphene platelets having the specific surface area of 500 m2/g in the base fluid of Distilled Water-Ethylene Glycol (DW-EG 70:30) and 100 % vol. of Ethylene Glycol (EG 100) were determined after 120 minutes of sonication time. The graphene nanofluids with the platelet
S, PalanisamySelvan, Arul Mozhi
A diesel engine with a Yttria Stabilised Zirconium (YSZ) thermal barrier layer (TBL) on the piston crown was used in an experiment. The aim of the investigation was to evaluate the influence of the thermal barrier layer on the efficiency and pollution levels of a diesel engine. The selection of YSZ as the coating material was based on its desirable physical properties including a high coefficient of expansion when exposed to heat, low degree of thermal conductivity, and a high Poisson's number. These characteristics make it a suitable material for use in coatings applied to engine components. In addition to their current research, the scientists are also focusing on identifying sustainable substitutes for conventional petroleum fuels. This is because of the growing concern over environmental impacts and the limited availability of fossil fuel resources. The researchers are seeking new options that are both environmentally friendly and capable of meeting the world's energy demands. By
Sagaya Raj, GnanaNatarajan, ManikandanPasupuleti, Thejasree
The present study is focused on the integration of phase change materials (PCMs) and Al2O3 nanoparticles into solar stills presents a promising approach to enhance their efficiency. This paper explores the design and performance analysis of a solar still system incorporating PCMs and Al2O3 nanoparticles with different concentration like 200ppm and 400ppm. The primary goal is to investigate the impact of these enhancements on the solar still’s productivity and thermal efficiency.The Aluminium Oxide Nanoparticle were synthesized by chemical co-precipitation method. XRD and TEM were used to characterize the aluminum oxide particles. In this study, Aluminum oxide nanoparticles were employed as thermal conductivity materials, while TN+30 were utilized as a phase change material. After taking about 25 (liters) of water, it was discovered that 1 cm was the ideal depth. Compared to PCM, the energy materials TN+30 and Al2O3 increased collection efficiency with 200 ppm and 400 ppm of 21.65% and
R L, KrupakaranSagaya Raj, GnanaPetla, Ratna KamalaKala, Lakshmi KAnchupogu, Praveen
This paper explores the augmentation of thermal conductivity in paraffin wax through the incorporation of aluminum oxide (Al2O3) and copper oxide (CuO) nanoparticles, leading to the development of composite phase change materials (PCMs). The objective is to enhance heat transfer rates, crucial for various energy storage applications including industrial waste heat recovery and solar thermal energy storage. Differential Scanning Calorimetry (DSC) testing was employed to experimentally investigate the thermal properties of the resulting nanocomposite PCM. The experimental results reveal that the nanocomposite PCM, composed of 96.14% paraffin wax, 2% aluminum oxide, and 1.6% copper oxide, exhibits 1.35 times increase in heat transfer rate compared to conventional paraffin wax. The integration of nanoparticles into the PCM matrix, facilitated by a magnetic stirrer at 50oC for 4 hours, results in uniform distribution and improved grain morphology, as evidenced by SEM images. Moreover, the
Tarigonda, HariprasadKumar, YB KishoreKala, Lakshmi KR L, Krupakaran
The substantial growth of power converters in electric vehicles necessitates more energy consumption and, as a result, greater heat generation. To avoid the power converter’s excessive heat, an innovative curved microchannel with diamond-shaped and pentagonal cross-sections was developed. The flow and heat transfer characteristics of the Gc3N4/Water (0.3%), Al2O3/Water (0.3%), and Al2O3-Gc3N4/Water (0.3%) hybrid nanofluid were assessed. The experimental investigation was carried out by different mass flow rates of about 0.1 to 0.5 LPM under a uniform heat flux of 50 kW/m2. The heat sink had a cross-sectional area of 80×48mm2. In comparison to the diamond channel heat sink through hybrid nanofluids, findings from experiments resulted that the heat transfer rate and pressure drop for the diamond channel enhanced by 14.2% and 18.9%, respectively. In comparison to Gc3N4/Water and Al2O3/Water nanofluids, the hybrid nanofluid improved the heat transfer rate for the diamond micro channel heat
R L, KrupakaranPetla, Ratna KamalaAnchupogu, PraveenKala, Lakshmi KGangula, Vidyasagar ReddyTarigonda, Hariprasad
This research explores the use of salt gradient solar ponds (SGSPs) as an environmentally friendly and efficient method for thermal energy storage. The study focuses on the design, construction, and performance evaluation of SGSP systems integrated with reflectors, comparing their effectiveness against conventional SGSP setups without reflectors. Both experimental and numerical methods are employed to thoroughly assess the thermal behavior and energy efficiency of these systems. The findings reveal that the SGSP with reflectors (SGSP-R) achieves significantly higher temperatures across all three zones—Upper Convective Zone (UCZ), Non-Convective Zone (NCZ), and Lower Convective Zone (LCZ)—with recorded temperatures of 40.56°C, 54.2°C, and 63.1°C, respectively. These values represent an increase of 6.33%, 11.12%, and 14.26% over the temperatures observed in the conventional SGSP (SGSP-C). Furthermore, the energy efficiency improvements in the UCZ, NCZ, and LCZ for the SGSP-R are
J, Vinoth Kumar
Disc brakes play a vital role in automotive braking systems, offering a dependable and effective means of decelerating or halting a vehicle. The disc brake assembly functions by converting the vehicle's kinetic energy into thermal energy through friction. The performances of the brake assembly and user experience are significantly impacted by squeal noise and wear behaviour. This paper delves into the fundamental mechanisms behind squeal noise and assesses the wear performance of the disc brake assembly. Functionally graded materials (FGMs) are an innovative type of composite material, characterized by gradual variations in composition and structure throughout their volume, leading to changes in properties such as mechanical strength, thermal conductivity, and corrosion resistance. FGMs have emerged as a groundbreaking solution in the design and manufacturing of brake rotors, addressing significant challenges related to thermal stress, wear resistance, and overall performance. These
C V, PrasshanthS, GurumoorthyBhaskara Rao, LokavarapuS, SridharS, Badri NarayananKumar, AjayBiswas, Sayan
Thermal runaway propagation (TRP) within lithium-ion batteries (LIBs) poses critical barriers to the safe operation and large-scale application of cell-to-chassis (CTC) batteries. Such events can lead to severe safety incidents, including explosions and fires, in systems utilizing these batteries. However, there is a lack of research on the thermal runaway model coupled with vented gases at the CTC systems. In this study, a thermal runaway coupling model for the battery pack system was established utilizing Star-CCM+ software, allowing for the examination of thermal runaway propagation characteristics and vented gas characteristics a within power battery systems based on the measured parameters of battery thermal safety characteristic. The simulation results indicated that once thermal runaway becomes uncontrollable, combustible flue gases escape through the exhaust hole located on the side plate of the cell, thereby facilitating heat transfer to adjacent cells. The primary components
Ma, NiyaZhang, AnweiZhou, WentaiZhou, YouJia, YuanFan, Zehong
In the field of static power generation, thermoelectric technology has become an important solution for utilizing automotive exhaust waste heat. This study presents a new design for a heat exchanger integrated with heat pipes, aimed at augmenting the installation area of thermoelectric modules and improving the hot end temperature by high heat transfer rate. Moreover, the number of heat pipes in each region is optimized to reduce the temperature gradient along the direction of exhaust flow and maximize overall output performance. A comprehensive numerical model of the thermoelectric generator system is developed to conduct the performance prediction and parameter optimization. The results reveal that the integration of heat pipes substantially boosts the performance of the automotive thermoelectric generator system, characterized by enhanced heat transfer, increased power output, and improved conversion efficiency. And the optimization yields an optimal configuration with 5 heat pipes
Zhao, JinFuDing, RenkaiChen, JieWang, RuochenLuo, Ding
With the rapid development of new energy vehicles, lithium-ion batteries (LIBs) have been widely used in the automotive sector. The performance and safety of LIBs in electric vehicles (EVs) are significantly influenced by operating temperature, making the development of an effective battery thermal management system (BTMS) crucial. In recent years, phase change material (PCM)-based BTMS technology has been recognized as one of the most promising solutions. Compared to traditional air and liquid cooling systems, PCM cooling technology exhibits superior cooling performance due to its large latent heat and efficient heat dissipation capabilities, while also eliminating the need for additional pump power consumption. Therefore, in-depth research on PCM cooling technology is of significant academic and practical value for enhancing the effectiveness and safety of power battery thermal management. This study investigates the effects of thermal conductivity, melting point, and thickness of
Lv, Kang-MinSu, Chu-QiWang, Yi-PingYuan, Xiao-HongLiu, Xun
The thermoelectric generator system is regarded as an advanced technology for recovering waste heat from automotive exhaust. To address the issue of uneven temperature distribution within the heat exchanger that limits the output performance of the system, this study designs a novel thermoelectric generation system integrated with turbulence enhancers. This configuration aims to enhance convective heat transfer at the rear end of the heat exchanger and improve overall temperature uniformity. A multiphysics coupled model is established to evaluate the impact of the turbulence enhancers on the system's temperature distribution and electrical output, comparing its performance with that of traditional systems. The findings indicate that the integration of turbulence enhancers significantly increases the heat transfer rate and temperature uniformity at the rear end of the heat exchanger. However, it also leads to an increase in exhaust back pressure, which negatively affects system
Chen, JieDing, RenkaiWang, RuochenLiu, WeiLuo, Ding
To explore the heat and mass transfer processes within the low-temperature catalyst layer, a coupled heat and mass transfer lattice Boltzmann model and electrochemical model were established, creating a pore-scale model for heat and mass transfer in the catalyst layer. The influence of the catalyst layer parameters was investigated. The results indicate that as time progresses, heat gradually accumulates at the top of the catalyst layer (CL) and is transmitted towards the bottom. Once oxygen enters the CL, it quickly fills the pores within the CL, resulting in a rapid decrease in oxygen concentration within the ionomer. As the platinum volume fraction increases, there is a significant rise in temperature across the entire calculation domain. With the increasing platinum volume fraction, the current density also increases rapidly due to the larger reaction area. When the carbon volume fraction is 0.15, more oxygen enters the ionomer to participate in reactions, and the large porosity
Xu, ShengChen, XinSheng, Tao
Thermal management system of electric vehicles (EVs) is critical for the vehicle's safety and stability. While maintaining the components within their optimal temperature ranges, it is also essential to reduce the energy consumption of thermal management system. Firstly, a kind of architecture for the integrated thermal management system (ITMS) is proposed, which can operate in multiple modes to meet various demands. Two typical operating modes for vehicle cooling in summer and heating in winter, which utilizes the residual heat from the electric drive system, are respectively introduced. The ITMS based on heat pump enables efficient heat transfer between different components. Subsequently, an ITMS model is developed, including subsystems such as the battery system, powertrain system, heat pump system and cabin system. The description of modeling process for each subsystem is provided in detail. The model is tested under world light vehicle test cycle (WLTC) condition of six different
Zhao, LuhaoTan, PiqiangYang, XiaomeiYao, ChaojieLiu, Xiang
Magnesium oxide (MgO) nanofluids are of great interest for enhancing the performance in thermal management especially in automotive applications, where efforts have been made to reduce parasitic losses from traditional cooling systems. These findings highlight the effects of Water–ethylene glycol and MgO nanofluids on viscosity and thermal conductivity in specific filling a gap in research that allows to clarify how these states behave at different temperature (T) and concentration (C) conditions. Test results demonstrate that the thermal conductivity of MgO nanofluids improved adequately /while its corresponding change in viscosity remained under control, affirming a significant improvement for energy savings by means heat transfer enhancement using new generation coolants based on this nano-additive. The results also provide useful information for design and development of automotive cooling systems, including real numbers on performance improvements that lead to more efficient and
Jeyanthi, P.
Cold thermal energy storage using phase changing materials is being researched to find freezing and thawing points. The use of inorganic hydrated salts, a type of phase changing material (PCM) used in cold energy storage systems without the use of existing renewable energy systems, allows for a longer cooling effect and saves energy. A high volumetric storage density and relatively high thermal conductivity make hydrated salts suitable materials for thermal energy storage. They can be used only as inorganic mixtures or else they can also be used as eutectic mixtures, which involve mixtures of inorganic–inorganic salts or simply a combination of two or more inorganic salts. This research deals with eutectic mixtures, which are 4% KNO3 + 96% H2O, 4% NaHCO3 + 96% H2O, and 2% KNO3 + 2% NaHCO3 + 96% H2O. Three different novel eutectic mixtures were examined and found a suitable mixture for a cold thermal energy system. An efficient phase change approach involving 2% KNO3 + 2% NaHCO3 + 96
Vasanthkumar, P.Santhoshkumar, A.Gopika, P.Murali, M.Meera, C.
This research investigates the development of a heat pipe heat exchanger coated with graphene for cooling and purification of automobile exhausts. The heat exchanger directly affects the performance of the engine because proper heat dissipation and transfer can improve engine performance, reduce fuel consumption, and decrease the emission. Moreover, this effect is much more noticeable on coated heat pipes because of the enhanced thermal conductivity and mechanical properties of the graphene films. A heat null emitted by internal combustion engines was used in the experimental setup to test the thermal performance, cooling efficiency, and purification efficiency of the newly designed in-house exhaust simulation system where the new heat pipes were inserted. The results of the experiment show that the heat pipes have very high thermal performance as the efficiency of the heat pipes was calculated to be around 85%. Furthermore, the temperature decrease over the surfaces of the heat
Karthigairajan, M.Seeniappan, KaliappanBalaji, N.Natrayan, L.Sheik, Salman BashaRavi, D.
Otto Cycle can operate with both gasoline and ethanol; however, these fuels have different properties that will result in different performance parameters. This work aims to compare the thermal energy balance of an internal combustion engine fueled with gasoline and ethanol. The experimental tests were carried out on a dynamometer bench varying engine speed between 1500 and 6000 rpm and at full load condition. The results showed that the engine’s maximum thermal efficiency ranged from 30.51% with gasoline to 31.72% with ethanol. The percentage of energy dissipated to the cooling system varied from 16.93% with gasoline from 16.12% with ethanol. The percentage of energy dissipated to the exhaust system ranged from 32.82% with gasoline from 34.64% with ethanol. The percentage of energy wasted due to incomplete fuel combustion varied from 3.50% with gasoline from 10.00% with ethanol. The percentage of energy dissipated to the lubrication system ranged from 3.95% with gasoline from 3.76
Santana, Claudio MarcioSantana, Linicker Lopes BrunoAlmeida, Helder Giostri Alves
The research introduces the thermal properties of silicon dioxide (SiO2) nanofluids and the promising application of these fluids in hybrid vehicle cooling systems. How to make fluids is simply to disperse a 50-50 mixture of both Ethylene Glycol and Water; into this solution add SiO2 nanoparticles concentration ranges from 0.1% up to 0.5% volume according desired properties or material characteristics etc. When viscosities and thermal conductivities of nanofluid were measured over the temperature range from 25 to 120 °C using Brookfield viscometer and transient hot-wire method; results were as follows: Viscosity of SiO2 nanofluids at 120°C higher concentrations 0.5%, more viscous fluids, thermal conductivity also rose with results, although there was a plateau at around 40% increase compared to that of water-based slurries. At 0.5% concentration, thermal conductivity increased by up to 20% at 120 °C, compared with the value of pure ethylene glycol. These results suggest that SiO2
Sundaram, V.Madhu, S.Vidhyalakshmi, S.Saravanan, A.Manikandan, S.
In this study, we investigate the thermal conductivity optimization of nanodiamond nanofluids for application in high-performance automotive engines. Nanodiamond particles, known for their superior thermal properties and stability, are dispersed in a base fluid composed of ethylene glycol and water. Various concentrations of nanodiamonds are prepared to evaluate their impact on thermal conductivity and viscosity. The experimental setup includes precise measurements of thermal conductivity using the transient hot-wire method and viscosity using a rotational viscometer over a temperature range of 25°C to 100°C. The results demonstrate significant enhancements in thermal conductivity with acceptable increases in viscosity, suggesting the potential of nanodiamond nanofluids in improving engine cooling efficiency. The study concludes with recommendations for future research to explore the long-term stability and performance of these nanofluids in real-world automotive applications.
Jeyanthi, P.Gulothungan, G.
This study points to potentiality of studying Aluminum Oxide (Al2O3) nanofluid on viscosity (μ) and thermal conductivity (K) for automotive cooling system. The Al2O3 nanoparticles dispersed in 50:50 ethylene glycol-water with5 varying concentrations of 0.1, 0.2, 0.3, 0.4 and 0.5 vol%. The viscosity at 25°C, 40°C, 60°C and 80°C was measured by using a Brookfield viscometer; and thermal conductivity was measured by the transient hot wire method. The results indicate that the viscosity increases with the concentration of nanoparticles but decreases with the temperature. Due to comparative importance of thermal conductivity with increasing temperatures and nanoparticle concentrations. In nanofluid Al2O3 can enhance heat transfer automotive cooling system can be good performance and efficient as well as engine, in 0.5% concentration, thermal conductivity at 25°C and increase 27% at 60°C, paranormal found for development and Al2O3 nanofluids apply can be effective improvement at heat
Vickram, A.S.Manikandan, S.Madhu, S.Saravanan, A.
In this study, the viscosity and thermal performance of nanofluids based on ZnO-MgO mixed oxide nanoparticles added in different concentrations to ethylene glycol-water mixture are characterized with potential applications in engine cooling. The work began with two needs: the increasing importance of better heat removal in automotive engines, where traditional coolants struggle to adequately maintain good thermal conductivity but at low viscosity to acceptable levels; and a chance opportunity for exploration provided by MMD/MILab Engineer Andrew Cricee. The work wants to improve the cooling properties, but still keeping good fluidity by integrating ZnO-MgO nanoparticles. Preparation method the preparation of ZnO-MgO nanofluids was done using volume concentrations of 0.1%, 0.3% and 0.5%. To determine chemical properties, viscosity measurements were made on the Dragonfly using a Brookfield viscometer at temperatures ranging from 25 ° C to 80 ° C while varying the nanoparticle
Manikandan, S.Vickram, A. S.Madhu, S.Saravanan, A.
Nanofluids have emerged as effective alternatives to traditional coolants for enhancing thermal performance in automotive applications. This study conducts a comparative analysis of the viscosity and thermal conductivity of ZnO and Cu hybrid nanofluids. Nanofluids were prepared with ZnO and Cu nanoparticle concentrations of 0.1%, 0.3%, and 0.5% by volume and were characterized over temperatures ranging from 25°C to 100°C. The results demonstrate that ZnO and Cu hybrid nanofluids achieve an increase in thermal conductivity by up to 22% and 28%, respectively, compared to the base fluid. Concurrently, the viscosity of these nanofluids increases by up to 12% at the highest concentration and temperature. This study addresses a critical research gap by investigating the combined effects of ZnO and Cu nanoparticles in hybrid nanofluids, an area that has been underexplored. By providing new insights into optimizing both thermal conductivity and viscosity, this research contributes to the
Sivasubramanian, M.Sundaram, V.Madhu, S.Saravanan, A.Vidhyalakshmi, S.
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