Browse Topic: Thermodynamics

Items (5,778)
In numerous automotive and industrial applications, efficient heat extraction is crucial to prevent system inefficiencies or catastrophic failures. The design of heat exchangers is inherently complex, involving multiple stages defined by the depth of analysis, number of design variables, and the accuracy of physical models. Designers must navigate the trade-offs between highly accurate yet computationally expensive models and less accurate but computationally cheaper alternatives. Multi-fidelity modeling offers a solution by integrating different fidelity models to deliver precise results at a reduced computational cost. In addition to managing these trade-offs, designers often face multi-objective challenges, where optimizing one aspect may lead to compromises in others. Multi-objective optimization, therefore, becomes essential in balancing these competing objectives to achieve the best overall design. In this context, Gaussian Process-based methods have gained prominence as
Chaudhari, PrathameshTovar, Andres
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
With the increasingly prominent environmental problems and energy crisis, wind power, solar power and other new energy has been rapid development, and energy storage technology is of great significance to the development of new energy. Compared with the power batteries applied in electric vehicles, battery energy storage systems gather a larger number of batteries and a larger scale, usually up to megawatts or 100 megawatts. During the operation of the energy storage system, the lithium-ion battery continues to charge and discharge, and its internal electrochemical reaction will inevitably generate a lot of heat. If the heat is not dispersed in time, the temperature of the lithium-ion battery will continue to rise, which will seriously affect the service life and performance of the battery, and even cause thermal runaway leading to explosion. It is of great significance for promoting the development of new energy technologies to carry out research on the thermal model of lithium-ion
Chen, JianxiangLi, LipingZhou, FupengLi, ChunchengShangguan, Wen-Bin
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
The advancement of automotive industry demand compact size of HVAC with better cabin comfort. To achieve this, HVAC has to be optimized in all the aspects such as in shape & size, thermal comfort as well as in noise comfort. from an HVAC perspective, aeroacoustics noise is more significant due to its intensity at higher speeds and frequencies. Since HVAC is mounted inside the cabin, noise can transfer directly inside cabin. To avoid this, noise reduction or noise controlling is of very important. This is possible with HVAC design and simulation at the initial level and acoustic prediction after the CFD/CAA analysis. The present paper describes the aeroacoustic simulation of one of the HVAC to predict the noise during face mode. For that, 1-D simulation has been done initially to find the porosity of heat exchangers and coupled with a CFD solver. STAR CCM+ software is used for the CFD analysis. Transient simulation is performed with compressible fluid using a moving mesh approach. To
Kame, ShubhamParayil, PaulsonGoel, Arunkumar
Thermal runaway is a critical phenomenon in lithium batteries, characterized by a self-sustaining process due to internal chemical reactions, that is triggered once a certain temperature is reached within the cell. This event is often caused by overheating due to charge and discharge cycles and can lead to fires or explosions, posing a significant safety threat. The aim of this study is to induce thermal runaway on single cells in different ways to characterize the phenomenon and validate the simulation models present in Altair SimLab®. The work was conducted in several key phases. Initially, an experimental test was performed in a calorimeter (EV ARC HWS test) to collect temperature data of the Molicel 21700 P45B cell during thermal runaway under adiabatic conditions. These data were used for a simulation on a single cell, allowing a detailed comparison with the experimental results. Subsequently, a test was conducted on a single cell under operational conditions, overheated using a
Giuliano, LucaScrimieri, LuigiReitano, SimoneBerti Polato, DavideFerraris, AlessandroComerford, AndrewBhatnagar, Saakaar
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
Charging a battery electric vehicle at extreme temperatures can lead to battery deterioration without proper thermal management. To avoid battery degradation, charging current is generally limited at extreme hot and cold battery temperatures. Splitting the wall power between charging and the thermal management system with the aim of minimizing charging time is a challenging problem especially with the strong thermal coupling with the charging current. Existing research focus on formulating the battery thermal management control problem as a minimum charging time optimal control problem. Such control strategy force the driver to charge with minimum time and higher charging cost irrespective of their driving schedule. This paper presents a driver-centric DCFC control framework by formulating the power split between thermal management and charging as an optimal control problem with the goal of improving the wall-to-vehicle energy efficiency. Proposed energy-efficient charging strategy
Gupta, ShobhitKang, Jun-MoZhu, YongjieLee, ChunhaoZanardelli, Wesley
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
With better performance and usage of clean and renewable energy, electric vehicles have ushered in more and more consumers’ favor nowadays. However, insufficient driving range especially in hot and cold ambient conditions still greatly restricts the extensive application of electric vehicles. This paper presents a methodology of establishing multi-discipline coupled full vehicle model in AMESim to investigate the energy consumption and driving range of an electric vehicle in normal and hot ambient conditions. Full vehicle energy consumption test was carried out in the climate chamber to check the accuracy of simulation results. Firstly, basic framework of the full vehicle model established in AMESim was introduced. Next, modeling details of sub-systems including vehicle dynamic system, electrical system, coolant circuit system, air-conditioning system and control strategy were illustrated. Then, full vehicle energy consumption tests were carried out in 23°C and 38°C ambient conditions
Zhou, ShuaiLiu, HuaijuYu, HuiliYan, XuYan, Junjie
This paper presents an advanced control system design for an engine cooling system in an internal combustion engine (ICE) vehicle. Building upon our previous work, we have derived models for crucial temperatures within the engine, including combustion wall temperature, coolant-out temperature, block temperature, as well as temperatures in external components such as heat exchangers and radiator. To accurately predict these temperatures in a rapid manner, we have utilized a lumped parameter concept with a mean-value approach. This approach allows for precise temperature estimation while maintaining computational efficiency. Given the complexity of the cooling system, we have proposed a linear time-varying (LTV) model predictive control (MPC) system to regulate the temperatures. This control system linearizes the model at each time step and applies linear MPC over the control and prediction horizons. By doing so, we effectively control the highly nonlinear and time-delayed system
Chang, InsuSun, MinEdwards, David
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
Proton exchange membrane fuel cell (PEMFC) is widely used in transportation and high-efficiency energy systems for their high power density and rapid start-up capability. The temperature control of its thermal management system is characterized by slow response and system oscillation, and the temperature control process suffers from problems such as large temperature fluctuations and slow temperature rise during cold starts. To effectively control the fuel cell thermal management system, this paper proposes a fuzzy PID-based control strategy to optimize the temperature control of the stack by comprehensively controlling the cooling fan, thermostat, temperature control valve, and heat components. By modeling the 60kW PEMFC thermal management system on the MATLAB/Simulink platform, the flow distribution and heat exchange of each component are analyzed and the optimized fuzzy control strategy is compared with the traditional PID control strategy. The simulation results show that the
Zhang, YilongZhang, YunqingGuo, JunWu, Jinglai
Optimal control of battery electric vehicle thermal management systems is essential for maximizi ng the driving range in extreme weather conditions. Vehicles equipped with advanced heating, ventilation and air-conditioning (HVAC) systems based on heat pumps with secondary coolant loops are more challenging to control due to actuator redundancy and increased thermal inertia. This paper presents the dynamic programming (DP)-based offline control trajectory optimization of heat pump-based HVAC aimed at maximizing thermal comfort and energy efficiency. Besides deriving benchmark results, the goal of trajectory optimization is to gain insights for practical hierarchical control strategy modifications to further improve real-time controllers’ performance. DP optimizes cabin inlet air temperature and flow rate to set the trade-off between thermal comfort and energy efficiency while considering the nonlinear dynamics and operating limits of HVAC system in addition to typically considered cabin
Cvok, IvanDeur, Josko
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
Battery cell aging and loss of capacity are some of the many challenges facing the widespread implementation of electrification in mobility. One of the factors contributing to cell aging is the dissimilarities of individual cells connected in a module. This paper reports the results of several aging experiments using a mini-module consisting of seven 5 Ah 21700 lithium-ion battery cells connected in parallel. The aging cycle comprised a constant current-constant voltage charge cycle at a 0.7C C-rate, followed by a 0.2C constant current discharge, spanning the useful voltage range from minimum to maximum according to the cell manufacturer. Charge and discharge events were separated by one-hour rest periods and were repeated for four weeks. Weekly reference performance tests were executed to measure static capacity, pulse power capability and resistance at different states of charge. All diagnostics were normalized with respect to their starting numbers to achieve a percentage change
Swarts, AndreSalvi, Swapnil S.Juarez Robles, Daniel
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 electric vehicle thermal management system is a critical sub-systems of electric vehicles, and has a substantial impact on the driving range. The objective of this paper is to optimize the performance of the heat pump air conditioning system, battery, and motor thermal management system by adopting an integrated design. This approach is expected to effectively improve the COP (Coefficient of Performance) of cabin heating. An integrated thermal management system model of the heat pump air conditioning system, battery, and motor thermal management system is established using AMEsim. Key parameters, such as refrigerant temperature, pressure, and flow rate at the outlet of each component of the system are compared with the measured data to verify the correctness of the model established in this paper. Using the established model, the impact of compressor speed on the heating comfort of the cabin under high-temperature conditions in summer was studied, and a control strategy for rapid
Zhang, MinLi, LipingZhou, JianhuaHuang, YuZhen, RanShangguan, Wen-Bin
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 use of lithium-ion batteries in electric vehicles marks a major progression in the automotive sector. Energy storage systems extensively make use of these batteries. The extended life cycle, low self-discharge rates, high energy density, and eco-friendliness of lithium-ion batteries are well-known. However, Temperature sensitivity has an adverse effect on lithium-ion battery safety, durability, and performance. Thus, maintaining ideal operating conditions and reducing the chance of thermal runaway depend heavily on efficient thermal management. To address this, experimental study was conducted on various battery thermal management techniques, including active, passive, and hybrid approaches. These techniques were investigated for their cooling efficiencies under different operating conditions. The electro-thermal behavior of cylindrical lithium-ion battery cells, battery packs, and supervisory control techniques were simulated in the study using MATLAB Simulink, Simscape, and
Thangaraju, ShanmuganathanN, MeenakshiGanesan, Maragatham
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
On electric vehicle the low voltage (nominal 12 volt) battery serves mostly as an energy storage buffer for supporting features and actuators on the 12 volt power supply network. Within an EV, unlike an internal combustion engine car, as there is no cranking requirement needed to be supported by this battery, it presents a significant opportunity for downsizing. In a premium car there are a significant number of features which inhibits the car to go into “deep sleep” and hence remains on a “stand-by” mode of operation. During this period of stand-by the low voltage energy storage system needs to cater for up to 0.4 W when in sleep/standby mode of operation. To sustain longer periods of stand-by mode the low voltage battery needs to have enough stored energy to maintain the appropriate level of state of charge (SOC) so that enough critical threshold of SOC is maintained for 12 volts essential system startup at vehicle restart. This can potentially inhibit downsizing of the low voltage
Dutta, NilabzaOvers, Sheldon
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
In modern vehicles, effective thermal management is crucial for regulating temperatures across various components and sub-systems, ensuring optimal performance, efficiency, safety, and passenger comfort. As the industry shifts towards reducing carbon emissions, powertrain electrification - encompassing electric and hybrid vehicles - has emerged as a prominent trend. This transition introduces greater complexities, as the powertrain system must now precisely control the temperatures of not only traditional components but also batteries, power electronics, and motors. Typically, the performance of vehicle-level thermal management systems is fully evaluated only after physical prototypes are developed and tested, particularly during summer and winter road trials. Conducting development and validation at such a late stage in the development process significantly increases both development risks and costs. To address these challenges, a comprehensive vehicle-level thermal management
Xu, ZhengQiu, JieLu, YuanWang, Yingzhen
The shift towards hybrid and electric powertrains in off-road vehicles aims to enhance mobility, extend range, and improve energy efficiency. However, heat pump-based battery thermal management systems in these vehicles continue to consume significant energy, impacting overall range and efficiency. Effective thermal management is essential for maintaining battery performance and safety, particularly in extreme conditions. Although high-fidelity models can capture the complex dynamics of heat pumps, real-time control within model-based optimization frameworks often depends on simplified models, which can degrade system performance. To address this, we propose a novel data-driven grey box control-oriented model (COM) that accurately represents the thermal dynamics of a vapor-compression refrigeration-based heat pump system. This COM is integrated into a model-predictive control (MPC) framework, optimizing thermal management during transient and burst-power operations of the battery pack
Sundar, AnirudhGhate, AtharvaZhu, QilunPrucka, RobertRuan, YeefengFigueroa-Santos, MiriamBarron, Morgan
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
Efficient thermal management is essential for maintaining the performance and safety of large-capacity battery packs. To overcome the limitations of traditional standalone air or liquid cooling methods, which often result in inadequate cooling and uneven temperature distribution, a hybrid air-liquid cooling structure was designed. A three-dimensional model was developed, and heat transfer and fluid flow characteristics were analyzed using computational fluid dynamics (CFD) simulations. Experimental validation was carried out through discharge temperature rise tests on individual battery cells and flow resistance tests on the liquid cooling plate. The thermal performance of the hybrid system was compared to that of standalone cooling methods under various discharge rates. The results indicated that the hybrid system significantly enhanced cooling performance, reducing the maximum temperature difference by 5.54°C and 3.37°C, and the peak temperature by 11.66°C and 4.5°C, compared to air
Li, HaoGuo, YimingZhou, FupengLi, KunyuanShangguan, Wen-Bin
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
The maximum temperature and the maximum temperature difference of lithium battery energy storage systems are of great importance to their lifespan and safety. The energy storage module targeted in this research utilizes a forced air-cooling thermal management system. In this article, the maximum battery temperature, temperature difference, and cooling fan power are used as evaluation indicators. The thermal–fluid coupling simulation technology is utilized to restore the real structure of the module, ensuring the reliability of the simulation results. The P-Q curve is introduced for the boundary conditions of the heat dissipation fan to investigate the influence of the flow channel structure on the airflow volume and distribution. First, the thermal–fluid coupling simulation results of the original structure were compared with the measured parameters. Subsequently, the study on the airflow and temperature distribution of the original flow channel structure reveals that a significant
Guo, YuChengBao, YiDongJiang, BingYunLu, FeiFei
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
In this article, a finite element analysis for the passenger car tire size 235/55R19 is performed to investigate the effect of temperature-dependent properties of the tire tread compound on the tire–road interaction characteristics for four seasons (all-season, winter, summer, and fall). The rubber-like parts of the tire were modeled using the hyperelastic Mooney–Rivlin material model and were meshed with the three-dimensional hybrid solid elements. The road is modeled using the rigid body dry hard surface and the contact between the tire and road is modeled using the non-symmetric node-to-segment contact with edge treatment. At first, the tire was verified based on the tire manufacturer’s data using numerical finite element analysis based on the static and dynamic domains. Then, the finite element analysis for the rolling resistance analysis was performed at three different longitudinal velocities (10 km/h, 40 km/h, and 80 km/h) under nominal loading conditions. Second, the steady
Fathi, HaniyehEl-Sayegh, ZeinabRen, Jing
The Object of research in the article is the ventilation and cooling system of bulb hydrogenerators. The Subject of study in the article is the design and efficiency of using the cooling system of various structural types for bulb hydro units. The Purpose of the work is to carry out a three-dimensional study of two cooling systems (axial and radial) of the bulb hydro unit of the Kanivskaya HPP with a rated 22 MW. Research Tasks include analysis of the main design solutions for effective cooling of bulb-type hydrogenerators, in particular, the use of radial, axial, and mixed cooling systems; formulation of the main assumptions for the three-dimensional ventilation and thermal calculation of the bulb hydrogenerator; carrying out a three-dimensional calculation for a hydrogenerator with axial ventilation; determining airflow speeds in the channels and temperatures of active parts of the hydrogenerator under the conditions of using discharge fans and without them; carrying out a three
Tretiak, OleksiiArefieva, MariiaMakarov, PavloSerhiienko, SerhiiZhukov, AntonShulga, IrynaPenkovska, NataliiaKravchenko, StanislavKovryga, Anton
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