Thermal Management Simulation Research Articles

Thermal management performance analysis and improvement for a commercial vehicle engine compartment through a 1D/3D co-simulation method

The thermal management performance of a commercial vehicle engine compartment is crucial for improving overall vehicle performance and promoting green transportation. In this study, a one-dimensional (1D) and three dimensional (3D) CFD co-simulation method has been proposed for the modeling and simulation of thermal management of a commercial vehicle engine compartment. The steady-state temperature and velocity vector distribution in engine compartment has been obtained through 3D CFD approach. With data exchange between the cooling circuit and air conditioning circuit, the mathematical characterizations of the thermal management performance have been further investigated through 1D simulation and validated using test results. The comparison show that the obtained results for thermal management performance are consistent with test results, validating the accuracy of the co-simulation model. The results indicate an obvious thermal backflow phenomenon in the upper area of the intercooler module, causing a high outlet water temperature of the engine cooler. Thus, a deflector structure for eliminating the thermal backflow problem has been presented, and the heat dissipation effect has been analyzed. The co-simulation results show an improvement in cooling performance that the ATO value of cooling circuit decreased by 2.5% and intercooler constant of air conditioning circuit decreased by 12.1%. The proposed 1D/3D co-simulation method provides a reliable reference for developing the thermal management system of commercial vehicle engine compartment.

Numerical simulation of battery thermal management based on ring microchannel cold plate

Efficient heat dissipation methods have been the focus of battery thermal management research. Due to the limitations of flow and heat transfer in traditional straight channel cold plates (SCCP), this paper introduces a ring channel cold plate (RCCP) and utilizes the j/f factor to evaluate the comprehensive thermal performance of the cold plates. Through comparison and analysis, it is found that the RCCP has a lower pressure drop and better comprehensive thermal performance. As the mass flow rate increases, the j/f improvement effect of the RCCP becomes more pronounced. Additionally, when the branch channel width is 6 mm, the RCCP exhibits higher comprehensive thermal performance. However, in the RCCP of equal width, the innermost channels have the shortest flow path and the largest flow rate. To further enhance heat transfer, the influence of non-uniform structure on the performance of RCCP is investigated. The result shows that the narrow inside and wide outside channel arrangement can enhance the heat transfer performance of the RCCP but at the cost of increasing pressure drop. Among them, the outermost, middle, and innermost channel widths of 6.66 mm, 6 mm, and 4 mm, the cold plate has better comprehensive thermal performance, more suitable for battery thermal management. The RCCP with a narrow inside and wide outside provides a new option for more efficient battery thermal management.

Research on the performance failure of phase change materials thermal management for lithium battery

Lithium batteries are highly favored in the industry due to their high efficiency performance and long service life, but their thermal safety has always been a major challenge. The application of phase change materials (PCM) can effectively ensure the thermal safety. However, the inability to immediately dissipate heat from the PCM will result in their performance failure. The purpose of this study is to obtain the optimal parameter range considering the critical melting state of PCM through reverse analysis, to overcome the thermal issues during the discharge process of lithium batteries. The experiment and simulation of PCM thermal management are operated by considering input parameters, including liquidus temperature, discharge rate, thermal conductivity, filling thickness, and late heat. An explanation was provided for the entire melting process of PCM. The results showed that the simulation is reliable. The temperature of battery cooled by PCM is 15.4 K lower than that of battery not cooled for a discharge rate of 2C. The PCM with high liquidus temperatures is less likely to result in performance failure for conditions with high discharge rate. The cooling performance increases with the increase of discharge rate under the premise of effective thermal management. There is an optimal value for the filling thickness of PCM in terms of cooling performance and economic benefits. When the latent heat increased from 195 to 275 kJ/kg, the battery temperature decreased from 311.54 K to 311.02 K and the liquid fraction decreased from 83.16 % to 63.61 % at a discharging rate of 2C. This study provides an important insight for the application and further study of PCM in lithium batteries.

Construction of three-dimensional interconnected boron nitride/sliver networks within epoxy composites for enhanced thermal conductivity

With the advent of the 5G era, the conspicuous increases in operating power and thermogenic capacity of integrated electronic components necessitated the development of enhanced thermal conductive polymeric composites with excellent heat dissipation properties. Herein, the polydopamine (PDA) and silver (Ag) modified BN (BN-PDA-Ag) was synthesized and a three-dimensional (3D) interconnected BN-PDA-Ag porous network was successfully fabricated by the salt template-assisted method to improve the thermal conductivity property of epoxy based composites. The high thermal conductive epoxy resin composites (3D BN-PDA-Ag/EP) were obtained by infiltrating epoxy into the 3D BN-PDA-Ag porous network. On one hand, the 3D BN-PDA-Ag porous skeleton provided continuous transfer paths for phonons, which was conducive to reducing phonon scattering. On the other hand, the Ag nanoparticles loaded on the BN surface bridged the adjacent BN sheets, significantly decreasing the thermal contact resistance between adjacent fillers. The isotropic thermal conductivity (TC) of 3D BN-PDA-Ag/EP composite with a BN-PDA-Ag content of 20.3 wt% reached 1.37 W/(m·K), which exhibited a evident enhancement of 661% compared with pure epoxy. The thermal management simulation and application results showed the composite had enormous application potential for electronic devices and components in heat dissipation.

Simulation study on the interaction between the battery module and busbar under typical driving conditions of electric vehicles

Accurate simulation of the battery thermoelectric coupling characteristics is the key to the thermal design and thermal management. As the electrically connected component between the battery electrodes, the heat production and heat transfer of the busbars have a significant impact on the battery thermoelectric behavior. A small number of battery thermal management studies have begun to model busbars recently, but the thickness, length, and material of the busbars are diverse. There is a lack of perfect simulation analysis and optimization methods. There is an urgent need to conduct in-depth research on the influence of characteristic parameters of the busbars on the battery thermoelectric behavior. Based on the MSMD-NTGK model, this paper investigates the influence of the thickness, length, and material of the busbars on the battery thermoelectric behavior without considering the economic cost and differences in the battery structure design. In this paper, a simulation analysis method and an ideal improvement solution for the design of the busbars are proposed. This paper compares the changes in the battery thermal behavior before and after the improvement of the busbars under the constant-rate discharge process, FTP75 condition, NEDC condition and WLTC condition respectively. This study can improve the realism of the battery thermal behavior simulation, provide a reliable simulation analysis method and reference basis for the industrial design and optimization of the busbars, and further improve the reliability of the subsequent battery thermal management simulation.

Numerical Simulation of Thermal Management of Lithium Battery Based on Air Cooled Heat Dissipation

In recent years, due to the rapid increase in the number of vehicles in the world, the traditional vehicles using gasoline or diesel as energy have led to serious air pollution and energy depletion. It is urgent to develop practical clean energy vehicles. The performance of electric vehicle depends on the power battery pack. The working temperature of the battery pack has a great impact on the performance of the battery, so it is necessary to carry out thermal management on the battery pack. Taking a lithium-ion battery as the research object, the temperature field of the battery pack in the charge and discharge state is simulated and analyzed by using CFD simulation software in the way of air cooled heat dissipation, so as to understand the influencing factors of uneven temperature field. At the same time, the development trend of battery temperature can be well predicted through simulation, so as to provide theoretical basis for the design of battery pack.

Hybrid model for exhaust systems in vehicle thermal management simulations

AbstractUsing Vehicle Thermal Management (VTM) simulations to predict the thermal load experienced by components is a popular method within the automotive industry. The VTM simulation approach is fast becoming equivalent to conducting thermal load tests with prototypes for vehicles powered by internal combustion engines. This is especially true in the early development phase of the vehicle. The accuracy of the VTM simulations plays a pivotal role at them being accepted as an eventual replacement for physical testing. The correct prediction of thermal loads in VTM simulations depends on a multitude of different parameters, but the modelling of the exhaust system plays a central role in it. This is because the exhaust gas, and with it the exhaust system, is the primary source of heat in a vehicle powered by an internal combustion engine. The developed approach not only needs to be accurate but also modular enough to allow for different exhaust configurations to be tested. It also needs to be capable of integration into any VTM simulation workflow while maintaining an industrially acceptable turnaround time. This paper explores a new methodology to achieve these requirements. A 1D/3D hybrid approach to exhaust system modelling is presented. In this, the components that have an enthalpy change of the exhaust gas, such as the turbocharger, have been modelled as 1D and simple components such as pipes have been modelled in 3D. This has the advantage of combining the speed of 1D simulations with the spatial accuracy of 3D simulations. The method uses a unique three-code co-simulation technique for full vehicle VTM simulations. The coupling is between a 3D CFD software, a 1D simulation tool, and a Finite Element based thermal solver. The methodology was validated against experimental data for multiple loadcases. The results show good agreement with experiment within acceptable tolerances.

Optimize Thermal Management And Experiment Of Lifepo4 Battery Pack For Hybrid Electrical Vehicle

Hybrid Electric Vehicles (HEV) combines the benefits of gasoline engines and electric motors which can be configured for improving fuel efficiency. Lithium Iron Phosphate (LiFePO4) Phosphate based technology possesses superior thermal and chemical stability which provides better safety characteristics than those of Lithium-ion technology made with other cathode materials. This research conducted by two methods , methods of part 1 is a comparison of the results with the thermal management simulation and experiment, part 2 is a method of optimizing the thermal management for battery pack by using solidwork software. When the fan is on, the forced air flow over the cells removes some of the generated heat. Results of method part 1 is simulation more heat than experiment in the amount of 0.11% – 1.56%. The results of the method part 2 is simulated using the fan 4 fan with a speed of 415 rad/s and battery gap 30mm most efficient compared with 4 fans the other , while the simulation using 6 fan, fan speed 415 rad/s and battery gap 30mm most efficient for all.

Numerical simulation of thermal management during natural convection in a porous triangular cavity containing air and hot obstacles

A numerical study is presented of laminar viscous magnetohydrodynamic natural convection flow in a triangular-shaped porous enclosure filled with electrically conducting air and containing two hot obstacles. The mathematical model is formulated in terms of dimensional partial differential equations. The pressure gradient term is eliminated by using the vorticity–stream (\(\omega - \psi\)) function approach. The emerging dimensionless governing equations are employed by the regular finite difference scheme along with thermofluidic boundary conditions. The efficiency of the obtained computed results for isotherms and streamlines is validated via comparison with previously published work. The impact of physical parameters on streamlines and temperature contours for an extensive range of Rayleigh number (Ra = 103–105), Hartmann magnetohydrodynamic number (Ha = 5–30), Darcy parameter (Da = 0.0001–0.1) for fixed Prandtl number (Pr = 0.71) is considered. Numerical results are also presented for local and average Nusselt numbers along the hot base wall. Interesting features of the thermofluid behaviour are revealed. At lower Rayleigh number, the isotherms are generally parallel to the inclined wall and only distorted substantially near the obstacles at the left vertical adiabatic wall; however, with increasing Rayleigh number, this distortion is magnified in the core zone and simultaneously warmer zones expand towards the inclined cold wall. The simulations are relevant to magnetic materials processing and hybrid magnetic fuel cells.

Thermal management simulation analysis of cylindrical lithium-ion battery pack coupled with phase change material and water-jacketed liquid-cooled structures

Thermal management simulation analysis of cylindrical lithium-ion battery pack coupled with phase change material and water-jacketed liquid-cooled structures

Analysis on the development of micro gas turbine generation technology

Similar to the structure of small aero engines, the existing micro gas turbines generally apply radial impeller machinery and regenerative cycles to improve efficiency. This paper analyzes the development of micro gas turbine generation technology. After making breakthroughs in basic research fields such as combustion, structural materials and coatings, additive manufacturing, thermal management, and comprehensive simulation and verification experiments, the next-generation micro cogeneration system composed of micro gas turbine and renewable energy power generation equipment will effectively obtain stable power output, improve power energy quality, and overcome difficulty in technology, economy, and application scenarios.

Modelling and optimal control of energy-saving-oriented automotive engine thermal management system

The thesis simulates the engine?s installation and uses conditions in the whole vehicle, such as the water tank, fan, the engine?s arrangement in the engine room, accessories and pipe-line connections, etc. to build a test bench for the engine thermal management system. According to the thermal management simulation analysis software KULI modelling, the article designs the bench test conditions according to the parameter input requirements of the thermal management simulation analysis software. The accuracy of the model is verified by comparing simulation and test data, and the NEDC driving cycle is used to simulate the performance of the vehicle cooling system to guide the selection and matching of thermal management system components.

Thermal Management System Modeling and Simulation of a Full-Powered Fuel Cell Vehicle

Abstract Thermal management is an important factor in securing the safe and effective operation of a fuel cell vehicle (FCV). A parameterized stack model of a 100 kW proton exchange membrane fuel cell (PEMFC) is constructed by matlab/Simulink to design and asses the thermal management characteristics of a 100 kW full-powered FCV. The cooling components model, with parameters obtained by theoretical calculation based on the cooling requirement, is developed in the commercial solver GT-COOL. A thermal management simulation platform is constructed by coupling the stack model and cooling components. The accuracy of the modeling method for the stack is validated by comparing with the experimental data. The relationship between the operating temperature and output performance of the fuel cell stack is revealed based on the simulation model. The simulation results show that the operating temperature has a considerable influence on stack performance under high-current operation, and the inlet and outlet temperatures of the stack change nearly linearly with the increasing environmental temperature. The heat dissipation potential of the thermal management system under the high-load condition is also verified. The temperatures and coolant flow of core components, including the stack, DC/DC, air compressor, and driving motor, can meet the cooling requirements.

Development of Vehicle Thermal Management Simulation

Development of Vehicle Thermal Management Simulation

Design and Implementation of a Compact 3-D Stacked RF Front-End Module for Micro Base Station

In the current 4G Long Term Evolution and the incoming 5G mobile communication technology, as the number of radio frequency (RF) devices in the RF front-end module is increasing fast, miniaturization is essential and significant. The 3-D RF system-in-package (SiP) technology is an excellent miniaturization solution. In this paper, a 700–2900-MHz 3-D stacked RF module with the size of 23 mm $\times$ 23 mm $\times$ 3.3 mm has been designed and implemented, which is used for a micro base station. It is more compact than other reported 3-D RF SiP products used for micro base stations. The 3-D RF module integrates four bare dies, one quad flat no-lead packaged chip, and more than 200 passive devices. Considering the electromagnetic isolation requirement, mechanical performance, and effective interconnection, the detailed structure design is presented in this paper. Simulations are performed for the electrical characterization and the thermal performance evaluation of the stacked module. The simulation results show that the insertion loss ( $S_{21}$ ) and return loss ( $S_{11}$ ) of the RF signal transmission lines are controlled below 0.42 dB and over 15 dB within 3 GHz, respectively. The electromagnetic isolation between different RF and/or intermediate frequency signal transmission lines is no less than 65 dB within 3 GHz. In thermal management simulation, the highest junction temperature of the chips in the 3-D structure is below 94 °C at the severe condition (50 °C ambient temperature and nature air convection). Finally, the assembly flow is presented, and the test results indicate the good electrical performance of the 3-D RF module.

(Invited) Thick, Low-Doped Homoepitaxial Ga2O3 for Power Electronics Applications

Monoclinic β-Ga2O3 has attracted significant attention as a high power electronics material based on its ultra-wide energy gap (4.9 eV), high theoretical critical field (8 MV/cm), as well as the commercially availability of inexpensive substrates grown from the melt. In order to achieve breakdown field consistent with the theoretical expectations, however, very high quality epitaxial films with very low doping and defect density will be required. Wong et al. have reported a β-Ga2O3 MOSFET with carrier concentration below 4x1014 cm-3, which is the lowest reported value for epitaxial β-Ga2O3 to date [1]. This talk will discuss the structural and electronic properties for thick homoepitaxial β-Ga2O3 with doping as low as 8x1012 cm-3, corresponding to breakdown voltage in excess of 2.38 kV (3.18 MV/cm), measured without field termination for vertical measurements or edge effects correction in the case of lateral devices. Our results show that current β-Ga2O3 halide vapor phase epitaxial technology can produce epilayers with breakdown field approaching the theoretical value of GaN. In addition, we will discuss the annealing of bulk and epitaxial β-Ga2O3 films in O2 atmosphere as a potential pathway to reduce carrier concentration and possibly improve the breakdown voltage of Ga2O3 Schottky diodes. We show that annealing Ga2O3 in O2 will reduce ND-NA by about an order of magnitude, similar to earlier observations by Kuramata et al. [2]. Furthermore, we will present our approach for overcoming the polaron-induced suppression of room-temperature p-type conductivity in Ga2O3, causing holes to preferentially self-trap instead of being available as free carriers [3]. We show that natural p-type semiconducting oxides such as NiO can be integrated with β-Ga2O3 to form a rectifying heterojunction as a fundamental building block for any viable Ga2O3 power device. Finally, we will discuss the low thermal conductivity of Ga2O3 and present our preliminary thermal management simulations and experimental results. [1] A. Kuramata, et al., Jpn. Jour. Appl. Phys. 55, 1202A2 (2016). [2] M.H. Wong, et al., Appl. Phys. Express 10, 041101 (2017). [3] J.B. Varley, et al., Phys. Rev. B 85, 081109(R) (2012).

The Borexino Thermal Monitoring & Management System and simulations of the fluid-dynamics of the Borexino detector under asymmetrical, changing boundary conditions

A comprehensive monitoring system for the thermal environment inside the Borexino neutrino detector was developed and installed in order to reduce uncertainties in determining temperatures throughout the detector. A complementary thermal management system limits undesirable thermal couplings between the environment and Borexino’s active sections. This strategy is bringing improved radioactive background conditions to the region of interest for the physics signal thanks to reduced fluid mixing induced in the liquid scintillator. Although fluid-dynamical equilibrium has not yet been fully reached, and thermal fine-tuning is possible, the system has proven extremely effective at stabilizing the detector’s thermal conditions while offering precise insights into its mechanisms of internal thermal transport. Furthermore, a Computational Fluid-Dynamics analysis has been performed, based on the empirical measurements provided by the thermal monitoring system, and providing information into present and future thermal trends. A two-dimensional modeling approach was implemented in order to achieve a proper understanding of the thermal and fluid-dynamics in Borexino. It was optimized for different regions and periods of interest, focusing on the most critical effects that were identified as influencing background concentrations. Literature experimental case studies were reproduced to benchmark the method and settings, and a Borexino-specific benchmark was implemented in order to validate the modeling approach for thermal transport. Finally, fully-convective models were applied to understand general and specific fluid motions impacting the detector’s Active Volume.

Advances in Integrated Vehicle Thermal Management and Numerical Simulation

With the increasing demands for vehicle dynamic performance, economy, safety and comfort, and with ever stricter laws concerning energy conservation and emissions, vehicle power systems are becoming much more complex. To pursue high efficiency and light weight in automobile design, the power system and its vehicle integrated thermal management (VITM) system have attracted widespread attention as the major components of modern vehicle technology. Regarding the internal combustion engine vehicle (ICEV), its integrated thermal management (ITM) mainly contains internal combustion engine (ICE) cooling, turbo-charged cooling, exhaust gas recirculation (EGR) cooling, lubrication cooling and air conditioning (AC) or heat pump (HP). As for electric vehicles (EVs), the ITM mainly includes battery cooling/preheating, electric machines (EM) cooling and AC or HP. With the rational effective and comprehensive control over the mentioned dynamic devices and thermal components, the modern VITM can realize collaborative optimization of multiple thermodynamic processes from the aspect of system integration. Furthermore, the computer-aided calculation and numerical simulation have been the significant design methods, especially for complex VITM. The 1D programming can correlate multi-thermal components and the 3D simulating can develop structuralized and modularized design. Additionally, co-simulations can virtualize simulation of various thermo-hydraulic behaviors under the vehicle transient operational conditions. This article reviews relevant researching work and current advances in the ever broadening field of modern vehicle thermal management (VTM). Based on the systematic summaries of the design methods and applications of ITM, future tasks and proposals are presented. This article aims to promote innovation of ITM, strengthen the precise control and the performance predictable ability, furthermore, to enhance the level of research and development (R&D).

Experiment and simulation of thermal management for a tube-shell Li-ion battery pack with composite phase change material

A novel tube-shell Li-ion battery pack with a passive thermal management system (TMS) using composite phase change material (PCM) was designed to control cells temperature rising and improve battery module heat transfer. The battery pack consisted of expanded graphite (EG)/paraffin composite, aluminum tubes, baffles and a shell. EG/paraffin was applied to control cells temperature rising and create a thermal balance from one cell to another. The TMS was coupled with a forced air cooling to initialize PCM temperature (PCM solidification). In order to evaluate the effect of the baffles on improving air fluid heat transfer, a three dimensional numerical model of the tube-shell battery module with forced air cooling was performed using ANYSYS FLUENT. The thermal characteristics of the tube-shell battery pack were investigated both experimentally and numerically. The results show that: (1) EG/paraffin composite significantly reduces cells temperature rising and keeps the maximum temperature difference across the battery module within a low value of 1–2°C. The tube-shell battery module with EG/PCM exhibits high heat dissipation efficiency. (2) The baffles change the air fluid flow direction, improving the interaction of fluid and its heat transfer efficiency.

항공기 시스템 레벨 열관리 기술개발 동향

ABSTRACT Modern aircraft is facing the increase of power demands and thermal challenges. In accordance with the application of more electric technology and advanced mission requirement, aircraft system requires increase of power generation and it cause increase of internal heat generation. Simultaneously, restrictions have significantly been imposed to the thermal management system. Modern aircraft must maintain low radar observability and infra-red signature. In addition, new composite aircraft skins have reduced the amount of heat that can be rejected to the environment. The combination of these characteristics has increased the challenges faced by thermal management. In order to mitigate the thermal challenges, the concept of system level thermal management should be applied and new modeling and simulation tools need to be developed. To develop and utilize system level thermal management technology, three key points are considered. Firstly, the performance changes of subsystems and components must be assessed at an integrated thermal system. It is because that each subsystem and component interacts with other subsystems or components and it can directly effects on overall system performance. Secondly, system level thermal management requirements and solutions must be evaluated early in conceptual design process as vehicle and propulsion system configuration decisions are being made. Finally, new component level thermal management technologies must focus on reducing heat generation and increasing the availability of heat sinks.Key Words : System Level Thermal Management, Fuel Thermal Management System, Adaptive Power Thermal Management System, Heat Load, Modeling and Simulation