Browse Topic: Heat transfer
Linear time-invariant (LTI) reduced-order models (ROMs) have been widely used in battery thermal management simulations due to their low hardware requirements, high computational efficiency, and good accuracy. However, the inherent assumption of LTI behavior limits their applicability in scenarios with varying coolant flow rates, where this assumption is no longer valid. To address this limitation, a novel ROM is developed by decomposing the entire battery thermal system into two subsystems. All solid components are modeled as a traditional LTI ROM, while the coolant channel is represented using Newton’s cooling law. The two subsystems are then coupled through the exchange of heat transfer rate and temperature at the fluid–solid interface between the coolant and the cold plate. Model fidelity is further enhanced by introducing a spatially distributed heat flux during the generation of the LTI ROM for solid components. Validation is performed against CFD simulations at both module and
Oil churning and windage power losses in dip-lubricated gearboxes can significantly affect overall transmission efficiency, particularly at high rotational speeds. As modern gearbox systems are pushed toward higher efficiency and reliability, understanding and predicting these losses becomes increasingly important. In addition to energy dissipation, the associated multiphase flow phenomena—such as oil splashing, thin film formation along gear surfaces, and aeration of the sump—strongly influence lubrication effectiveness, heat transfer, and component durability. Capturing these effects requires a robust numerical strategy that can resolve both power loss mechanisms and multiphase flow dynamics with sufficient accuracy. In this study, a single spur gear is numerically analyzed under varying oil depths and rotational speeds to quantify total power loss and investigate oil flow patterns. The computational approach employs a volume-of-fluid multiphase framework, and the predictions are
This study presents a fully integrated, vehicle-level thermal management model for gasoline fuel tanks, designed to predict transient fuel temperatures, tank wall heating, and vapor generation under real-world driving conditions. The model simulates coupled thermal contributions from exhaust radiation, transient underbody airflow, conductive heat transfer, in-tank pump heating, and dynamic changes in fuel composition and level. Validation against on-road measurements shows strong agreement for fuel temperature and vapor flow profiles. Results confirm that exhaust radiative heating is the dominant thermal load, particularly during the post-shutdown heat soak period. A well-designed heat shield reduced peak tank wall temperature by approximately 27 °C, significantly lowering fuel heating and evaporation. Parametric analysis indicates that while fuel Reid Vapor Pressure (RVP) and tank material influence evaporation, their effect is secondary to external heat mitigation. While this model
The demand for lightweight, high-efficiency components in electric vehicles (EVs) highlights the critical need for reliable Al-Cu joints with superior electrical and thermal conductivity. While diffusion bonding has emerged as a promising approach, interfacial impurities and voids often degrade joint quality and conductivity. Conventional manual polishing was initially employed to prepare Cu and Al surfaces; however, this method proved insufficient in consistently removing oxides and contaminants, leading to non-uniform bonding. In addition, the larger surface area of the samples made traditional polishing impractical, further motivating the use of electropolishing. To overcome these limitations, we introduce electropolishing pretreatment to achieve cleaner, void-free interfaces. Electropolishing effectively dissolves surface asperities and contaminants, enabling intimate atomic contact during bonding and minimizing the formation of brittle intermetallic phases. A systematic
A computational study based on a conjugate heat transfer (CHT) method in SimericsMP+ was performed to predict the winding temperatures in an X76 emotor. In this study, the thermal load was represented in the simulation through the solution of electromagnetic equations in SimericsMP+, where heat generation was driven by root-mean-square (RMS) current, while liquid cooling was applied at flow rates ranging from 1 LPM to 6 LPM. Simulations were conducted to measure the temperature on three thermocouple locations on each side of the winding crown and weld regions under steady operation. The computational strategy employed a loosely coupled approach. A fluid-only simulation was first carried out to establish stable flow conditions, followed by coupling with solid conduction where the winding acted as the heat source. The predicted temperature distributions were then compared with test data. Results obtained show good agreement, with differences remaining within an acceptable range, thereby
This SAE Recommended Practice is applicable to all heat exchangers used in vehicle and industrial cooling systems. This document outlines the tests to determine the heat transfer and pressure drop performance of heat exchangers under specified conditions. This document has been reviewed and revised by adding several clarifying statements to Section 4.
The objective of this paper is to evaluate the thermal performance of the brake discs in the design stage of its life cycle by developing a methodology to replicate dynamometer testing using multi-disciplinary Finite Element Analysis (FEA) methods. A simulation workflow was formulated in which Computational Fluid Dynamics (CFD) was used to create temperature and velocity dependent Heat Transfer Coefficients (HTC) which were in turn used in Computer Aided Engineering (CAE) to do a thermo-mechanical analysis. With this workflow various designs of the brake discs were analyzed. A sensitivity study was done to determine critical design features that affected its thermal performance. A final design was fixed that met both the weight and thermal performance targets. This design was evaluated in dynamometer testing, and 93% correlation was achieved. Thus, the developed simulation workflow ensured that a first-time right brake disc can be finalized in the design stage, which will meet the
Gears play a critical role in automotive transmission systems. During operation, frictional heat is generated in the intermeshing region due to loading. Effective lubrication and cooling are essential to minimize heat generation and ensure smooth operation. Lubrication failure can lead to a significant local temperature rise, potentially causing gear scuffing—a phenomenon where intermeshed gear teeth weld together and tear apart during rotation—resulting in severe damage and compromised transmission performance. To prevent this, gears are typically lubricated using splash or jet lubrication techniques. This study presents a Conjugate Heat Transfer (CHT) simulation of a jet-lubricated gear pair in an automotive transmission system to predict the local temperature rise due to frictional heating in the intermeshing region of the gears. The paper focuses on implementation of the frictional heat generation on the gear teeth and resultant transient temperature rise in the gear contact region
The HVAC (Heating, Ventilation, and Air conditioning) system is designed to fulfil the thermal comfort requirement inside a vehicle cabin. Human thermal comfort primarily depends upon an occupant’s physiological and environmental condition. Vehicle AC performance is evaluated by mapping air velocity and local air temperature at various places inside the cabin. There is a need to have simulation methodology for cabin heating applications for cold climate to assess ventilation system effectiveness considering thermal comfort. Thermal comfort modelling involves human manikin modeling, cabin thermal model considering material details and environmental conditions using transient CAE simulation. Present study employed with LBM (Lattice-Boltzmann Method) based PowerFLOW solver coupled with finite element based PowerTHERM solver to simulate the cabin heat up. Human thermal comfort needs physiological modelling; thus, the in-built Berkeley human comfort library is used in simulation. Human
Battery Thermal Management Systems (BTMS) play a critical role in ensuring the longevity, safety, and efficient operation of lithium-ion battery packs. These systems are designed to better dissipate the heat generated by the cells during vehicle operation, thereby maintaining a uniform temperature distribution across the battery modules, preventing overheating and mitigating the chances of thermal runaway. However, one of the primary challenges in BTMS design lies in achieving effective thermal contact between the battery cells and the cooling plate. Non-uniform or excessive application of Thermal Interface Materials (TIMs) without ensuring robustness and uniformity can increase interfacial thermal resistance, leading to significant temperature variations across the battery modules, which may trigger power limitations via the Battery Management System (BMS) and these thermal changes can cause inefficient cooling, ultimately affecting battery performance and lifespan. In this paper, a
Virtual reality (VR), Augmented Reality (AR) and Mixed reality (MR) are advanced engineering techniques that coalesces physical and digital world to showcase better perceiving. There are various complex physics which may not be feasible to visualize using conventional post processing methods. Various industrial experts are already exploring implementation of VR for product development. Traditional computational power is improving day-by-day with new additional features to reduce the discrepancy between test and CFD. There has been an increase in demand to replace actual tests with accurate simulation approaches. Post processing and data analysis are key to understand complex physics and resolving critical failure modes. Analysts spend a considerable amount of time analyzing results and provide directions, design changes and recommendations. There is a scope to utilize advanced features of VR, AR and MR in CFD post process to find out the root cause of any failures occurred with
Thermal management is critical for modern vehicles, particularly for Zero Emission Vehicles (ZEVs), where maintaining optimal temperature ranges directly influences thermal system efficiency and vehicle range. Accurate prediction of underhood airflow behavior is essential for effective thermal management and also to estimate overall energy consumption by cooling system, with air-side dynamics playing a pivotal role in heat transfer over the heat exchangers of cooling package. Simulation tools like GT-Suite are indispensable for this purpose, enabling engineers to evaluate complex thermal interactions without the cost and time constraints of extensive physical testing. While 3D Computational Fluid Dynamics (CFD) models offer detailed insights into flow characteristics, they are computationally expensive and time consuming. In contrast, 1D models provide faster simulation times, making them ideal for system-level analysis and iterative design processes. However, 1D models inherently lack
In automotive systems, efficient thermal management is essential for refining vehicle performance, enhancing passenger comfort, and reducing MAC Power Consumption. The performance of an air conditioning system is linked to the performance of its condenser, which in turn depends on critical parameters such as the opening area, radiator fan ability and shroud design sealing. The opening area decides the airflow rate through the condenser, directly affecting the heat exchange efficiency. A larger opening area typically allows for greater airflow, enhancing the condenser's ability to dissipate heat. The shroud, which guides the airflow through the condenser, plays a vital role in minimizing warm air recirculation. An optimally designed shroud can significantly improve the condenser's thermal performance by directing the airflow more effectively. Higher fan capacity can increase the airflow through the condenser, improving heat transfer rates. However, it is essential to balance fan
Thermal or infrared signature management simulations of hybrid electric ground vehicles require modeling complex heat sources not present in traditional vehicles. Fast-running multi-physics simulations are necessary for efficiently and accurately capturing the contribution of these electrical drivetrain components to vehicle thermal signature. The infrared signature and heat transfer simulation tool, “Multi-Service Electro-optic Signature” (MuSES), is being updated to address these challenges by expanding its thermal-electrical simulation capabilities, provide a coupling interface to system zero- and one-dimensional modeling tools, and model three-dimensional air flow and its convection effects. These simulation capabilities are used to compare the infrared signatures of a tactical ground vehicle with a traditional powertrain to a hybrid electric version of the same vehicle and demonstrate a reduction in contrast while operating under electrically powered conditions of silent watch and
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