Browse Topic: Heat transfer

Items (1,611)
Find
Performance Analysis of Graphene-Coated Heat Pipe Heat Exchangers for Automobile Exhaust Cooling and Purification2025-01-500601/23/2025
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, Kaliappan, Balaji, N., Natrayan, L., Sheik, Salman Basha, Ravi, D.
Technical Paper
Analyses of Cold Thermal Energy Storage Systems Using Eutectic Mixtures of Inorganic Hydrated Salts as Phase Change Materials2025-01-500301/23/2025
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.
Technical Paper
Design Optimization and Thermal Simulation of a Plate Type Heat Exchanger (“Chiller”) for EVs Applications2022-28-044111/09/2022
The rapid evolution of electric vehicles (EVs) has considerably forced the automotive industry to design compact & highly efficient heat exchangers due to lower temperature applications. The plate type heat exchangers (Also known as "Chillers" in automotive industry) are one of the most important components in EVs thermal management systems. It is a type of heat exchanger, which uses metallic plates arranged like a staggered sandwiched structure to exchange heat between two working fluids. The heat transfer between the plates occurs due to highly compact structural design as compare to any conventional heat exchangers. The chiller is having very large surface area, which is exposed to the working fluids as the distribution happens all across the plates. The chillers are more suitable design for transferring heat between ranges of working fluids pressure varying from low to high pressures. Various types of welded, semi-welded plate heat exchangers are available. The working fluids flow
Suman, Saurabh, Kushwah, Yogendra Singh, SHUKLA, ANKIT, Singh, Shobhit Kumar
Technical Paper
Non-parametric Optimization of Heat Sinks for Power Dense Motor Controllers2022-26-117505/26/2022
With the future of mobility moving towards electrification there is an ever-increasing demand in both aerospace and automotive industry for achieving higher power density in inverters, controllers, etc. In the aviation industry, the trend of more electric aircraft has resulted in transition from central to zonal architecture. In zonal architecture, controller units are kept close to the actuator systems and localized harsh bay conditions, space constraints coupled with the necessity for high power density has made thermal management a challenging task. This warrants a need for exploring innovative cooling techniques to manage the dissipated heat. This paper focuses on a liquid cooled thermal management system for power dense applications. The heatsink design presented here is a pin fin arrangement staggered to induce swirling flow, which has been proven to enhance heat transfer. The traditional heatsink optimization involves creating a design of experiments (DoE) with parameters like
Bhardwaj, Divyanshu, Datta, Sauradeep, Borkar, Kishor
Technical Paper
To Develop the model for heat transfer coefficient with Machine Learning Techniques.2022-26-123505/26/2022
Being the Need of Increasing the heat transfer for domain which under heat stress index,key parameter is heat transfer coefficient, Which majorly depends upon the float rate of the context, the input of the heating element which ultimately decide the the time of contact of fluid which raise the concern about heat transfer. The Main goal of the presented study is to Investigate and develope model for the heat transfer coefficient in forced convection.The study comprising two section as conduction the experiment by considering the parameters like air flow, heater input, varying one at a time, which will creat the dataset, with dependent label as heat transfer coefficient using empirical relation. Three Machine learning algorithm i.e is Support Vector Machines, Decision Tree and XG boost are tested over the dataset. The metrics like Root mean squre error and Mean absolute error is plooed with the doamin, All algorithm implemented with the Python.
Dorwat, Ajit L., Dhotre, Sanchit, Biradar, Ashish, Lokhande, Pravin
Technical Paper
Machine learning assisted analysis of heat transfer characteristics of a heavy duty natural gas engine2022-01-057203/29/2022
Heat transfer affects engine performance, efficiency, and emissions. Hence, it was essential to investigate the heat transfer characteristics after converting a compression ignition engine to a spark ignition and natural gas. The heat transfer for each engine speed and load was calculated based on Woschni’s correlation. As the number of experiments that provided engine response was limited, an artificial neural network approach was proposed to predict the engine heat transfer characteristics and aid in the analysis. The good agreement between the experimental results and data predicted by the machine learning algorithm validated the predictive capability of the artificial neural network model. The results of the data-driven analyses suggested that the heat transfer increased as the spark timing advanced. Moreover, increasing the engine speed reduced the heat flux form the combustion chamber to the engine coolant. Further, leaning the mixture lowered the heat transfer rate to the
Liu, Jinlong, Dumitrescu, Cosmin, Ulishney, Christopher
Technical Paper
Engine Thermodynamic Design, Optimization, Test & Analysis of Daimler SuperTruck2 Program Towards 55% BTE Target2022-01-050403/29/2022
Daimler's effort toward demonstration of 55% brake thermal efficiency for the US Department of Energy SuperTruck2 program relied on a holistic approach to optimization of the Daimler heavy-duty 12.8L diesel engine. Core technical approaches used in this effort include efficient two-stage turbocharging with intercooling, valve timing optimization, improved combustion system design, friction and parasitics reduction through optimized lubrication system, and in-cylinder heat transfer reduction. These measures in combination provided an anticipated engine efficiency of over 50% BTE before application of an additional waste heat recovery system. Utilization of high-fidelity simulations from 1D physical model simulation studies and CFD/FEA framework allowed for optimization of the engine pumping loop and heat transfer reduction efforts. Test bench data provides high-level overview of combustion improvement, friction & parasitics reduction, improvement in in-cylinder heat transfer reduction
Bashir, Murad
Technical Paper
Heat Transfer Analysis of an Electric Motor Cooled by a Large Number of Oil Sprays Using Computational Fluid Dynamics2022-01-023703/29/2022
This paper reports on an analytical study of the heat transfer and fluid flow in an electric vehicle e-Motor cooled by twenty five sprays/jets of oil. A three-dimensional, steady state, multi-phase, computational fluid dynamics (CFD) and conjugate heat transfer (CHT) model was created using a commercial CFD software. The transport equations of mass, momentum, energy and volume fraction were solved together with models for turbulence and wall treatment. An explicit formulation of the volume of fluid (VOF) technique was used to simulate the sprays, a time-implicit formulation was used for the flow-field and three dimensional conduction heat transfer with non-isotropic thermal conductivities was used to simulate the heat transfer in the windings. An important challenge was to formulate an efficient solution algorithm that can rigorously comprehend twenty five sprays in order to accurately predict the temperature distributions in the windings, without thrifting physics, and within
Srinivasan, Chiranth, Wan, Jingyi, Saha, Rohit, DHAR, Sujan, Paciura, Krzysztof, Nichani, Varun, Ranganathan, Raj
Technical Paper
The Rotating Liner Engine under Medium Loads and Speeds. Fuel economy benefit exceeds 10%2022-01-050703/29/2022
The Rotating Liner Engine (RLE) is a design concept where the cylinder liner of a Heavy Duty Diesel engine rotates by about 2-4 m/s surface speed in order to eliminate the piston ring and skirt boundary friction near top and bottom dead center. Based on testing results from our single cylinder RLE prototype (a converted four cylinder Cummins ISB 3.9 diesel) compared to a similar baseline, under idle conditions, the friction reduction is approximately 50 kPa in FMEP (friction mean effective pressure), which translates to about 40% for a complete engine. In this new set of experiments, we are comparing the RLE performance under load of up to about 7 bar IMEP (indicated mean effective pressure). It has been proven that the elimination of metallic contact between the compression rings and cylinder persists under up to 75 bar peak cylinder pressure and 1.5-2 m/s liner surface speed (283-383 rpm) for the 850-1150 rpm crankshaft speed. Additionally, the RLE FMEP is substantially reduced under
Dardalis, Dimitrios, ALHAJ ASAD, Osama, Basu, Amiyo, Hall, Matthew, Matthews, Ron
Technical Paper
Simulation of 2-Stroke D-Cycle Engine Concept for Agricultural Tractor2022-01-046403/29/2022
This paper explains to modify conventional 4-Stroke 2.7L 4-Cylinder CRS (Common Rail System) Naturally aspirated (NA) Diesel engine into 2-Stroke D-Cycle (i.e. Differential Stroke) engine for Agricultural Tractor applications. 1D Performance simulation was performed using GT-POWER to focus on how to maximize the combustion efficiency and power/torque demand using a 2-stroke D-Cycle by taking advantages of deficits in a 4-stroke engine, optimizing for improving emissions and realizing higher torque demands for Tractor field applications. Furthermore, appropriate cam geometries ensuing specific application of puddling, tillage etc. are generated which can be accommodated without major design changes. Exhaust, heat transfer, pumping, frictional losses, and volumetric efficiency are analyzed. Performance Simulation results shows that Fuel economy improvement of ~ 10%, average increase in Power output of ~ 30%, average NOx emission reduction of ~ 15% and better drivability at low engine
S, SHANKAR, Paulraj, Lemuel
Technical Paper
Analysis of energy and exergy distribution for improving fuel economy of marine low-speed two-stroke diesel engine2022-01-046303/29/2022
Increasingly strict emission regulations and unfavorable economic climate bring severe challenges to energy conservation of marine low-speed engine. Besides traditional methods, the energy and exergy analysis could acknowledge the losses of fuel energy from a global perspective to further improve the engine economy. Therefore, in this study, a thermodynamic model is built based on experimental data to conduct the energy and exergy analysis for marine low-speed engine. Results of energy analysis shows that the exhaust gas accounts for the highest proportion of energy losses, and it rises with the increment of engine load. The proportion from heat transfer is just after the exhaust gas. But, it is negatively correlated to engine load. The energy analysis results indicate that reducing the proportions of exhaust gas and heat transfer is the best way to improve the fuel economy of engine. However, the exergy analysis demonstrates that there is still another more effective approach to
Zhang, Heng, Deng PhD, Kangyao, Wang, Dawei, LONG, Wuqiang, Qian, Yuehua
Technical Paper
An experimental study of heat loss and spatially temperature distributions of the impinging plate2022-01-060703/29/2022
Spray impingement tends to occur in compact-size engines and it affects the fuel-air mixing, local heat transfer between fluid and solid, and possibly leads to fuel deposition on the hard surface. The deposits which are typically called “film” become one of the main sources of soot particles generated in the subsequent combustion. Wall temperature is one of the factors that affect fuel deposition. A higher wall temperature would enhance the film evaporation and reduces the risks of fuel deposition to partially avoid the soot particles formed from the film. Also, the wall temperature would affect the ignition characteristics such as ignition delay and ignition location. However, in realistic operating engines, the wall temperature is not consistent but changed by the heat conduction from charge gas and heat convection when the spray hits the wall and propagates near the surface. Due to the arrangement of injectors in the engines, an oblique injection is typically observed. This scenario
Zhao, Zhihao, Lee, Seong-Young
Technical Paper
Research on Heat Dissipation Performance of Automobile Motor Based on Heat Pipe Optimization Design2022-01-088403/29/2022
In new energy vehicles, the electric motor, as the main power source, is developing toward high power density. However, its heat generation problem always affects the overall performance of the motor, so an efficient motor cooling system is especially important. In desert or water-scarce areas, liquid cooling cannot meet the needs of new energy vehicle motor cooling. When glycol or other liquid coolants are low or depleted, motor heat dissipation becomes less effective. Heat pipe is a heat dissipation technology with advantages such as fast thermal response and light weight. In this paper, by improving the heat pipe arrangement and reducing the overall mass of the heat dissipation system, a heat pipe optimization design based on a drive motor heat dissipation scheme is proposed, and the overall stability of the motor working under high temperature conditions is improved. In this paper, the heat pipe arrangement scheme is set up with the heat pipe heat transfer characteristics, and the
Yang, Chunyun
Technical Paper
Impact of the vehicle environment on the thermal behavior of the electrical wiring2022-01-015403/29/2022
The thermal behavior of wires within the electrical distribution system (EDS) has a strong impact on the conductor cross section, the type of insulation, the derating and the fusing system, and therefore on weight, cost, and reliability. Consequently, significant efforts have been made to develop sound static and dynamic thermal models for single wires and wire bundles. However, these models are based on the simplifying assumption that the object is completely surrounded by air, where, with the exception of internal convection, airflow can be neglected, and where no interaction with other objects is considered. The approach presented in this paper takes into account the real environment and routing within a vehicle, where some objects such as metal sheets can be considered as heat sinks and other objects, e.g. a motor block, as heat sources. For this reason, measurements were performed using an experimental set-up that allows any desired positioning and alignment of the DuT (device
Brabetz, Ludwig, Ayeb, Mohamed, Koppe, Christian, Hesse PhD, Benjamin
Technical Paper
Use of Thermally Conductive Electrically Insulative (TCEI) Materials in E-motor Slot Liner Applications2022-01-022403/29/2022
Slot liners are commonly used in electric motors to electrically insulate the motor windings from the laminated core. However, thermal conductivity of materials commonly used as slot liners is very low compared to other components in the motor thus creating a barrier for heat transfer. This thermal barrier affects overall motor performance and efficiency. Also, slot liners typically lack intimate contact with the laminated core resulting in air gaps which further increase thermal resistance in the system. Slot liners are traditionally made from high temperature films/papers that are cut and slid into slots of motors. The proposed work looks at developing an injection moldable slot liner to minimize air gaps. Additionally, use of TECI materials further lowers thermal resistance. A thermal finite element model has been developed to evaluate effects of slot liner thermal properties and air gaps on temperature distribution within the motor. The model incorporates varying material
Sundararaman, Saikrishna, Szparagowski, Ray
Technical Paper
Multiple Heat Exchangers for Automotive Systems – A Design Tool2022-01-020503/29/2022
A single radiator cooling system architecture has been widely applied in ground vehicles for safe equipment (e.g., engine block, electronics, and motors) temperature control. The introduction of multiple smaller heat exchangers provides additional energy management features and alternate pathways for continued operation in case of critical subsystem failure. Although cooling performance is often designed for maximum thermal loads, systems typically operate at a fraction of the peak values for most of their life cycle. In this project, a two-radiator configuration with variable flow rates and valve positions has been mathematically modelled and experimentally validated to study its performance feasibility. A multi-node resistance-capacitance thermal model was derived using the ε-NTU approach with accompanying convective and conductive heat transfer pathways within the system. This engineering model provides an analytical description of the system behavior that can be leveraged for
Syed, Zaker, Miller, Richard, Wagner, John
Technical Paper
Thermal Design and Performance of Airplane In-Flight Food Storage CarsARP8058A (Current)11/09/2021
This SAE Aerospace Recommended Practice (ARP) provides design guidance and a method for testing thermal performance of airplane in-flight food storage carts. It is noted that thermal performance criteria is not part of AS8056.
S-9B Cabin Interiors and Furnishings Committee
Recommended Practice
Decoding Genuine Ceramic Pad Formulations- Materials and Processing2021-01-127710/11/2021
The need to develop genuine ceramic composites for PV applications arose to overcome the challenges associated with traditional semi-metallic pads. The main focus is to achieve better performance, low noise, better pad and rotor wear, and low dust compared to semi- metallic pads. In general, brake pads convert kinetic energy to thermal energy through friction, and operating temperature in semi-metallic brake pads is higher due to the presence of steel having high thermal conductivity. Over the last decade, the customer preference has moved over to ceramic pads due to light coloured pad surface, low rotor and pad wear and low dust compared to semi-metallic pads. The traditional steel has been replaced by Aramid, engineered ceramic fibre, potassium titanate (TISMO D), lapinus fibre (RB 250) to impart similar/better performance. The current work investigates the characterisation of genuine ceramic and semi-metallic composites. Three genuine ceramic and one semi-met composite have been
Tomar, Bharat, Ali, Sharafat, Ellis, Keith, Choudhary, Yogesh
Technical Paper
A Molecular Dynamics Study of Tribological Properties of Silicon Carbide as a Metal-Free Friction Material2021-01-128410/11/2021
Friction materials containing metal ingredients used in the automotive industry can cause unfavorable environmental impacts. Existing laws and regulations require heavy metals in brake pads to be phased out of production. Substitutions for metals in friction materials, however, may introduce operational safety issue and other unforeseen problems. In the current study, a molecular dynamics model based on LAMMPS has been developed to study the effect of material composition, density, and geometric configurations on the tribological, mechanical, and thermal properties of silicon carbide under various contact conditions at the atomic level. Simulations which incorporate interfacial contact between surface asperities were performed to predict the elastic modulus, thermal conductivity, wear rate, and coefficient of friction. The resulting predicted properties may help enhance the performance of engineered metal-free friction materials against thermal-mechanical failures. The following
Zhang, Yizhan, LeNeave, Cortney, Yi, Yun-Bo
Technical Paper
Thermomechanical Instabilities in Metal-Free Friction Materials Using a Nonlinear Transient Simulation Approach2021-01-128610/11/2021
The invention of metal-free friction materials is gaining popularity in the manufacturing of brake pads and clutch friction discs because of the negative factors associated with metals such as copper. To gain more insight into the failure mechanism of the recent invention during brake or clutch applications, a nonlinear transient thermomechanical model is established using Finite Element Code. The model is based on a two-dimensional configuration for an investigation on the onset of TMI (Thermo-Mechanical Instability) during sliding contact in such material. The model is validated by comparing the transient simulation results for a full-contact regime to the result from the existing eigenvalue method. A parametric study is carried out to examine how the thermal conductivities and the elastic moduli influence TMI. The simulation results show that the thermal conductivities in the transverse direction and elastic moduli in the longitudinal direction can stabilize the system. Conversely
Koranteng, Kingsford, Shaahu, Joseph-shaahu, Yi, Yun-Bo
Technical Paper
Comparing and analysing the static and thermal characteristics of brake disc for three different materials2021-28-025310/01/2021
In automobiles, the most commonly used braking system is disc brake. In the brake disc, rotor is the rotating part of a wheel's disc brake assembly, against which the brake pads are applied by the driver through mechanical action. So, the disk is the important component in either slowing down or stopping the vehicle. These discs were commonly made of cast iron conventionally. But the limitations with respect to cast iron are that they have less corrosion resistance and heavy in weight. In order to overcome the above-said complications, alternate materials for disc have to be found. The main objective of this paper is to analyze the characteristics of three different materials and compare their results and suggest a suitable material that highly influences the conventional material and has better performance under on-road rigorous braking conditions. In order to find an alternative material for Cast Iron (CI), EN31, Ti-6Al-4V(Ti alloy) acts as a potential candidate in offering great
K, Kaviyarasan, R, Soundararajan, Richter R, Abhisheak, K, Siva, Purusothaman, S, S, Shiva Gurunathan
Technical Paper
Numerical and Experimental Investigation of heat transfer enhancement in an off-road radiator using Al2O3 nano fluids2021-28-017710/01/2021
Water and ethylene glycol are considered as conventional coolants from years in automotive industry for engine cooling. With the advancements in nanotechnology, Nano fluids have become prominent in increasing the rate of heat transfer compared to that of conventional fluids. Present study enlightens the CFD simulation of Nano-fluids in a radiator with base fluid as Ethylene glycol- water and Al2O3 as nanoparticles at different volume concentrations. The Nano fluid rheology is simulated in Ansys-Fluent CFD tool using standard k-ε two equation turbulence model with enhanced wall treatment and a standard y plus values. Various available fluent single phase and multiphase models are evaluated and compared with the experimental results in a simple circular pipe to setup the standard simulation methodology for radiator analysis. The effective temperature dependent thermos-physical properties of Nano fluids were estimated from the literatures. The result shows that alumina oxide nano fluids
Dewangan, Nitin, Kattula, Nitin, Kumar PhD, Kiran, naidu, Ramesh
Technical Paper
Tribological Behavior of Thermal and Mechanical Composite Reinforced Sisal Characteristics and Influence SiC Filling Material2021-28-027710/01/2021
In order to investigate the possible use of normal capital, we have tried by hand to manufacture sisal fibre polymer composites. Natural fibre composites are reusable, low-cost and biodegradable. Simple source, lesser compactness, superior basic property, lower quality, acceptable physical and mechanical properties, non acidic in environment, make them a good-looking biological substitute for glass, carbon or other artificial fibres. The outcome of SiC on the physical and mechanical properties of organic sisal composite materials is studied in this work. The composite was manufactured with and without SiC, mixing natural sisal fibre with polyester as a reinforcement medium. The investigational results showed that the tensile force of the mixture with 12 % SiC was 2.52 times better than that of the composite devoid of SiC. The collision strength of the 12% SiC merged is 1.72 times higher than that of the SiC pure polyester composite. The physical properties deliberate include thermal
RAJU, GANESAMOORTHY, NATARAJAN, Balaji, Chakaravarthy, Ezilarasan, Samikannu, Poovaragan, R, Soundararajan
Technical Paper
A Holistic Approach of Developing New High Strength Cast Iron for Weight Optimization2021-26-024409/22/2021
Cast Iron is being used in various Industries like Automotive, Agriculture, Construction etc., for many decades. Metal casting processes have its unique advantages like ease of heavy weight castings, intricate shapes, higher productivity. Commercially viable (low cost) etc., using wide range of materials like Gray cast iron, Spheroidal cast iron, Malleable cast iron ,cast steel etc., Cast iron have an excellent properties like high dampening capacity, higher thermal conductivity, wear resistance required by many critical applications. These unique combinations will be chosen to serve the purposes both functionally and commercially. However, in last one-decade automotive and agriculture industries are facing issue of fuel economy which directly influenced by the weight of the vehicle. For off-road vehicle like tractors, One of the major contributor in vehicle weight is cast iron. Many material grades and strengthening mechanisms are recently being evolved to optimize the cast iron
Gunalan, Magendran, Anandeswaran, V.A
Technical Paper
3D CFD coolant system simulation for a full vehicle drive-cycle2021-26-040709/22/2021
The present work deals with the 3-D, transient, system level CFD simulation of automotive coolant system, which includes actual CAD of radiator, cooling jacket, coolant pump, bypass valve and thermostat valve, using a 3D CFD solver Simerics MP+®. This work is in continuation of the work done by Srinivasan et al. (2017) where wax melting, conjugate heat transfer, Fluid Structure Interaction of the valve had been solved. Thermostat valve was controlled by wax phase change model which incorporates the hysteresis effect of wax melting and solidification. The current model will also include rigorous treatment of cavitation to account for the presence of dissolved gases and vaporization of the liquid coolant. The previous work dealt with simulation of opening and closing cycle of the thermostat/by-pass valve system. A methodology has been developed and implemented where the run-time of such a system has been made considerably faster enabling us to simulate complete drive cycle tests. The
Varshney, Mehul, Ballani, Abhishek, Pasunurthi, Shyam Sundar, Maiti, Dipak, Srinivasan, Chiranth
Technical Paper
Simulation based approach to improve the engine oil warmup behavior using exhaust gas during NEDC cycle2021-26-042209/22/2021
During the cold start conditions engine must overcome higher friction loss, at the cost of fuel penalty till the optimum temperatures are reached in coolant and lubrication circuits. The lower thermal capacity of the lubrication oil (with respect to the coolant) inverses the relation of viscosity with temperature, improves engine thermal efficiency benefit. Engine oil takes full NEDC test cycle duration to reach 90°C. This leads to higher friction loss throughout the test cycle, contributing a significant increase in fuel consumption. Increasing oil temperature reduces viscosity, thereby reducing the engine friction. This helps to identify the focus for thermal management in the direction of speeding up the temperature rise during a cold engine starting. This work aims at the study and experiment of an exhaust recovery mechanism to improve the NEDC fuel economy. The objective of the work is to use the exhaust gas energy, post after treatment system to heat up the engine oil temperature
Krishnan, Karthikeyan N., Ramadandi, Padmavathi, M, Vikramraj, Elumalai, Sakthivel
Technical Paper
Engine mounted Oil cooler 3D CFD CHT Analysis for predicting Thermal Performance2021-26-035109/22/2021
This paper describes steady state, computationally rigorous, three-dimensional conjugate heat transfer 3D CFD analysis of an engine mounted oil cooler. Thermal performance of an oil cooler is very significant from engine oil consumption, bearings performance etc. In an engine water jacket, coolant flows around and through the oil cooler making the flow three dimensional. Therefore, demanding the need of a 3D CFD analysis for capturing all the flow and heat transfer aspects and thereby accurate prediction of thermal performance. An oil cooler contains intricate turbulators in flow paths and have dimensions varying from as small as 0.25 mm to as large as 300 mm, therefore making the meshing and solution a formidable task. In current work an oil cooler with all the intricate details is modelled in a commercial CFD code. Objective is to develop a solution approach which can predict thermal performance of an oil cooler in an accurate way. An engineering practice with guidelines for geometry
Tawar, Ranjit Ramchandra, Brasmer, Susan, Bedekar, Sanjeev
Technical Paper
Drivetrain Lubricants with High Cooling and Efficiency-Boosting Properties for Electric Vehicles2021-01-121509/21/2021
In electric vehicles (EVs), drivetrain lubricants (EV fluids) are often relied upon to aid in cooling the motors. In such cases, the lubricants must provide high cooling performance. They should also improve the efficiency of the transmissions and reduction gearboxes in EV drivetrains. Both requirements can be met by lowering the viscosity of the fluid. This effectively improves the heat transfer coefficient and also helps increase efficiency by reducing churning loss. However, a viscosity that is too low can negatively affect the fatigue life of mechanical parts such as gears and bearings. Another problem is that common defoamers often do not work well with low viscosity oils, and increased foaming can further reduce fatigue life and lead to poor cooling performance and lower efficiency. To solve the issues associated with lower viscosities, we optimized the anti-wear agents, dispersants, and other additives to develop formulations specially designed for EV drivetrains. The result are
Iino, Mari, Tada, Akira, Masuda, Kohei, Matsuki, Shingo, Onumata PhD, Yasushi
Technical Paper
Advanced developments in solid desiccant coated heat exchangers and their potential applications2021-28-014209/15/2021
To meet the increasing thermal comfort requirements in recent times, applying a solid desiccant coated heat exchanger (SDCHE) air-conditioning system is one of the thrust areas of focus due to its energy efficiency benefits. Fixed stationary bed and rotary wheel desiccant systems are being used widely for dehumidification. In these systems, the increase in the relative humidity of intake process air increases the adsorption heat release from the desiccant, and the desiccant’s temperature increases due to the lower heat transfer efficiency. This effect reduces the COP of these systems since the desiccant adsorption capacity is inversely proportional to the desiccant’s temperature. To overcome the limitations of the fixed stationary beds and rotary wheel desiccant dehumidifiers, SDCHE is a suitable technology for standard vapor-compression air conditioners. These heat exchangers can deliver combined heat and mass transfer between the process air and the working fluid. The process air can
Muthu, Selvaraji, N, Sekarapandian, KANNAIYAN, Ashok, ARIVUKKARASU, Hariprasath
Technical Paper
Simulating Thermal comfort for a vehicle2021-28-013209/15/2021
The vehicle HVAC system is designed to meet both the safety and thermal comfort requirements of the passengers inside the cabin. The thermal comfort requirement, however, is highly subjective and is usually met objectively by carrying out time dependent mapping of parameters like the velocity and temperature at various in-cabin locations. These target parameters are simulated for the vehicle interior for a case of hot soaking and its subsequent cool-down to test the efficacy of the AC system. Typically, AC performance is judged by air temperature at passenger locations, thermal comfort estimation alongwith time to reach comfortable condition for human. Simulating vehicle cabin for thermal comfort evaluation is computationally expensive and requires complex cabin material modelling. Coupled simulation between LBM based Powerflow and Finite element based Powertherm solver is employed and discussed here to simulate thermal comfort. Additionally, the human thermal physiology is modelled
Shelar, Sujit, Kandekar, Ambadas, Deshmukh, Ganesh, Nomani, Mustafa, Sivakumar, Vignesh, Nagarajan, Vijaisri
Technical Paper
Test Method for Determining Cold Cracking of Flexible Plastic MaterialsJ323_202109 (Current)09/15/2021
This SAE Recommended Practice is applicable for determining the cold characteristics of flexible plastic materials, as applicable. It consists of three different methods for determining low-temperature properties of materials depending on type of material and end use. The method used shall be as specified by the contractual parties.
Textile and Flexible Plastics Committee
Recommended Practice
Reduced Heat Leakage Improves Wearable Health DeviceTBMG-3961708/01/2021
Researchers have enhanced a flexible body heat harvester by preventing heat leakage. The harvesters use heat energy from the human body to power wearable technologies. The technology relies on the same principles governing rigid thermoelectric harvesters that convert heat to electrical energy.
Magazine Article
Assembly and Soldering Criteria for High Quality/High Reliability Soldering Wire and Cable Termination in Aerospace VehiclesAS4461D (Current)07/23/2021
This standard is applicable to manual soldering and machine soldering processes utilizing controlled soldering devices, for electrical connections for wiring and cabling used in aerospace vehicles. Description of a component or device herein is not to be construed as authorizing the use of the component or device.
AE-8A Elec Wiring and Fiber Optic Interconnect Sys Install
Technical Standard
Assembly and Soldering Criteria for High Quality/High Reliability Soldering Wire and Cable Termination in Aerospace VehiclesAS4461D-TEST-REC (Historical)07/23/2021
This standard is applicable to manual soldering and machine soldering processes utilizing controlled soldering devices, for electrical connections for wiring and cabling used in aerospace vehicles. Description of a component or device herein is not to be construed as authorizing the use of the component or device.
AE-8A Elec Wiring and Fiber Optic Interconnect Sys Install
Technical Standard
How 3D printing could add efficiency to EV power electronics21AUTP05_0805/01/2021
“Think production!” Perhaps that advice should be posted on the wall of every design office, R&D lab and advanced technology center in the auto industry. Although obeying that warning is clearly not cost-effective in some instances, others are ostensibly perfect to take their place in volume manufacture. An example is 3D printing (aka additive manufacturing, or AM), but despite a broadening scope that now embraces rapid prototyping and tooling by entire houses, it could do better in series production of auto components, particularly in the new world of EVs. Prof. Peter Wilson of the U.K.'s newly established Institute for Advanced Automotive Propulsion Systems (IAAPS) at the University of Bath, noted the growing adoption of high-speed SiC (silicon carbide) and other wide-band-gap semiconductor devices demonstrates the benefits that 3D printing could have in the production of EV inverters. “SiC devices offer so much opportunity to improve inverter performance,” Wilson said. “But system
Birch, Stuart
Magazine Article
Determination of Efficiency Losses in Entry Ignition Engines2021-01-044104/06/2021
In 2020, Cheeseman (SAE Paper 2020-01-1314) introduced Entry Ignition (EI) as a potential engine combustion process to rival traditional Spark Ignition (SI) and Compression Ignition (CI). The EI process premixes fuel with compressed air, which then enters a hot cylinder at top dead center, autoigniting upon entry. The original proposed concept for an engine separates the compression and expansion processes allowing for it to be modeled as a 2-stroke Brayton cycle. Theoretically, an EI engine allows for higher compression ratios than SI engines with less emissions than CI engines. However, the original EI engine analysis made several assumptions that merit further investigation. First, the original analysis did not look at the temperatures and pressures in the air/fuel mixing chamber to ensure that it does not autoignite prior to entering the cylinder. Second, the analysis did not account for the large amount of heat transfer associated with keeping half the end-gas in the cylinder
Mittal, Vikram, Novoselich, Brian
Technical Paper
Assessment of In-Cylinder Thermal Barrier Coatings over a Full Vehicle Drive Cycle2021-01-045604/06/2021
In-cylinder thermal barrier coatings (TBCs) have the capability to reduce fuel consumption by reducing wall heat transfer and to increase exhaust enthalpy. Low thermal conductivity, low volumetric heat capacity thermal barrier coatings tend to reduce the gas-wall temperature difference, the driving potential for heat transfer from the gas to the combustion chamber surfaces. This paper presents a coupling between an analytical methodology for multi-layer coated wall surface temperature prediction with a fully calibrated production model in a commercial system-level simulation software package (GT-Power). The wall surface temperature at each time step was calculated efficiently by convolving the engine wall response function with the time-varying surface boundary condition, i. e., in-cylinder heat flux and coolant temperature. This tool allows the wall to be treated either as spatially uniform with one set of properties, or with independent head/piston/liner components. Steady state
Koutsakis, George, Miles, Scott, Ghandhi, Jaal
Technical Paper
A Simulation Study to Understand the Efficiency Analysis of Multiple Injectors for the Double Compression Expansion Engine (DCEE) Concept2021-01-044404/06/2021
Heavy-duty vehicles face increasing demands of emission regulations. Reduced carbon-dioxide (CO2) emission targets motivate decreased fuel consumption for fossil fuel engines. Increased engine efficiency contributes to lower fuel consumption and can be achieved by lower heat transfer, friction and exhaust losses. The double compression expansion engine (DCEE) concept achieves higher efficiency, as it utilizes a split-cycle approach to increase the in-cylinder pressure and recover the normally wasted exhaust energy. However, the DCEE concept suffers heat losses from the high-pressure approach. This study utilizes up to three injectors to reduce the wall-gas temperature gradient rendering lower convective heat losses. The injector configuration consists of a standard central injector and two side-injectors placed at the rim of the bowl. An increased distance from side-injector to the wall delivered lower heat losses by centralizing hot gases in the combustion chamber. Computational fluid
Goyal, Harsh, Nyrenstedt, Gustav, Moreno Cabezas, Kevin, Panthi, Niraj, Im, Hong, Andersson, Arne, Johansson, Bengt
Technical Paper
Research on Heat Management Performance of Heat Pipe-Fin Based on Optimal Design2021-01-075204/06/2021
As one of the core components of electric vehicle, the performance of power battery is largely determined by thermal management system. Air cooling is difficult to meet the heat dissipation requirements of high-power power batteries. Liquid cooling arrangement is complex and requires high sealing performance. Phase change materials will increase the mass of battery packs. Heat pipes have good heat conduction, temperature equalization performance and light weight, and it is an ideal cooling and heat dissipation technology with efficient cooling fins. In this paper, a thermal management system of power battery based on heat pipe and fin is proposed. The maximum temperature and wall temperature difference of power battery are reduced by heat pipe and fin heat dissipation. The influence of different fin spacing and heights on the thermal management system is studied, and then the fin spacing and height are optimized. The models of battery heat generation and heat transfer, heat pipe heat
Li, Changxi, Tan, Gangfeng, Ling, Hongwei, Liu, Li, Liu, ZhiQiang, Yang, Zujie
Technical Paper
Sensitivity Study of Battery Thermal Response to Cell Thermophysical Parameters2021-01-075104/06/2021
Lithium-ion batteries (LiBs) have been widely used in electrified vehicles, and the battery thermal management (BTM) system is needed to maintain the temperature that is critical to battery performance, safety, and health. Conventionally, three-dimensional battery thermal models are developed at the early stage to guide the design of the BTM system, in which battery thermophysical parameters (radial thermal conductivity, axial thermal conductivity, and specific heat capacity) are required. However, in most literature, those parameters were estimated with greatly different values (up to one order of magnitude). In this paper, an investigation is carried out to evaluate the magnitude of the influence of those parameters on the battery simulation results. The study will determine if accurate measurements of battery thermophysical parameters are necessary. A unified method based on the understanding of the sensitivity of the key battery thermophysical parameters is proposed to identify the
Sun, Zeyu, Wang, Chongming, Zhou, Quan, Xu, Hongming
Technical Paper
SAE STANDARDS NEWS21AUTP02_0602/01/2021
In late Spring 2020, SAE International released SAE J3178 - Adhesives, Sealants, and Heat Transfer Materials in Battery Systems: A Primer on Materials, Applications, and End-Use Performance Requirements. The 44-page Information Report offers an introduction to the use of adhesives, sealants and heat-transfer materials (HTMs) for battery systems. Adhesives, sealants and HTMs play a pivotal role in the assembly and performance of battery systems for mobility applications. Proper selection of such materials from the cell to the pack level is vital for achieving high-throughput manufacturing and for effectively and safely managing mechanical, environmental and thermal loads in the end product.
Magazine Article
High-Performance, Lightweight, Easy-to-Fabricate Heat ExchangerTBMG-3819412/01/2020
Thermoelectric generator systems require high-performance hot-side and cold-side heat exchangers to provide the temperature differential needed to transfer thermal energy while withstanding temperatures up to 650 °C. Because the hot-side heat exchangers must have a high heat flux, they are often made of metals such as stainless steel or Inconel alloys.
Magazine Article
Aircraft Thermal Heat Conduction MethodTBMG-3819812/01/2020
An aircraft thermal management technology using one-way heat transfer of planar bridging-droplet thermal diodes was developed for use with electronics, aircraft, and spacecraft. Diodes are a special kind of device that allow heat to conduct in only one direction by use of engineered materials. For management of heat, diodes are attractive because they enable the dumping of heat entering one side, while resisting heat on the opposite side. In the case of aircraft, heat is absorbed from an overheated plane but resisted from the outside environment.
Magazine Article
Why Heat Exchanger Manufacturers Need to Rethink Design and FabricationTBMG-3822512/01/2020
Wherever oil, fuel, or electronics are located in a commercial or defense aircraft, spacecraft, or UAV, there’s likely a heat exchanger nearby. Some heat exchangers channel fuel stored in aircraft wings to cool the hot oil that lubricates the power system— as well as preheat the fuel on its way to the engines. Gearboxes produce an excess amount of heat that needs to be dissipated. And the increasing amount of electronics in modern aircraft must be precisely maintained at safe temperatures to function properly.
Magazine Article
Eco-Friendly Brake-Pads Using Ferritic Stainless-Steel Particles of Varying Sizes: Influence on Performance Properties2020-01-160210/05/2020
Metallic particles in brake-friction materials (FMs) play a vital role in improving mainly strength, friction level, thermal conductivity and hence resistance to fade during braking operations. Although Copper was the most efficient and popular metallic ingredient in FMs, it is being phased out because of its proven threat to the aquatic life in the form of wear debris. Hardly any successful efforts are reported in open literature barring few on in the authors’ laboratory. It is well-known that the size and shape of particles affect the performance of composites apart from their type, concentration, etc. In this paper, Ferritic stainless steel (SS 434) particles were selected as a theme ingredient in two forms, first particulate (SSP) with two sizes, larger (30-45 micron) and smaller (10-20 micron) and also in the form of swarf. The aim was to investigate the size and shape effect of these ingredients when used to manufacture the brake-pads on the performance properties. A series of
Kalel, Navnath, Bhatt, Bhaskar, Darpe, Ashish, Bijwe, Jayashree
Technical Paper
Transient Heat Transfer Simulation and Buckling Analysis of Disc Brakes in In-Wheel Motor-Driven Vehicles2020-01-161810/05/2020
High-temperature distributions in disc brake mounted within in-wheel motor-driven vehicles have several negative effects on braking performance. This is mainly due to the enclosed nature of the brake components. This paper aims to determine the effect of contact geometry on temperature distribution and thermal buckling in such a brake. Numerical analysis is conducted to investigate the variation of temperature field on the brake disc at different cover angles of pads while maintaining the same moment of friction. The effect of different radial positions of the pads is a second consideration in the current work, using a transient modeling approach. To validate the simulation results, an approximate, analytical solution is derived according to energy conservation. The results show that, for the same work done by the pads, the maximum temperature on the disc increases with a decrease in the pad cover angle. Also, the pad positions were found to affect temperature distribution
Koranteng, Kingsford, Shaahu, Joseph-shaahu, Yi, Yun-Bo
Technical Paper
Controlling the Performance of Copper-Free Brake-Pads by Varying Size of Graphite Particles2020-01-160410/05/2020
Graphite plays a crucial role in friction materials, since it has good thermal conductivity, lubricity and act as a friction modifier. The right type, amount, shape, and size of the particles control the performance of the brake-pads. The theme of the study was investigating the influence of size of graphite particles (having all other specifications identical) on performance properties of brake-pads containing graphite particles in the average size of 60 μm, 120 μm, 200 μm and 400 μm. Physical, mechanical and chemical characterization of the developed brake-pads was done. The tribological performance was studied using a full- scale inertia brake dynamometer following a Japanese automobile testing standard (JASO C406). Tribo-performance in terms of fade resistance, friction stability and wear resistance were observed best for smaller graphite particles. It was concluded that smaller size serves best for achieving best performance properties barring compressibility.
Singh, Sandeep, Kalel, Navnath, Darpe, Ashish, Gilardi, Raffaele, Bijwe, Jayashree
Technical Paper
Toward Predictive Combustion Modeling of CNG SI Engines in 1D Simulation Tools2020-01-207909/15/2020
In the recent years, the interest in heavy-duty engines fueled with Compressed Natural Gas (CNG) is increasing due to the necessity to comply with the stringent CO2 limitation imposed by national and international regulations. Indeed, the reduced number of carbon atoms of the NG molecule allows to reduce the CO2 emissions compared to a conventional fuel. The possibility to produce synthetic methane from renewable energy sources, or bio-methane from agricultural biomass and/or animal waste, contributes to support the switch from conventional fuel to CNG. To drive the engine development and reduce the time-to-market, the employment of numerical analysis is mandatory. This requires a continuous improvement of the simulation models toward real predictive analyses able to reduce the experimental R&D efforts. In this framework, 1D numerical codes are fundamental tools for system design, energy management optimization, and so on. The present work is focused on the improvement of the
Riccardi, Marco, Tufano, Daniela, Beatrice, Carlo, Bozza, Fabio, De Bellis, Vincenzo, Napolitano, Pierpaolo
Technical Paper
Design and Analysis of Modified Radiator Fins to Improve Overall Cooling Efficiency2020-01-202909/15/2020
Internal Combustion engines have been a significant component of the industrial development in the 20th and 21st centuries. However, the high working temperatures cause extensive wear and tear among the parts and results in a loss in fuel efficiency and ultimately seize the engine. To prevent this, there was a need for a cooling system. The current systems cool the vehicle's engine by transferring heat from the engine to the coolant/water in the water jacket from where it reaches the radiator via tubes, and the hot temperature coolant is cooled. This article proposes a change in the design of radiator fins to improve the overall cooling efficiency of such systems. As radiator fins are instrumental in the heat transfer process, a design change in them results in substantial changes in the output efficiency results. The central concept that is utilized is to increase the surface area of the fins, which would increase the rate of heat loss from the pipes. This increase in surface area of
Mittal, Ankit, Misra, Ashwin, Sharma, Ayush, Gupta, Animesh, Ansari, Naushad
Technical Paper
Infrared Diagnostics of a Li-Polymer Battery for the Estimation of the Surface Temperature Distribution and the Heat Transfer Parameters2020-01-202609/15/2020
A growing number of electric vehicles (EV) and hybrid electric vehicles (HEV) in the present market depicts the rapid growing demand for energy storage systems. The battery’s main peculiarities must be the power density and reliability over time. The temperature strongly affects battery performance for low and high intensity. In particular, the management of the heat generated by the battery itself is one of the main aspects to handle to preserve the performance over time. The objective of this paper is to compare the surface temperature of the lithium-ion polymer battery at different discharging rates by infrared thermography. Thermal imaging is performed to detect the battery surface temperature distribution, focusing on its variation over time and the local inhomogeneity. Temperature measurements are then used to estimate the contributions of the different heat transfer mechanisms for the dissipation of the heat generated by the battery. A reverse-logic approach is used to derive
Sequino, Luigi, Vaglieco, Bianca Maria
Technical Paper
Items per page:
1 – 50 of 1611