Browse Topic: Thermal management

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Advanced Signal Domain Techniques for Real-Time Control and Prognostics in VTOL SystemsSM-2026-VLADA-52051/27/2026
Vertical Take-Off and Landing (VTOL) aircraft introduce complex monitoring challenges due to distributed propulsion, lightweight structures, and variable operating conditions. This paper presents advanced Frequency and Orders domain techniques that repurpose existing flight control, propulsion, and structural sensor data to enhance observability without additional instrumentation. By transforming vibration, acoustic, and electrical signals into frequency and order domains, the approach enables detection of harmonics, resonance, and fault signatures tied to rotor dynamics, supporting adaptive control and predictive maintenance. Beyond rotor systems, these techniques are equally effective for monitoring electric motor health, gearbox wear, bearing degradation, and structural coupling effects in composite airframes. They also provide insight into power electronics and thermal management systems by identifying spectral anomalies linked to electrical imbalance or cooling inefficiencies. Aggregated fleet data strengthens prognostic capabilities, enabling early detection of systemic issues and trend analysis. Applications include mitigating ground resonance and modal instabilities, as well as improving reliability of propulsion and structural subsystems. Integration into avionics emphasizes computational efficiency, scalability, and compliance with standards such as DO-160 [1], DO-178 [2], ARP4761 [3] and ARP4764 [4]. Simulation and bench testing confirm feasibility, demonstrating potential to enhance safety, reliability, and lifecycle cost for next-generation urban air mobility platforms.
LaRue, David
Future Vertical Lift Digital Backbone, Navigating Technology and Implementation DetailsF-0076-2020-1643110/5/2020
The current US DoD has recognized that their asymmetric advantage is eroding1. Adversaries have had over 25 years to counter the US playbook and weapon systems (Ref. [1]). The US Army Future Vertical Lift (FVL) programs have identified several key tenets that their airborne weapon systems need to ensure they maintain asymmetric advantage. (1) New and upgraded mission capabilities of their airborne platforms need to get to the field faster (Ref. [2]). One of the current roadblocks to achieving this is the extensive full-system regression testing that ends up being required when there are mission system changes (Ref. [3]). (2) More competition is needed to help generate "quicker, better, faster" capabilities (Ref. [4]). "Vendor lock" inherent in current system designs hinders the speed at which technology advances (Ref. [4, 5]). (3) Improved portability of mission capability across the FVL and enduring fleet (Ref. [6, 7]). The ability to more easily reuse technology will help maintain advantage by eliminating the time needed to develop platform specific solutions (Ref. [4, 6]). The request for Modular Open System Architecture (MOSA) solutions has been a practice to try to address the items above (Ref. [8]). Most air vehicle and mission system providers are today providing MOSA solutions but the required benefits have not yet been fully realized. MOSA standards as they exist today do a very good job of identifying electronics hardware and software architectures. However, they fall short on physical aircraft integration and consistency in architecture among aircraft systems. Minimizing aircraft wiring and structural modifications, increasing speed to fielding, and portability among multiple systems types are all part of integrating highly MOSA compliant solutions. The US Army FVL programs have required a "digital backbone" (Ref. [7, 9, 10]) to address these integration issues and ensure that they can maintain asymmetric advantage. Unique requirements affecting the digital backbone include: - Power and power distribution (Ref. [9]) - Thermal management (Ref. [9, 11]) - Packaging and installation (Ref. [9]) - Air Vehicle data distribution (Ref. [9]) - Mission System data distribution (Ref. [9]) - Isolation of air vehicle and mission system (Ref. [9]) This paper will provide an introduction to the envisioned digital backbone for US Army, Future Vertical Lift aircraft. The paper will also offer discussion of digital backbone impacts on aircraft and avionics size, weight, power and cost, as well as technology considerations to address interoperability, safety, security, qualification, and accommodations for new, as well as, legacy avionics technology.
G., Harold, Sletteland, Branden, Taylor, Max
More / All Electric Vertical Take-Off and Landing (VTOL) Vehicle Sensitivities to Propulsion and Power PerformanceF-0076-2020-1644710/5/2020
Battery power and energy density are important parameters for emerging concepts for more / all-electric vehicles. Electric propulsion and power system performance is also important. To better understand how electric propulsion and power systems component performance influences overall vehicle design, a sensitivity assessment was performed noting changes in vehicle gross weight and energy usage. Updated versions of the Revolutionary Vertical lift Technology (RVLT) Project vertical takeoff and landing (VTOL) urban air mobility (UAM) reference vehicles and missions were used. NASA electric vehicle studies are discussed which were used to help select the range of electric propulsion and power system performance parameters used in this assessment. Thermal management systems (TMS) considerations are also important; new and innovative power management and distribution (PMAD) systems can reduce electric system weight and losses, reducing thermal management constraints often imposed by electric systems modest maximum use temperatures. Vehicles with higher disk loadings require higher power levels per unit weight for VTOL operations, which make them more sensitive to electric system weights and efficiencies. Battery, all-electric vehicles show different sensitivities to component performance than turboelectric or hybrids systems. Battery, all-electric propulsion systems may increase vehicle weight and size, but still results in lower mission energy usage than their hydrocarbon-fueled versions. Significant vehicle weight growth to electric propulsion and power system power-to-weight reductions also occurs at different levels among the various concepts. From these results, one can more readily identify required component performance levels, potential component choices, or research and development paths.
Snyder, Christopher
A Calculation Methodology for Predicting Exhaust Mass Flows and Exhaust Temperature Profiles for Heavy-Duty Vehicles02-13-02-00097/20/2020
The predictive control of commercial vehicle energy management systems, such as vehicle thermal management or waste heat recovery (WHR) systems, are discussed on the basis of information sources from the field of environment recognition and in combination with the determination of the vehicle system condition. In this article, a mathematical method for predicting the exhaust gas mass flow and the exhaust gas temperature is presented based on driving data of a heavy-duty vehicle. The prediction refers to the conditions of the exhaust gas at the inlet of the exhaust gas recirculation (EGR) cooler and at the outlet of the exhaust gas aftertreatment system (EAT). The heavy-duty vehicle was operated on the motorway to investigate the characteristic operational profile. In addition to the use of road gradient profile data, an evaluation of the continuously recorded distance signal, which represents the distance between the test vehicle and the road user ahead, is included in the prediction model. Using a Fourier analysis, the trajectory of the vehicle speed is determined for a defined prediction horizon. To verify the method, a holistic simulation model consisting of several hierarchically structured submodels has been developed. A map-based submodel of a combustion engine is used to determine the EGR and EAT exhaust gas mass flows and exhaust gas temperature profiles. All simulation results are validated on the basis of the recorded vehicle and environmental data. Deviations from the predicted values are analyzed and discussed.
Kreyer, Jörg, Müller, Marvin, Esch, Thomas
Vehicle Design Considerations Enabling High-Performance Charging2020-01-14404/14/2020
Customer requirements such as range anxiety and charging time are the driver for increasing the charging power of battery-electric vehicles (BEV). High-performance charging (HPC) theoretically enables time targets of faster than 30 kilometers (19 miles) recharging per minute. Due to physical limitations (i.e., current limits of the components) a charging power of more than 200 kilowatt arises the question of the voltage level required to fulfill the power demand. One possible approach to achieve a high charging power is increasing the battery voltage, i.e., increase the voltage level from 400 V to 800 V. This publication discusses the main aspects of charging by incorporating all high-voltage components in the vehicle. An increase of the voltage level and charging power affect all high-voltage components. The thermal management of the battery has to be considered. High-voltage vehicle architecture design considerations are discussed including thermal-management and battery-design aspects. Different charging characteristics from electric vehicles (EVs) available, are compared with an estimated fast charging profile which is based on theoretical background of available cells including consideration of physical and chemical limits (e.g., thermal-limits, cell-degradation). Additionally, higher-performance charging (HPC) also require consideration of the public charging infrastructure. Extending the technical point of view with customer values, the charging efficiency is considered including the infrastructure. Furthermore, customer acceptance and market forecasts are considered. Higher voltage levels enable higher power also for other components in the vehicle, such as the electric drives, high-voltage heaters, compressors and voltage converters. To determine the optimum voltage level, for a reference vehicle used in this paper, all those considerations are compared in the discussion. Focusing on the early development phase of a complete vehicle, criteria for conceptual design considerations are discussed incorporating the high-voltage vehicle architecture and the battery from the thermal point of view.
Paar, Christian Josef, Waser, Helmut Martin, Kreimaier, Heimo, Cuenca-Jaen, Inés, Eibler, Florian
Simulation of Aftertreatment Thermal Management Strategies for Low-Load Operation2020-01-03594/14/2020
The low-NOx regulation for heavy duty trucks proposed by California’s Air Resources Board (CARB) will present a significant challenge to truck, engine and aftertreatment system manufacturers. This regulation will include a new test cycle representative of low-load operation. With low-load cycles, NOx conversion by the SCR (selective catalytic reduction) system is limited primarily by the exhaust temperature; thus, thermal management will dominate development. Simulation can be used to examine different thermal management strategies, and to define high-level requirements for new components. In this study, modeling was used to investigate SCR performance on two different low-load cycles, including the one selected by CARB for the low-NOx regulation. First, the “thermal deficit” of the cycle was quantified using a constant heat input. Next, direct heating of the exhaust with a fuel mini-burner or an electric heater, using realistic controls, was simulated to determine their capability to overcome the thermal deficit. For comparison, the performance of a dual-injection SCR system on these cycles was also modeled.
Harris, Thomas
Effect of Stator Surface Area on Braking Torque and Wall Heat Dissipation of Magnetorheological Fluid Retarder2020-01-09374/14/2020
Magnetorheological fluid (MRF) is used as the transmission medium of the hydraulic retarder. The rheological properties are regulated by changing the magnetic field to achieve accurate control of the retarder's braking torque. Under the action of the external magnetic field, the flow structure and performance of the MRF retarder will be changed in a short time. The apparent viscosity coefficient increases by several orders of magnitude, the fluidity deteriorates and the heat generated by the brake cannot be transferred through the liquid circulation, which will affect the braking torque of the retarder. Changing the surface area of the stator also has an influence on the braking torque of the retarder and the wall heat dissipation. In this study, the relationship between the braking torque of the MRF retarder and the stator surface area of the retarder was analyzed. In addition, phase change materials were used to directly dissipate heat on the retarder surface to improve the heat dissipation rate of retarder and improve the stability of the retarder's braking torque. In order to study the effect of stator radius on braking torque of MRF retarder under an external magnetic field, a braking torque model was established based on MRF with Bingham model properties, and a heat transfer model of wall phase change material was established to analyze the relationship between heat transfer and braking torque of MRF retarder. The results show that the braking torque of the MRF retarder increases rapidly with the increase of the radius outside the effective working area of MRF, which increases faster at high speed and increases the stator wall surface heat dissipation, but the rate of heat dissipation increases relatively slowly. The wall surface with a heat pipe can take away the heat generated by the retarder and cool the retarder. Under the appropriate stator surface conditions, phase change materials are used on the wall surface of the retarder to dissipate heat, which improves the stability of the braking torque of the retarder and promotes the development of MRF retarder to high power.
Liu, ZhiQiang, Tan, Gangfeng, Tian, Zhongpeng, Zhou, Mi, Agyeman, Philip, Frimpong, Justice
A MATLAB Simulink Based Co-Simulation Approach for a Vehicle Systems Model Integration Architecture2020-01-00053/10/2020
In this paper, a MATLAB-Simulink based general co-simulation approach is presented which supports multi-resolution simulation of distributed models in an integrated architecture. This approach was applied to simulating aircraft thermal performance in our Vehicle Systems Model Integration (VSMI) framework. A representative advanced aircraft thermal management system consisting of an engine, engine fuel thermal management system, aircraft fuel thermal management system and a power and thermal management system was used to evaluate the advantages and tradeoffs in using a co-simulation approach to system integration modeling. For a system constituting of multiple interacting sub-systems, an integrated model architecture can rapidly, and cost effectively address technology insertions and system evaluations. Utilizing standalone sub-system models with table-based boundary conditions often fails to effectively capture dynamic subsystem interactions that occurs in an integrated system. Additionally, any control adjustments, model changes or technology insertions that are applied to any one of the connecting subsystems requires iterative updates to the boundary conditions. When evaluating a large set of trade studies, the number of boundary condition models and time to generate these models becomes intractable and affects capturing the results accurately. A single interconnected model of all the subsystems may be impractical and using additional external packages may be prohibitive in terms of cost or compatibility. This general approach requires no additional MATLAB toolboxes. Two different data interchange mechanisms are presented. A dynamic vehicle system integrated model was developed to enable customizability and flexibility. The developed co-simulation approach was combined with this flexible architecture to enable system evaluation. Example applications using the vehicle system model integrated architecture with the co-simulation approach are discussed.
Raczkowski, Brian C., Jones, Nicholas, Deppen, Tim, Lucas, Charles, Yeu, Rodney, Walters, Eric, Donovan, Adam, Patnaik, Soumya, Bodie, Mark
Low-Inductance DC Power BusTBMG-361603/1/2020
Anew generation of power electronic conversion systems is being enabled by wide-bandgap (WBG) devices. Applications in civilian and defense sectors are already realizing improved power density and efficiency in power converters that utilize silicon carbide (SiC) and/or gallium nitride (GaN) switches; however, as semiconductor switches become capable of greater hold-off voltage, higher switching frequency, and higher junction temperature, limits on converter performance will depend on the remainder of the system: device packaging, filter components, and thermal management, as examples.
Layered Composite InsulationTBMG-361633/1/2020
NASA's Layered Composite Insulation (LCI) technology is an easy-to-use system that can benefit multiple industries that depend on regulation of low temperatures in equipment and products. The technology combines a unique layered cryogenic insulation system with specific manufacturing, packaging, wrapping, and rolling methods.
RAD-HARD Microelectronics for Space ApplicationsTBMG-360712/1/2020
For orbiting satellites, design requirements are extensive as a result of the extreme environment in space, including wide-ranging and rapidly changing temperatures, satellite body charging effects and high-energy particle bombardment and radiation. These dynamics drive the need for high-reliability engineering concepts for all system components. In the case of microelectronics, this takes a unique form and drives innovation for techniques to overcome these damaging effects.
Safer Helmets Reduce Potential for Traumatic InjuryTBMG-360072/1/2020
“Seventy-five percent of all fatal motorcycle accidents globally involve brain injury, with rotational forces acting on the brain being the primary cause of death,” According to NHTSA. By implementing a novel helmet design and materials set, KIRSH Helmets is to working to develop a more effective helmet for motorcycle riders, as well as in other applications. A patented design, in which fluid displacement technology replaces the typically used foam compression, utilizes a silicone liner injected with fluid. The resulting structure reduces rotational and angular forces during acceleration impacts.
Outsourcing Plasma Treatments for Surface ModificationTBMG-360642/1/2020
In manufacturing, plasma treatments are often utilized to solve problems that cannot be resolved other ways. Whether attempting to improve adhesion of dissimilar materials; depositing coatings; cleaning surfaces; applying a protective coating that repels water, for example, or biological fluids; or enhancing surface wettability or functional coating, plasma treatments often add significant value to products.
Q&A: A Shape-Morphing, Self-Healing Soft CompositeTBMG-357881/1/2020
Carmel Majidi, Professor of Mechanical Engineering at Carnegie Mellon University, and his team has developed a material with a unique combination of high electrical and thermal conductivity, with actuation and self-repair capabilities that are unlike any other soft composite.
CubeSat Form Factor Thermal Control LouversTBMG-358261/1/2020
Thermal control of small spacecraft, including CubeSats, is a challenge for the next era of NASA spaceflight. Science objectives and components will still require strict thermal control while smaller volumes will inherently absorb and shed heat more quickly than a larger body. Thus, game-changing technologies must be developed to stabilize the thermal environment inside of small spacecraft.
Hardening Lightweight Metal Foams with NanocoatingTBMG-358181/1/2020
Bones are strong and stable and can cope with loads almost as well as steel. But despite their strength, they are light enough to be easily moved by humans and animals. The secret lies in the combination of a hard, exterior shell that encases a porous lattice-like network of bone tissue in the interior of the bone. This structure saves on material and reduces weight.
Embedded Gas and Temperature Sensors for Extreme EnvironmentsTBMG-358291/1/2020
Innovative process control systems for improved efficiency and lower emissions in current and future fossil-fuel-based power systems and related applications require durable, embedded sensor technology that can operate at higher temperatures and in harsh conditions.
Understanding Base Oils and Lubricants for Electric Drivetrain Applications2019-01-233712/19/2019
ABSTRACT The penetration of hybridization and electrification (HEV and EV) technology into automotive powertrain designs is an evolving trend resulting from global regulations intended to reduce transportation-related emissions of greenhouse gases and other pollutants and to improve vehicle fuel efficiency. In many HEV and EV hardware designs, drivetrain fluids have contact with the integrated electric motor (e-motor), which requires electrical and thermal properties to be considered in addition to traditional fluid properties. This paper discusses new insights gained around electrical and thermal properties of drivetrain fluids, with a specific emphasis on understanding the critical impacts of base oils (BOs). Electrical and thermal properties data as a function of temperature for a range of BOs as well as automatic transmission fluids are shared. We found that BOs and their viscosities play a critical role in cooling performance, while additives play a critical role in electrical conductivity (EC). That being said, we also have observed that additives in BOs can modify cooling performance. We will demonstrate how each component in the additive package affects EC and in some cases cooling performance. The successful utilization of this knowledge is demonstrated on a proof-of-principle basis to show that fluids with appropriate electrical and thermal properties can be designed to meet critical factors for electrification such as cooling capacity and EC, while still maintaining essential performance features for conventional driveline fluids.
Kwak, Yungwan, Cleveland, Christopher, Adhvaryu, Atanu, Fang, Xinggao, Hurley, Susie, Adachi, Tsuneo
Reducing winter range loss for electric trucks19TOFHP12_0212/1/2019
Researchers at the Austrian Institute of Technology have developed an air exchange system that's capable of reducing heat load by 37% in real-world tests. Battery-electric vehicle (BEV) range loss from winter use of PTC (positive temperature coefficient) heating has become a source of major concern as the industry works to make EVs a mainstream choice. Addressing this particular problem area with an economically viable solution was deemed a worthwhile effort by the Austrian Institute of Technology (AIT), which is jointly owned by the Austrian government and the Federation of Austrian Industries. A fleet test of electric delivery trucks is underway on European roads. The AIT project, results of which were presented at the recent SAE Thermal Management Systems Symposium (TMSS), began by noting a 20% loss in range at −15°C (+5°F) from the heating system. AIT set a target of recovering 25% of that loss, primarily with the use of a ventilation module. Available reference data (at −10°C/+14°F) showed approximately 75% of the cabin heat losses are from ventilation, AIT said, with the remaining 25% from heated air transmission through the interior.
Weissler, Paul
Heat-Regulating Material for Next-Generation Space BlanketTBMG-3572012/1/2019
Drawing design inspiration from the skin of squid, researchers developed an adaptive space blanket that gives users the ability to control their temperature. The drawback to current Mylar heat-regulating blankets is static. The new material has changeable properties to regulate how much heat is trapped or released.
Q&A: Refrigeration by Twisting FibersTBMG-3571312/1/2019
Dr. Ray Baughman, Director of the Alan G. MacDiarmid Nano Tech Institute at the University of Texas, Dallas, and his team discovered a new technology for refrigeration that is based on twisting and untwisting fibers.
Metallization for SiC SemiconductorsTBMG-3570412/1/2019
Scientists at NASA’s Glenn Research Center have developed and patented improved ohmic contacts, and a fabrication method for them, that will speed the production of silicon carbide (SiC) sensors and electronics that operate in high-temperature, harsh environments.
Products of Tomorrow: December 2019TBMG-3570712/1/2019
This column presents technologies that have applications in commercial areas, possibly creating the products of tomorrow. To learn more about each technology, see the contact information provided for that innovation.
Transport Method Boosts Capacity of Heat ExchangersTBMG-3572312/1/2019
Turbulent heat exchange is a method of heat transport widely used in heating, ventilation, and air conditioning (HVAC) systems. Adding a readily available organic solvent to common water-based turbulent heat exchange systems can boost their capacity to move heat by 500%. Other methods for increasing heat flux — nanoparticle additives or other techniques — have achieved about 50% improvement.
Durable Polyimide AerogelsTBMG-3572712/1/2019
Innovators at NASA's Glenn Research Center have developed polyimide aerogel technologies that are 500 times stronger than traditional silica aerogels. These durable polyimide aerogels are highly flexible and foldable in contrast to traditional silica aerogels, which shed dust particles and are notoriously fragile and brittle. Polyimide aerogels possess remarkable strength, flexibility, and moisture resistance and make excellent “wrappable” insulators. No other aerogel possesses the compressive and tensile strength of this organic polyimide aerogel while still retaining its ability to be flexibly folded to contour to whatever shape is needed such as automotive shields, pipeline insulation, and protective clothing.
The 6 Most Important Parts of a Temperature Monitoring SystemTBMG-3546211/1/2019
In the past few years, it has become increasingly common for hospitals, clinics, healthcare and life science organizations, and other businesses to use an electronic temperature monitoring system to safeguard their products and satisfy regulatory demands. You may know that you need a monitoring system, possibly with alarming capabilities, but aren't sure how to select the best one to meet your needs. To complicate matters, there are literally dozens of different types of temperature monitoring systems with different features and a wide range of prices.
CFD Simulation on Turbulent Forced Convection of Copper Oxide (CuO) -Water Nanofluids in a Horizontal Circular Pipe2019-28-013110/11/2019
The present study provides a detailed investigation on simulation of Copper oxide nanofluids in a simple horizontal circular pipe considering turbulent forced convection, with a constant heat flux boundary condition. The simulation is carried out using three different models available in fluent viz. Newtonian single phase model, Eulerian-mixture and Eulerian-Eulerian multiphase models. The Reynold number of the flow is varied along with volume concentration of nanoparticles varying form low to high. Nanofluids rheology is studied by considering standard k-ε two equation turbulence model with enhanced wall treatment considering appropriate wall y+ values. The effective temperature dependent thermo-physical properties for nanofluids were seized from the literatures. The results from the simulation clearly showed an increase in the heat transfer characteristics with the addition of nanoparticles compared to that of base fluid alone. Eulerian-Mixture model predicted the Nusselt number near to that of the experimental results from literature.
Dewangan, Nitin, Kattula, Nitin
Atomically Thin Heat Shield Protects Electronic DevicesTBMG-3526610/1/2019
Excess heat given off by smartphones, laptops, and other electronic devices contributes to malfunctions and, in extreme cases, can even cause lithium batteries to explode. To guard against issues, engineers often insert glass, plastic, or layers of air as insulation to prevent heat-generating components like microprocessors from causing damage.
Acceleration Resistant HiK Heat Spreader19AERP09_049/1/2019
As electronic technologies advance in defense and aerospace applications, heat fluxes are becoming larger and more centralized[1,2]. In order to meet the performance specifications of new technologies, thermal solutions must also advance. The push for more capable thermal technologies is evident with the U.S. Air Force Research Laboratory (AFRL) signing an agreement with private companies and contractors for the development of innovative vapor cooling technologies capable of handling high heat fluxes[2]. Basic aluminum spreaders are no longer a viable means of spreading the heat as increased heat fluxes result in large thermal gradients across aluminum alone. Embedding heat pipes, a passive two-phase thermal solution, into an aluminum or copper spreader could distribute the heat flux to areas where it could be easily removed without a large thermal gradient. This technology is referred to as a HiK™ plate.
Low-Cost Thermoelectric Material Works at Room TemperatureTBMG-351259/1/2019
The widespread adoption of thermoelectric devices that can directly convert electricity into thermal energy for cooling and heating has been hindered, in part, by the lack of materials that are both inexpensive and highly efficient at room temperature. A new material was developed that works efficiently at room temperature while requiring almost no costly tellurium, a major component of the current state-of-the-art material. Future work could close the slight performance gap between the new material and the traditional material, a bismuth-tellurium-based alloy.
Robot “Eye” Provides 360° Field of ViewTBMG-351599/1/2019
The production of precision products depends on robot control systems knowing the location of the adhesive bonding head or welding head to the nearest millimeter at all times. This means the robot needs some sort of eye. Specialized sensors can perform this function, most of which operate on the principle of laser triangulation. A laser diode projects a line of red light onto the workpiece, from which the light is reflected at a specific angle before being detected by a camera. From the position of the light striking the camera chip, the position and distance of the sensor with respect to the workpiece within the coordinate system can be calculated.
Acceleration Resistant HiK Heat SpreaderTBMG-351139/1/2019
As electronic technologies advance in defense and aerospace applications, heat fluxes are becoming larger and more centralized[1,2]. In order to meet the performance specifications of new technologies, thermal solutions must also advance. The push for more capable thermal technologies is evident with the U.S. Air Force Research Laboratory (AFRL) signing an agreement with private companies and contractors for the development of innovative vapor cooling technologies capable of handling high heat fluxes[2].
Material for Faster Computer MemoryTBMG-351529/1/2019
Scientists are studying bismuth ferrite (BFO) material that has the potential to store information much more efficiently than is currently possible. BFO could also be used in sensors, transducers, and other electronics.
5 Ws of the Wearable Cooling and Heating PatchTBMG-349228/1/2019
The patch — which serves as a personal thermostat — provides personalized cooling and heating at home, work, or on the go by cooling or warming the user's skin to a comfortable temperature and keeping it there as the ambient temperature changes.
Products of Tomorrow: August 2019TBMG-348868/1/2019
This column presents technologies that have applications in commercial areas, possibly creating the products of tomorrow. To learn more about each technology, see the contact information provided for that innovation.
Textile Cools or Insulates AutomaticallyTBMG-349158/1/2019
Researchers have created a fabric that automatically regulates the amount of heat that passes through, depending on conditions; for example, when conditions are warm and moist — such as those of a sweating body on a summer day — the fabric allows infrared radiation (radiant heat) to pass through. When conditions become cooler and drier, the fabric reduces the heat that escapes. Infrared radiation is a primary way the body releases heat and is the focus of this new technology.
Products of Tomorrow: July 2019TBMG-347577/1/2019
This column presents technologies that have applications in commercial areas, possibly creating the products of tomorrow. To learn more about each technology, see the contact information provided for that innovation.
A Study on NVH Performance Improvement of TPE Air Intake Hose Based on Optimization of Design and Material2019-01-14916/5/2019
Environmental and fuel economy regulations (Eu 6d and WLTP RDE) on automobiles have been tightened recently. To counter this regulation, the global automobile industry is focusing on weight reduction, fuel efficient turbo charger, cooled EGR, thermal management, low friction and so on. However, the high-speed turbocharger makes turbulence, and resulting in airflow noise. This noise is transmitted indoor through the air intake system, which adversely affects the vehicle's competitiveness. Therefore, for turbo engine, it is essential to reduce the noise of the air intake system. The air intake system consists of air cleaner, air filter, air intake hose and air duct. The air flow noise of turbo-engine is mainly the emission noise emitted from the walls of air intake system. And the transfer path of turbo noise is in order of air intake hose, air cleaner and air duct. Therefore, it is effective to reduce the noise of the air intake hose located at the beginning of noise transfer path. In the past, rubber hoses with vibration and acoustic insulation were mainly used to reduce the emission noise of air intake hose, but these can’t be recyclable and have high density (heavy). To overcome these shortcomings, TPE hoses are being applied, which are lighter, more competitive, durable and recyclable than rubber hoses. However, the air intake hoses with thin bellows and rigid TPE material have less noise attenuation performance than rubber hoses, so need to be improved noise insulation performance. This paper describes how to improve the NVH performance by optimizing the bellows design of air intake hose related to mass (m) and stiffness (k) and developing high damping material (c).
Jung, Hyunsoo, Jin, Jungkook, Park, Jong Min, Jin, Yong Sun (Steven), Han, Won Hee, Kim, Younghae, Gu, Yu
Running an LED in Reverse Could Cool Future ComputersTBMG-346356/1/2019
Researchers devised a method in which running a light emitting diode (LED) with electrodes reversed was able to cool another device nanometers away. They harnessed the chemical potential of thermal radiation — a concept more commonly used to explain how a battery works.
SAE Truck & Off-Highway Engineering: June 201919TOFHP066/1/2019
Bullish on biomethane The CEO of CNH Industrial says biomethane is cleaner path than electric, as Case demos the alt fuel in cool wheel-loader concept. Unique hybrids required Power systems expert at Perkins stresses that on-highway electric solutions cannot be directly applied to the more-rugged and varied applications in off-highway. Getting driverless trucks onto roadways Autonomous developers at TuSimple address many technical issues, but they also must consider regulations and operating modes. Stronger, quieter cabs Worthington expert sees AHSS and active noise cancellation making off-highway cabs safer and less-stressful places to work. Hydrogen boom! Nikola reveals Two and Tre fuel-cell trucks and its H2 fueling roadmap, as well as battery-electric military and powersports vehicles. Rearview cameras come into sight Momentum is building behind replacing mirrors with camera monitor systems as the technology edges closer to regulatory approval. Supplier Directory Complete listing of industry suppliers categorized by technology area. Editorial Diesel's doing just fine, thank you. Achieving better power management by optimizing thermal management Security, bandwidth drive over-the-air development SAE launches Office of Automation Cleaner Trucks Initiative starts NOx-reduction journey JCB adds three new X Series crawler excavators Toyota's proven fuel-cell stack reduces cost, complexity in H2 semi-truck Q&A Volvo CE's Calle Skillsäter talks about trialing 5G connectivity in construction
Ultrasensitive Heat Sensor for Wound Healing and Electronic SkinTBMG-344375/1/2019
Linköping University Linköping, Sweden
Development of a Correlation for Predicting Condensation Heat Transfer Coefficients for Refrigerant HFO-1234yf2019-01-01504/2/2019
Author has developed a correlation to predict condensation heat transfer coefficients for refrigerant condensation in an automotive parallel flow condenser. This is a first correlation in the open literature for HFO-1234yf to predict heat transfer coefficients for an automotive condenser. The system refrigerant mass flowrate was varied from 180 to 475 kg/hr; inlet refrigerant qualities from 1 to exit qualities of 0. The tests were conducted at an average condenser saturation temperature of 50°C and the oil circulation ratio was maintained at 3%.
Mathur, Gursaran D.
Investigation of Drag Reduction Technologies for Light-Duty Vehicles Using Surface, Wake and Underbody Pressure Measurements to Complement Aerodynamic Drag Measurements2019-01-06444/2/2019
A multi-year, multi-vehicle study was conducted to quantify the aerodynamic drag changes associated with drag reduction technologies for light-duty vehicles. Various technologies were evaluated through full-scale testing in a large low-blockage closed-circuit wind tunnel equipped with a rolling road, wheel rollers, boundary-layer suction and a system to generate road-representative turbulent winds. The technologies investigated include active grille shutters, production and custom underbody treatments, air dams, wheel curtains, ride height control, side mirror removal and combinations of these. This paper focuses on mean surface-, wake-, and underbody-pressure measurements and their relation to aerodynamic drag. Surface pressures were measured at strategic locations on four sedans and two crossover SUVs. Wake total pressures were mapped using a rake of Pitot probes in two cross-flow planes at up to 0.4 vehicle lengths downstream of the same six vehicles in addition to a minivan and a pick-up truck. A smaller rake was used to map underbody total pressures in one cross-flow plane downstream of the rear axle for three of these vehicles. The results link drag reduction due to various technologies with specific changes in vehicle surface, rear underbody and wake pressures, and provide a database for numerical studies. In particular, the results suggest that existing or idealized prototype technologies such as active grille shutters, sealing the external grille and ride height control reduce drag by redirecting incoming flow from the engine bay or underbody region to smoother surfaces above and around the vehicle. This mechanism can enhance the reduction in wheel drag due to reduced wheel exposure at lowered ride height. Sealing the external grille was found to redirect the flow more efficiently than closing the grille shutters, and resulted in greater drag reduction. Underbody treatments were also found in some cases to redistribute the flow around the vehicle to reduce pressure drag in addition to underbody friction drag. The magnitude and spatial extent of the measured pressure changes due to the various technologies were often consistent with the amount of drag reduction.
de Souza, Fenella, Raeesi, Arash, Belzile, Marc, Caffrey, Cheryl, Schmitt, Andreas
Optimization of a Diesel Engine with Variable Exhaust Valve Phasing for Fast SCR System Warm-Up2019-01-05844/2/2019
Early exhaust valve opening (eEVO) increases the exhaust gas temperature by faster termination of the power stroke and is considered as a potential warm up strategy for diesel engines aftertreatment thermal management. In this study, first, it is shown that when eEVO is applied, the engine main variables such as the boost pressure, exhaust gas recirculation (EGR) and injection (timing and quantity) must be re-calibrated to develop the required torque, avoid exceeding the exhaust temperature limits and keep the air fuel ratio sufficiently high. Then, a two-step procedure is presented to optimize the engine operation after the eEVO system is introduced, using a validated diesel engine model. In the first step, the engine variables are optimized at a constant eEVO shift. In the second step, optimal eEVO trajectories are calculated using Dynamic Programming (DP) for a transient test cycle. The optimized results indicate that with early EVO, the boost pressure should be increased to provide enough cylinder air charge and to maintain the engine torque. External EGR can be reduced due to increased internal EGR while maintaining the same engine out NOx. An optimal zone to maximize temperature benefit with least impact to BSFC has been observed. The study also shows some of the penalties related to eEVO including increased flow pulsation at the air flow sensor location. Finally, with optimal eEVO, a 6.5% - 11% reduction is observed in the light-off time of the selective catalytic reduction (SCR) catalyst and 45% reduction in tailpipe NOx compared to the baseline operation without eEVO.
Srinivas, Pavan Kumar, Salehi, Rasoul
EDITORIAL: Bigger barrier to CBEVs: Batteries or infrastructure?19TOFHP04_064/1/2019
Batteries have long been considered the main barrier to deployment of commercial battery-electric vehicles (CBEVs), but many industry insiders now say charging infrastructure is a bigger impediment as battery costs continue to decline. “A decade ago we would have said battery cost is the biggest barrier, but I think we're moving beyond that,” Gary Parker, Director of Electrified Power Engineering Programs at Cummins, said at the recent Green Truck Summit in Indianapolis. “Infrastructure is going to be one of the big barriers, if we can get through not just basic capital costs but also the grid and its stability.”
Gehm, Ryan
Q&A19AUTP04_184/1/2019
Volvo Cars has set one of the industry's most ambitious engineering goals: to have zero traffic fatalities in any of its new models beginning in 2020. It also aims to have one-third of its new-vehicle range be capable of SAE Level 4 autonomous operation by 2025. First to arrive with Level 4 capability will be the next-generation XC90 due in 2021. Henrik Green (below), the senior VP of research & development, is pleased with his company's progress in both the electrification and automated-driving areas. As a computer-engineering graduate, Green joined Volvo in 1996. He's since led engine development, powertrain-controls, and the 40-series vehicle program, and has headed global product strategy. He spoke recently with editor-in-chief Lindsay Brooke on Volvo's technology trajectory.
Thin, Durable Heating PatchesTBMG-341404/1/2019
Thin, durable heating patches were created using intense pulses of light to fuse tiny silver wires with polyester. Their heating performance is nearly 70 percent higher than similar patches. The inexpensive patches can be powered by coin batteries and can generate heat where the human body needs it since they can be sewed on as patches.
Metal 3D Printing for Complex Heat ExchangersTBMG-341544/1/2019
Renishaw West Dundee, IL
A Multi-Domain Component Based Modeling Toolset for Dynamic Integrated Power and Thermal System Modeling2019-01-13853/19/2019
Design of modern aircraft relies heavily on modeling and simulation for reducing cost and improving performance. However, the complexity of aircraft architectures requires accurate modeling of dynamic components across many subsystems. Integrated power and thermal modeling necessitates dynamic simulations of liquid, air, and two-phase fluids within vapor cycle system components, air cycle machine and propulsion components, hydraulic components, and more while heat generation of many on-board electrical components must also be precisely calculated as well. Integration of these highly complex subsystems may result in simulations which are too computationally expensive for quickly modeling extensive variations of aircraft architecture, or will require simulations with reduced accuracy in order to provide computationally inexpensive models. As such, a need for software toolsets with the ability to model complex aircraft architectures with accurate calculations while maintaining high computational speeds is apparent. This paper details the development of the ATTMOSphere toolset which enables modeling of electrical, mechanical, thermal, fluid flow and heat transfer across a range of components applicable to integrated power and thermal systems. Graphical user interfaces provide user-friendly parameterization of components, as well as sizing of many of the available components. All ATTMOSphere components operate within universal mechanical, thermal, electrical, and fluid domains allowing for seamless integration of components across many architectures, providing end-users with the ability to simultaneously model vapor cycle systems, air cycle systems, pumped refrigeration systems, and other power and thermal systems along with their interactions with parallel subsystems. This paper provides details of the components developed in ATTMOSphere along with examples of user interfaces and design codes. Demonstration models are presented to illustrate the integrated dynamic analysis capability of the toolset.
McCarthy, Patrick Thomas, McCarthy, Kevin, Hasan, Maher, Boyd, Michelle, Chang, Michael, Walters, Eric, Niedbalski, Nicholas
A Dynamic Two-Phase Component Model Library for High Heat Flux Applications2019-01-13863/19/2019
Pumped two-phase systems using mini or microchannel heat sink evaporators are prime candidates for high heat flux applications due to relatively low pumping power requirements and efficient heat removal in compact designs. A number of challenges exist in the implementation of these systems including: ensuring subcooled liquid to the pump to avoid cavitation, avoiding dry out conditions in heat exchangers that can lead to failures of the components under cooling, and avoiding flow instabilities that can damage components in an integrated system. To reduce risk and cost, modeling and simulation can be employed in the design and development of these complex systems, but such modeling must include the relevant behavior necessary to capture the above dynamic effects. To this end, a component model library has been developed in this work that demonstrates the ability to model dynamic and steady-state flow characteristics commonly observed in pumped two-phase refrigeration systems using microchannel heat sinks. The library is comprised of components that can either be used to model individual components or be coupled with other components to form an integrated system. The dynamic model of the microchannel cold plate component is based on common formulations of the time dependent mass, momentum, and energy balances, which are solved using the finite volume method to capture the two-phase flow behavior. Additionally, to accurately capture pressure drop and heat transfer, friction factors and heat transfer coefficients are based on correlations that compare well with a comprehensive list of academic publications. The mathematical description of the components, the implementation through Simulink and graphical user interfaces, and the application of the toolset will be presented herein. Comparison to hardware results will be shown along with verification of the tool’s ability to capture critical pumped two-phase phenomena such as dry out and flow instabilities.
Hodson, Stephen, McCarthy, Kevin, McCarthy, Patrick, Mudawar, Issam
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