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Continuous improvements and innovations towards sustainability in the aviation industry has brought interest in electrified aviation. Electric aircrafts have short missions in which the temporal variability of thermal loads are high. Lithium-ion (Li-ion) batteries have emerged as prominent power source candidate for electric aircrafts and Urban Air Mobility (UAM). UAMs and Electric aircrafts have large battery packs with battery capacity ranging in hundreds or thousands of kWh. If the battery is exposed to temperatures outside the optimum range, the life and the performance of the battery reduces drastically. Hence, it is crucial to have a Thermal Management System (TMS) which would reduce the heat load on battery in addition to cabin, and machinery thermal loads. Thermal management can be done through active or passive cooling. Adding a passive cooling system like Phase Change Material (PCM) to the TMS reduces the design maximum thermal loads.

The Selective Laser Melting (SLM) process is employed in high-precision layer-by-layer Additive Manufacturing (AM) on powder bed and aims to fabricate high-quality structural components. To gain a comprehensive understanding of the process and its optimization, both modeling and simulation in conjunction with extensive experimental studies along with laser calibration studies have been attempted. Multiscale and multi-physics-based simulations have the potential to bring out a new level of insight into the complex interaction of laser melting, solidification, and defect formation in the SLM parts. SLM process encompasses various physical phenomena during the formation of metal parts, starting with laser beam incidence and heat generation, heat transfer, melt/fluid flow, phase transition, and microstructure solidification. To effectively model this Multiphysics problem, it is imperative to consider different scales and compatible boundary conditions in the simulations.

In recent years, the burgeoning applications of hydrogen fuel cells have ignited a growing trend in their integration within the transportation sector, with a particular focus on their potential use in multi-rotor drones. The heightened mass-based energy density of fuel cells positions them as promising alternatives to current lithium battery-powered drones, especially as the demand for extended flight durations increases. This article undertakes a comprehensive exploration, comparing the performance of lithium batteries against air-cooled fuel cells, specifically within the context of multi-rotor drones with a 3.5kW power requirement. The study reveals that, for the specified power demand, air-cooled fuel cells outperform lithium batteries, establishing them as a more efficient solution.

Abstract For spacecraft with high power consumption, it is reasonable to build the thermal control system based on a two-phase mechanically pumped loop. The heat-controlled accumulator is a key element of the two-phase mechanically pumped loop, which allows for the control of pressure in the loop and maintains the required level of coolant boiling temperature or cavitation margin at the pump inlet. There can be two critical modes of loop operation where the ability to control pressure will be lost. The first critical mode occurs when the accumulator fills with liquid at high heat loads. The second critical mode occurs when the accumulator is at low heat loads and partial loss of coolant, for example, due to the leak caused by micrometeorite breakdown. Both modes are caused by insufficient accumulator volume or working fluid charge.

Measurements in snow conditions performed in the past were rarely initiated and best suited for pure and extremely detailed quantification of microphysical properties of a series of microphysical parameters, needed for accretion modelling. Within the European ICE GENESIS project, a considerable effort of natural snow measurements has been made during winter 2020/21. Instrumental means, both in-situ and remote sensing were deployed on the ATR-42 aircraft, as well as on the ground (ground station at ‘Les Eplatures’ airport in the Swiss Jura Mountains with ATR-42 overflights). Snow clouds and precipitation in the atmospheric column were sampled with the aircraft, whereas ground based and airborne radar systems allowed extending the observations of snow properties beyond the flight level chosen for the in situ measurements.

The purpose of this standard is to provide uniform methods for defining, quantifying, and classifying the residual stress in metallic structural alloy products and finished parts. These stresses may exist within a single element, or they may be the result of a joining process. Such quantification and classification may be required when residual stresses within mill stock or preforms can impact further in-process distortion during machining or other processes, and when residual stresses within finished components can impact final mechanical properties and performance (especially strength, durability, and fracture performance).

The applications of unmanned aerial vehicles (UAV) are growing exponentially with advances in hybrid powertrain architecture design tools. The thermal management system (TMS) as an integral part of the powertrain architecture greatly affects the system performance of aerial vehicles. In this study, a comparative analysis of two types of thermal management technologies for a UAV with a series-hybrid powertrain architecture was performed. Conventional TMS based on single-phase (no phase change) cooling technologies using air and liquid (e.g., antifreeze water mixture and oil) as heat transfer fluid has been commonly used because of simple design and operation, although it is considered to be inefficient and bulky. As advanced designs, phase change-based TMS is being slowly adopted although it promises superior cooling capabilities.

Most of current jet aircraft circulate fuel on the airframe to match heat loads with available heat sink. The demands for thermal management in wide range of air vehicle systems are growing rapidly along with the increased mission power, vehicle survivability, flight speeds, and so on. With improved aircraft performance and growth of heat load created by Aircraft Mounted Accessory Drive (AMAD) system and hydraulic system, effectively removing the large amount of heat load on the aircraft is gaining crucial importance. Fuel is becoming heat transfer fluid of choice for aircraft thermal management since it offers improved heat transfer characteristics and offers fewer system penalties than air. In the scope of this paper, an AMESim model is built which includes airframe fuel and hydraulic systems with AMAD gearbox of a jet trainer aircraft. The integrated model will be evaluated for thermal performance.

This test method provides the capabilities, limitations, and suggested possible applications of TGA as it pertains to the detection of counterfeit electronic components. Additionally, this document outlines requirements associated with the application of TGA including: equipment requirements, test sample requirements, methodology, control and calibration, data analysis, reporting, and qualification and certification. If AS6171/10 is invoked in the contract, the base document, AS6171 General Requirements shall also apply.

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. This has made thermal management a challenging task and 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 fin diameter, spacing and height and performing thermal simulations to arrive at a design with enhanced heat transfer characteristics.

The thermal heat load requirement for the cabin and the cockpit of aerial vehicle varies with various conditions comprises of altitudes and different weather conditions. The mapping of the heat load w.r.t. the above conditions is a complex phenomenon, which involves difficult mathematical modeling. The aerodynamic design of the aerial vehicle allows the flow of ambient air to contribute in the cabin and cockpit heat load along with passengers, pilots & co-pilots heat load at various weather conditions. The current study considers the mathematical modeling of the cabin and cockpit of aerial vehicle w.r.t. various weather conditions and altitudes and simulate the heat load requirements. The estimation of the heat load plays a key role in thermal management systems of the aerial vehicle for both the cabin and cockpit. The objective of this study is to highlight the importance of heat load requirement of the aerial vehicle and methods to simulate it.

Abstract The increase in worldwide awareness of environmental issues has necessitated the air transport industry to drastically reduce carbon dioxide emissions. To meet this goal, one solution is the electrification of aircraft propulsion systems. In particular, single-aisle aircraft with partial turboelectric propulsion with approximately 150 passenger seats in the 2030s are the focus. To develop a single-aisle aircraft with partial turboelectric propulsion, an air-cooled interior permanent magnet (IPM) motor with an output of 2 MW is desired. In this article, mathematical system equations that describe heat transfer inside the target air-cooled IPM motor are formulated, and their mathematical analytical solutions are obtained.

Mechanical systems accomplish their tasks better when enhanced with cyber technologies. With the rapidly escalating desire for high efficiency, optimization and flexibility, these physical systems ought to be integrated with cyber technologies that enhance exhaustive manipulation of resources and productivity. The gateway for such a synergetic integration can be referred to as digitalization. Details regarding the digitization of a High-altitude Simulation chamber are discussed thoroughly in this paper. The simulation chamber was originally designed and developed as a test bench to study the characteristics of alternative fuels used in the engines of handheld tools in different altitudes and thermal conditions. It encompasses all the possible realistic temperature variations with altitude raising to 3500m above sea level.

Restrictions on emissions have been made to guide society into a more sustainable development. The impasse between regulations and the expectation of a growing demand for aviation exposes the need for decarbonization of the sector. In this way, the utilization of hydrogen associated with fuel cells stands out as means to eliminate emissions during flight. This study evaluates the feasibility of using cryogenic liquid hydrogen (LH2) tanks as both energy source and cooling advantage for a small aircraft with electric propulsion. First, a propulsion system powered by a hybrid setup with Proton-Exchange Membrane Fuel Cells (PEMFC) and batteries is proposed for a small aircraft replacing an Internal Combustion Engine (ICE) and fuel tanks. Then, the new powerplant is integrated into the aircraft and simulated using the SUAVE tool.

Current trends in the rotorcraft market favor aircraft with higher power electronic equipment, smaller, more efficient propulsion systems, and higher flight speeds. The power consumers are putting a greater tax on electrical systems, but also pushing already stressed thermal management systems. The first goal of this brief study aims to calculate and identify major trending of drag and power consumption imposed by equipment cooling on high-speed rotorcraft. Major contributors to these quantities include total heat load, equipment qualification temperature, flow passage sizing and inlet/exhaust orientation to free stream. During preliminary aircraft design, these factors are sometimes disregarded or deprioritized, as they may lead to weight increases, design challenges, and schedule changes.

Thermal Management Techniques in Avionics Cooling Curing the Porosity Problem in Additive Manufacturing Space-Qualified Crystal Oscillators Reimagining Automated Test During a Pandemic EW: New Challenges, Technologies, and Requirements Software Enables New-Age, Flexible Test Solution for Analog and Digital Radios Formal Process Modeling to Improve Human-Decision-Making During Test and Evaluation Range Control Using the Innoslate software tool to formally model the process of conducting test range events can expose previously overlooked ambiguities and identify high-value decision points? Test and Evaluation of Autonomy for Air Platforms Tools, approaches, and insights to confidently approach the safe, secure, effective, and efficient testing of autonomy on air platforms.

A low-speed, open-circuit wind tunnel at Youngstown State University has been converted to a multi-modal facility, enabling interchangeable configurations from boundary-layer test section to an open-jet test cell to support flexible capabilities for ground and air vehicle technology development. The existing test-section entrance geometry of 0.24- by 1.0-m (internal flow configuration) was converted to a 0.50- by 0.50-m cross-section (external flow configuration), making use of the commonality of upstream flow conditioning components. Redistribution of the contraction exit area from the internal flow configuration enables the facility to maintain the same maximum test speed between the two modes. Reynolds-Averaged Navier-Stokes (RANS) calculations of the flow in the new three-dimensional contraction section and evolution of the free jet in the test cell are reported from the design study phase to assess boundary-layer separation margin and modeled plane jet spreading rate.

Empowering Soldiers Through ISPDS Dispensable Gels vs Gap Filler Pads An Analysis of Thermal Management Materials Electronic Warfare Vying for Control of the Electromagnetic Spectrum More Bang for the Buck A New Design and Manufacturing Method for Deep Penetrating Bomb Cases A Comprehensive Way to Use Bonding to Improve RF Performance of Low Noise Amplifiers Army and Universities Deploy New Warfighter Communication Technology Radiation Effects on Electronics in Aligned Carbon Nanotube Technology (RadCNT) Characterizing the fundamental mechanisms and charge transport phenomena governing the interactions between ionizing and non-ionizing radiation with carbon-based (nanotube and graphene) field-effect transistors (FETs) devices and integrated circuits (ICs).

The intent of this report is to encourage that the thermal management system architecture be designed from a global platform perspective. Separate procurements for air vehicle, propulsion system, and avionics have contributed to the development of aircraft that are sub-optimized from a thermal management viewpoint. In order to maximize the capabilities of the aircraft for mission performance and desired growth capability, overall system efficiency and effectiveness should be considered. This document provides general information about aircraft Thermal Management System Engineering (TMSE). The document also discusses approaches to processes and methodologies for validation and verification of thermal management system engineering. Thermal integration between the air vehicle, propulsion system, and avionics can be particularly important from a thermal management standpoint.

Abstract Improving the energy performance of batteries can increase the reliability of electric aircraft. To achieve this goal, battery management systems (BMS) are required to keep the temperature within the battery pack and cells below the safety limits and make the temperature distribution as even as possible. Batteries have a limited service life as a result of unwanted chemical reactions, physical changes that cause the loss of active materials in the structure, and internal resistance increase during the charging and discharging cycle of the battery. These changes usually affect the electrical performance of batteries. Battery life can be increased only by reducing or preventing unwanted chemical reactions. Lithium-ion (Li-ion) batteries are a suitable option due to their high specific energy and energy density advantages. In this study, the necessity of heat management is emphasized. The discharge tests of the Li-ion battery provided 94.6 Wh under 10C and 90.9 Wh under 1C.