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White Paper


The exponential increase in the number of aircraft and air travelers has triggered new innovations aimed to make airline services more reliable and consumer friendly. Quick and efficient maintenance actions with minimum downtime are the need of the hour. Another major challenge is ensuring maintenance personnel are trained effectively; technology like augmented reality and Virtual Maintenance Trainers (VMTs) may provide safe and efficient training in lieu of live, instructor-led arrangements. And while traditional User/Maintenance Manuals provide useful information when dealing with simple machines, when dealing with complex systems of systems and miniaturized technologies, like unmanned aerial vehicles (UAVs), new technologies like augmented reality can rapidly and effectively support the maintenance operations.
White Paper

Studies into Additive Manufacturing for In-Space Manufacturing

NASA has embarked on an ambitious program to integrate additive manufacturing techniques and to develop processes for the microgravity environment. The most recent example of this program is the successful launch and deployment of the first 3D printer on the International Space Station. In this one-year effort, students were required to meet a series of milestones to design, manufacture, and test their ideas in close cooperation with members of the NASA Exploration Augmentation Module (EAM) concept team.The participants in this project were tasked with thinking of new solutions using AM that would simultaneously be recyclable with minimal loss in mechanical properties but also have the capacity for high mechanical properties. Working in interdisciplinary teams, the participant teams investigated the use of recycled materials, characterization, testing, modeling, and tool development.
White Paper

The Use of Imaging for Powder Metal Characterization and Contamination Identification

As AM technologies are being used with higher frequencywithin the automotive and aerospace industries, the interest in powder characterization and contaminant identification is growing—especially for suppliers looking to gain entry into these highly regulated industries. Standards for powder materials and methods used for aerospace applications are still be developed, and regulatory agencies such as the Federal Aviation Administration have been requesting that standards be developed as guidance for the industry. Methods such as CCSEM and HLS could be viable options for suppliers needing to adhere to a powder specification by demonstrating compliance. Solutions exist to integrate such methods into a production environment as exemplified by RJ Lee Group.
Tech Insights

Balance of Plant: Integrating PEM Fuel Cells into Aircraft

While all-electric aircraft remain at the bleeding edge of the aviation industry, incorporating technologies like proton exchange membrane fuel cells into existing aircraft can result in considerable auxiliary capability with low environmental impact. However, proper consideration must be given to supporting systems to achieve a reliable balance of plant-especially when those systems interface with existing aircraft architectures. The scope of the BoP is to manage and condition the reactant flows to and from the fuel-cell module and to provide power to system components.
Solution Notes

The Right Balance for Small UAVs: Defining top-level requirements for the power

Small tactical UAVs (SUAVs) have made their mark in military operations with their ability to gather and provide localized, real-time information. Typical uses include perimeter surveillance of remote military compounds, over-the-horizon surveillance, and remote monitoring of critical logistics routes. However, their potential to take on increased and increasingly complex missions is hampered by their limited endurance. This work explores research done under the auspices of the European Commission’s Fuel Cell and Hydrogen Joint Undertaking on a fuel cell and battery hybrid energy storage system that could increase the total amount of onboard energy storage, while continuing to deliver the peak power needs of the SUAV.
White Paper

Electric Flight Technology

The environmental impact of hydrocarbon-burning aircraft, both from the perspective of gas emissions and that of noise, is one of the main motivations for the move to electric propulsion. The added benefit from this shift to electric propulsion is that it has resulted in lowering the costs of electrical components such as motors, power electronic (PE) circuits, and batteries that are essential to this technology. This white paper seeks to explore the history, architecture, electrical components, and future trends of electric flight technology.
Technical Paper

A New Tool for Corrosion Inhibitor Research

Electrochemical techniques such as repassivation potential measurements and electrochemical impedance spectroscopy (EIS) have become important tools in corrosion and corrosion inhibitor research. However, these techniques reflect the response of the total surface area of the exposed sample and cannot distinguish between types of localized corrosion e.g. pitting or crevice corrosion. Current density mapping (CDM) is a technique that uses a fine stainless steel needle, vibrating at a set frequency and scans over the surface of a sample in a plane micrometers above the sample surface. By mapping the current distribution over a surface, sites of localized corrosion can be characterized and the effect of a corrosion inhibitor monitored.
Technical Paper

Liquid Film Evaporation Off the Piston of a Direct Injection Gasoline Engine

An optical access engine was used to image the liquid film evaporation off the piston of a simulated direct injected gasoline engine. A directional injector probe was used to inject liquid fuel (gasoline, i-octane and n-pentane) directly onto the piston of an engine primarily fueled on propane. The engine was run at idle conditions (750 RPM and closed throttle) and at the Ford World Wide Mapping Point (1500 RPM and 262 kPa BMEP). Mie scattering images show the liquid exiting the injector probe as a stream and directly impacting the piston top. Schlieren imaging was used to show the fuel vaporizing off the piston top late in the expansion stroke and during the exhaust stroke. Previous emissions tests showed that the presence of liquid fuel on in-cylinder surfaces increases engine-out hydrocarbon emissions.
Technical Paper

Influences of Gas Quality on a Natural Gas Engine

1 The topic of investigation of this work was the influence of different gas qualities on the engine parameters and particularly on the air excess factor λ. For this research the normalized gases with extreme compositions were used. At stationary operation there are no differences of the leaning capability of the different gases. The gas with the highest content of inert components causes the lowest full load power, the highest fuel consumption and the highest cyclic irregularity. With the same air flow and the same injection duration for different gases result different air excess factors λ according to the density and to the necessary stoichiometric air quantity of each gas. This fact influences the λ at transient operation conditions as: cold starting, gas quality jump, or load increase, if there is no λ-control. With an active λ-control, which is today fast enough, especially with an adaptive system there are no problems with λ- differences.
Technical Paper

Sound Design in the Passenger Compartment with Active Noise Control in the Air Intake System

In the future, the requirements of acoustic behavior in air intake systems will continue to increase. Active systems will be necessary to reach the higher legislative standards and customer expectations regarding noise levels. The optimization of the Active Noise Control System regarding the sound design in the interior is based on the transfer function between the engine and the passenger compartment as well as the design of the air intake system. This paper shows the development process, with a focus on the investigation of transfer functions in passenger cars and the computational calculation for the system configuration.
Technical Paper

Flow Visualization Study of an HVAC Module Operated in Water

Centrifugal blowers serve as the primary source of airflow and aero-acoustic noise in automotive HVAC modules. Flow field measurements inside blowers indicate very complex flow patterns. A detailed flow visualization study was conducted on an actual HVAC fan module operated in water under dynamically similar conditions as those in air with the purpose of studying the complex flow patterns in order to improve the aerodynamic performance of the fan/scroll casing and diffuser components. Fan-scroll/diffuser interaction was also studied as function of fan speed. Conventional and special (shear thickening) dye injection flow visualization techniques were used to study the complex 3-dimensional vortical and unsteady flow patterns that occur in typical HVAC fans. A major advantage of the flow visualization technique using shear-thickening dye is its usefulness in high the Reynolds number flows that are typically encountered inside HVAC modules.
Technical Paper

Optimization of Vehicle Warm-up Using Simulation Tools

A comprehensive simulation method is presented for the optimization of vehicle warm-up. Sophisticated one dimensional simulation methods based on network theory are used for flow simulation to limit computation time and guarantee high simulation quality. Partial integration of three dimensional flow simulation methods help to improve accuracy. Simulation sub-models for the engine, the HVAC system, and the passenger cabin are combined to simulate the warm-up process of the vehicle. This functionality is implemented in a modern software tool named KULI to support the development engineer as good as possible. Steady state and transient simulation are used to optimize the warm-up behavior.
Technical Paper

Comparison of CFD Simulation Methods and Thermal Imaging with Windscreen Defrost Pattern

The measured windscreen defrost pattern for a saloon car has been compared with two CFD simulation methods and with the results obtained using a thermal imaging camera. The objectives were to determine: if CFD could be used with confidence to simulate defrost performance; the difference between the two CFD methods; the ability of the thermal imaging technique to predict defrost performance; the most appropriate use of these techniques during an HVAC development programme. There was a good comparison between the defrost pattern on the windscreen and the results from the thermal imaging camera and the two CFD methods. The CFD methods have been shown to be suitable for fault finding and recommending their use is reinforced for development work of ducts and vents in the HVAC system. Airflow direction and distribution could be implied from the thermal camera images, which makes it a suitable tool for fine tuning duct and vent designs at the final stages of the design programme.
Technical Paper

Model Based Analysis of Compressor Valve Leakage and its Effects on the Efficiency of the Motor-Compressor

In the development of algorithms to detect and diagnose component malfunctions impacting system performance and efficiency, engineers are often faced with the following questions: what is the relevant information required, what sensor or set of sensors is needed to provide this information, how should the information from the sensor signals be extracted, which sensor provides the earliest signal of system efficiency deterioration, and how do these signals change as the severity of the fault increases? A typical approach used to answer these questions is to experiment empirically with the actual system; however, this approach can be expensive and time consuming because it involves a variety of complex instrumentation and requires a fair amount of time to run the tests and analyze the data. An alternate approach, which is considerably less expensive is to use a model of the system and run computer simulations to get insight and understanding into its behavior.
Technical Paper

Application of Mathematical Models to Detect and Diagnose Reciprocating Compressor Valve Leakage

This report presents results from the model simulation of the pressure, vibration, and current signatures as derived in the accompanying publication [1] and compares the simulated data with measured data from an actual laboratory motor-compressor system. The simulations from the models were used to determine the information content of the sensor signals, compare the various diagnostic techniques and develop a multisensor approach based on the integration of these techniques to detect and diagnose reciprocating compressor valve leakage.
Technical Paper

Thermal Management Evolution and Controlled Coolant Flow

A tremendous amount of research has been done on the coolant system of engines, however, the configuration remains virtually the same since the early 1900's. Recent testing has shown that by controlling components such as thermostats and water pumps, efficiency and emission improvements can be realized. With the nearing of higher voltage and hybrid systems, along with the availability of high efficiency electric pumps and valves, we are fast approaching the implementation of controlled coolant flow technology. This paper will discuss the problems with the current cooling systems, some of the work that has been done recently and what an ideal controlled coolant system may look like in the future.
Technical Paper

Active Control of Automotive Air Induction Noise via Source Coupling

Engine noise emanating from the air intake of automotive induction systems can be effectively suppressed through active noise control. Source coupling is used as the active noise control strategy. A small woofer, co-axially mounted inside the fresh air duct, is located in the plane of the fresh air intake and acts as the secondary noise source. An error microphone is located near the air intake and a synchronous reference signal is provided by an engine tachometer signal. This active noise control system has been tested on several engines. The radiated engine noise from the induction system has been effectively eliminated over the control bandwidth. The power draw of the speaker is minimal and the flow restriction of the actively controlled inlet has been significantly reduced compared to the production air induction system.
Technical Paper

Active Boom Noise Damping of Dodge Durango

Two active boom noise damping techniques using a Helmholtz resonator-based compensator and a lead compensator called a positive pressure feedback have been developed at the University of Dayton [1]. The two damping techniques are of feedback type and their compensators can be implemented in software or hardware (using inexpensive operational amplifiers). The active damping system would rely on a speaker, a low-cost microphone, two accelerometers, and an electronic circuit (or a micro-controller) to add damping to the offending low-frequency vibroacoustic modes of the cavity. The simplicity of the active boom noise damping system lends itself to be incorporated into a vehicle's sound system. The Helmholtz resonator-based strategy is implemented on a Dodge Durango sport utility vehicle. The control scheme adds appreciable amount of damping to the first cavity mode and the first structurally induced acoustic mode of the cabin.