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2015-06-15
Technical Paper
2015-01-2134
Tom Currie, Dan Fuleki
There is significant recent evidence that ice crystals ingested by a jet engine at high altitude can partially melt and then accrete within the forward stages of the compressor, potentially producing a loss of performance, rollback, combustor flameout, compressor damage, etc. Several studies of this ice crystal icing (ICI) phenomenon have been conducted in the past 5 years using the RATFac (Research Altitude Test Facility) altitude chamber at the National Research Council of Canada (NRCC), which includes an icing wind tunnel capable at operating at Mach numbers (M), total pressures (po) and temperatures (To) pertinent to ICI. Humidity can also be controlled and ice particles are generated with a grinder. The ice particles are entrained in a jet of sub-freezing air blowing into the tunnel inlet. Warm air from the altitude cell also enters the tunnel, where it mixes with the cold ice-laden jet, increasing the wet-bulb temperature (Twb) and inducing particle melting.
2015-06-15
Technical Paper
2015-01-2348
Richard Kolano
This paper presents the results of a study to reduce the background noise level within a large Quiet Room built as part of the original building construction circa 1990. This room is located adjacent to other laboratory testing environments and below a mechanical mezzanine which houses an extensive array of mechanical and electrical equipment including banks of low-temperature chiller compressors, air handling units, and electrical switchgear that serves the entire building complex. This equipment was installed atop the concrete mezzanine floor deck without provisions for isolating vibration. As a result, structure borne noise from that equipment travels through the floor, radiates from the underside of the floor deck, and intrudes into the Quiet Room below. This causes the background noise level within the Quiet Room to be too high for conducting low sound level measurements and studies on vehicles brought into the Quiet Room.
2015-06-15
Technical Paper
2015-01-2347
James A. Mynderse, Alexander Sandstrom, Zhaohui Sun
Mechanical engineering students at Lawrence Technological University (Lawrence Tech) must complete a capstone project, some of which are industry-sponsored projects (ISPs). American Axle & Manufacturing Inc. (AAM) partnered with LTU to provide a senior design experience in NVH through a proposed improvement to the AAM driveline dynamometer. AAM proposed that students design, develop, and fabricate a decoupling mechanism that minimizes the vibration disturbances transmitted from the driver shaft to the driven shaft. This work describes the LTU-AAM partnership, the design problem and the completed decoupler mechanism with experimental validation. The AAM driveline dynamometer provides immense value for experimental validation of product NVH performances. It has been intensively used to evaluate product design robustness in terms of build variations, mileage accumulation, and temperature sensitivity.
2015-06-15
Technical Paper
2015-01-2346
Balakumar Swaminathan
From a facility perspective, engine test cells are rarely evaluated for their vibration levels in their functional configuration. When complicated dynamic systems such as an internal combustion engine and a dynamometer are coupled together using driveshafts and coupling components, the overall system behavior is significantly different from that of the individual sub-systems. This paper details an instance where system level experimental testing and finite element analysis methods were used to mitigate high vibration levels in an engine test cell. Modal and operational test data were taken to establish baseline vibration levels at a diesel engine test cell during commissioning. Measurements were taken on all major sub-systems such as the engine assembly, dynamometer assembly, intermediate driveshaft bearing pedestal and driveshaft components.
2015-06-15
Technical Paper
2015-01-2156
Michael Oliver
The National Aeronautics and Space Administration conducted a full scale ice crystal icing turbofan engine test in the NASA Glenn Research Center’s Propulsion Systems Laboratory (PSL) Facility in February 2013. Honeywell Engines supplied the test article, an obsolete, unmodified Lycoming ALF502-R5 turbofan engine serial number LF01 that experienced an uncommanded loss of thrust event while operating at certain high altitude ice crystal icing conditions. These known conditions were duplicated in PSL for this testing. The data generated during this testing contained three subsets: known event conditions, altitude scaling conditions and a design of experiment (DOE) data set. The key roll back indicating parameter was found to be the reduction of the measured load parameter, the average of two measured load cells mounted on the thrust stand.
2015-06-15
Technical Paper
2015-01-2155
Tadas P. Bartkus, Peter Struk, Jen-Ching Tsao
This paper describes a numerical model that simulates the thermal interaction between ice particles, water droplets, and the flowing air applicable during icing wind tunnel tests where there is significant phase-change of the cloud. The model is compared to measurements taken during wind tunnel tests simulating ice-crystal and mixed-phase icing that relate to ice accretions within turbofan engines. This model, written in MATLAB, is based on fundamental conservation laws and empirical correlations. Due to numerous power-loss events in aircraft engines, potential ice accretion within the engine due to the ingestion of ice crystals is being investigated. To better understand this phenomenon and determining the physical mechanism of engine ice accretion, fundamental tests have been collaboratively conducted by NASA Glenn Research Center and the National Research Council of Canada (NRC).
2015-06-15
Technical Paper
2015-01-2107
Tom Currie, Dan Fuleki, Craig Davison
There is significant recent evidence that ice crystals ingested by a jet engine at high altitude can partially melt and then accrete within the forward stages of the compressor, potentially producing a loss of performance, rollback, combustor flameout, compressor damage, etc. Several studies of this ice crystal icing (ICI) phenomenon have been conducted in the past 5 years using the RATFac (Research Altitude Test Facility) altitude chamber at the National Research Council of Canada (NRCC), which includes an icing wind tunnel capable at operating at Mach numbers (M), total pressures (po) and temperatures (To) pertinent to ICI. Humidity can also be controlled and ice particles are generated with a grinder. The ice particles are entrained in a jet of sub-freezing air blowing into the tunnel inlet. Warm air from the altitude cell also enters the tunnel, where it mixes with the cold ice-laden jet, increasing the wet-bulb temperature (Twb) and inducing particle melting.
2015-06-15
Technical Paper
2015-01-2116
Peter Struk, Tadas Bartkus, Jen-Ching Tsao, Tom Currie, Dan Fuleki
This paper describes ice accretion measurements from experiments conducted at the National Research Council (NRC) of Canada’s Research Altitude Test Facility during 2012. Due to numerous engine power-loss events associated with high-altitude convective weather, potential ice accretion within an engine due to ice-crystal ingestion is being investigated collaboratively by NASA and NRC. These investigations examine the physical mechanisms of ice accretion on surfaces exposed to ice-crystal and mixed-phase conditions, similar to those believed to exist in core compressor regions of jet engines. A further objective of these tests is to examine scaling effects since altitude appears to play a key role in this icing process. While the 2012 experiments had multiple objectives such as cloud characterization and the evaluation of imaging techniques, several tests were dedicated to observe ice accretions using both a NACA 0012 and a wedge-shaped airfoil.
2015-06-15
Technical Paper
2015-01-2143
Christian Mendig
In the project SuLaDI (Super Large Droplet Icing) research about the icing of airfoils through super large and super cooled droplets is done at the Institute of Composite Structures and Adaptive Systems (German Aerospace Center) and at the institute of Adaptronics and Function Integration (Technische Universität Braunschweig). In the framework of the project a deicing facility was built. It consists of a cooling chamber and a wind tunnel of the Eiffel-type therein. The icing of specimen takes place in the test chamber of the wind tunnel at temperatures below 0 °C. Between the flow straightener and the contraction section a spray system is built in, which sprays water droplets into the wind tunnel. The droplets are accelerated by the airstream and supercool on the way to the specimen. That means they cool down below the freezing point temperature, but they stay fluid. When hitting the specimen they freeze on it to rime ice, clear ice or mixed ice.
2015-04-14
Technical Paper
2015-01-1562
Matts Karlsson, Roland Gårdhagen, Petter Ekman, David Söderblom, Claes Löfroth
Abstract There is a need for reducing fuel consumption and thereby also reducing CO2 and other emissions in all areas of transportation and the forest industry is no exception. In the particular case of timber trucks special care have to be taken when designing such vehicles; they have to be sturdy and operate in harsh conditions and they are being driven empty half the time. It is well known that the aerodynamic resistance constitutes a significant part of the vehicles driving resistance and four areas in particular, front of vehicle, gap, side/underbody and rear of the vehicle contributes about one quarter each. In order to address these issues a wind tunnel investigation was initiated where a 1:6 scale model of a timber truck was designed to operate in a 3.6 m wind tunnel. The present model resembles a generic timber truck with a flexible design such that different configurations could be tested easily.
2015-04-14
Technical Paper
2015-01-0639
Adebola Ogunoiki, Oluremi Olatunbosun
Abstract This research proposes the use of Artificial Neural Networks (ANN) to predict the road input for road load data generation for variants of a vehicle as vehicle parameters are modified. This is important to the design engineers while the vehicle variant is still in the initial stages of development, hence no prototypes are available and accurate proving ground data acquisition is not possible. ANNs are, with adequate training, capable of representing the complex relationships between inputs and outputs. This research explores the implementation of the ANN to predict road input for vehicle variants using a quarter vehicle test rig. The training and testing data for this research are collected from a validated quarter vehicle model.
2015-04-14
Journal Article
2015-01-1557
Reinhard Blumrich, Nils Widdecke, Jochen Wiedemann, Armin Michelbach, Felix Wittmeier, Oliver Beland
Abstract For many years FKFS has operated the full-scale aeroacoustic wind tunnel of University of Stuttgart. To keep this wind tunnel as one of the most modern ones of its kind, it has again been upgraded significantly. The upgrade improved the aerodynamic as well as the aeroacoustic performance and accelerated the operational processes. Additionally, new innovative features have significantly enlarged the test capabilities. A new patented, modular belt system (FKFS first®) allows high performance measurements for race cars in a 3-belt mode as well as efficient measurements for production vehicle development in a 5-belt mode. The belt system is accompanied by a new, larger turntable and a new under-floor balance which enables high-accuracy measurements of forces and moments also for a high resolution in time. For the elimination of parasitic forces generated at the wheel drive units, a specific correction procedure has been implemented, which is patented, too (FKFS pace®).
2015-04-14
Journal Article
2015-01-1530
Todd Lounsberry, Joel Walter
Abstract In recent years, there has been renewed attention focused on open jet correction methods, in particular on the two-measurement method of E. Mercker, K. Cooper, and co-workers. This method accounts for blockage and static pressure gradient effects in automotive wind tunnels and has been shown by both computations and experiments to appropriately adjust drag coefficients towards an on-road condition, thus allowing results from different wind tunnels to be compared on a more equitable basis. However, most wind tunnels have yet to adopt the method as standard practice due to difficulties in practical application. In particular, it is necessary to measure the aerodynamic forces on every vehicle configuration in two different static pressure gradients to capture that portion of the correction.
2014-12-22
WIP Standard
AIR6508
This SAE Aerospace Information Report (AIR) provides a performance station designation system for unconventional propulsion cycles and their derivatives. The station numbering conventions presented herein are for use in all communications concerning propulsion system performance such as computer programs, data reduction, design activities, and published documents. They are intended to facilitate calculations by the program user without unduly restricting the method of calculation used by the program supplier. The contents of this document will follow AS755 where applicable.
2014-12-12
Standard
AS755F
This SAE Aerospace Standard (AS) provides a performance station designation system for aircraft propulsion systems and their derivatives. The station numbering conventions presented herein are for use in all communications concerning propulsion system performance such as computer programs, data reduction, design activities, and published documents. They are intended to facilitate calculations by the program user without unduly restricting the method of calculation used by the program supplier. The contents of this document were previously a subset of AS755E. Due to the growing complexity of station numbering schemes and an industry desire to expand nomenclature descriptions, a decision was made to separate the “station numbering” and “nomenclature” contents of AS755 into two separate documents. AS755 will continue to maintain standards for station numbering. SAE Aerospace Standard AS6502 will maintain standards for classical nomenclature moving forward.
2014-09-30
Journal Article
2014-01-2445
Shaoyun Sun, Yin-ping Chang, Qiang Fu, Jing Zhao, Long Ma, Shijie Fan, Bo Li, Andrea Shestopalov, Paul Stewart, Heinz Friz
Abstract In the development of an FAW SUV, one of the goals is to achieve a state of the art drag level. In order to achieve such an aggressive target, feedback from aerodynamics has to be included in the early stage of the design decision process. The aerodynamic performance evaluation and improvement is mostly based on CFD simulation in combination with some wind tunnel testing for verification of the simulation results. As a first step in this process, a fully detailed simulation model is built. The styling surface is combined with engine room and underbody detailed geometry from a similar size existing vehicle. From a detailed analysis of the flow field potential areas for improvement are identified and five design parameters for modifying overall shape features of the upper body are derived. In a second step, a response surface method involving design of experiments and adaptive sampling techniques are applied for characterizing the effects of the design changes.
2014-06-17
Magazine
DuPont: from art to part DuPont's newly appointed global automotive technology director Jeffrey Sternberg, in conversation with Ian Adcock. Igniting the creative spark Ryan Gehm and Lindsay Brooke report on breakthrough technologies at the SAE Congress. Winning ways Ian Adcock exclusively reveals the newly formed Williams Advanced Engineering facility. Driverless future: steering a safe course Google unleashing 100 driverless, motorised pods on to the road has put the need for rigorous safety standards centre stage, as Ian Adcock reports
2014-05-07
Magazine
Defying convention Rapid prototyping has the potential to play a beneficial role in unconventional autonomous airship design. By reducing model cost, build time, difficulty of construction, and maintaining acceptable surface quality and finish, designers have greater ability to analyze several configurations of airships and to change the geometry to increase stability, reduce drag, or fulfill mission requirements.
2014-04-28
Technical Paper
2014-28-0032
Christian Fischer, Rainer Wagener, Tobias Melz, Heinz Kaufmann
Abstract The fatigue life approach is the main topic of structural durability. Improved methods for the numerical fatigue analysis should be based on experimental results. In some fields of material testing progress in research are very hard to achieve. Especially the regime of amplitudes below the knee point of the SN-curve with a huge number of load cycles to failure is one of these challenges with respect to fatigue tests. With standard testing devices, 108 to 1010 cycles cannot be achieved in a reasonable time span because of their low and limited testing frequencies or their inflexible control systems concerning variable amplitude loading. For this reason, a new piezo based testing facility has been developed by Fraunhofer LBF which is capable to master this challenge. Built up with a high performance piezo actuator and a specially designed high frequency load frame this testing facility enables test frequencies up to 1.000Hz and locking forces of 10kN.
2014-04-01
Technical Paper
2014-01-0817
Chenaniah Langness, Michael Mangus, Christopher Depcik
Abstract In order to perform cutting-edge engine research that applies to modern Compression Ignition (CI) engines, a sophisticated test cell is needed that allows control of the engine and its auxiliary systems. The primary obstacle to the completion of such a test cell is the up-front expense. This paper covers the construction of a low cost, single-cylinder engine test cell while demonstrating the type of research that can be accomplished along the way. The components necessary for the construction, instrumentation, and operation of such a test cell, neglecting emissions analysis equipment, can be obtained for less than $150,000. The engine utilized, a naturally-aspirated single-cylinder Yanmar L100V, was purchased as an engine-generator package.
2014-04-01
Technical Paper
2014-01-0579
Gerhard Wickern
Abstract Open jet wind tunnels are normally tuned to measure “correct” results without any modifications to the raw data. This is an important difference to closed wall wind tunnels, which usually require wind tunnel corrections. The tuning of open jet facilities is typically done experimentally using pilot tunnels and adding final adjustments in the commissioning phase of the full scale tunnel. This approach lacked theoretical background in the past. There is still a common belief outside the small group of people designing and using open jet wind tunnels, that - similar to closed wind tunnels, which generally measure too high aerodynamic forces and moments without correction - open jet wind tunnels measure coefficient too low compared to the real world. The paper will try to show that there is a solid physical foundation underlying the experimental approach and that the expectation to receive self-correcting behavior can be supported by theoretical models.
2014-04-01
Technical Paper
2014-01-0611
Kevin R. Cooper, Miroslav Mokry
Abstract The solid-wall wind tunnel boundary correction method outlined in this paper is an efficient pressure-signature method that requires few wall-mounted pressures. These pressures are used to determine the strengths of model- and wake-representing singularities that are used with the method of images to calculate the longitudinal and lateral velocity increments induced by the wind tunnel walls. Two force correction models are presented that convert these velocity increments to force and moment corrections. The performances of the correction procedures are demonstrated by their application to data from two sets of four, geometrically identical, differently sized, simplified automotive models.
2014-04-01
Journal Article
2014-01-0615
Sofie Koitrand, Lennart Lofdahl, Sven Rehnberg, Adrian Gaylard
Automotive aerodynamics measurements and simulations now routinely use a moving ground and rotating wheels (MVG&RW), which is more representative of on-road conditions than the fixed ground-fixed wheel (FG&FW) alternative. This can be understood as a combination of three elements: (a) moving ground (MVG), (b) rotating front wheels (RWF) and (c) rotating rear wheels (RWR). The interaction of these elements with the flow field has been explored to date by mainly experimental means. This paper presents a mainly computational (CFD) investigation of the effect of RWF and RWR, in combination with MVG, on the flow field around a saloon vehicle. The influence of MVG&RW is presented both in terms of a combined change from a FG&FW baseline and the incremental effects seen by the addition of each element separately. For this vehicle, noticeable decrease in both drag and rear lift is shown when adding MVG&RW, whereas front lift shows little change.
2014-04-01
Journal Article
2014-01-0559
Michael Guerrero, Kapil Butala, Ravi Tangirala, Amy Klinkenberger
NHTSA has been investigating a new test mode in which a research moving deformable barrier (RMDB) impacts a stationary vehicle at 90.1 kph, a 15 degree angle, and a 35% vehicle overlap. The test utilizes the THOR NT with modification kit (THOR) dummy positioned in both the driver and passenger seats. This paper compares the behavior of the THOR and Hybrid III dummies during this oblique research test mode. A series of four full vehicle oblique impact crash tests were performed. Two tests were equipped with THOR dummies and two tests were equipped with Hybrid III dummies. All dummies represent 50th percentile males and were positioned in the vehicle according to the FMVSS208 procedure. The Hybrid III dummies were instrumented with the Nine Accelerometer Package (NAP) to calculate brain injury criteria (BrIC) as well as THOR-Lx lower legs. Injury responses were recorded for each dummy during the event. High speed cameras were used to capture vehicle and dummy kinematics.
2014-04-01
Journal Article
2014-01-0587
Oliver Mankowski, David Sims-Williams, Robert Dominy
This paper outlines the creation of a facility for simulating on-road transients in a model scale, ¾ open jet, wind tunnel. Aerodynamic transients experienced on-road can be important in relation to a number of attributes including vehicle handling and aeroacoustics. The objective is to develop vehicles which are robust to the range of conditions that they will experience. In general it is cross wind transients that are of greatest significance for road vehicles. On-road transients include a range of length scales but the most important scales are in the in the 2-20 vehicle length range where there are significant levels of unsteadiness experienced, the admittance is likely to be high, and the reduced frequencies are in a band where a dynamic test is required to correctly determine vehicle response.
2014-04-01
Journal Article
2014-01-0609
Daichi Katoh, Kensuke Koremoto, Munetsugu Kaneko, Yoshimitsu Hashizume
An air-dam spoiler is commonly used to reduce aerodynamic drag in production vehicles. However, it inexplicably tends to show different performances between wind tunnel and coast-down tests. Neither the reason nor the mechanism has been clarified. We previously reported that an air-dam spoiler contributed to a change in the wake structure behind a vehicle. In this study, to clarify the mechanism, we investigated the coefficient of aerodynamic drag CD reduction effect, wake structure, and underflow under different boundary layer conditions by conducting wind tunnel tests with a rolling road system and constant speed on-road tests. We found that the air-dam spoiler changed the wake structure by deceleration of the underflow under stationary floor conditions. Accordingly, the base pressure was recovered by approximately 30% and, the CD value reduction effect was approximately 10%.
2014-04-01
Journal Article
2014-01-0598
Kenji Tadakuma, Takashi Sugiyama, Kazuhiro Maeda, Masashi Iyota, Masahiro Ohta, Yoshinao Komatsu
A new wind tunnel was developed and adopted by Toyota Motor Corporation in March 2013. This wind tunnel is equipped with a 5-belt rolling road system with a platform balance that enables the flow simulation under the floor and around the tires in on-road conditions. It also minimizes the characteristic pulsation that occurs in wind tunnels to enable the evaluation of unsteady aerodynamic performance aspects. This paper describes the technology developed for this new wind tunnel and its performance verification results. In addition, after verifying the stand-alone performance of the wind tunnel, a vehicle was placed in the tunnel to verify the utility of the wind tunnel performance. Tests simulated flow fields around the vehicle in on-road conditions and confirmed that the wind tunnel is capable of evaluating unsteady flows.
2014-04-01
Journal Article
2014-01-0613
Dirk Wieser, Hanns-Joachim Schmidt, Stefan Müller, Christoph Strangfeld, Christian Nayeri, Christian Paschereit
The experimental investigation was conducted with a 25%-scaled realistic car model called “DrivAer” mounted in a wind tunnel. This model includes geometric elements of a BMW 3 series and an Audi A4, accommodating modular, rear-end geometries so that it represents a generalized modern production car. The measurements were done with two different DrivAer rear end configurations (fastback and notchback) at varying side-wind conditions and a Reynolds number of up to Re=3.2·106. An array of more than 300 pressure ports distributed over the entire rear section measured the temporal pressure distribution. Additionally, extensive flow visualizations were conducted. The combination of flow visualization, and spatially and temporally resolved surface pressure measurements enables a deep insight into the flow field characteristics and underlying mechanisms.
2014-04-01
Journal Article
2014-01-0620
Austin Hausmann, Christopher Depcik
This study investigates the practicality of vehicle coast down testing as a suitable replacement to moving floor wind tunnel experimentation. The recent implementation of full-scale moving floor wind tunnels is forcing a re-estimation of previous coefficient of drag determinations. Moreover, these wind tunnels are relatively expensive to build and operate and may not capture concepts such as linear and quadratic velocity dependency along with the influence of tire pressure on rolling resistance. As a result, the method elucidated here improves the accuracy of the fundamental vehicle modeling equations while remaining relatively affordable. The trends produced by incorporating on road test data into the model fit the values indicated by laboratory tests. This research chose equipment based on a balance between affordability and accuracy while illustrating that higher resolution frequency equipment would further enhance the model accuracy.
2014-03-31
WIP Standard
AS4191A
This SAE Aerospace Standard (AS) provides a method for gas turbine engine performance computer programs to be written using FORTRAN COMMON blocks. If a "function-call application program interface" (API) is to be used, then ARP4868 and ARP5571 are recommended as alternatives to that described in this document. When it is agreed between the program user and supplier that a particular program shall be supplied in FORTRAN, this document shall be used in conjunction with AS681 for steady-state and transient programs. This document also describes how to take advantage of the FORTRAN CHARACTER storage to extend the information interface between the calling program and the engine subroutine.
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