Criteria

Display:

Results

Viewing 1 to 30 of 8628
2017-10-08
Technical Paper
2017-01-2408
Lei Zhou, Hongxing Zhang, Zhenfeng Zhao, Fujun Zhang
The Opposed Piston Two-Stroke (OPTS) engine has several advantages for power density, fuel tolerance, fuel efficiency and package space. A new type of balanced opposed-piston folded-crank train two-stroke engine for Unmanned Aerial Vehicle (UAV) was studied in this paper. The effects of high altitude environment on engine performance and emissions are investigated by thermodynamic simulation. Moreover, the matching between the engine and turbocharger was designed and optimized for different altitude levels. The results indicate that a suitable turbocharger for OPTS engine can achieve the purpose of improving the quality of scavenging, lowering the fuel consumption and recovering power at high altitude environment. Finally, an optimized OPTS engine model especially for UAV is proposed in this research.
2017-10-08
Technical Paper
2017-01-2442
Bingqing Xiao, Wei Wu, Jibin Hu, Shihua Yuan, Chenhui Hu
Abstract The prediction of temperature distribution and variation of oil-cooled sliding disk pair is essential for the design of wet clutches and brakes in a vehicle transmission system. A two-phase coupled heat transfer model is established in the study and some fluid-solid coupled heat transfer simulations are performed to investigate the thermal behaviors of wet clutch during sliding by CFD method. Both cooling liquid and grooved solid disks are contained in the heat transfer model and the heat convection due to the cooling liquid in the radial grooves is also considered by fluid-solid coupled transient heat transfer simulations. The temperature distribution and variation of the grooved disk are discussed and analyzed in detail. The results indicate that the temperature distribution on the grooved disk is nonuniform. The temperature within the middle radius area is higher than that in the inner and outer radius area.
2017-10-08
Technical Paper
2017-01-2222
ZhenYang Liu, Xihui Wang
The ever increasing popularity of electric vehicles and demand in passengers comfort and safe requirements of vehicle have led more efficient heat pump air conditioning system to an indispensable device in electric vehicle. Many studies have shown that the addition of nano particles contributes to improving the thermal conductivity of nano fluids more than that of conventional refrigerants. Therefore, the appliance of the magnetic nano-refrigerant in heat pump air conditioning system has great potential to improve the heat transfer efficiency. This paper aims at studying the magnetic nano-refrigerant comprised of the magnetic nano powder Fe3O4 and refrigerant R134a.According to the relevant theoretical analysis and different empirical formula, the heat transfer coefficient, density, viscosity, and other physical parameters are calculated approximately.
2017-10-08
Technical Paper
2017-01-2229
Byeongsoek Lee, Heechang Oh, SeungKook Han, SooHyung Woo, JinWook Son
There are two way to improve engine thermal efficiency. One is to improve the theoretical thermal efficiency by increasing the compression ratio and specific heat ratio. The other is to reduce various engine losses like friction, pumping, heat loss. For the development of Ultra High Efficiency, We designed the new 2.0L NA GDI engine based on HMC's Nu 2.0L GDI engine. We conducted various parameter studies related to gasoline combustion characteristic, such as compression ratio, ignition system, intake port design, cam duration, Cooled EGR, etc. As a result, we achieved the maximum thermal efficiency up to 42%(~200g/kWh) in stoichiometric AFR. This paper described the ways and possibilities to improve the maximum thermal efficiency.
2017-10-08
Technical Paper
2017-01-2381
Kristian Hentelä, Ossi Kaario, Vikram Garaniya, Laurie Goldsworthy, Martti Larmi
In the present study, a new approach for modelling emissions of coke particles or cenospheres from large diesel engines using HFO (Heavy fuel oil) was studied. The model used is based on a multicomponent droplet mass transfer and properties model that uses a continuous thermodynamics approach to model the complex composition of the HFO fuel and the resulting evaporation behavior of the fuel droplets. Cenospheres are modelled as the residue left in the fuel droplets towards the end of the simulation. The mass-transfer and fuel properties models were implemented into a cylinder section model based on the Wärtsilä W20 engine in the CFD-code Star CD v.4.24. Different submodels and corresponding parameters were tuned to match experimental data of cylinder pressures available from Wärtsilä for the studied cases. The results obtained from the present model were compared to experimental results found in the literature.
2017-10-08
Technical Paper
2017-01-2196
Giuseppe Cicalese, Fabio Berni, Stefano Fontanesi, Alessandro D'Adamo, Enrico Andreoli
Abstract High power-density Diesel engines are characterized by remarkable thermo-mechanical loads. Therefore, compared to spark ignition engines, designers are forced to increase component strength in order to avoid failures. 3D-CFD simulations represent a powerful tool for the evaluation of the engine thermal field and may be used by designers, along with FE analyses, to ensure thermo-mechanical reliability. The present work aims at providing an integrated in-cylinder/CHT methodology for the estimation of a Diesel engine thermal field. On one hand, in-cylinder simulations are fundamental to evaluate not only the integral amount of heat transfer to the combustion chamber walls, but also its point-wise distribution. To this specific aim, an improved heat transfer model based on a modified thermal wall function is adopted to estimate correctly wall heat fluxes due to combustion.
2017-10-08
Technical Paper
2017-01-2204
Hoon Lee, Kwangwoo Jeong, Sanghoon Yoo, Byungho Lee, Sejun Kim
Abstract Hyundai-Kia Motor Company recently developed a multi-way, electrical coolant valve for engine thermal management module (TMM). The main purposes of the TMM are to boost fuel economy by accelerating engine warm-up and also to enhance engine thermal efficiency by actively controlling the operating temperature. In addition to those, the system can improve vehicle heating and cooling performance as well. The electrical coolant valve is a key component in the TMM as it modulates the amount of coolant flow to individual components in cooling system such as engine oil heat exchanger, heater core, and radiator. The coolant flow modulation is done by controlling the electric valve’s position with using an electric motor attached to the valve. The objective of the valve control is to manage coolant temperature at a desired level that varies depending on vehicle’s operating condition. This paper discusses the control algorithm developed for controlling electrical coolant valve.
2017-09-23
Technical Paper
2017-01-1984
Jun Ma, Junyi Li, Zaiyan Gong, Jihong Yu
Abstract Given the wide adoption of touchscreens in vehicles, an interesting debate is taking place regarding the good screen size, length-width ratio and whether the usability of in-vehicle information system (IVIS) would be decreased by a larger screen, especially. Moreover, the lack of scientific evidence about the concrete impact of touch screen size on usability raises questions to practitioners. In this paper, we investigated the impact of in-vehicle touch screen size on users’ visual behavior and usability as measured using eye tracker and questionnaire. Two experiments were conducted on 30 participants. In the first experiment, participants were asked to seek same information on four different in-vehicle screens based on simulated driving environment, while eye movement was recorded for analyzing efficiency of visual behavior.
2017-09-19
Journal Article
2017-01-2156
Philippe Coni, Jean Luc BARDON, Xavier servantie
Abstract A new concept of Head Up Display is presented, using the windshield as a transparent screen. This breakthrough technology does not need the use of complex combiner, bulky optics and overhead projection unit. The novel system uses several holographic optical elements to perform a 3D stereoscopic display, with the ability to present floating graphical objects in a large field of view. Augmented Reality display will be possible, increasing considerably the User Experience and situational awareness, without the need of wearing a bulky and complex Head Mounted Display.
2017-09-19
Technical Paper
2017-01-2158
Fernando Stancato, Luis Carlos dos Santos, Marcelo Pustelnik
Abstract A problem of interest of the aeronautical industry is the positioning of electronic equipment in racks and the associated ventilation system project to guarantee the equipment operational conditions. The relevance of the proper operation of electronic equipment increases considerably when high economical costs, performance reduction and safety are involved. The appropriate operational conditions of the electronic components happen when the working temperature of the equipment installed in the rack is inside a safety project temperature margin. Therefore, the analysis and modelling of heat transfer processes for aircraft rack design becomes mandatory. This paper presents a parametric study considering volumetric and superficial heat generation in electronic equipment within racks in an aircraft. Simulations were performed using the commercial CFD Fluent code and results were compared to experimental data.
2017-09-19
Technical Paper
2017-01-2052
K Friedman, G Mattos, K Bui, J Hutchinson, A Jafri, J Paver PhD
Abstract Aircraft seating systems are evaluated utilizing a variety of impact conditions and selected injury measures. Injury measures like the Head Injury Criterion (HIC) are evaluated under standardized conditions using anthropomorphic dummies such as those outlined in 14 CFR part 25. An example test involves decelerating one or more rows of seats and allowing a lap-belted dummy to impact components in front of it, which typically include the seatback and its integrated features. Examples of head contact surfaces include video monitors, a wide range of seat back materials, and airbags. The HIC, and other injury measures such as Nij, can be calculated during such impacts. A minimum test pulse, with minimum allowable acceleration vs time boundaries, is defined as part of the regulations for a frontal impact. In this study the effects of variations in decelerations that meet the requirements are considered.
2017-09-19
Technical Paper
2017-01-2054
K Friedman, G Mattos, K Bui, J Hutchinson, A Jafri, J Paver
Abstract Aircraft seating systems are evaluated utilizing a variety of impact conditions and select injury measures. Injury measures like the Head Injury Criterion (HIC) are evaluated under standardized conditions using anthropomorphic test devices such as those outlined in 14 CFR part 25. An example test involves decelerating one or more rows of seats and allowing a lap-belted ATD to engage components in front of it, which typically include the seatback and its integrated features. Examples of head contact surfaces include video monitors, various plastic and composite fascia, and a wide range of seat back materials. The HIC, and other injury measures such as Nij, can be calculated during such impacts. It has been shown in other safety applications that the friction between a headform and contact surface can affect the test results.
2017-09-19
Technical Paper
2017-01-2038
Russell H. Strehlow
Abstract A Vapor Envelope is an ultra-thin-walled vapor chamber that enables a unique combination of lighter weight, lower profile, and lower cost for heat spreading or heat removal applications. It evolved from work done as part of a DARPA program on Thermal Ground Planes. This paper examines a published testing protocol for the measurement of the thermal resistance of thin flexible thermal ground planes. It then applies an adapted version of the published technique to measure the thermal resistance of a vapor envelope and a dimensionally equivalent solid copper heat spreader. Finally, it looks at the implications of a significantly lower thermal resistance for a specific configuration. The analysis of whether this adapted technique would provide a sufficient metric for industrial application identified the control and understanding of the thermal interface materials as a key determinate.
2017-09-19
Technical Paper
2017-01-2040
Salvatore Cezar Pais
Abstract It may be possible to generate high power / high frequency gravitational waves (HFGWs) by high frequency accelerated axial rotation (spin) and/or accelerated high frequency vibration of an electrically charged, possibly asymmetric structure, within the context of non-equilibrium thermodynamics, namely far-from-equilibrium physics, highly non-linear in nature. The structure which is the HFGW generator (HFGWG), has the ability to control the accelerated modes of vibration and spin of its electrically charged surfaces, in particular the rapid rates of change of accelerated-decelerated-accelerated vibration and/or accelerated-decelerated-accelerated gyration (axial spin) of these electrified surfaces, in this manner delaying the onset of relaxation to thermodynamic equilibrium, thus generating a physical mechanism which may induce anomalous effects.
2017-09-19
Technical Paper
2017-01-2039
Michael Sielemann, Changsoo Lee, Victor-Marie LeBrun, Chiwoo Ahn, Arnaud Colleoni, Dongkyu Lee, JeongSeok Lee, Anh Nguyen, Katrin Proelss, Hyon Min Yoon
Abstract Thermal management on aircraft has been an important discipline for several decades. However, with the recent generations of high performance aircraft, thermal management has evolved more and more into a critical performance and capability constraint on the whole aircraft level. Fuel continues to be the most important heat sink on high performance aircraft, and consequently the requirements on thermal models of fuel systems are expanding. As the scope of modeling and simulation is widened in general, it is not meaningful to introduce a new isolated modeling and simulation capability. Instead, thermal models must be derived from existing model assets and eventually enable integration across several physical domains. This paper describes such an integrated approach based on the Modelica Fuel System Library and the 3DExperience Platform.
2017-09-19
Technical Paper
2017-01-2071
Keith Miazgowicz
The advent of turbochargers and the Eco-Boost technology at Ford in gasoline engines creates new challenges that need to be addressed with innovative designs. One of them is flow induced noise caused by airflow entering the turbocharger during off design operation. At certain vehicle operation conditions, the mass flow rate and pressure ratio are such that compressor wheel can generate a wide range of acoustic frequencies. Characterization of ‘whistles’ or pure tonal noises, ‘whoosh’ or broad band frequency noise caused by flow separation from the blade surfaces, and chirps, where the frequency increases or decreases with time are a few of the common error states. Understanding the fundamental mechanisms of such noise generation is necessary for developing effective countermeasures for the noise source generation. Computational Aero-Acoustic (CAA) analyses are performed to study the effects of inlet and outlet conditions to find the source of the noise.
2017-09-19
Technical Paper
2017-01-2113
Michael Schultz
Abstract Passenger boarding is always part of the critical path of the aircraft turnaround: both efficient boarding and online prediction of the boarding progress are essential for a reliable turnaround progress. However, the boarding progress is mainly controlled by the passenger behavior. A fundamental scientific approach for aircraft boarding enables the consideration of individual passenger behaviors and operational constraints in order to develop a sustainable concept for enabling a prediction of the boarding progress. A reliable microscopic simulation approach is used to model the passenger behavior, where the individual movement is defined as a one-dimensional, stochastic, and time/space discrete transition process. The simulation covers a broad range of behaviors and boarding strategies as well as the integration of new technologies and procedures.
2017-09-19
Technical Paper
2017-01-2161
Alexander J. Pollok
Abstract For thermal cabin control of commercial aircraft, the cabin is usually divided into a small number of temperature zones. Each zone features its own air supply pipe. The necessary installation space for ducting increases significantly with the number of zones. This requires the number of temperature zones to be low. Factors such as seating layout, galley placement and passenger density result in deviations in heat flux throughout the cabin. These deviations cannot be compensated by the control system, if they occur within the same temperature zone. This work presents a novel temperature regulation concept based on local mixing. In this concept, two main ducts span the complete cabin length, and provide moderately warm and cold air. At each temperature zone, cabin supply air is locally mixed using butterfly valves.
2017-09-19
Technical Paper
2017-01-2160
Ferdinand Spek, Maarten Weehuizen, Ilja Achterberg
Abstract In new aircraft programs, systems’ functionality is increasingly becoming integrated into modular avionics. Controllers may not be delivered by the systems supplier so this trend creates a new interface between systems and controllers. A functional software specification is therefore needed to facilitate the building of the software by the controller supplier. In the case of an ECS system controller, the hardware was obtained from different suppliers and a software functional specification was needed for the controller supplier. To be able to design and verify the system functionality, an integrated ECS simulation model was created which coupled the thermodynamics of the aircraft and ECS system to the controller actions. The model also included functionality to simulate sensor noise and component failures. The thermodynamic model was created in Matlab/Simulink and consisted of a combination of direct programming as well as data on a Flowmaster model for the bleed system.
2017-09-19
Technical Paper
2017-01-2037
Daniel Schlabe, Dirk Zimmer, Alexander Pollok
Abstract The thermal inertia of aircraft cabins and galleys is significant for commercial aircraft. The aircraft cabin is controlled by the Environment Control System (ECS) to reach, among other targets, a prescribed temperature. By allowing a temperature band of ± 2 K instead of a fixed temperature, it is possible to use this thermal dynamic of the cabin as energy storage. This storage can then be used to reduce electrical peak power, increase efficiency of the ECS, reduce thermal cooling peak power, or reduce engine offtake if it is costly or not sufficiently available. In the same way, also the aircraft galleys can be exploited. Since ECS and galleys are among the largest consumers of electrical power or bleed air, there is a large potential on improving energy efficiency or reducing system mass to reduce fuel consumption of aircraft. This paper investigates different exploitation strategies of cabin and galley dynamics using modelling and simulation.
2017-09-19
Technical Paper
2017-01-2046
Pejman Akbari, Ian Agoos
Abstract The Wave Disk Engine (WDE) is a novel engine that has the potential for higher efficiency and power density of power-generation systems. A recent version of wave disk engine architecture known as the two-stage WDE has been studied to address existing challenges of an existing WDE. After describing the engine operation, a cold air-standard thermodynamic model supporting the physical phenomena occurring inside the device is introduced to evaluate performance of the engine. The developed model is general and does not depend on the shape of the wave rotor, it can be applied to radial and axial combustion wave rotors integrated with turbomachinery devices. The analysis starts with predicting internal waves propagating inside the channels of the engine and linking various flow states to each other using thermodynamics relationships. The goal is to find analytical expressions of work output and efficiency in terms of known pressure and temperature ratios.
2017-09-19
Technical Paper
2017-01-2044
Mithilesh Kumar Sahu, Tushar Choudhary, Sanjay Y
Abstract Aircraft engines powering propulsion of the aircraft is the key component of the system. In aircraft industry it is desirable that an aircraft engines should supply high speeds (for military fighters) with low maintenance (for civil airplanes). In this regard an integration of gas turbine engines with traditional propeller has been introduced and termed as turboprop engine. In present work, a gas turbine with cooled blading has been proposed to be the turboprop engine which has been exergoeconomically analyzed to assess the performance and economics related to the proposed turboprop engine. Exergo-economic analysis is a tool which combines thermodynamic analysis and economic principles to provide information that is helpful to predict thermodynamic performance and total cost of the engine (thermal system). The methodology includes energy, exergy and cost balance equations for component-wise modelling of whole system.
2017-09-19
Technical Paper
2017-01-2045
Shivam Mishra, Sanjay Y
Abstract Air-film cooled gas turbine is widely used in aero-derivative gas turbines. The present paper reviews previously developed air-film blade cooling models. The article further proposes a new blade cooling model for estimating blade coolant mass fraction which takes into account the effect of radiative heat transfer from hot flue gases to aero-derivative gas turbine blade surface. Various possibilities to achieve enhanced performance from aero-derivative gas turbine have been enumerated namely effect of advanced design philosophies, thermal barrier coatings, advancement in blade material. Also adoption of advanced design philosophies such as 3-D CFD would lead to improved component design. Further use of advanced blade material specifically for gas turbine blade application including single-crystal blade, directionally solidified blade material being nickel-chrome-molybdenum alloys may be explored.
2017-09-19
Technical Paper
2017-01-2062
Tushar Choudhary, Mithilesh Sahu, Shreya KRISHNA
Abstract Gas turbine technology has traditionally been used by the aviation industry for powering the aircraft including acting as APU. Operational unmanned aerial vehicle (UAV) has a gas turbine which is used as Auxiliary Power Unit (APU) which generically have overall efficiency not exceeding 35% which limits the range in terms of time in the air for the same APU fuel carried onboard. Gas turbine exhaust heat energy is largely wasted and there is scope of its utilization by thermally coupling it with a solid-oxide fuel cell (SOFC). By coupling SOFC with the gas turbine (GT) based power system, a hybrid SOFC-GT based APU system has been proposed for thermodynamic analysis, and the thermal efficiency of the proposed system can be enhanced by 77%. This paper focuses on a thermodynamic cycle analysis of an internal reformed solid oxide fuel cell which is integrated with the gas turbine to form a hybrid APU system for an UAV.
2017-09-17
Technical Paper
2017-01-2500
Bo Huang, Wanyang Xia, Gangfeng Tan, Longjie Xiao, Zongsong Wang
Abstract Head-up Display (HUD) system can avoid drivers’ distraction on dashboard and effectively reduce collisions caused by emergency events, which is gradually being realized by researchers around the world. However, the current HUD only displays information like speed, fuel consumption, other information like acceleration and braking can’t be displayed yet. This research will use the indicator symbol‘s color and position change to remind drivers to brake or accelerate. Drivers can do driving operation timely and accurately. The system has the advantages of safety, intuition and real-time. The vehicle safe speed is calculated according to the road parameters, like adhesion coefficient and slope, and vehicle parameters, such as vehicle mass and centroid. Then, the appropriate braking operations are obtained by combining the vehicle driving state.
2017-09-04
Technical Paper
2017-24-0016
Morris Langwiesner, Christian Krueger, Sebastian Donath, Michael Bargende
Abstract The real cycle simulation is an important tool to predict the engine efficiency. To evaluate Extended Expansion SI-engines with a multi-link cranktrain, the challenge is to consider all concept specific effects as best as possible by using appropriate submodels. Due to the multi-link cranktrain, the choice of a suitable heat transfer model is of great importance since the cranktrain kinematics is changed. Therefore, the usage of the mean piston speed to calculate a heat-transfer-related velocity for heat transfer equations is not sufficient. The heat transfer equation according to Bargende combines for its calculation the actual piston speed with a simplified k-ε model. In this paper it is assessed, whether the Bargende model is valid for Extended Expansion engines. Therefore a single-cylinder engine is equipped with fast-response surface-thermocouples in the cylinder head. The surface heat flux is calculated by solving the unsteady heat conduction equation.
2017-09-04
Technical Paper
2017-24-0032
Gilles Decan, Stijn Broekaert, Tommaso Lucchini, Gianluca D'Errico, Jan Vierendeels, Sebastian Verhelst
Abstract The present work details a study of the heat flux through the walls of an internal combustion engine. The determination of this heat flux is an important aspect in engine optimization, as it influences the power, efficiency and the emissions of the engine. Therefore, a set of simulation tools in the OpenFOAM® software has been developed, that allows the calculation of the heat transfer through engine walls for ICEs. Normal practice in these types of engine simulations is to apply a wall function model to calculate the heat flux, rather than resolving the complete thermo-viscous boundary layer, and perform simulations of the closed engine cycle. When dealing with a complex engine, this methodology will reduce the overall computational cost. It however increases the need to rely on assumptions on both the initial flow field and the behavior in the near-wall region.
2017-09-04
Technical Paper
2017-24-0107
Alessandro Montanaro, Luigi Allocca, Vittorio Rocco, Michela Costa, Daniele Piazzullo
Abstract Gasoline direct injection (GDI) engines are characterized by complex phenomena involving spray dynamics and possible spray-wall interaction. Control of mixture formation is indeed fundamental to achieve the desired equivalence ratio of the mixture, especially at the spark plug location at the time of ignition. Droplet impact on the piston or liner surfaces has also to be considered, as this may lead to gasoline accumulation in the liquid form as wallfilm. Wallfilms more slowly evaporate than free droplets, thus leading to local enrichment of the charge, hence to a route to diffusive flames, increased unburned hydrocarbons formation and particulate matter emissions at the exhaust. Local heat transfer at the wall obviously changes if a wallfilm is present, and the subtraction of the latent heat of vaporization necessary for secondary phase change is also an issue deserving a special attention.
2017-09-04
Technical Paper
2017-24-0158
Teresa Castiglione, Giuseppe Franzè, Angelo Algieri, Pietropaolo Morrone, Sergio Bova
Abstract In this paper, we propose a novel control architecture for dealing with the requirements arising in a cooling system of an ICE. The idea is to take advantage of the joint action of an electric pump and of an ad-hoc regulation module, which is used to determine adequate flow rates despite engine speeds. Specifically, a robust Model Predictive Control approach is exploited to take care formally of input/output constraints and disturbance effects of the resulting lumped parameter model of the engine cooling system, which incorporates the nucleate boiling heat transfer regime. Numerical simulations and test rig experimental data are presented. The results achieved show that the proposed control scheme is capable of providing effective and safe cooling while mitigating disturbance effects and minimizing coolant flow rates when compared with the action pertaining to standard crankshaft driven pumps.
2017-09-04
Journal Article
2017-24-0161
Noboru Uchida, Hideaki Osada
Abstract To reduce heat transfer between hot gas and cavity wall, thin Zirconia (ZrO2) layer (0.5mm) on the cavity surface of a forged steel piston was firstly formed by thermal spray coating aiming higher surface temperature swing precisely synchronized with flame temperature near the wall resulting in the reduction of temperature difference. However, no apparent difference in the heat loss was analyzed. To find out the reason why the heat loss was not so improved, direct observation of flame impingement to the cavity wall was carried out with the top view visualization technique, for which one of the exhaust valves was modified to a sapphire window. Local flame behavior very close to the wall was compared by macrophotography. Numerical analysis by utilizing a three-dimensional simulation was also carried out to investigate the effect of several parameters on the heat transfer coefficient.
Viewing 1 to 30 of 8628