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2016-05-05
Journal Article
2015-01-9148
Saeed Asgari, Shailendra Kaushik
Abstract A linear parameter varying (LPV) reduced order model (ROM) is used to approximate the volume-averaged temperature of battery cells in one of the modules of the battery pack with varying mass flow rate of cooling fluid using uniform heat source as inputs. The ROM runs orders of magnitude faster than the original CFD model. To reduce the time it takes to generate training data, used in building LPV ROM, a divide-and-conquer approach is introduced. This is done by dividing the battery module into a series of mid-cell and end-cell units. A mid-cell unit is composed of a cooling channel sandwiched in between two half -cells. A half-cell has half as much heat capacity as a full-cell. An end-cell unit is composed of a cooling channel sandwiched in between full-cell and a half-cell. A mass flow rate distribution look-up-table is generated from a set of steady-state simulations obtained by running the full CFD model at different inlet manifold mass flow rate samples.
2016-04-05
Technical Paper
2016-01-0637
Yusheng Wang, David L.S. Hung, Hanyang Zhuang, Min Xu
Cycle-to-cycle variation of in-cylinder flows is considered a significant problem affecting the stability, fuel economy, and emission of engine performance. In this experimental investigation, high-speed time-resolved particle image velocimetry (PIV) is applied to quantify the flow field along the swirl plane under different both low and high swirl flow conditions. The swirl flow is created by controlling the opening of a control valve mounted in one of the two intake ports. The objective is to quantify the cycle-to-cycle variation of the in-cylinder flow fields at different crank angles of the engine cycle. Four zones along the measured swirl plane are divided according to the positions of four valves in the cylinder head respectively. Relevant index is used to evaluate the cycle-to-cycle variation of the velocity flow field for each zone. A comparison of relevant index for each zone between intake and compression strokes is made.
2016-04-05
Technical Paper
2016-01-0017
Alessandro Biondi, Marco Di Natale, Youcheng Sun
Several application developers are currently faced with the problem of moving a complex system from a single-core to a multicore platform. The problem encompasses several issues that go from modeling issues (the need to represent the system features of interest with sufficient accuracy) to analysis and optimization techniques, to the selection of the right formulations for constraints that relate to time. We report on the initial findings in a case study in which the application of interest is a fuel injection system. We provide an analysis on the limitations of AUTOSAR and the existing modeling tools and we discuss applicable optimization methods and analysis algorithms.
2016-04-05
Technical Paper
2016-01-0784
Shuojin Ren, Zhi Wang, Shouzhi Xiang, Hongxue Zhao, Jianxin Wang
Homogeneous charge induced ignition (HCII) combustionis believed to be a promising approach to achieve clean and high efficiency combustion. HCII can be realized by using port-injection of the high-volatile fuel (gasoline) to prepare in-cylinder homogeneous charge and direct injection ofthe high-ignitable fuel (diesel) near the top dead center (TDC) to control the start of combustion. In the current study, a numerical study was carried out to understand mixing and auto-ignition process in HCII combustion. A multi-component chemical kinetic mechanism for gasoline and diesel, consisting of n-heptane, iso-octane, ethanol, toluene, diisobutylene and n-decane, has been developed for predicting their ignition and oxidation. The final mechanism consists of 104 species and 398 reactions. This mechanism was validated with the experimental data of ignition delay times and laminar flame speeds for each component, mixed multi-component surrogate fuels as well as real transportation fuels.
2016-04-05
Technical Paper
2016-01-1356
Can Li, Yadong Deng, Yuhua Xin
As a key component of airstream system equipped in the road sweeper, the structure of the suction nozzle determines the distribution of the internal flow field, which affects the dust-sucking efficiency and capability to a great degree. The goal of this research is to determine a better structure of the suction nozzle. Starting with an analysis of the one used in a certain type of road sweeper, the initial model of the suction nozzle is established, and the internal flow field is simulated with typical CFD software named FLUENT. Based on the simulation results, the dust-sucking capability of the initial structure is evaluated from the aspects of pressure and velocity distribution. Furthermore, in order to explore the influence of different structural parameters on the flow field distribution within the suction nozzle, models with different cavity heights and shoulder angles are established, and Univariate Method is used to analyze the contrast models.
2016-04-05
Technical Paper
2016-01-1608
Asiful Islam, Ben Thornber
Current vehicle aerodynamic development makes extensive use of Computational Fluid Dynamics (CFD) to enable cost-effective design and parametric exploration of features. Although larger-scale, high fidelity simulations are increasingly popular, practical Reynolds number ranges (105-108) necessitate hybrid modelling approaches which offer practical alternatives to fully-resolved Large-Eddy Simulation (LES) to provide improved predictive capability for separated, turbulent flows. This paper presents a new hybrid turbulence modelling algorithm which combines a high-order, enhanced Spalart-Allmaras model with an Implicit LES, to effectively relax associated grid resolution requirements and eliminate the need for explicit subgrid scale models.
2016-04-05
Technical Paper
2016-01-1364
Martin Schifko, Hans Steiner, Bernhard Kornberger
The last enhancements of the solver allows one to use multipart objects as body in whites and combine them similar to reality. The triangulated surface got well prepared in a way that the possible output can be a high quality tetrahedral mesh possible to use for CFD or CAE simulations. One of the main advantages are that no manual work is needed and the process runs fully automatic. In this paper we will explain some algorithms behind the latest enhancements.
2016-04-05
Technical Paper
2016-01-1600
Pruthviraj Mohanrao Palaskar, Vivek Kumar, Rohit Vaidya
Important vehicle performance parameters such as, fuel economy and high speed stability are directly influenced by its aerodynamic drag and lift. Wind tunnel testing to asses these parameters is a late stage in vehicle development. Hence to save cost and compress development time, it is essential to asses and optimize parameters of a vehicle in very early stages of development. Using numerical flow simulations optimization runs can be carried out digitally. Industry demands to predict aerodynamics drag and lift coefficients(CD,CL) within the accuracy of few counts, consuming minimal HPC resources and in short turnaround time. Different OEMs deploy different testing methods and different softwares for numerical simulations. Hence, correlation level for numerical prediction depends on factors viz; type of meshing, boundary conditions, turbulent models, CAD geometry and wind tunnel used for correlation.
2016-04-05
Technical Paper
2016-01-1368
Hongwen Wu, Johan Brunberg, Mireia Altimira, Niclas Bratt, Henrik Nyberg, Andreas Cronhjort, Justinas Peciura
Due to the requirement of contemporary automotive engine bay downsizing, air filter box has to be packed in a limit space without losing pressure drop, load capacity and efficiency. Yet, the air mass flow measurement at filter box outlet is sensitive to the flow changing. For those two reasons, this paper has developed an industrial affordable model to count the dust load on filter elements and calculate flow behavior over the life time in the air filter box. The model use semi-empirical models which are carried out by fundamental researches of calculating flows over pleated filters. This work also introduces an experiment method to record dust pattern in order to correlate the simulation result.
2016-04-05
Technical Paper
2016-01-0638
Suresh Gadekar, Akhilendra Pratap Singh, Avinash Kumar Agarwal
In this study, 3D air-flow-field evolution in a single cylinder optical research engine was determined using tomographic particle imaging velocimetry (PIV) at different engine speeds. Two directional projections of captured flow-field were pre-processed to reconstruct the 3D flow-field by using the MART (multiplicative algebraic reconstruction technique) algorithm. Ensemble average flow pattern was used to investigate the air-flow behavior inside the combustion chamber during the intake and compression strokes of an engine cycle. In-cylinder air-flow characteristics were significantly affected by the engine speed. Experimental results showed that high velocities generated during the first half of the intake stroke dissipated in later stages of the intake stroke. In-cylinder flow visualization indicated that large part of flow energy dissipated during the intake stroke and energy dissipation was the maximum near the end of the intake stroke.
2016-04-05
Technical Paper
2016-01-0587
Vamshi Krishna Dawat, Ganesan Venkitachalam
This paper deals with a numerical investigation on swirl generation by a helical intake port and its effects on in-cylinder flow characteristics with axisymmetric piston bowls in a small four-valve direct injection diesel engine. The novelty of this study is in determining the appropriate design and orientation of the helical port to generate high swirl. A commercial CFD software STAR-CD is used to perform the detailed three dimensional simulations. Preliminary studies were carried out at steady state conditions with the helical port which demonstrated a good swirl potential and the CFD predictions were found to have reasonably good agreement with the experimental data taken from literature. For transient cold flow simulations, the STAR-CD code was validated with Laser Doppler Velocimetry (LDV) experimental velocity components’ measurements available in literature.
2016-04-05
Technical Paper
2016-01-1340
Vikram Dang, Subhash chander PhD
This paper presents a CFD simulation methodology for solving complex physics of methane/air swirling turbulent flame impinging on a flat surface. Turbulent burner is simulated using Re-Normalized Group k-ε model while Stress-omega Reynolds Stress Model was used for flame structure. Turbulence-Chemistry Interaction is accounted for using Eddy – Dissipation Model. The effect of varying burner exit nozzle to plate distance is also investigated and comparisons of simulated results with experiments are discussed. Dip observed in heat flux distribution is due to the axial velocity profile close to the impingement surface, which further depends on the presence of central weak flow region created at and around the central axis.
2016-04-05
Technical Paper
2016-01-1346
Tomoyuki Hosaka, Taisuke Sugii, Eiji Ishii, Kazuhiro Oryoji, Yoshihiro Sukegawa
For the internal combustion engine, the improved fuel economy and low pollutant emissions are unequivocally demanded. The motivation of the study is to develop the computational fluid dynamics (CFD) technologies to investigate the internal combustion engine (ICE). In this study, the gasoline direct injection (GDI) engine is aimed to be studied. GDI system is considered to have an ability of the high fuel efficiency, but the further investigations are required to reduce the particulate matter (PM) or the particle number (PN). From the view of the industrial use, CFD is a useful tool to determine the spray specification which is important in GDI systems. In the current study the open-source software OpenFOAM® is adopted to a practical use of study on the in-cylinder process. The study presents the ability of OpenFOAM® as a numerical simulation tool for ICE, and its application to a 4-stroke engine.
2016-04-05
Technical Paper
2016-01-0221
Roberto Monforte, Fabrizio Mattiello, Andrea Perosino, Fabrizio Porta, Susanna Paz, Pablo Lopez del Rincón
The adoption of a low-GWP refrigerant gas in MAC systems is mandatory from 2017 according to the European Directive 2006/40/EC requirements for new vehicles registration. The paper will present the activities held by CRF to support the FCA evaluation of the risk involved by the adoption of the low-GWP refrigerant gas R-1234yf in the MAC systems equipping both new types and current programs, which MACs have to be converted in order to exploit the low-GWP refrigerant gas R-1234yf in order to comply with the 2006/40/EC Directive requirements and gain vehicle registrations from January 1st, 2017. In certain concentrations, R-1234yf could present a safety hazard to the vehicle occupants or to a technician required to service the vehicle. Hazard: event which has the potential to cause harm to an individual. Risk: numerical estimate of the probability or likelihood that a given hazard will occur. Risks are estimated via the process of risk assessment.
2016-04-05
Technical Paper
2016-01-0648
Sinan Eroglu, Ipek Duman, Alp Ergenc, Rıfat Yanarocak
The exhaust manifold bridges the gap between the engine structure and the hot-end after-treatment system, the burned in-cylinder gases are disposed through the manifold. The automotive exhaust manifolds are designed and developed for providing a smooth flow with low/least back pressure and must be able to withstand extreme heating under very high temperatures and cooling under low temperatures. The present paper describes three different CAE thermal analysis approaches to obtain the metal temperature distribution of the exhaust manifold. Also, comparison with thermal camera measurements is presented. The computational fluid dynamics (CFD) of the exhaust manifold system was carried out to understand the flow pattern within the system and to obtain the surface convection loading distribution which was used to calculate temperature distribution of exhaust manifold structure.
2016-04-05
Technical Paper
2016-01-0636
Kevin L. Hoag, Anthony Megel
The objective of this work was to develop a methodology to assess comparative intake port designs for their capability to produce tumble flow in spark-ignition engine combustion chambers. A literature review and prior work with a steady-flow cylinder head test bench led to the conclusion that existing approaches fell far short of that needed. In creating intake ports to optimize tumble characteristics, engine development engineers have had to adopt resource-intensive approaches such as particle velocity measurements in engines with optical access, or computationally detailed, moving piston, three-dimensional finite element modeling. There have been a number of efforts to generate a “tumble number” or “tumble ratio” from steady-state cylinder head flow benches. These efforts have been loosely based on the previous development of “swirl numbers” or swirl ratios.” Steady-state bench measurements of swirl are well established, and correlate quite well to engine test results.
2016-04-05
Technical Paper
2016-01-1617
Yoshinobu Yamade, Chisachi Kato, Shinobu Yoshimura, Akiyoshi Iida, Keiichiro Iida, Kunizo Onda, Yoshimitsu Hashizume, Yang GUO
The objective of this research is to predict accurately aeroacoustical interior noise of a car for a wide range of frequency between 100 Hz and 4 kHz. One-way coupled simulations of CFD, structural analysis and acoustical analysis were performed to predict the interior aeroacoustical noise. Statistical Energy Analysis (SEA), which is a traditional method for evaluating transmission of sound and interior sound field, cannot be used for a low frequency range, while the proposed method can be used for a wide range of frequency including a low frequency range. We predicted pressure fluctuations on the external surfaces of a car by computing unsteady flow around a car as the first step. Secondly, the predicted pressure fluctuations were fed to the subsequent structural analysis to predict vibration accelerations on the internal surfaces of the car.
2016-04-05
Technical Paper
2016-01-1084
Chendi Sun, Vinson Jia
With rigorous fuel consumption regulation and emission law implemented, accuracy requirement of design and measurement signal is increasing, it becomes more and more indispensable to consider the influence on pressure loss and flow behavior coming from the incrementally loaded dust on filter element of Air Intake System (AIS). Dust is composed of many different sizes of particles, and studies shows that these different sizes of particles have very distinct influence on pressure loss of filter elements, which makes dust a challenge to model in Computational Fluid Dynamics (CFD) simulation. In order to precisely simulate pressure loss behavior of dust loaded filter element, a methodology for 3-D CFD dust loading simulation is developed, where the influence of particles sizes on pressure loss of filter element are taken into consideration by introducing a pressure loss weighting factors.
2016-04-05
Technical Paper
2016-01-0858
Piotr Strek, Daniel Duke, Andrew Swantek, Alan Kastengren, Christopher F. Powell, David P. Schmidt
The salient features of modern gasoline direct injection include cavitation, flash boiling, and plume/plume interaction, depending on the operating conditions. These complex phenomena make the prediction of the spray behavior particularly difficult to understand and predict. The present investigation combines mass-based experimental diagnostics with an advanced, in-house modeling capability in order to provide a multi-faceted study of the Engine Combustion Network's Spray G injector. First, radiography is used to distinguish the actual injector geometry from the nominal geometry used in past works. The actual geometry is used as the basis of multidimensional CFD simulations which are compared to measurements for validation under cold conditions. The influence of nozzle diameter and corner radius are of particular interest. Next, the model is used to simulate flash-boiling conditions, in order to understand how the cold flow behavior corresponds to flashing performance.
2016-04-05
Technical Paper
2016-01-1582
Dirk Wieser, Sabine Bonitz, Lennart Lofdahl, Alexander Broniewicz, Christian Nayeri, Christian Paschereit, Lars Larsson
In this experimental investigation the surface flow pattern is visualized on a full scale passenger car in the Volvo wind tunnel in Gothenburg. The entire rear end of a Volvo S60 was equipped with a large amount of tufts. The movement of the tufts is recorded by a single lens reflex camera which takes pictures continuously. A new and efficient tuft image processing algorithm has been developed to calculate the statistical behavior of the tuft orientation. This allows the extraction of the mean angle and the standard deviation for individual tufts. This information on the surface flow can be used to identify unsteady and steady flow phenomena such as separation and reattachment lines, flow direction, stagnation points, and regions with increased turbulence and footprints of vortices. The main advantages over other flow visualization methods such as oil paint is that experimental facilities are not soiled and that statistical data can be extracted.
2016-04-05
Technical Paper
2016-01-0847
Le Zhao, Ahmed Abdul Moiz, Seong-Young Lee, Jeffrey Naber, Sam Barros, William Atkinson
Impingement of jets has been found to give improved spray penetration characteristics and higher vaporization rates when compared to industrially utilized multi-hole outwardly injecting fuel injectors. The current work studies a non-reacting spray by using a 5-hole colliding-jet style direct-injection (DI) injector. The jet-to-jet collision induced by the inwardly opening nozzles of the multi-hole injector produces rapid and short jet breakup which is fundamentally different from how traditional fuel injectors operate. A non-reacting spray study is performed using a 5-hole colliding jet injector and a traditional Bosch HDEV-5 injector with gasoline as a fuel injected at 172 bar pressure at two different start of injection (SOI) timings of a spark-ignition gasoline engine. The engine-like thermodynamic conditions of were generated in a constant-volume high pressure-temperature pre-burn type combustion vessel for the two corresponding conditions.
2016-04-05
Technical Paper
2016-01-1616
Keiichiro Iida, Kunizo Onda, Akiyoshi Iida, Chisachi Kato, Shinobu Yoshimura, Yoshinobu Yamade, Yoshimitsu Hashizume, Yang GUO
The objective of this research is to predict accurately aeroacoustical interior noise of a car for a wide range of frequency between 100 Hz and 4 kHz. In this study, one-way coupled simulation of computational fluid dynamics (CFD), structural and acoustical analyses were performed to predict flow induced interior noise. Statistical Energy Analysis (SEA), which is a traditional method for evaluating transmission of sound and interior sound field, cannot be used for a low frequency range. In this study, structural and vibrational analysis and acoustical analysis were performed to predict the interior noise. This proposed method can be used for a wide range of frequency between 100 Hz and 4 kHz including a low frequency range. In this paper, the structural and vibrational analyses were performed by using the finite element method (FEM). The acoustical analysis results were compared the wind tunnel experimental results.
2016-04-05
Technical Paper
2016-01-1376
Feng Qi, Sujan Dhar, Varun Haresh Nichani, Chiranth Srinivasan, De Ming Wang, Liang Yang, Zhonghui Bing, Jinming Jim Yang
External gear pumps are positive displacement devices which perform with excellent efficiencies over a wide load and speed range. This wide range of performance is primarily due to micron-level leakage gaps in such machines which prevent large leakages at increasing loads. The present paper details a novel approach implemented in the commercial CFD tool PumpLinx that can capture the details of the micron level gaps, and model such machines accurately. The steps in creation of the model from original CAD geometry are described. In particular, the CFD mesh is created using a specialized template structured meshing method within PumpLinx especially created for external gear pumps and motors. This makes process of mesh creation and flow solution through complicated geometries of a gear pump efficient and streamlined.
2016-04-05
Technical Paper
2016-01-1606
Charalampos Kounenis, Sabine Bonitz, Emil Ljungskog, David Sims-Williams, Lennart Lofdahl, Alexander Broniewicz, Lars Larsson, Simone Sebben
The aerodynamic drag, and hence fuel consumption and CO2 production, of a road vehicle depends strongly on the rear end flow which is an area of complex three-dimensional flow structures. This paper seeks to provide improved insight into this flow region to better inform future drag reduction strategies. Using experimental and numerical techniques, two vehicle shapes have been studied; a 30% scale model of a Volvo S60 representing a 2008MY vehicle and a full scale 2010MY S60.First the surface topology of the rear end (rear window and boot lid) of both configurations is analysed, using paint to visualise the skin friction pattern. By means of critical points, the pattern is characterized and changes are identified studying the location and type of the occurring singularities. The flow field away from the surface is then analysed using PIV measurements for the scale model and CFD simulations for the full scale vehicle.
2016-04-05
Technical Paper
2016-01-1276
Hanzhengnan Yu, Xingyu Liang, Ge-Qun Shu, Yuesen Wang, Hongsheng Zhang, Weijian Chen
Impingement of spray against the cylinder wall or piston bowl is an important physical process in homogeneous charge compression ignition (HCCI) and premixed charge compression ignition (PCCI) engines using early injection strategy. It directly affects fuel-air mixture formation, combustion process and exhaust emission level. In addition, the alcohol fuels such as methanol, ethanol and n-butanol are regarded as hopeful alternative fuels as well as fuel additive for HCCI and PCCI diesel engines to improve the emission level. The better understanding for the effect of alcohol-diesel blending fuel on the spray-wall impingement process is helpful for the improvement of HCCI and PCCI diesel engines. In this paper, the effects of three different alcohol-diesel blending fuels (methanol, ethanol and n-butanol) on the spray-wall impingement process are studied. Numerical investigation is performed in AVL FIRE code.
2016-04-05
Technical Paper
2016-01-0311
Umashankar Mohan Chandra Joshi, Manan Jyotin Trivedi, Ziliang Zheng, Peter Schihl, Naeim A. Henein
All previous correlations of the ID period in diesel engines show a positive activation energy, which means that shorter ID periods occur at higher charge temperatures, while the compressed air temperature at start of injection is in the range of ( 850-1000 K). This is not the case in the autoignition of most homogeneous hydrocarbons/air mixtures which experience the NTC regime in the same temperature range, where the ignition delay increases at higher temperatures. Accordingly the global activation energy, measured by the slope in the Arrhenius plot, should vary from positive to negative values.
2016-04-05
Technical Paper
2016-01-0593
Riccardo Scarcelli, Keith Richards, Eric Pomraning, P. K. Senecal, Thomas Wallner, James Sevik
Reynolds-averaged Navier-Stokes (RANS) modeling is expected to deliver an ensemble-averaged result for the majority of turbulent flows. This could lead to the conclusion that multi-cycle internal combustion engine (ICE) simulations performed using RANS must exhibit a converging numerical solution after a certain number of consecutive cycles. For some engine configurations, unsteady RANS simulations are not guaranteed to deliver an ensemble-averaged result. In this paper it is shown that, when using RANS modeling to simulate multiple engine cycles, the cycle-to-cycle variations (CCV) coming from different initial conditions at each cycle are not damped out even after a large number of cycles. A single-cylinder GDI research engine is simulated using RANS modeling and the numerical results for 20 consecutive engine cycles are evaluated for two specific operating conditions.
2016-04-05
Technical Paper
2016-01-1345
Chiranth Srinivasan, Darshak Joshi, Sujan Dhar, De Ming Wang
This paper details the capability of PumpLinx® and Simerics® in simulating both Steady-State (Multiple Reference Frame) and transient, three dimensional torque converter performance and predicting the coupling point in a closed torque converter system in automatic transmission. The focuses of the simulation is in predicting the performance characteristics of the torque converters at different turbine to impeller rotating speeds (speed ratios) for 5 different torque converter designs and determine the coupling point at 90°C temperature. The computational domain includes the complex 3D design of all the impeller, turbine and reactor blades, the path ways that the oil travels between the above three components and the leakage gaps between these components. The physics captured in the simulation include the turbulence in the flow field and the rigorous treatment of the Fluid Structure Interaction (FSI) for the one-way free wheel reactor in predicting coupling point.
2016-04-05
Technical Paper
2016-01-1618
Yoshihiro Okada, Takuji Nakashima, Makoto Tsubokura, Yousuke Morikawa, Ryousuke Kouno, Satoshi Okamoto, Tanaka Matsuhiro, Takahide Nouzawa
Road vehicle’s cornering motion is known to be compound motion mainly of forward motion, side slip motion and yaw motion, but little is known about vehicle’s aerodynamics in this compound motion. It is thought that by clarifying and understanding vehicle’s aerodynamic characteristic in cornering motion, vehicle’s maneuvering stability during high speed driving could be aerodynamically improved. Therefore, in this study, aerodynamic characteristic during vehicle’s cornering motion, i.e. compound motion of forward motion, side slip motion and yaw motion, was investigated. Furthermore, evaluation method for aerodynamic force generated by the compound motion of forward motion, side slip motion and yaw motion was studied. CFD analysis of vehicle in dynamic meandering motion, forward motion with side slip motion and forward motion with yaw motion were conducted.
2016-04-05
Technical Paper
2016-01-0779
Radu Florea, Gary D. Neely, Zainal Abidin, Jason Miwa
For the US market, recent green-house gas (GHG) regulations coupled with ample supply of natural gas (NG) have spurred renewed interest in dual-fuel combustion regimes. This paper explores the potential of co-direct injection to improve the efficiency and reduce the methane emissions versus equivalent fumigated dual-fuel combustion systems. Using the Westport HPDI experimental test platform, the paper reports the results obtained using both diffusion controlled (HPDI) combustion strategy as well as the proposed partially-premixed combustion strategy (DI2).
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