scholarly journals Experimental Validation of Combustion Models for Diesel Engines Based on Tabulated Kinetics in a Wide Range of Operating Conditions

2017 ◽  
Author(s):  
Tommaso Lucchini ◽  
Gianluca D'Errico ◽  
Tarcisio Cerri ◽  
Angelo Onorati ◽  
Gilles Hardy
Keyword(s):  
Diesel Engines ◽  
Experimental Validation ◽  
Operating Conditions ◽  
Combustion Models ◽  
Wide Range

Experimental Validation and Design Simulations of a Passive Two-Phase Cooling System for Datacenters

2020 ◽  
Author(s):  
Jackson B. Marcinichen ◽  
John R. Thome ◽  
Raffaele L. Amalfi ◽  
Filippo Cataldo
Keyword(s):  
Thermal Performance ◽  
Experimental Validation ◽  
Cooling System ◽  
Electronics Cooling ◽  
Operating Conditions ◽  
Two Phase ◽  
Data Set ◽  
Pressure Drops ◽  
Wide Range ◽  
Important Challenge

Abstract Thermosyphon cooling systems represent the future of datacenter cooling, and electronics cooling in general, as they provide high thermal performance, reliability and energy efficiency, as well as capture the heat at high temperatures suitable for many heat reuse applications. On the other hand, the design of passive two-phase thermosyphons is extremely challenging because of the complex physics involved in the boiling and condensation processes; in particular, the most important challenge is to accurately predict the flow rate in the thermosyphon and thus the thermal performance. This paper presents an experimental validation to assess the predictive capabilities of JJ Cooling Innovation’s thermosyphon simulator against one independent data set that includes a wide range of operating conditions and system sizes, i.e. thermosyphon data for server-level cooling gathered at Nokia Bell Labs. Comparison between test data and simulated results show good agreement, confirming that the simulator accurately predicts heat transfer performance and pressure drops in each individual component of a thermosyphon cooling system (cold plate, riser, evaporator, downcomer (with no fitting parameters), and eventually a liquid accumulator) coupled with operational characteristics and flow regimes. In addition, the simulator is able to design a single loop thermosyphon (e.g. for cooling a single server’s processor), as shown in this study, but also able to model more complex cooling architectures, where many thermosyphons at server-level and rack-level have to operate in parallel (e.g. for cooling an entire server rack). This task will be performed as future work.

Yaw Rate Estimation for Vehicle Control Applications

1998 ◽  
Vol 120 (2) ◽  
pp. 267-274 ◽  
Author(s):  
N. Sivashankar ◽  
A. G. Ulsoy
Keyword(s):  
Experimental Validation ◽  
Vehicle Control ◽  
Operating Conditions ◽  
Angle Sensor ◽  
Control Applications ◽  
Rate Estimation ◽  
Yaw Rate ◽  
Wide Range ◽  
Simulation Results ◽  
Instrumented Vehicle

This paper describes a method for vehicle yaw rate estimation using two accelerometers and a steer angle sensor. This yaw rate estimate can be used as an inexpensive alternative to commercial yaw rate sensors in vehicle control applications. The proposed method combines two complementary approaches to yaw rate estimation using accelerometers. This new method is superior to either method used by itself. This paper presents the new approach, supporting analyses, simulation results and experimental validation. The simulation results are based upon both linear and nonlinear vehicle dynamics models and include important effects such as sensor drift and noise, disturbances acting on the vehicle, and model uncertainties. The experimental validation is based on test data from a specially instrumented vehicle driven on a test track. These results indicate that the proposed yaw rate estimation scheme performs well for a wide range of operating conditions and is not difficult to implement.

An Investigation of the Sources of Blowby in Single-Cylinder Supercharged Diesel Engines

1978 ◽  
Vol 192 (1) ◽  
pp. 39-48 ◽  
Author(s):  
B. Bull ◽  
M. A. Voisey
Keyword(s):  
Carbon Dioxide ◽  
Diesel Engines ◽  
Piston Ring ◽  
Carbon Dioxide Concentration ◽  
Operating Conditions ◽  
Exhaust Valve ◽  
Simple Method ◽  
Single Cylinder ◽  
Carbon Dioxide Concentrations ◽  
Wide Range

Measurements of carbon dioxide concentrations in the exhaust and in the crankcase of two different types of single-cylinder, supercharged diesel engines have been used to determine the amount of exhaust gas reaching the crankcase as piston ring blowby and as leakage through the exhaust valve stem-to-guide clearance. Over a wide range of operating conditions in both engines the carbon dioxide concentration was found to be more dependent on engine fuelling rate per hour than on fuel input per stroke. It was established that blowby through the exhaust valve guide was a major contributor to crankcase contamination. A simple method has been devised, requiring only minor modifications to the engine, that permits the blowby through the piston ring pack and the exhaust valve guides to be determined separately in turbocharged production engines.

Modeling heavy-duty diesel engines using tabulated kinetics in a wide range of operating conditions

2020 ◽  
pp. 146808741989616 ◽  
Author(s):  
Qiyan Zhou ◽  
Tommaso Lucchini ◽  
Gianluca D’Errico ◽  
Gilles Hardy ◽  
Xingcai Lu
Keyword(s):  
Diesel Engines ◽  
Operating Conditions ◽  
Scalar Dissipation ◽  
Cylinder Pressure ◽  
Heavy Duty ◽  
Variable Model ◽  
Progress Variable ◽  
Wide Range ◽  
Heavy Duty Diesel ◽  
Operating Points

Fast and high-fidelity combustion models including detailed kinetics and turbulence chemistry interaction are necessary to support design and development of heavy-duty diesel engines. In this work, the authors intend to present and validate tabulated flamelet progress variable model based on tabulation of laminar diffusion flamelets for different scalar dissipation rate, whose predictability highly depends on the description of fuel–air mixing process in which engine mesh layout plays an important role. To this end, two grids were compared and assessed: in both grids, cells were aligned on the spray direction with such region being enlarged in the second one, where the near-nozzle and near-wall mesh resolution were also improved, which is expected to better account for both spray dynamics and flame–wall interaction dominating the combustion process in diesel engines. Flame structure, in-cylinder pressure, apparent heat release rate, and emissions for different relevant operating points were compared and analyzed to identify the most suitable mesh. Afterwards, simulations were carried out in a heavy-duty engine considering 20 operating points, allowing to comprehensively verify the validity of tabulated flamelet progress variable model. The results demonstrated that the proposed approach was capable to accurately predict in-cylinder pressure evolution and NO x formation across a wide engine map.

Control-Oriented Model Development and Experimental Validation for a Modern Diesel Engine

2020 ◽  
Author(s):  
Kuo Yang ◽  
Pingen Chen
Keyword(s):  
Diesel Engine ◽  
Diesel Engines ◽  
Model Development ◽  
Engine Performance ◽  
Operating Conditions ◽  
Least Square ◽  
Injection Timing ◽  
Model Based ◽  
Wide Range ◽  
Mean Square Errors

Abstract Modern Diesel engines have become highly complex multi-input multi-output systems. Controls of modern Diesel engines to meet various requirements such as high fuel efficiency and low NOx and particulate matter (PM) emissions, remain a great challenge for automotive control community. While model-based controls have demonstrated significant potentials in achieving high Diesel engine performance. Complete and high-fidelity control-oriented Diesel engine models are much needed as the foundations of model-based control system development. In this study, a semi-physical, mean-value control-oriented model of a turbocharged Diesel engine equipped with high-pressure exhaust gas recirculation (EGR) and variable geometry turbocharger (VGT) is developed and experimentally validated. The static calibration of Diesel engine model is achieved with the least-square optimization methodology using the experimental test data from a physical Diesel engine platform. The normalized root mean square errors (NRMSEs) of the calibration results are in the range of 0.1095 to 0.2582. The cross-validation results demonstrated that the model was capable of accurately capturing the engine torque output and NOx emissions with the control inputs of EGR, VGT and Start of Injection timing (SOI) in wide-range operating conditions.

Evaluation of a Cyclone-Based Particulate Filtration System for High-Speed Diesel Engines

1994 ◽  
Vol 208 (4) ◽  
pp. 269-279 ◽  
Author(s):  
C Arcoumanis ◽  
L N Barbaris ◽  
R I Crane ◽  
P Wisby
Keyword(s):  
Diesel Engines ◽  
High Speed ◽  
Direct Injection ◽  
Operating Conditions ◽  
Exhaust Pipe ◽  
Filtration System ◽  
High Speed Diesel ◽  
Wide Range ◽  
Mass Flowrate ◽  
Particulate Filtration

A cyclone-based filtration system has been developed and its potential for reduction of exhaust particulates in high-speed direct injection diesel engines is evaluated; the filtration efficiency of the four cyclones has been enhanced by means of particulate agglomeration induced by cooling in a heat exchanger. With this system installed in the exhaust pipe of a 2.5 litre direct injection engine, tests covering a wide range of speed, load and exhaust gas recirculation (EGR) fraction resulted in reductions of up to 77 per cent in emitted particulate mass flowrate. The dependence of the system's performance on engine operating conditions, EGR configuration and cyclone geometry is presented and discussed.

CFD Modeling of Pilot Injection and EGR in DI Diesel Engines

2004 ◽  
Author(s):  
Arturo de Risi ◽  
Teresa Donateo ◽  
Domenico Laforgia
Keyword(s):  
Shell Model ◽  
Diesel Engines ◽  
Direct Injection ◽  
Operating Conditions ◽  
Spray Angle ◽  
Cfd Modeling ◽  
Pilot Injection ◽  
Wide Range ◽  
Combustion Processes ◽  
Injection Strategies

The simulation of direct injection diesel engines requires accurate models to predict spray evolution and combustion processes. Several models have been proposed and widely tested for traditional injection strategies characterized by single injection pulse close to top dead center. Unfortunately, these models show some limits when applied to different injection strategies so that a correct simulation of engine performances and emission cannot be achieved without changing variables included in spray and combustion models. The aim of the present investigation is to improve the prediction capability of the KIVA3V code in case of pilot injection in order to use numerical simulations to define optimized pilot injection strategies. This goal was achieved by eliminating the hypotheses of constant fuel density and constant spray angle in the KIVA3V code and by using a modified version of the Shell model. The proposed modifications to the Shell model allow a better description of low temperature kinetics by the addition of two more radicals and three new kinetics reactions. The improvements in the code were verified by comparing experimental data and numerical results over a wide range of operating conditions including single injections, pilot injections and EGR.

Validating Phenomenological Smoke Model at Different Operating Conditions of DI Diesel Engines

2006 ◽  
Author(s):  
Y. V. Aghav ◽  
P. A. Lakshminarayanan ◽  
M. K. G. Babu ◽  
Azeem Udin ◽  
A. D. Dani
Keyword(s):  
Diesel Engines ◽  
Operating Conditions ◽  
Low Velocity ◽  
Injection Parameters ◽  
Wide Range ◽  
K Factor ◽  
Wall Impingement ◽  
Nozzle Hole ◽  
Wall Interaction ◽  
Geometrical Consideration

A new phenomenological model that was published in ref [1] encompasses the spray and the wall interaction by a simple geometrical consideration. The current study extends this earlier work with investigations made on 16 different engines from 6-engine families of widely varying features applied to off-highway as well as on-road duty. A dimensionless factor was introduced to take care of the nozzle hole manufactured by hydro-erosion, (HE) as well as the conical shape of the nozzle hole (K factor) in case of valve closed orifice type of nozzles. The smoke emitted from the wall spray formed after wall impingement is the major contributor to the total smoke at higher loads. As the fuel spray impinges upon the walls of the combustion chamber, its velocity decreases. This low velocity jet contributes to the higher rate of the smoke production. Therefore, the combustion bowl geometry alongwith injection parameters play a significant role in the smoke emissions. The satisfactory comparison of predicted and observed smoke over the wide range of operation demonstrated applicability of the model in simulation study of combustion occurring in DI diesel engines.

Validating the Phenomenological Smoke Model at Different Operating Conditions of DI Diesel Engines

2008 ◽  
Vol 130 (1) ◽  
Author(s):  
Y. V. Aghav ◽  
P. A. Lakshminarayanan ◽  
M. K. G. Babu ◽  
Azeem Uddin ◽  
A. D. Dani
Keyword(s):  
Diesel Engines ◽  
Direct Injection ◽  
Operating Conditions ◽  
Low Velocity ◽  
Engine Operation ◽  
Wide Range ◽  
Wall Impingement ◽  
Nozzle Hole ◽  
Wall Interaction ◽  
Geometrical Consideration

A new phenomenological model that was published in Aghav et al. (2005, “Phenomenology of Smoke From Direct Injection Diesel Engines,” Proceedings of ICEF2005, ASME Paper No. 1350) encompasses the spray and the wall interaction by a simple geometrical consideration. The current study extends this earlier work with investigations made on 16 different engines from six-engine families of widely varying features, applied to off-highway as well as on-road duty. A dimensionless factor was introduced to take care of the nozzle hole manufactured by hydroerosion, as well as the conical shape of the nozzle hole (k factor) in the case of valve-closed-orifice type of nozzles. The smoke emitted from the wall spray formed after wall impingement is the major contributor to the total smoke at higher loads. As the fuel spray impinges upon the walls of the combustion chamber, its velocity decreases. This low-velocity jet contributes to the higher rate of the smoke production. Therefore, the combustion bowl geometry along with injection parameters play a significant role in the smoke emissions. The new model is one dimensional and based on the recent phenomenological description of spray combustion in a direct injection diesel engine. The satisfactory comparison of the predicted and observed smoke over the wide range of engine operation demonstrated applicability of the model in simulation study of combustion occurring in direct injection (DI) diesel engines.

Experimental Study of Micronized Coal/Water Slurry Rheology at High Shear Rates

1990 ◽  
Vol 112 (1) ◽  
pp. 36-40 ◽  
Author(s):  
Y. I. Cho ◽  
U. S. Choi
Keyword(s):  
Diesel Engines ◽  
Rheological Behavior ◽  
Capillary Tube ◽  
Operating Conditions ◽  
Rheological Characterization ◽  
Shear Rates ◽  
Water Slurry ◽  
Wide Range ◽  
Coal Water Slurry ◽  
Slurry Rheology

The rheological behavior of four micronized coal water slurry (CWS) samples was studied experimentally for a wide range of shear rates between 3 and 30,000 s−1. The systematic rheological characterization of the slurry fuel shows that the rheological behavior of these CWS is very complex and depends on coal particle size, temperature, coal loading, conditioning additives, and the capillary tube diameter as well as the shear rate. This study indicates that better appreciation of the unique and complex rheological behavior of non-Newtonian CWS fuels is vital to developing high-quality slurries suitable for use in coal-fired diesel engines, and suggests that a more comprehensive data base for CWS rheology under actual diesel engine operating conditions is needed prior to using such CWS fuels in diesel engines.

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