Enhanced Splash Models for High Pressure Diesel Sprays

2006 ◽  
Author(s):  
L. Allocca ◽  
L. Andreassi ◽  
S. Ubertini
Keyword(s):  
Diesel Engines ◽  
Second Harmonic ◽  
Laser Sheet ◽  
Combustion Process ◽  
Numerical Data ◽  
Ccd Camera ◽  
Operating Conditions ◽  
Injection System ◽  
Correct Operation ◽  
Common Rail Injection System

Mixture preparation is a crucial aspect for the correct operation of modern DI Diesel engines as it greatly influences and alters the combustion process and therefore, the exhaust emissions. The complete comprehension of the spray impingement phenomenon is a quite complete task and to completely exploit the phenomenon a mixed numerical-experimental approach has to be considered. On the modeling side, several studies can be found in the scientific literature but only in the last years complete multidimensional modeling has been developed and applied to engine simulations. Among the models available in literature, in this paper, the models by Bai and Gosman [1] and by Lee et al. [2, 3] have been selected and implemented in the KIVA-3V code. On the experimental side, the behavior of a Diesel impinging spray emerging from a common rail injection system (injection pressures of 80 MPa and 120 MPa) has been analysed. The impinging spray has been lightened by a pulsed laser sheet generated from the second harmonic of a Nd-YAG laser. The images have been acquired by a CCD camera at different times from the start of injection (SOI). Digital image processing software has enabled to extract the characteristic parameters of the impinging spray with respect to different operating conditions. The comparison of numerical and experimental data shows that both models should be modified in order to allow a proper simulation of the splash phenomena in modern Diesel engines. Then the numerical data in terms of radial growth, height and shape of the splash cloud, as predicted by modified versions of the models are compared to the experimental ones. Differences among the models are highlighted and discussed.

Enhanced Splash Models for High Pressure Diesel Spray

2006 ◽  
Vol 129 (2) ◽  
pp. 609-621 ◽  
Author(s):  
L. Allocca ◽  
L. Andreassi ◽  
S. Ubertini
Keyword(s):  
Diesel Engines ◽  
Yttrium Aluminum Garnet ◽  
Second Harmonic ◽  
Laser Sheet ◽  
Direct Injection ◽  
Combustion Process ◽  
Numerical Data ◽  
Operating Conditions ◽  
Injection System ◽  
Correct Operation

Mixture preparation is a crucial aspect for the correct operation of modern direct injection (DI) Diesel engines as it greatly influences and alters the combustion process and, therefore, the exhaust emissions. The complete comprehension of the spray impingement phenomenon is a quite complete task and a mixed numerical-experimental approach has to be considered. On the modeling side, several studies can be found in the scientific literature but only in the last years complete multidimensional modeling has been developed and applied to engine simulations. Among the models available in literature, in this paper, the models by Bai and Gosman (Bai, C., and Gosman, A. D., 1995, SAE Technical Paper No. 950283) and by Lee et al. (Lee, S., and Ryou, H., 2000, Proceedings of the Eighth International Conference on Liquid Atomization and Spray Systems, Pasadena, CA, pp. 586–593; Lee, S., Ko, G. H., Ryas, H., and Hong, K. B., 2001, KSME Int. J., 15(7), pp. 951–961) have been selected and implemented in the KIVA-3V code. On the experimental side, the behavior of a Diesel impinging spray emerging from a common rail injection system (injection pressures of 80 and 120MPa) has been analyzed. The impinging spray has been lightened by a pulsed laser sheet generated from the second harmonic of a Nd-yttrium-aluminum-garnet laser. The images have been acquired by a charge coupled device camera at different times from the start of injection. Digital image processing software has enabled to extract the characteristic parameters of the impinging spray with respect to different operating conditions. The comparison of numerical and experimental data shows that both models should be modified in order to allow a proper simulation of the splash phenomena in modern Diesel engines. Then the numerical data in terms of radial growth, height and shape of the splash cloud, as predicted by modified versions of the models are compared to the experimental ones. Differences among the models are highlighted and discussed.

A New Predictive ID Model for Advanced High Speed Direct Injection Diesel Engines

2004 ◽  
Author(s):  
Lurun Zhong ◽  
Naeim A. Henein ◽  
Walter Bryzik
Keyword(s):  
Diesel Engines ◽  
High Speed ◽  
Direct Injection ◽  
Combustion Process ◽  
Operating Conditions ◽  
Injection System ◽  
Injection Timing ◽  
Common Rail Injection System ◽  
Common Rail Injection ◽  
Starting Conditions

Advance high speed direct injection diesel engines apply high injection pressures, exhaust gas recirculation (EGR), injection timing and swirl ratios to control the combustion process in order to meet the strict emission standards. All these parameters affect, in different ways, the ignition delay (ID) which has an impact on premixed, mixing controlled and diffusion controlled combustion fractions and the resulting engine-out emissions. In this study, the authors derive a new correlation to predict the ID under the different operating conditions in advanced diesel engines. The model results are validated by experimental data in a single-cylinder, direct injection diesel engine equipped with a common rail injection system at different speeds, loads, EGR ratios and swirl ratios. Also, the model is used to predict the performance of two other diesel engines under cold starting conditions.

scholarly journals Thermodynamic Fundamentals for Fuel Production Management

2019 ◽  
Vol 11 (16) ◽  
pp. 4449 ◽  
Author(s):  
Karol Tucki ◽  
Remigiusz Mruk ◽  
Olga Orynycz ◽  
Andrzej Wasiak ◽  
Antoni Świć
Keyword(s):  
Diesel Engines ◽  
Carbon Dioxide Emissions ◽  
Fossil Fuels ◽  
Production Management ◽  
Combustion Process ◽  
Experimental Studies ◽  
Road Transport ◽  
Injection System ◽  
Common Rail Injection System ◽  
Common Rail Injection

An increase of needs for replacement of fossil fuels, and for mitigation of Carbon Dioxide emissions generated from fossil fuels inspires the search for new fuels based on renewable biological resources. It would be convenient if the biological component of the fuel required as little as possible conversion operations in the production. The obvious response is an attempt to use unconverted, neat plant oils as a fuel for Diesel engines. The present paper is devoted to the experimental studies of the combustion process of neat rapeseed oil, and its mixtures with gasoline and ethanol as additional components of the mixtures. The investigation of combustion was carried out in a fixed volume combustion chamber equipped with a Common Rail injection system. It is shown that the instant of ignition, as well as time-dependence of heat emanation, are strongly dependent upon mixture composition. The results enable the design of mixture compositions that could serve as commercial fuel for Diesel engines. Such fuels are expected to fulfill the requirements for the sustainability of road transport.

Fuzzy Logic Control of Diesel Combustion Phasing Using Ion Current Signal

2012 ◽  
Author(s):  
Tamer Badawy ◽  
Nassim Khaled ◽  
Naeim Henein
Keyword(s):  
Fuzzy Logic ◽  
Diesel Engines ◽  
Fuzzy Logic Controller ◽  
Combustion Process ◽  
Open Loop ◽  
Operating Conditions ◽  
Ion Current ◽  
Injection System ◽  
Loop Control ◽  
Engine Life

Diesel engines have to meet stringent emissions standards without penalties in performance and fuel economy. This necessitated the use of elaborate after treatment devices to reduce the tail pipe emissions. In order to decrease the demand on the after treatment devices, there is a need to reduce the emissions in the formation stage during combustion. This requires a precise control of the phasing of the combustion process. Currently, diesel engines are controlled by pre-set open loop schedules that require extensive, time consuming and costly laboratory tests and calibration tasks to meet the production target goals which are stricter than the emission standards. Such goals are set as a safe guard against the deterioration during engine life cycle. This paper presents an incremental fuzzy logic controller that adjusts the combustion phasing as per desired targets to meet production goals over the engine life period. An ion current/ glow plug sensor and its circuit are used to produce a signal indicative of different combustion parameters. Signal conditioning and filtering are applied to improve the quality of ion current. The algorithm developed in this paper optimizes the ion current feed back to increase its reliability for stable engine control while maintaining fast controller response, and high accuracy. Experiments are carried out on a four cylinder, turbo-charged, 4.5L heavy duty diesel engine equipped with a common rail injection system and an open ECU. The response of the controller is evaluated from experimental data obtained by running the engine under different steady, and transient operating conditions. The results demonstrate the ability of the closed-loop control system in achieving the desired combustion phasing.

Experimental and Analytical Characterization of Alternative Aviation Fuel Sprays Under Realistic Operating Conditions

2018 ◽  
Author(s):  
Andrew Corber ◽  
Nader Rizk ◽  
Wajid Ali Chishty
Keyword(s):  
Experimental Data ◽  
Alternative Fuels ◽  
Laser Sheet ◽  
National Research Council ◽  
Diagnostic System ◽  
Operating Conditions ◽  
Aviation Fuel ◽  
Injection System ◽  
Test Time

The National Jet Fuel Combustion Program (NJFCP) is an initiative, currently being led by the Office of Environment & Energy at the FAA, to streamline the ASTM jet fuels certification process for alternative aviation fuels. In order to accomplish this objective, the program has identified specific applied research tasks in several areas. The National Research Council of Canada (NRC) is contributing to the NJFCP in the areas of sprays and atomization and high altitude engine performance. This paper describes work pertaining to atomization tests using a reference injection system. The work involves characterization of the injection nozzle, comparison of sprays and atomization quality of various conventional and alternative fuels, as well as use of the experimental data to validate spray correlations. The paper also briefly explores the application viability of a new spray diagnostic system that has potential to reduce test time in characterizing sprays. Measurements were made from ambient up to 10 bar pressures in NRC’s High Pressure Spray Facility using optical diagnostics including laser diffraction, phase Doppler anemometry (PDA), LIF/Mie Imaging and laser sheet imaging to assess differences in the atomization characteristics of the test fuels. A total of nine test fluids including six NJFCP fuels and three calibration fluids were used. The experimental data was then used to validate semi-empirical models, developed through years of experience by engine OEMs and modified under NJFCP, for predicting droplet size and distribution. The work offers effective tools for developing advanced fuel injectors, and generating data that can be used to significantly enhance multi-dimensional combustor simulation capabilities.

Parametric Study of the Scavenging Process in Marine Two-Stroke Diesel Engines

2015 ◽  
Author(s):  
Fredrik Herland Andersen ◽  
Stefan Mayer
Keyword(s):  
Diesel Engines ◽  
Vortex Breakdown ◽  
Initial Conditions ◽  
Combustion Process ◽  
Operating Conditions ◽  
Exhaust Valve ◽  
Delivery Ratio ◽  
Exhaust Gas ◽  
Scale Production ◽  
Cfd Model

Large commercial ships such as container vessels and bulk carriers are propelled by low-speed, uniflow scavenged two-stroke diesel engines. The integral in-cylinder process in this type of engine is the scavenging process, where the burned gas from the combustion process is evacuated through the exhaust valve and replaced with fresh air for the subsequent compression stroke. The scavenging air enters the cylinder via inlet ports which are uncovered by the piston at bottom dead center (BDC). The exhaust gas is then displaced by the fresh air. The scavenging ports are angled to introduce a swirling component to the flow. The in-cylinder swirl is beneficial for air-fuel mixture, cooling of the cylinder liner and minimizing dead zones where pockets of exhaust gas are trapped. However, a known characteristic of swirling flows is an adverse pressure gradient in the center of the flow, which might lead to a local deficit in axial velocity and the formation of central recirculation zones, known as vortex breakdown. This paper will present a CFD analysis of the scavenging process in a MAN B&W two-stroke diesel engine. The study include a parameter sweep where the operating conditions such as air amount, port timing and scavenging pressure are varied. The CFD model comprise the full geometry from scavenge receiver to exhaust receiver. Asymmetric inlet and outlet conditions is included as well as the dynamics of a moving piston and valve. Time resolved boundary conditions corresponding to measurements from an operating, full scale production, engine as well as realistic initial conditions are used in the simulations. The CFD model provides a detailed description of the in-cylinder flow from exhaust valve opening (EVO) to exhaust valve closing (EVC). The study reveals a close coupling between the volume flow (delivery ratio) and the in-cylinder bulk purity of air which appears to be independent of operating conditions, rpm, scavenge air pressure, BMEP etc. The bulk purity of air in the cylinder shows good agreement with a simple theoretical perfect displacement model.

Ion Current, Combustion and Emission Characteristics in an Automotive Common Rail Diesel Engine

2012 ◽  
Vol 134 (4) ◽  
Author(s):  
Naeim A. Henein ◽  
Tamer Badawy ◽  
Nilesh Rai ◽  
Walter Bryzik
Keyword(s):  
Diesel Engine ◽  
Diesel Engines ◽  
Direct Injection ◽  
Common Rail ◽  
Ion Current ◽  
Injection System ◽  
Feedback Signal ◽  
Common Rail Injection System ◽  
Common Rail Injection ◽  
No Emissions

Advanced electronically controlled diesel engines require a feedback signal to the ECU to adjust different operating parameters and meet demands for power, better fuel economy and low emissions. Different types of in-cylinder combustion sensors are being considered to produce this signal. This paper presents results of an experimental investigation on the characteristics of the ion current in an automotive diesel engine equipped with a common rail injection system. The engine is a 1.9 L, 4-cylinder, direct injection diesel engine. Experiments covered different engine loads and injection pressures. The relationships between the ion current, combustion parameters and engine out NO emissions and opacity are presented. The analysis of the experimental data identified possible sources of the ion current produced in diesel engines.

scholarly journals RME CO-COMBUSTION WITH HYDROGEN IN COMPRESSION IGNITION ENGINE: PERFORMANCE, EFFICIENCY AND EMISSIONS / SLĖGINIO UŽDEGIMO VARIKLIO ENERGINIŲ, EFEKTYVUMO IR DEGINIŲ EMISIJOS RODIKLIŲ TYRIMAS NAUDOJANT RAPSŲ METILESTERĮ IR VANDENILĮ

2018 ◽  
Vol 10 (0) ◽  
pp. 1-9
Author(s):  
Romualdas Juknelevičius
Keyword(s):  
Combustion Process ◽  
Engine Performance ◽  
Fuel Mixture ◽  
Common Rail ◽  
Injection System ◽  
Intake Manifold ◽  
Compression Ignition Engine ◽  
Common Rail Injection System ◽  
Wide Range ◽  
The Rich

The article presents the test results of the single cylinder CI engine with common rail injection system operating on biofuel – Rapeseed Methyl Ester with addition supply of hydrogen. The purpose of this investigation was to examine the influence of the hydrogen addition to the biofuel on combustion phases, engine performance, efficiency, and exhaust emissions. HES was changed within the range from 0 to 44%. Hydrogen was injected into the intake manifold, where it created homogeneous mixture with air. Tests were performed at both fixed and optimal injection timings at low, medium and nominal engine load. After analysis of the engine bench tests and simulation with AVL BOOST software, it was observed that lean hydrogen – RME mixture does not support the flame propagation and efficient combustion. While at the rich fuel mixture and with increasing hydrogen fraction, the combustion intensity concentrate at the beginning of the combustion process and shortened the ignition delay phase. AVL BOOST simulation performed within the wide range of HES (16–80%) revealed that combustion intensity moves to the beginning of combustion with increase of HES. Decrease of CO, CO2 and smoke opacity was observed with increase of hydrogen amounts to the engine. However, increase of the NO concentration in the engine exhaust gases was observed. Santrauka Straipsnyje pateikti tyrimo rezultatai, gauti atlikus bandymą vieno cilindro slėginio uždegimo variklyje su biodegalais – rapsų metilesterį (RME) ir vandenilį. Biodegalai įpurškiami akumuliatorine įpurškimo sistema „Common rail“. Šio tyrimo tikslas – ištirti, kaip vandenilis veikia biodegalų degimą, variklio veikimą, jo efektyvumą ir deginių susidarymą. Vandenilio energinė dalis degimo mišinyje buvo keičiama nuo 0 iki 44 %. Vandenilis buvo tiekiamas įsiurbimo fazės metu įsiurbimo kanalu į degimo kamerą, kurioje jis, susimaišęs su oru, sudaro homogeninį mišinį. Bandymai buvo atliekami nekeičiant įpurškimo kampo, nustačius optimalų įpurškimo kampą esant žemai, vidutinei ir nominaliai variklio apkrovai. Išnagrinėjus variklio bandymų rezultatus ir sumodeliavu AVL BOOST programa, buvo pastebėta, kad, esant liesam vandenilio ir RME mišiniui, liepsnos plitimas yra lėtas, mišinys dega neveiksmingai. Tačiau riebus degalų mišinys ir padidinta vandenilio energijos dalis užtikrina degimo intensyvumą degimo proceso pradžioje ir sutrumpina uždegimo gaišties trukmę. AVL BOOST modeliavimas, atliktas plačiu vandenilio energijos dalies diapazonu (16–80 %), patvirtino teiginį, kad degimas tampa intensyvesnis degimo pradžioje dėl padidinto vandenilio kiekio. Didinant vandenilio kiekį, buvo pastebėta, kad išmetamosiose dujose sumažėjo CO, CO2 ir kietųjų dalelių, tačiau padidėjo NO koncentracija.

Design and CFD Simulation of a Micro Gas Turbine Combustor Fuelled With Low LHV Producer Gas

2020 ◽  
Author(s):  
Francesco F. Nicolosi ◽  
Massimiliano Renzi
Keyword(s):  
Natural Gas ◽  
Combustion Process ◽  
Operating Conditions ◽  
Inert Gases ◽  
Injection System ◽  
Small Scale ◽  
Producer Gas ◽  
Part Load ◽  
Average Temperature ◽  
Gasification Process

Abstract In this paper, the authors analyze the feasibility of fuelling a small-scale 3.2 kWe MGT, manufactured by the Dutch company MTT, with a low LHV fuel produced via a gasification process. In particular, a CFD analysis on the combustor of the MGT is carried out in order to assess the behaviour of the component when it is fuelled with a traditional fuel (natural gas) and with a producer gas coming from a gasification process. The operating conditions of the combustor, used as boundary conditions for the simulations, are obtained by analyzing the characteristic performance curves of the turbo-machines used in the MGT. The simulation of the combustion process with methane has been validated using the temperature output from experimental tests and the NOX emissions. A RANS simulation using the Non-Adiabatic Non-Premixed Combustion Model Approach has been adopted. NOX formation has been simulated by the adoption of the extended Zel’dovich mechanism. Both nominal and part load simulations have been performed. This simplified modelling strategy allows to assess the main issues and figures of the combustion process with a reasonable computational effort. The CFD simulations showed that the combustion with a low LHV fuel are feasible but some modifications of the present configuration of the combustor are required, with specific attention to the fuel injection system. Results showed that, with Natural Gas, the average temperature of the exhaust mass flow is 1297 K, the level of CO and NOX referred to the 15% of O2 are respectively less than 1 ppm and 30.365 ppm, respectively. With S the original design of the injector proved to be non-adequate for a proper air and fuel mixing; therefore, a modified design has been proposed with an increased injection section. In the novel design for syngas, a better temperature distribution and lower emissions have been found: an average temperature of the flue gas at the combustor discharge of 1249 K is obtained, and the level of CO and NOX are both less than 1 ppm. The lower operating temperature is determined by the higher fuel flow rate and, in particular, by the high share of inert gases in the fuel. Additional simulations have been run at part load operation to assess the viability of the proposed design also in off-design conditions.

Experimental Stand to Investigate the Injection Process in Diesel Engines

2021 ◽  
Vol 42 ◽  
pp. 79-84
Author(s):  
Dragoș Tutunea ◽  
Ilie Dumitru ◽  
Laurenţiu Racilă
Keyword(s):  
Diesel Engines ◽  
Electric Motor ◽  
High Performance ◽  
Fuel Injection ◽  
Combustion Process ◽  
Injection Pressure ◽  
Injection System ◽  
Injection Process ◽  
Experimental Stand ◽  
Fuel Injection Pressure

The objective of this paper is to investigate the fuel injection system in diesel engines by using inline pumps. In a diesel engines, the fuel injection pressure plays an important role in the combustion process in order to obtain high performance and low fuel consumption. The experiments in this paper are been performed on a 6 cylinder inline pump which is actioned by an electric motor with variable r.p.m.-s The quantity of the fuel injected by each injector is measured function of time and the speed of electric motor. The experiments show the degree of non-uniformity of the fuel delivered by the pump to injectors.

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