scholarly journals Study of Visualization Experiment on the Influence of Injector Nozzle Diameter on Diesel Engine Spray Ignition and Combustion Characteristics

Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5337
Author(s):  
Yuanzhi Tang ◽  
Diming Lou ◽  
Chengguan Wang ◽  
Pi-qiang Tan ◽  
Zhiyuan Hu ◽  
...  
Keyword(s):  
Diesel Engines ◽  
Liquid Fuel ◽  
Combustion Process ◽  
Nozzle Orifice ◽  
Injector Nozzle ◽  
Visualization Experiment ◽  
Wall Impingement ◽  
Air Mixing ◽  
Gas Ignition ◽  
Ignition And Combustion

The elementary research of spray and combustion is of great significance to the development of compactness of modern diesel engines. In this paper, three injectors with different nozzle orifice diameters (0.23 mm, 0.27 mm and 0.31 mm) were used to study the diesel spray, ignition and flame-wall impingement visualization experiment. This paper studied the influence of different nozzle sizes on the trends of spray, ignition and flame diffusion under the flame-wall impinging combustion and used the flame luminosity to characterize the soot generation in combustion. By analyzing the quantitative data, such as spray penetration, ignition delay, flame area and flame luminosity systematically, it was shown that the smaller nozzle benefitted diesel combustion to some extent. The 0.23 mm nozzle injector in these experiments had the best fuel-air mixing effect under 800 K. The length of the spray liquid under the 0.23 mm nozzle condition was 19% and 23% shorter than that of 0.27 and 0.31 mm, respectively. Smaller orifice size of the nozzle can help to reach the gas ignition conditions more effectively. Without liquid fuel impingement, the simple flame-wall impingement will not change the trend of the nozzle influence on combustion. The total amount of accumulated soot according to the approximate luminosity spatial integral calculation in the combustion process was reduced by 37% and 43% under 0.27 mm and 0.23 mm nozzles, respectively, which is favorable for the clean combustion of diesel engines.

Investigation of Fuel Spray Propagation, Combustion and Soot Formation/Oxidation in a Single Cylinder Medium Speed Diesel Engine

2012 ◽  
Author(s):  
Fridolin Unfug ◽  
Uwe Wagner ◽  
Kai W. Beck ◽  
Juergen Pfeil ◽  
Ulf Waldenmaier ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Diesel Engines ◽  
High Speed ◽  
Liquid Fuel ◽  
Combustion Process ◽  
Fuel Spray ◽  
Soot Concentration ◽  
Single Cylinder ◽  
Medium Speed ◽  
532 Nm

To fulfil strict emission regulations and the need for higher efficiency of future Diesel engines require an optimized combustion process. Optical investigations represent a powerful tool for getting a better understanding of the ongoing processes. For medium speed Diesel engines, optical investigations are relatively rare or not available. The “Institut für Kolbenmaschinen” (IFKM) and MAN Diesel & Turbo SE performed extensive optical in-situ investigations of the injection and combustion process of a MAN 32/44 CR single cylinder medium speed Diesel engine that provide previously unavailable insights into the ongoing processes. The optical investigations aimed on fuel spray visualization, high-speed soot luminescence measurement and two colour pyrometry applied for five combustion chamber regions. To apply the optical measurement techniques, two optical accesses were designed. Access no. 1 is placed near the cylinder liner. Access no. 2 is located close to the injector in a 46° angle to the cylinder vertical axis. An insert was used which consists of an illumination port and a visualization endoscope. Additionally some special nozzle designs were used beside the standard nozzle, which have one separated nozzle hole. This enables a simultaneous view from both optical accesses on the same flame cone. For Mie-Scattering investigation a pulsed Nd:YAG-Laser with 532 nm wavelength was used for illumination and a CCD-camera with an upstream 532 nm optical filter was used for visualization. This combination allows observing the liquid fuel distribution even after start of combustion. Penetration depth of liquid fuel spray was analysed for different swirl numbers, intake manifold pressures, injection timings and injection pressures. High-speed flame visualization was done by two CMOS cameras which were mounted at two different optical accesses with view on the same flame cone. Due to this application a simultaneous measurement of the flame distribution of two different views was possible. This enables a 3-dimensional investigation of the flame propagation process. In addition, the advanced two colour pyrometry was applied for five different regions of the same flame cone. Due to a calibration after each measurement the absolute radiant flux can be calculated and thus the absolute temperature and soot concentration. With this procedure it was possible to give a real temperature and soot concentration distribution of the flame cone. To provide more detailed information about the combustion process, selected engine operation points were simulated with a modified version of the CFD code KIVA3v-Release2 at the IFKM. The simulated results were compared to the measured data.

Penetration and Vaporization of Diesel Fuel Sprays

1969 ◽  
Vol 184 (10) ◽  
pp. 147-170 ◽  
Author(s):  
R. Burt ◽  
K. A. Troth
Keyword(s):  
Combustion Chamber ◽  
Diesel Engines ◽  
Direct Injection ◽  
Combustion Process ◽  
Major Effect ◽  
Engine Fuel ◽  
Liquid Droplets ◽  
Fuel Sprays ◽  
Air Movement ◽  
Air Mixing

In the diesel engine, fuel is injected into the hot, compressed air in the combustion chamber. Thus the process of diesel combustion is essentially inhomogeneous, and the mixing of the fuel and air in the combustion chamber dominates the whole combustion process. Since fuel–air mixing is so important the distribution of the injected fuel has a major effect on combustion performance. This is particularly true of direct-injection diesel engines which have relatively low rates of air movement. In all diesel engines, fuel is injected into the combustion chamber at high pressure through small nozzles. The high-velocity liquid jet atomizes, after emerging from the nozzle, into a spray of liquid droplets. The penetration, distribution, and vaporization of the sprays, together with the air movement, govern the mixing of fuel and air. The penetration of fuel sprays is dealt with in Part 1 of the paper; Part 2 describes a study of the vaporization of fuel sprays.

A Numerical Investigation of Non-Evaporating and Evaporating Diesel Sprays

2008 ◽  
Author(s):  
Sibendu Som ◽  
Suresh K. Aggarwal
Keyword(s):  
Diesel Engines ◽  
Fuel Injection ◽  
Spray Penetration ◽  
Nozzle Orifice ◽  
Fuel Droplets ◽  
Injector Nozzle ◽  
Primary Breakup ◽  
Penetration Data ◽  
Modeling Code ◽  
Breakup Model

Fuel injection characteristics, in particular the atomization and penetration of the fuel droplets, are known to affect emission and particulate formation in diesel engines. It is also well established that the primary atomization process is induced by aerodynamics in the near nozzle region, as well as cavitation and turbulence from the injector nozzle. However, most breakup models used to simulate the primary breakup process in diesel engines only consider the aerodynamically induced breakup. In this paper, the standard breakup models in Diesel Engine modeling code called “CONVERGE” are examined in constant volume spray chamber geometry using the available spray data. Since non-evaporating sprays provide a more stringent test for spray models, the x-ray data from Advanced Photon Source is used for detailed validation of the primary breakup model, especially in the region very close to the nozzle. Extensive validation of the spray models is performed under evaporating conditions using liquid length and spray penetration data. Good agreement is observed for global spray characteristics. However, the breakup model could not reproduce some of the experimental trends reported in literature thus identifying the need for a more comprehensive primary breakup model. An attempt is made to statically couple the internal nozzle flow with spray simulations, and examine the effect of nozzle orifice geometry on spray penetration.

The Interaction of Air Motion, Fuel Spray, and Combustion in the Diesel Combustion Process

1972 ◽  
Vol 94 (1) ◽  
pp. 11-14
Author(s):  
R. B. Melton ◽  
A. R. Rogowski
Keyword(s):  
Diesel Engines ◽  
Fuel Injection ◽  
Combustion Process ◽  
Central Area ◽  
Combustion Efficiency ◽  
Fuel Spray ◽  
Spray Penetration ◽  
Buoyancy Forces ◽  
Fluid Jets ◽  
Air Mixing

This paper is pertinent mainly to combustion in open-chamber diesel engines employing air swirl. It is shown how an increase in air swirl rate can cause a marked loss of combustion efficiency unless fuel spray penetration is increased. High swirl reduces radial fuel spray penetration with central injection and the resulting excess fuel in the central area may be trapped by buoyancy forces following ignition, becoming isolated for as much as a tenth of a second in a chamber of four in. diameter. A brief explanation of fuel injection in terms of the mechanics of fluid jets is given and circumstances described in which buoyancy forces assist fuel-air mixing following ignition.

Simulation of Liquid Fuel Atomization in an Industrial Spray Nozzle of a Powerplant Boiler

2010 ◽  
Author(s):  
Iman Mirzaii ◽  
Hasan Sabahi ◽  
Mohammad Passandideh-Fard ◽  
Nasser Shale
Keyword(s):  
High Pressure ◽  
Combustion Chamber ◽  
Liquid Fuel ◽  
Drop Size ◽  
Liquid Jet ◽  
Nozzle Orifice ◽  
Injector Nozzle ◽  
Fuel Atomization ◽  
Pressure Steam ◽  
Atomization Zone

In this study, the liquid fuel atomization in the injector nozzle of the combustion chamber of a powerplant boiler is numerically simulated. The atomization of a liquid fuel injector is characterized by drop size distribution of the nozzle. This phenomenon plays an important role in the performance of the combustion chamber such as the combustion efficiency, and the amount of soot and NOx formation inside the boiler. The injector nozzle, considered in this study, belongs to a powerplant boiler where the liquid fuel is atomized using a high pressure steam. First, the geometric characteristics of the injector are carefully analyzed using a wire-cut process and a CAD model of the nozzle is created. Next, one of the nozzle orifices and the atomization zone where the high pressure steam meets the liquid fuel is recognized. The computational domain is extended long enough to cover the whole atomization zone up to the end of the orifice. The flow governing equations are the continuity and Navier-Stokes equations. For tracking the liquid/gas interface, the Volume-of-Fluid (VOF) method along with Youngs’ algorithm for geometric reconstruction of the free surface is used. The simulation results show the details of the liquid and steam flow inside the nozzle including velocity distribution and shape of the liquid/gas interface. It is found that the liquid breakup to ligaments and the atomization of liquid to droplets do not occur inside the nozzle orifice. A liquid jet with certain cross sectional shape leaves the orifice surrounded by a high speed steam. The numerical model provides the shape of the liquid jet, and the steam and fuel velocity distributions at the exit of the nozzle orifice. These parameters are then correlated to the final drop size distribution using analytical/experimental correlations available in literature.

INFLUENCE OF NONEQUILIBRIUM FACTORS OF KEY REACTIONS ON SYNTHESIS GAS IGNITION

2020 ◽  
Author(s):  
I. V. Arsentiev ◽  
◽  
I. N. Kadochnikov ◽  
Keyword(s):  
Shock Wave ◽  
Synthesis Gas ◽  
Nonequilibrium Processes ◽  
Gas Ignition ◽  
Ignition And Combustion ◽  
Model Approach

The nonequilibrium processes of ignition and combustion of a syngas-air mixture behind a shock wave is studied using the mode model approach.

scholarly journals Jet A and Propane gas combustion in a turboshaft engine: performance and emissions reductions

2021 ◽  
Vol 3 (4) ◽  
Author(s):  
Ali Hasan ◽  
Oskar J. Haidn
Keyword(s):  
Combustion Process ◽  
Engine Performance ◽  
Emissions Reductions ◽  
Gas Combustion ◽  
Liquid Petroleum Gas ◽  
Performance And Emissions ◽  
Air Mixing ◽  
Turboshaft Engine ◽  
Engine Performance And Emissions ◽  
Lower Carbon

AbstractThe Paris Agreement has highlighted the need in reducing carbon emissions. Attempts in using lower carbon fuels such as Propane gas have seen limited success, mainly due to liquid petroleum gas tanks structural/size limitations. A compromised solution is presented, by combusting Jet A fuel with a small fraction of Propane gas. Propane gas with its relatively faster overall igniting time, expedites the combustion process. Computational fluid dynamics software was used to demonstrate this solution, with results validated against physical engine data. Jet A fuel was combusted with different Propane gas dosing fractions. Results demonstrated that depending on specific propane gas dosing fractions emission reductions in ppm are; NOx from 84 to 41, CO2 from less than 18,372 to less than 15,865, escaping unburned fuels dropped from 11.4 (just Jet A) to 6.26e-2 (with a 0.2 fraction of Propane gas). Soot and CO increased, this is due to current combustion chamber air mixing design.

An Improved Rate of Heat Release Model for Modern High-Speed Diesel Engines

2017 ◽  
Vol 139 (9) ◽  
Author(s):  
Peter G. Dowell ◽  
Sam Akehurst ◽  
Richard D. Burke
Keyword(s):  
Heat Release ◽  
Diesel Engines ◽  
Engine Speed ◽  
Fuel Injection ◽  
Maximum Pressure ◽  
Injection Model ◽  
Wall Impingement ◽  
Small Set ◽  
Rate Of Heat Release ◽  
Engine System

To meet the increasingly stringent emissions standards, diesel engines need to include more active technologies with their associated control systems. Hardware-in-the-loop (HiL) approaches are becoming popular where the engine system is represented as a real-time capable model to allow development of the controller hardware and software without the need for the real engine system. This paper focusses on the engine model required in such approaches. A number of semi-physical, zero-dimensional combustion modeling techniques are enhanced and combined into a complete model, these include—ignition delay, premixed and diffusion combustion and wall impingement. In addition, a fuel injection model was used to provide fuel injection rate from solenoid energizing signals. The model was parameterized using a small set of experimental data from an engine dynamometer test facility and validated against a complete data set covering the full engine speed and torque range. The model was shown to characterize the rate of heat release (RoHR) well over the engine speed and load range. Critically, the wall impingement model improved R2 value for maximum RoHR from 0.89 to 0.96. This was reflected in the model's ability to match both pilot and main combustion phasing, and peak heat release rates derived from measured data. The model predicted indicated mean effective pressure and maximum pressure with R2 values of 0.99 across the engine map. The worst prediction was for the angle of maximum pressure which had an R2 of 0.74. The results demonstrate the predictive ability of the model, with only a small set of empirical data for training—this is a key advantage over conventional methods. The fuel injection model yielded good results for predicted injection quantity (R2 = 0.99) and enabled the use of the RoHR model without the need for measured rate of injection.

Effect of H2 and CO Content in Syngas on the Performance and Emission of Syngas-Diesel Dual Fuel Engine - A Review

2014 ◽  
Vol 699 ◽  
pp. 648-653 ◽  
Author(s):  
Bahaaddein K.M. Mahgoub ◽  
Suhaimi Hassan ◽  
Shaharin Anwar Sulaiman
Keyword(s):  
Carbon Monoxide ◽  
Diesel Engines ◽  
Combustion Process ◽  
Exhaust Emission ◽  
Dual Fuel ◽  
Pure Liquid ◽  
Compression Ignition ◽  
Performance And Emission ◽  
Combustion Duration ◽  
Combustible Gases

In this review, a series of research papers on the effects of hydrogen and carbon monoxide content in syngas composition on the performance and exhaust emission of compression ignition diesel engines, were compiled. Generally, the use of syngas in compression ignition (CI) diesel engine leads to reduce power output due to lower heating value when compared to pure liquid diesel mode. Therefore, variation in syngas composition, especially hydrogen and carbon monoxide (Combustible gases), is suggested to know the appropriate syngas composition. Furthermore, the simulated model of syngas will help to further explore the detailed effects of engine parameters on the combustion process including the ignition delay, combustion duration, heat release rate and combustion phasing. This will also contribute towards the efforts of improvement in performance and reduction in pollutants’ emissions from CI diesel engines running on syngas at dual fuel mode. Generally, the database of syngas composition is not fully developed and there is still room to find the optimum H2 and CO ratio for performance, emission and diesel displacement of CI diesel engines.

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