Biodiesel Spray Characteristics and Their Effect on Engine Combustion and Particulate Emissions

2020 ◽  
Vol 142 (8) ◽  
Author(s):  
Akhilendra Pratap Singh ◽  
Avinash Kumar Agarwal
Keyword(s):  
Fuel Injection ◽  
Cone Angle ◽  
Fuel Spray ◽  
Particulate Emissions ◽  
Spray Parameters ◽  
Spray Characteristics ◽  
Spray Cone ◽  
Particulate Emission ◽  
Biodiesel Blends ◽  
Ci Engines

Abstract Spray analysis is used to characterize the fuel spray evolution and spray shape, which affects in-cylinder combustion and particulate emission characteristics of compression ignition (CI) engines. In this study, spray evolution of biodiesel blends and mineral diesel was captured using a high-speed charge coupled device (CCD) camera at different fuel injection pressures (FIPs) and ambient pressures (APs) in a constant volume spray chamber (CVSC). Results showed that spray parameters were significantly affected by FIP and AP. Higher FIPs resulted in longer fuel spray penetration length (Ls) and reduced spray cone angle (As). However, AP variation showed an exactly opposite trend of Ls and As. Increasing AP resulted in shorter Ls and increased As. Fuel properties also affected the spray characteristics, which slightly improved for lower biodiesel blends (B20: 20% v/v blend of biodiesel with mineral diesel) and then degraded for higher biodiesel blends (B40: 40% v/v blend of biodiesel with mineral diesel) with respect to baseline mineral diesel. The effects of these findings of fuel spray analysis were validated using engine experiments, which were performed in a single-cylinder research engine using identical test fuels and fuel injection parameters. Relatively superior combustion of B20-fueled engine and lower particulate emissions at higher FIPs showed good agreement with spray results.

Impacts of duct inner diameter and standoff distance on macroscopic spray characteristics of ducted fuel injection under non-vaporizing conditions

2020 ◽  
pp. 146808742091471
Author(s):  
Feng Li ◽  
Chia-fon Lee ◽  
Ziman Wang ◽  
Yiqiang Pei ◽  
Guoxiang Lu
Keyword(s):  
Large Scale ◽  
Fuel Injection ◽  
Soot Formation ◽  
Cone Angle ◽  
Mie Scattering ◽  
Standoff Distance ◽  
Spray Characteristics ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Inner Diameter

Ducted fuel injection spray is a new technology for reducing soot formation in heavy-duty diesel engines. In this work, the ducted fuel injection spray characteristics with different duct inner diameters and different standoff distances were investigated and compared with free spray. Duct inner diameter ranged from 1.5 to 4 mm, and standoff distance varied between 0.9 and 4.9 mm. Mie-scattering optical technique was used to characterize spray characteristics under various injection pressures in a constant-volume spray chamber. Ambient gas pressure of up to 6 MPa when spraying. The results showed that ducted fuel injection spray with smaller duct has better spray diffusion compared to those of ducted fuel injection sprays with larger ducts and free spray from the perspectives of spray tip penetration, spray cone angle and spray area. Increasing standoff distance could increase spray velocity. Ducted fuel injection spray with smaller duct formed a mushroom-shaped head and large-scale vortex flow close to the duct outlet. All the advantages of ducted fuel injection spray with smaller duct are interpreted as evidence of improving fuel–gas mixing quality significantly.

Macroscopic spray characteristics of long-chain alcohol-biodiesel fuels in a constant volume chamber

2017 ◽  
Vol 232 (2) ◽  
pp. 195-207 ◽  
Author(s):  
Fengyu Li ◽  
Bolun Yi ◽  
Lanbo Song ◽  
Wei Fu ◽  
Tao Liu ◽  
...  
Keyword(s):  
Cone Angle ◽  
Spray Characteristics ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Chain Alcohol ◽  
Biodiesel Blends ◽  
Spray Tip Penetration ◽  
Mixing Ratios ◽  
Long Chain Alcohol ◽  
Long Chain

In this research, three basic macroscopic spray characteristics (spray tip penetration, spray cone angle, and spray area) of long-chain alcohol-biodiesel blends were studied to investigate the differences of macroscopic spray characteristics of long-chain alcohol-biodiesel blends with different mixing ratios and to further investigate the effects of blending long-chain alcohols into biodiesel on the spray characteristics. Two kinds of long-chain alcohols, n-butanol, and n-pentanol, were selected to study effects of difference kinds of long-chain alcohols on macroscopic spray characteristics of long-chain alcohol-biodiesel blends. Results show that with the increase of proportion of n-butanol or n-pentanol in blends, spray tip penetration decreased while spray cone angle and spray area increased; in terms of the effects brought by different long-chain alcohols, n-pentanol-biodiesel blends showed slightly longer spray tip penetration, smaller spray cone angle and smaller spray area compared to n-butanol-biodiesel blends in the same mixing ratios, and the difference trends between those two kinds blends could easily be opposite due to the very similar properties of n-butanol and n-pentanol. Furthermore, a modified spray tip penetration model was proposed based on previous model and showed good agreement with experimental results.

Particulate Emissions From Karanja Biodiesel Fueled Turbocharged CRDI Sports Utility Vehicle Engine

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Jai Gopal Gupta ◽  
Avinash Kumar Agarwal ◽  
Suresh K. Aggarwal
Keyword(s):  
Particle Size ◽  
Fuel Injection ◽  
Direct Injection ◽  
Injection Pressure ◽  
Particulate Emissions ◽  
Promising Alternative ◽  
Biodiesel Blends ◽  
Particulate Number ◽  
Ci Engines ◽  
Utility Vehicle

Biodiesel has emerged as one of the most promising alternative fuel to mineral diesel in last two decades globally. Lower blends of biodiesel emit fewer pollutants, while easing pressure on scarce petroleum resources, without sacrificing engine power output and fuel economy. However, diesel engines emit significant amount of particulate matter (PM), most of which are nanoparticles. Due to the adverse health impact of PM emitted by compression ignition (CI) engines; most recent emission legislations restrict the total number of particles emitted, in addition to PM mass emissions. Use of biodiesel leads to reduction in PM mass emissions; however, the particle size–numbers distribution has not been investigated thoroughly. In this paper, PM emission characteristics from Karanja biodiesel blends (KB20 and KB40) in a modern common rail direct injection (CRDI) engine used in a sports utility vehicle (SUV) with a maximum fuel injection pressure of 1600 bar have been reported. This study also explored comparative effect of varying engine speeds and loads on particulate size–number distribution, particle size–surface area distribution, and total particulate number concentration from biodiesel blends vis-à-vis baseline mineral diesel. This study showed that particulate number emissions from Karanja biodiesel blends were relatively higher than baseline mineral diesel.

Atomization Characteristics of Jatropha-Derived Alternative Aviation Fuels From Aircraft Engine Injector

2017 ◽  
Author(s):  
Ramachandran Sakthikumar ◽  
Deivandren Sivakumar ◽  
B. N. Raghunandan ◽  
John T. C. Hu
Keyword(s):  
Size Distribution ◽  
Drop Size ◽  
Cone Angle ◽  
Fuel Spray ◽  
Jet Fuels ◽  
Spray Characteristics ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Atmospheric Air ◽  
Atomization Characteristics

Search for potential alternative jet fuels is intensified in recent years to meet stringent environmental regulations imposed to tackle degraded air quality caused by fossil fuel combustion. The present study describes atomization characteristics of blends of jatropha-derived biofuel with conventional aviation kerosene (Jet A-1) discharging into ambient atmospheric air from a dual-orifice atomizer used in aircraft engines. The biofuel blends are characterized in detail and meet current ASTM D7566 specifications. The experiments are conducted by discharging fuel spray into quiescent atmospheric air in a fuel spray booth to measure spray characteristics such as fuel discharge behavior, spray cone angle, drop size distribution and spray patternation at six different flow conditions. The characteristics of spray cone angle are obtained by capturing images of spray and the measurements of spray drop size distribution are obtained using laser diffraction particle analyzer (LDPA). A mechanical patternator system comprising 144 measurement cells is used to deduce spray patternation at different location from the injector exit. A systematic comparison on the atomization characteristics between the sprays of biofuel blends and the 100% Jet A-1 is presented. The measured spray characteristics of jatropha-derived alternative jet fuels follow the trends obtained for Jet A-1 sprays satisfactorily both in qualitative and quantitative terms.

Preliminary CFD Study on the Effect of Fuel Injector Coking on Fuel Spray Characteristics

2017 ◽  
Author(s):  
Parash Agarwal ◽  
Vishal Sethi ◽  
Pierre Q. Gauthier ◽  
Xiaoxiao Sun ◽  
Yize Liu
Keyword(s):  
Experimental Data ◽  
Cone Angle ◽  
Coke Formation ◽  
Spray Angle ◽  
Fuel Spray ◽  
Multiphase Model ◽  
Fuel Injector ◽  
Spray Characteristics ◽  
Spray Cone ◽  
Carbonaceous Particles

Fuel injector coking involves deposit formation on the external or the internal surfaces of an injector or nozzle. This deposition of carbonaceous particles can result in uneven fuel-spray characteristics or localised burning (hot spots), which may eventually lead to mechanical failure or simply have a detrimental effect on the combustion system. This study focuses on the use of numerical methods to investigate the effect of coke formation on both the atomiser internal flow passages and its spray characteristics. Three different cases are examined; one investigating the clean injector; the second investigating the effect of internal coking; and the third investigating the effect of nozzle tip coking. A pressure swirl atomiser was considered for the purpose of the study. Validation of the numerical results for the clean injector condition is carried out against published experimental data. Two arbitrary geometries of coke deposits were created. The Volume of Fluid (VOF) multiphase model has been used in conjugation with a Geometrical Reconstruction Scheme (GRS) to simulate the interface representing the two phases. Spray cone angle and the liquid film thickness for the clean injector condition predicted by numerical simulation agreed well with the experimental data. Instabilities in the air core and the spray angle were also observed because of the presence of coke layers. Fouling present on the injector tip resulted in an earlier breakup of the film which can thereby affect the flame lift-off length. These stated observations can have significant implications both on the performance as well as the life of the combustion systems, thereby establishing the relevance of this study.

Spray Characteristics of Alternative Jet Fuel at Elevated Ambient Conditions

2019 ◽  
Author(s):  
Kumaran Kannaiyan ◽  
Reza Sadr
Keyword(s):  
Cone Angle ◽  
Jet Fuel ◽  
Jet Fuels ◽  
Spray Parameters ◽  
Gas Temperature ◽  
Ambient Conditions ◽  
Spray Characteristics ◽  
Spray Cone ◽  
Ambient Gas ◽  
Alternative Jet Fuel

Abstract In recent years, Gas-to-Liquid (GTL) jet fuel is considered as an alternative jet fuel because of its cleaner combustion characteristics. The chemical and physical properties of GTL fuels are different from those of the conventional jet fuels. The objective of the present work is to investigate the effect of ambient conditions and fuel volatilization characteristics on the macroscopic spray features. To this end, the macroscopic spray performance is visualized using the shadowgraph imaging technique at elevated ambient conditions. The near nozzle spray parameters like spray cone angle, sheet breakup length, and the sheet velocity, are determined from the shadowgraph images using an in-house program. The effect of ambient conditions on the near nozzle spray characteristics for conventional fuels has been reported in the literature. However, these effects have not been reported in detail for the alternative, GTL jet fuels. The results show that the ambient gas pressure has a significant effect on the spray performance when compared to that of the ambient gas temperature. At atmospheric conditions, the spray performance of GTL fuel is comparable to those of Jet A-1 fuel. However, with the increase in ambient conditions, the difference in spray performance of GTL and Jet A-1 is significant.

scholarly journals Experimental Study of Spray Characteristics of Kerosene-Ethanol Blends from a Pressure-Swirl Nozzle

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Tao Zhang ◽  
Bo Dong ◽  
Xun Zhou ◽  
Linan Guan ◽  
Weizhong Li ◽  
...  
Keyword(s):  
Discharge Coefficient ◽  
Cone Angle ◽  
Injection Pressure ◽  
Spray Characteristics ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Breakup Length ◽  
Ethanol Blends ◽  
Pressure Swirl ◽  
Spray Velocity

Partial replacement of kerosene by ethanol in a gas turbine is regarded as a good way to improve the spray quality and reduce the fossil energy consumption. The present work is aimed at studying the spray characteristics of kerosene-ethanol blends discharging from a pressure-swirl nozzle. The spray cone angle, discharge coefficient, breakup length, and velocity distribution are obtained by particle image velocimetry, while droplet size is acquired by particle/droplet imaging analysis. Kerosene, E10 (10% ethanol, 90% kerosene), E20 (20% ethanol, 80% kerosene), and E30 (30% ethanol, 70% kerosene) have been considered under the injection pressure of 0.1–1 MPa. The results show that as injection pressure is increased, the discharge coefficient and breakup length decrease, while the spray cone angle, drop size, and spray velocity increase. Meanwhile, the drop size decreases and the spray velocity increases with ethanol concentration when the injection pressure is lower than 0.8 MPa. However, the spray characteristics are not affected obviously by the ethanol concentration when the injection pressure exceeds 0.8 MPa. A relation to breakup length for kerosene-ethanol blends is obtained. The findings demonstrate that the adding of ethanol into kerosene can promote atomization performance.

Investigation on Flat-Fan Spray Characterization in High-Speed Air Coflow for Gas Turbine Online Water Washing Application

2021 ◽  
Author(s):  
Kiran Kumar ◽  
Vasudev Chaudhari ◽  
Srikrishna Sahu ◽  
Ravindra G. Devi
Keyword(s):  
Droplet Size ◽  
Gas Turbines ◽  
High Speed ◽  
Numerical Models ◽  
Cone Angle ◽  
Operating Conditions ◽  
Spray Characteristics ◽  
Spray Cone ◽  
Water Washing ◽  
Spray Characterization

Abstract Fouling in compressor blades due to dirt deposition is a major issue in land-based gas turbines as it impedes the compressor performance and degrades the overall engine efficiency. The online water washing approach is an effective alternate for early-stage compressor blade cleaning and to optimize the time span between offline washing and peak availability. In such case, typically a series of flat-fan nozzles are used at the engine bell mouth to inject water sprays into the inflowing air. However, optimizing the injector operating conditions is not a straightforward task mainly due to the tradeoff between blade cleaning effectiveness and material erosion. In this context, the knowledge on spray characteristics prior to blade impingement play a vital role, and the experimental spray characterization is crucial not only to understand the basic process but also to validate numerical models and simulations. The present paper investigates spray characteristics in a single flat-fan nozzle operated in the presence of a coflowing air within a wind-tunnel. A parametric investigation is carried out using different air flow velocity in the tunnel and inlet water temperature, while the liquid flow rate was maintained constant. The spray cone angle and liquid breakup length are measured using back-lit photography. The high-speed shadowgraphy technique is used for capturing the droplet images downstream of the injector exit. The images are processed following depth-of-filed correction to measure droplet size distribution. Droplet velocity is measured by the particle tracking velocimetry (PTV) technique. As both droplet size and velocity are known, the cross-stream evolution of local droplet mass and momentum flux are obtained at different axial locations which form the basis for studying the effectiveness of the blade cleaning process due to droplet impingement on a coupon coated with foulant of known mass.

Development of a wall jet model dedicated to 1D combustion modelling for CI engines

2021 ◽  
Vol 13 (2-3) ◽  
pp. 146-163
Author(s):  
Alejandro Aljure Osorio ◽  
Xavier Tauzia ◽  
Alain Maiboom
Keyword(s):  
Fuel Injection ◽  
Fuel Spray ◽  
Wall Jet ◽  
Mixing Rate ◽  
Free Jet ◽  
Combustion Modelling ◽  
Using Data ◽  
Wall Interaction ◽  
The Impact ◽  
Ci Engines

Diesel engines are becoming smaller as technology advances, which means that the fuel spray (or jet) interacts with the cylinder walls before combustion starts. Most fuel injection 1D models (especially for diesel fuel) do not consider this interaction. Therefore, a wall-jet sub-model was created on an Eulerian 1D diesel spray model. It was calibrated using data from the literature and validated with experimental data from a fuel spray impacting a plate in a constant volume combustion chamber. Results show that the spray moving along the wall has a higher mixing rate but less penetration as an equivalent free jet, therefore they show a similar volume. Spray-wall interaction creates a stagnation zone right before the impact with the wall, and friction of the jet with the wall is relatively low. All these phenomena are well captured by the wall-jet sub-model.

Characterizing Diesel Fuel Spray Cone Angle From Back-Scattered Imaging by Fitting Gaussian Profiles to Radial Spray Intensity Distributions

2012 ◽  
Vol 134 (6) ◽  
Author(s):  
Jaclyn E. Johnson ◽  
Jeffrey D. Naber ◽  
Seong-Young Lee
Keyword(s):  
Charge Density ◽  
Diesel Fuel ◽  
Curve Fitting ◽  
Cone Angle ◽  
Injection Pressure ◽  
Fuel Spray ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Gaussian Curve

Quantifying fuel spray properties including penetration, cone angle, and vaporization processes sheds light on fuel-air mixing phenomenon, which governs subsequent combustion and emissions formation in diesel engines. Accurate experimental determination of these spray properties is a challenge but imperative to validate computational fluid dynamic (CFD) models for combustion prediction. This study proposes a new threshold independent method for determination of spray cone angle when using Mie back-scattering optical diagnostics to visualize diesel sprays in an optically accessible constant volume vessel. Test conditions include the influence of charge density (17.6 and 34.9 kg/m3) at 1990 bar injection pressure, and the influence of injection pressure (990, 1370, and 1980 bar) at a charge density of 34.8 kg/m3 on diesel fuel spray formation from a multi-hole injector into nitrogen at a temperature of 100 °C. Conventional thresholding to convert an image to black and white for processing and determination of cone angle is threshold subjective. As an alternative, an image processing method was developed, which fits a Gaussian curve to the intensity distribution of the spray at radial spray cross-sections and uses the resulting parameters to define the spray edge and hence cone angle. This Gaussian curve fitting methodology is shown to provide a robust method for cone angle determination, accounting for reductions in intensity at the radial spray edge. Results are presented for non-vaporizing sprays using this Gaussian curve fitting method and compared to the conventional thresholding based method.

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