Visual Spray and Evaporization Character of Biodiesel Blend Fuels in a Combustion Chamber

2011 ◽  
Vol 80-81 ◽  
pp. 654-660
Author(s):  
Yu Liu ◽  
Jun Li
Keyword(s):  
Ambient Temperature ◽  
High Speed ◽  
Combustion Process ◽  
Premixed Combustion ◽  
Copper Vapor Laser ◽  
Diffusion Combustion ◽  
Penetration Length ◽  
Constant Volume Chamber ◽  
Fuel Evaporation ◽  
Measured Liquid

Different from traditional engine test, an optical constant volume chamber simulated HTHP ambient condition was employed by using biodiesel-diesel-butanol blends. With high-speed camera and synchronized copper vapor laser, recorded fuel spray and combustion process, measured liquid jet penetration length and heat release rate under variable ambient temperature and fuel composition conditions. With ambient temperature increasing, burn process converted from premixed combustion to diffusion combustion, and the micro-explosion became weak and disappeared. It was concluded that micro-explosion could occur under particular initial ambient temperature and specific blend ratio conditions for the biodiesel-diesel-butanol fuel, that will distinctly enhance fuel evaporation and premixed combustion process.

Analysis of Micro-Explosion Phenomenon in a Constant Volume Chamber by Butanol-Biodiesel-Diesel Blend Fuel

2012 ◽  
Vol 443-444 ◽  
pp. 996-1006 ◽  
Author(s):  
Yu Liu ◽  
Jun Li ◽  
Ying Gao ◽  
Xin Mei Yuan
Keyword(s):  
Ambient Temperature ◽  
High Speed ◽  
Fuel Injection ◽  
Combustion Process ◽  
Constant Volume ◽  
Liquid Jet ◽  
Penetration Length ◽  
Temperature Conditions ◽  
Constant Volume Chamber ◽  
Jet Penetration

Different blend ratio of ternary component fuel was tested inside a constant volume chamber to investigate fuel injection and combustion under similar real engine working conditions. Because liquid spray light scattering is the different reflective rate from the liquid droplets and its surrounding background, butanol-biodiesel-diesel liquid jet penetration length can be highlighted in the images taken by high speed camera. Various ambient temperatures from 800K to 1200K and fuel composition were investigated. Measured results showed that sudden but repeatable drop of liquid jet penetration length at constant ambient temperature conditions of 800K and 900K. With ambient temperature increasing, this phenomenon became weak and disappeared. So more works focus on non-combusting experiments in order to delete combustion reflect. With butanol and biodiesel content increasing, micro explosion becomes prone excited and more violent because of the enlarged differences in volatilities and boiling point among the components. It is concluded that micro explosion which will distinctly enhances premixed combustion process and heat release rate but it present under certain initial ambient temperature conditions only and the light fuel content shouldn’t be lower than 10%.

Laser Diagnostic Investigation on the Spray and Combustion with Butanol-Biodiesel-Diesel Fuel Blends

2012 ◽  
Vol 443-444 ◽  
pp. 986-995 ◽  
Author(s):  
Yu Liu ◽  
Jun Li ◽  
Ying Gao ◽  
Xin Mei Yuan
Keyword(s):  
High Speed ◽  
Copper Vapor Laser ◽  
High Speed Imaging ◽  
Penetration Length ◽  
Spray Penetration ◽  
Sudden Drop ◽  
Ambient Temperatures ◽  
Fuel Blends ◽  
Constant Volume Chamber ◽  
Laser Diagnostic

. In this paper, blends of butanol-biodiesel-diesel were tested inside a constant volume chamber to investigate liquid spray and combustion of the fuels. With high-speed camera and synchronized copper vapor laser, spray penetration during injection is recorded since it has a higher light reflectivity. Various ambient temperatures and fuel composition were investigated. There is a sudden drop in spray penetration at 800 K and 900 K, but not at 1000 K and 1200 K. When the spray penetration of the butanol-biodiesel-diesel blends is compared to that of the biodiesel-diesel blends, under non-combusting environment, a sudden drop in spray penetration length is also observed at 1100 K. High speed imaging shows that, for the non-combusting case, at 1100 K, the tip of the spray jet erupts into a plume sometime after injection for the butanol-biodiesel-diesel blend. The same is not seen with the biodiesel-diesel blend, neither at lower ambient temperature of 900 K. It is concluded that micro-explosion can occurs under particular conditions for the butanol-biodiesel-diesel blend, and the results is consistent with previous study in the literature.

Computational Investigation of Diesel Combustion and Soot Formation With a Phenomenological Soot Model Under Different Temperatures in a Constant Volume Chamber

2014 ◽  
Author(s):  
Zhichao Zhao ◽  
Chia-Fon Lee ◽  
Yawei Chi ◽  
Jingping Liu
Keyword(s):  
Ambient Temperature ◽  
Soot Formation ◽  
Constant Volume ◽  
Diffusion Combustion ◽  
Soot Emission ◽  
Ambient Temperatures ◽  
Constant Volume Chamber ◽  
Constant Volume Combustion Chamber ◽  
Different Temperatures ◽  
Soot Model

The previous nine-step phenomenological soot model was revised by including the oxidation effect on soot number density. Using KIVA-3V Release 2 code coupled with this revised phenomenological soot model, multi-dimensional computational fluid dynamics (CFD) simulations of diesel spray combustion in a constant volume chamber was conducted to investigate the combustion physics and soot emission characteristics. Meanwhile, experiments were conducted in an optical constant volume combustion chamber under different ambient temperatures (800, 900, 1000 K), from which the combustion characteristics and soot distributions were obtained for validation. The results indicate that ignition retards with the decrease of ambient temperature, which results in more air-fuel mixing controlled diffusion combustion at high ambient temperature, and more premixed combustion at low ambient temperature. The corresponding soot formation and distribution shows that the soot emission is strongly related to the local equivalence ratio, which leads to lower soot emission in the lower initial temperature case with more homogeneous mixture. Compared to previous nine-step model, the revised model predicted lower soot number and bigger soot particles size.

Visualizing Diffusion Flame Formation in the Wake of Partially Premixed Combustion

2001 ◽  
Vol 123 (3) ◽  
pp. 221-227 ◽  
Author(s):  
K. M. Lyons ◽  
K. A. Watson
Keyword(s):  
Nozzle Exit ◽  
Diffusion Flame ◽  
High Speed ◽  
Combustion Process ◽  
Premixed Combustion ◽  
Turbulent Diffusion Flame ◽  
Partially Premixed Combustion ◽  
Combustion Region ◽  
Partially Premixed ◽  
Partially Premixed Flame

Results are presented on the formation of a diffusion flame in a methane nonpremixed jet following the propagation of partially premixed combustion. An initially nonreacting turbulent methane jet (Re=2700) in quiescent air is ignited at a downstream location x/d=70. High-speed video images (125 and 250 Hz) were obtained that chart the evolution of the combustion process. Partially premixed flame propagation is witnessed as the combustion front moves upstream (downward) toward the nozzle exit. As the front propagates, the blue (premixed) character of the flame is diminished, the combustion region narrows, and the transition to diffusion-limited combustion along the stratified methane/air layer takes place. Before reaching the nozzle exit, axial wisps of blue flame emission are witnessed along the jet-edge near the fuel/air interface (i.e., at larger radii than the eventual diffusion flame boundary). Luminosity from soot is first apparent just upstream of an axisymmetric flame bulge as the diffusion flame forms, and within 100 ms, soot attains levels present in the steady-state turbulent diffusion flame. Images are presented portraying the phenomenon, and three regimes are proposed to characterize the propagation of combustion.

Spray characterization of DMC and MeFo on multi-hole injectors for highly boosted DISI combustion engines

2021 ◽  
pp. 146808742110381
Author(s):  
Alexander Plaß ◽  
Malki Maliha ◽  
Heiko Kubach ◽  
Thomas Koch
Keyword(s):  
High Speed ◽  
Fossil Fuels ◽  
Dimethyl Carbonate ◽  
Combustion Process ◽  
Pollutant Emissions ◽  
Spray Angle ◽  
Combustion Engines ◽  
Synthetic Fuels ◽  
Constant Volume Chamber

In the future, synthetic fuels could replace fossil fuels to minimize the CO2 emissions of combustion engines. Dimethyl carbonate (DMC) and methyl formate (MeFo) represent not only possible synthetic fuels but, due to their oxygen content, also have properties to reduce the pollutant emissions. For a good combustion process, the spray targeting and evaporation properties are important. Due to the less known injection behavior of DMC and MeFo, the spray characteristics were examined in a pressure chamber. The penetration depth, projected spray area, and spray angle were investigated at injection pressures of 100 and 200 bar, chamber pressures of 1 and 2.5 bar, and a temperature variation of up to 90°C for two different injector spray angles and flow rates in comparison with gasoline E5. The spray was recorded with a high-speed camera in a constant-volume chamber with a N2 environment. Both fuels showed a faster evaporation than E5 even with a higher injection mass due to their lower LHV. MeFo showed extreme spray collapse and flash boiling effects, which lead to even faster evaporation rates and higher penetration velocities.

Numeberical Simulation of a New Enhanced Heat Transfer Burener

2011 ◽  
Vol 201-203 ◽  
pp. 2721-2726
Author(s):  
Xiao Feng Lu ◽  
Duo Liu ◽  
Yuan Qing Li
Keyword(s):  
Heat Transfer ◽  
Flue Gas ◽  
High Speed ◽  
Combustion Process ◽  
Flame Length ◽  
Combustion Model ◽  
Diffusion Combustion ◽  
Enhanced Heat Transfer ◽  
Local Overheating ◽  
New Type

In this paper, numerical simulation of a new type enhanced heat transfer burner was carried out by using the CFD commercial software FLUENT. Standard κ-ε turbulent model, P-1 radiation model and PDF diffusion combustion model were used to predict the influence of the combustor’s structure change on its performance in the combustion process. The results showed that: The added necking down at the outlet of the combustion chamber can significantly enhanced the jet action of the flue gas, the high speed flow flue gas formed a forced convection cyclical field, convective heat transfer rate was increased greatly and the temperature distribution in the furnace became more uniform, which guaranteed an excellent heating effect. New type of staged air distribution can promote the mixing of the fuel and air. Further more, it can improve the flame length to prevent the local overheating phenomenon during the combustion process. On the basis of the same total sectional areas, the added number of the jet orifice can also promote the mixing of the fuel and air to enhance the thermal intensity and thermal efficiency of the furnace.

Quantitative Investigation of Spray Characteristics of Unique Diesel Injector Tips

2001 ◽  
Author(s):  
Erica L. Blobaum ◽  
Stephen A. Ciatti ◽  
David E. Foster
Keyword(s):  
High Speed ◽  
Fuel Injection ◽  
Cone Angle ◽  
Digital Camera ◽  
Copper Vapor Laser ◽  
Injection Timing ◽  
Spray Characteristics ◽  
Penetration Length ◽  
Engine Testing ◽  
Diesel Fuel Injection

Abstract A quantitative study of diesel fuel injection was conducted to investigate minute differences in spray plume development from several unique injector tips. In this study, a set of six eight-hole injector tips was assessed to evaluate distinguishable spray characteristics. The tips have known variability in soot and NOx data during in-engine testing. A spray fixture was constructed with a cam-pressurized electronic unit injector and a 5.1L, nitrogen-pressurized spray chamber. Injection conditions such as injection timing and duration were experimentally controlled to replicate actual engine load conditions. A copper-vapor laser illuminated the fuel spray, and a high-speed digital camera was timed to capture the injection events. Digital analysis of the spray images produced quantified penetration length, cone angle, and two-dimensional area data as a function of crank angle. The first five observed spray images (up to a spray radius of approximately 6 cm) of each injection event are presented. Initial qualitative analysis of the spray images indicated clear and repeatable asymmetries, as well as plume development differences between the injector tips. These observations suggest that early penetration length measurements may be indicative of emissions trends. It is assumed that variations in spray shapes can be correlated to NOx and soot data. The level of these differences, however, is minute, suggesting that detailed characterization strategies must be implemented to detect the spray patterns that are most influential to engine emissions.

A multistage combustion model and soot formation model for direct-injection diesel engines

2002 ◽  
Vol 216 (6) ◽  
pp. 495-504 ◽  
Author(s):  
G J Micklow ◽  
W Gong
Keyword(s):  
Diesel Engines ◽  
Soot Formation ◽  
Direct Injection ◽  
Combustion Process ◽  
Oxidation Mechanism ◽  
Soot Oxidation ◽  
Premixed Combustion ◽  
Combustion Model ◽  
Diffusion Combustion ◽  
Soot Model

A multistage combustion model for diesel engines is presented in this paper. Three combustion stages, ignition of diesel, premixed combustion and diffusion combustion, are considered in the combustion process in a typical medium speed direct injection diesel engine. The transition from the ignition delay to the premixed combustion stage occurs when the highest temperature in the cylinder is beyond a critical value, and the transition from the premixed combustion model to the diffusion combustion model occurs when a calculated fraction of the premixed fuel is burned, which is determined from an empirical correlation based on the engine design and running conditions. Significant improvements in the predictions for in-cylinder pressure and heat release rate were achieved compared with previous models. A soot model based on the Hiroyasu soot formation mechanism and the Nagle and Strickland-Constable soot oxidation mechanism was implemented in a standard KIVA3V code. The effect of the OH radical in soot oxidation was also incorporated into the soot model. Computations show that OH plays an important role during the late combustion stage. Predicted soot and NOx were compared with measured values and a good agreement was achieved.

scholarly journals Effect of the HPDI and PPCI Combustion Modes of Direct-Injection Natural Gas Engine on Combustion and Emissions

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1957
Author(s):  
Shouying Jin ◽  
Jinze Li ◽  
Longfei Deng ◽  
Binyang Wu
Keyword(s):  
Natural Gas ◽  
Oil And Gas ◽  
Direct Injection ◽  
Combustion Process ◽  
Mixture Distribution ◽  
Premixed Combustion ◽  
Diffusion Combustion ◽  
Injection Timing ◽  
Combustion Modes ◽  
Ignition Characteristics

Natural gas (NG) engines have very broad application prospects. The pilot-ignited NG diesel engine can be organized into two combustion modes according to the sequence of oil and gas injection: (1) High-pressure direct injection, where NG is mainly diffused combustion; and (2) partially premixed compression ignition, where NG is mainly premixed combustion. In this study, we used CONVERGE to explore the influence of the NG injection timing on the distribution of the mixture equivalence ratio, ignition characteristics, thermal efficiency, emission, and combustion reaction rate under the two combustion modes. We also used a multi-step soot model to analyze the particle mass and quantity. We showed herein that the NG injection timing significantly affects the mixture distribution in the cylinder, thereby consequently affecting the combustion process. Both very early and very late injection times were not conducive to NG combustion. In addition, the mass, quantity, and diameter of the soot produced by diffusion combustion were larger than those produced with premixed combustion.

Numerical Simulation of Premixed Propane/Air Flame Propagation Using a Dynamically Thickened Flame Approach

2013 ◽  
Vol 444-445 ◽  
pp. 1574-1578 ◽  
Author(s):  
Hua Hua Xiao ◽  
Zhan Li Mao ◽  
Wei Guang An ◽  
Qing Song Wang ◽  
Jin Hua Sun
Keyword(s):  
Numerical Simulation ◽  
Flame Propagation ◽  
Numerical Study ◽  
Vortex Motion ◽  
Combustion Process ◽  
Single Step ◽  
Premixed Combustion ◽  
Premixed Flame ◽  
Flame Surface ◽  
Arrhenius Kinetics

A numerical study of premixed propane/air flame propagation in a closed duct is presented. A dynamically thickened flame (TF) method is applied to model the premixed combustion. The reaction of propane in air is taken into account using a single-step global Arrhenius kinetics. It is shown that the premixed flame undergoes four stages of dynamics in the propagation. The formation of tulip flame phenomenon is observed. The pressure during the combustion process grows exponentially at the finger-shape flame stage and then slows down until the formation of tulip shape. After tulip formation the pressure increases quickly again with the increase of the flame surface area. The vortex motion behind the flame front advects the flame into tulip shape. The study indicates that the TF model is quite reliable for the investigation of premixed propane/air flame propagation.

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