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Keywords— Injection Pressure, Jatropha Oil Methyl Ester, Spray break up region, Injection velocity, Sauter Mean Diameter

Abstract— The spray characteristic of the injected fuel is mainly depends upon fuel injection

pressure, temperature, ambient pressure, fuel viscosity and fuel density. An experimental study

was conducted to examine the effect of injection pressure on the spray was injected into direct

injection (DI) diesel engine in the atmospheric condition. In Diesel engine, the window of 20 mm

diameter hole and the transparent quartz glass materials were used for visualizing spray

characteristics of combustion chamber at right angle triangle position. The varying Injection

pressure of 180 - 240 bar and the engine was hand cranked for conducting the experiments. Spray

characteristics for Jatropha oil methyl ester (JOME) and diesel were studied experimentally.

Spray tip penetration and spray cone angle were measured in a combustion chamber of Direct

Injection diesel engine by employing high speed Digital camera using Mie Scattering Technique

and ImageJ software. The study shows the JOME gives longer spray tip penetration and smaller

spray cone angle than those of diesel fuels. The Spray breakup region (Reynolds number, Weber

number), Injection velocity and Sauter Mean Diameter (SMD) were determined for diesel and

JOME. SMD decreases for JOME than diesel and the Injection velocity, Reynolds Number,

Weber Number Increases for JOME than diesel.

INTRODUCTION

Biodiesel is biodegradable, non-poisonous and eco-friendly fuel, produced from vegetable

oil, animal fats and waste cooking oil by transesterification process. The biodiesel blends is used

for reduce the fuel properties of viscosity and density. The improvement of the spray

characteristics leads to better atomization in the DI diesel engine.

The fuel flow in the injector and the fuel propagation of the nozzle outlet provides the

initial condition for investigate the macroscopic and microscopic spray characteristics in the

combustion chamber [1].Improve the accurate calculation and the breakup model of injection

spray is modified by introducing Kelvin–Helmholtz and Rayleigh–Taylor (KH–RT) model and

the Comparison of experimental results with numerical ones about spray shapes, mean droplet

diameter and axial mean velocity [2]. The macroscopic spray characteristics of spray tip

penetration and spray cone angle are determined by lateral cross-sections at 80% of the shadow

level and the lateral integration of shadow intensities of the diesel fuel [3]. The characteristics of

fuel spray for the fuel injector obtained by using the shadowgraphs and particle image

P. Raghu M. Senthamil Selvan K. Pitchandim N. Nallusamy

India. OMR, Kalavakkam–603 110, Tamil Nadu, Department of Mechanical Engineering, SSN College of Engineering,

[email protected] [email protected]

Sriperumbudur- 602 117, Pennalur Irungattukottai, Department of Mechanical Engineering, Sri Venkateswara College of Engineering,

Varying Injection Pressurable Energy Sources

Spray Characteristics of Diesel and Biodiesel by Experimental Study on Diesel Engine and Analysis the

Tamil Nadu, India.

International Conference on Recent Advances in Mechanical Engineering and Interdisciplinary Developments [ICRAMID - 2014]

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velocimetry at various chamber pressure conditions [4]. Comparison of oxidation stability for

biodiesel from different manufacturers and the storage conditions of biodiesel has been reported

[5].

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Fig.1 Spray structure

In this work, the spray atomization was studied near nozzle tip to examine the effects of

injection pressure on spray characteristics for diesel and JOME under non evaporating conditions

for different injection pressure from 180 to 240 bar. Fig.1, illustrates the definition of spray tip

penetration and spray cone angle. Spray tip penetration indicates how far the spray travels in the

combustion chamber from the nozzle tip to spray end. This determines greatly the fuels

macroscopic distribution in the combustion chamber. This angle usually is between 5 and 30

degrees. The small droplet size represents the good atomization.

EXPERIMENTAL PROCEDURE

This experiment conducted in the modified single cylinder air cooled DI diesel engine.

This optical engine used for analyse spray characteristics. The experimental setup is shown in fig.

2. The fuel is supplied from the fuel tank to combustion chamber through the fuel filter and

pressure pump with fuel delivery pressure set at 180 to 240 bars. The whole experiments were

carried out at constant fuel injection timing at non-evaporating condition. The multi holes nozzle

(0.231 mm diameter) fuel injector was located on the side of the engine head. The injected fuel

was visualized by the optical window. The optical access to the combustion chamber is

accomplished from the side through a hole just beneath the cylinder head. There are two optical

windows arrested on the cylinder block with the help of flanges, which are used for visual

measurements and capturing the spray structure under various Injection pressure. The LED white

light source is used as illumination purpose for spray visualization. The 20 mm diameter hole

drill on the cylinder block in right angle triangle direction and arrested by quartz glass. Using this

fuel injection system, the fuel was injected into the combustion chamber and spray was captured

by a Sony cyber shot DSC-HX200V high speed digital Camera.

The high speed digital camera was located at 30 and placed one side of the optical

window to visualization for capture the spray structure and the LED light source is passed

through the other side of the optical window at exactly 90 for brightness. The both windows are

placed in right angle triangle direction. The camera was connected to a computing system with

the help of cable. Images are captured by using the camera and the images are taken in a multiple

shot mode or video mode for spray structure clearance. The captured images were further

processed using ImageJ software, which has graphical tools to analyse these captured images.

The macroscopic characteristics of spray tip penetration and spray cone angle were measured

from the captured images by Sony cyber shot DSC-HX200V high speed digital camera.


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Fig. 2 Experimental setup

Table 1. Engine specifications

Type Single cylinder ,vertical, air cooled 4-S CI engine

Engine Power (P) 4.4 kW

Engine Speed 1500 rpm

Bore Diameter (D) 87.5 mm

Stroke (L) 110 mm

Compression ratio 17.5:1

Table 2. Properties of neat diesel and JOME

Property Diesel Jatropha oil methyl ester

Density (kg/m3) 840 875

Viscosity(40 ) 3.4 4.27

Flash point ( ) 71 77

Fire point ( ) 103 270

Cetane number 48-56 51-52

RESULT AND DISCUSSION

The test fuels used for the investigations were JOME and diesel. Its properties were

shown in Table 2. The density and viscosity are the most important property which affects the

spray characteristics of fuel. Images are recorded for every injection pressure for diesel and

biodiesel by using the Sony cyber shot DSC-HX200V high speed digital Camera. The ImageJ

software was used for analyse the spray structure for varying the Injection pressure. The

macroscopic spray characteristics of spray tip penetration and spray cone angle were measured by

using the ImageJ software. The parameters like Injection velocity, Spray breakup region

(Reynolds Number, Weber Number) and Sauter mean diameter were determined for diesel and

JOME with increasing injection pressure.

Spray Structure for Diesel and Jatropha Oil Methyl Ester at Varying Injection Pressure

The images of diesel and Jatropha Oil Methyl Ester spray development are shown in

Fig.3.For various injection pressures. It is found that the fuel was ejected in a liquid column with

a larger mushroom shaped region at the injector tip. The five different images were taken to find


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out the macroscopic spray characteristics. First images are converting the 8 bit image. Then

change the image into black and white. Now fix the suitable threshold value to the image.

Fig. 3 The spray image for neat diesel and biodiesel at varying injection pressure

Spray Tip Penetration and spray cone angle

The spray tip penetration for JOME and diesel spray under various injection pressures is

shown in Fig. 4 It can be seen that JOME spray forms a longer tip penetration in comparison with

diesel at non evaporating condition, reason for that are high injection pressure and less

atomization of JOME. The less atomization of JOME has high viscosity and surface tension. This

leads to the higher spray tip penetration.

Fig.4 Variation of Injection pressure with spray tip penetration and spray cone angle for Diesel

and JOME

The spray cone angle for diesel and JOME spray under various injections pressure is shown in

Fig. 4. The higher injection pressure provides the high spray velocities and high injection flow

rates of JOME. This leads to a narrow spray cone angle. The high injection pressure eliminates

the effect of friction between JOME and nozzle surface due to high viscosity of JOME.

Injection Velocity

The Injection velocity for diesel and JOME spray under various injection pressures is

shown in Fig.5. The JOME have high viscosity and density so it has been low injection velocity

than diesel. The Injection velocity increases with increasing the injection pressure for both diesel

and JOME.


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Fig.5 Variation of Injection pressure with Injection Velocity for Diesel and JOME

Spray Breakup Region Reynolds Number and Weber Number is the Spray breakup region, which represent the

internal and external flow parameters of the spray. The spray Reynolds Number and Weber

Number for biodiesel and diesel spray under various injection pressures is shown in Fig.6. The

Reynolds Number and Weber Number both are increased for diesel and biodiesel with increasing

the injection pressure. The higher injection pressure leads to larger viscous forces and smaller

inertia forces. These provide a relatively large spray momentum for JOME. This leads to increase

the Reynolds Number and Weber Number for diesel.

Fig.6 Variation of Injection pressure with Reynolds Number and weber number for Diesel and

JOME

Sauter Mean Diameter The estimated value of Sauter Mean Diameter for JOME and diesel spray under various

Injection pressures is shown in Fig.7. The higher viscosity, density and surface tension are the

great responsible for larger values of SMD for JOME. So the JOME has greater SMD due to high

viscosity when compared to diesel. Whenever, increasing the injection pressure with decrease the

SMD value for both diesel and JOME because the small SMD value leads to better atomization.

Fig.7.Variation of Injection pressure with Sauter Mean Diameter for Diesel and JOME


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CONCLUSION

The experiments were carried out at different Injection pressure for diesel and JOME

Ester in a modified single cylinder air cooled DI diesel engine. The spray characteristics of spray

tip penetration and cone angle were measured under non-evaporating condition. The parameters

of Injection velocity, Breakup region (Reynolds number and Weber number) and SMD were

determined by varying the injection pressure from 180 to 240 bar. Spray tip penetration increases

with increasing the injection pressure for JOME because increase the fuel viscosity prevented the

breaking of spray jet, resulting in an increase the size of the spray droplets. Spray tip penetration

increases and cone angle decreases for JOME than diesel because the density and viscosity of

JOME is higher than the diesel fuel. Injection velocity of JOME is less than neat diesel because

the JOME have high viscosity and density. SMD is decreases for neat diesel than JOME with

increase in injection pressure. The high injection pressure is an effective way to improve the

atomization of diesel and JOME.

ACKNOWLEDGEMENT

The Authors would like to acknowledge the management of Sri Venkateswara College of

Engineering for the sincere help and providing the experimental setup to perform this research

work.

REFERENCES

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paper, 01-0100, 2004.

[2] Su TF, Reitz RD, Experimental and numerical studies of high pressure multiple injection

sprays, SAE paper 960861, 1996.

[3] W.A.de Boer, P.J.M.Frijters, Macroscopic diesel fuel spray shadowgraph using high

speed digital imaging in a high pressure cell, Fuel 86 (2007) 1994-2007.

[4] Yeom J, Senda J, Fujimoto H, Proceeding of ILASS-Asia, pp. 167-72, 2001.

[5] Bondioli P, Toso G, Della B. L, Biodiesel stability under commercial storage conditions

over one year, Eur J Lipid Sci Tech, (2003) 105:735-41.

[6] Ejilah I.R, Adisa A.B, Asere A.A and Ejila A, The effect of diesel fuel-Jatropha curcas oil

methyl ester blend on the performance of a variable speed compression ignition engine,

Journal of Agricultural Engineering-AJAE 1(3), (2000)80-85.

[7] Delacourt E,Besson B, Desmet B,Characterization of very high pressure diesel spray

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[8] Bondioli P,Toso G,Della B. L,Gaasparoli A, Tagliabue S, Biodiesel stability under

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Design

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