JOURNAL OF INFORMATION, KNOWLEDGE AND RESEARCH IN
MECHANICAL ENGINEERING
A CFD COMBUSTION ANALYSIS OF DIESELBIODIESEL A SINGLE CYLINDER RESEARCH
ENGINE WORKING WITH DIFFERENT
COMPRESSION RATIO.
1
SEJAL PATEL, 2 RAVINDRAKIRAR
1
M.Tech scholar,PCST, Bhopal
Mech Dept., PCST, Bhopal
2 Prof.
Sejal_patel2982@yahoo.com
ABSTRACT :This paper describes about the project work carried out to develop a CFD simulation model to
investigate the effect of the use of diesel-biodiesel duel fuel in a variable compression ratio(i.e.14,16,18) diesel
engine. Commercial CFD software is used in this project to study the effect of compression ration on the
performance of diesel-biodiesel engine. In the present study investigation is aimed at studying the effect of
compression ratio on the Brake thermal efficiency, Brake specific fuel combustion, Brake power use as pure
diesel. In this system engine is coupled to a DC dynamometer and all the experiments were carried out at a
constant speed of 1500R.P.M. CFD and experimental values are in close proximity.
Key words: Performance Varying compression ratio ,Diesel, CFD Simulation
1 . INTRODUCTION
As the world finds itself in the midst of universal
energy shortage, compounded by a parallel need to
reduce pollutants of all kinds, we must take an
increasingly serious look at novel sources of
abundant energy and methods for their best
utilization. The depleting resources of fuel in the
world today as well as the understanding of the need
of the world environment requires the search for
other types of fuel sources that may be renewed if
possible.[1-2] Biodiesel could be an excellent
renewable fuel for diesel engine. It is derived from
vegetable oils that are chemically converted into
biodiesel. As the name implies, it is similar to diesel
fuel except that it is produced from crops like
Jatropha, Pongamia, Soybean, Cottonseed. These
crops are all capable of producing several gallons of
fuel per acre that can power an unmodified diesel
engine. Vegetable oil is converted into biodiesel
through a chemical process that produces methyl or
ethyl ester[3-4].
Within ANSYS-CFX, the k-ε turbulence uses the
scalable wall function approach to improve
robustness and accuracy when the near wall mesh is
very fine. The scalable wall functions allow
simulation on arbitrarily fine near wall grids, which is
a significant improvement over standard wall
functions. While standard two equation models
provide good predictions for many flow of
engineering interest k is the turbulence kinetic energy
and is defined as the variance of the fluctuations in
velocity. ε is the turbulence eddy dissipation (the rate
at which the velocity fluctuations dissipate) and has
dimensions of per unit time. The k-ε model
introduces two new variables into the system of
equations. The k-ε model introduces two new
variables into the system of equations. The continuity
Equation is then
2. CFD SIMULATION:
One of the most prominent turbulence models, the kε (k-epsilon) model, has been implemented in most
general purpose CFD codes and is considered the
industry standard model. It has proven to be stable
and numerically robust and has a well established
regime of predictive capability. For general purpose
simulation, the model offers a good compromise in
term of accuracy and robustness.
Combustion Model: - Eddy Dissipation
Domain Type: - Fluid Domain
Domain Fluid:- Diesel + Air Mixture
Domain Motion: - Stationary
Mesh Deformation: - Moving Mesh
Define Heat Transfer, Turbulance and Combustion
Model.
Heat Transfer Model: - Total Energy Model
and the momentum equation becomes
Engine Specification
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1 cylinder, 4 stroke, water cooled, stroke 110 mm,
bore 87.5 mm.
Diesel mode: Power 3.5 KW , CR range 12:1-18:1 ,
Speed 1500 rpm , Injection variation 0-25 Deg
BTDC.
3.RESULT &DISSCUSSION
A) Brake Thermal Efficiency
As seen in Figure 2. CFD and experimental values
are in close proximity. Except at CR 16 they are very
close to each other. The difference between the
theoretical and experimental values for BTHE is
11%atCR18,it is 8% at CR16, it is 14%at CR14at full
load condition use fuel as pure diesel.
B) Brake Specific Fuel Combustion
As seen in Figure 3. CFD and experimental values
are in close proximity. Except at CR 14,CR16 they
are very close to each other. The difference between
the theoretical and experimental values for BSFC is
8%atCR18,it is 1% at CR16, it is 1%at CR14at full
load condition use fuel as pure diesel
Figure 1 mesh model
.
Figure 2: Comparison of BTHE Versus Load for Pure diesel at Full load
.
Figure 3: Comparison of BSFC Versus Load for Pure diesel at Full load
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.
Figure 4: Comparison of BP Versus Load for Pure diesel at Full load
.
Figure 5: Comparison of Exhaust Gas Temperature Versus Load for Pure diesel at Full load
As seen in Figure4. CFD and experimental values are
in close proximity. Except at CR 14,CR16,CR18 they
are very close to each other. The difference between
the theoretical and experimental values for BP is
increase with the increase in load use fuel as pure
diesel.
Pure diesel of exhaust gas temperature at
compression ratio 14, 16 and 18 . can observed from
figure that the value of exhaust gas temperature
decreases with increment of compression ratio. The
difference between the theoretical and experimental
values for exhaust gas temp is 8% at CR18,it is 4% at
CR16, it is 6%at CR14at full load condition use fuel
as pure diesel.
D)Exhaust Gas Temperature
3.CONCLUSIONS
C) Brake Power
As seen in Figure5. CFD and experimental values for
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The CFD analysis along with experimental
investigations is being carried out to compare pure
diesel combustion and emission analysis.CR 16 is
proximity result with compare both results for the
BTHE, BSFC, BP, Exhaust gas temperature. The
model needs further refinement in the computational
mesh.
4.References
1.Pramanik,K,2003 .Properties and use of jatropha
curcas oil and diesel fuel blends in compression
ignition engine, Renewable Ener,28(2):239-248.
2.Taku Tsujimura, shohei Mikai, T. Yoshiroh, J.
Senda and H. Fujimoto, A study of Direct Injection
Diesel Engine Fueled with Hydrogen, SAE paper
NO. 2003-01-061, March 2003
3. Anjana Srivastava and Ram Prasad, 2000.
Triglycerides based diesel fules, Renewable and
Austainable Energy revie.4:111-113
4.Senthil Kumar, M.,A. Ramesh and B. Nagalingam,
2003. An experimental comparision of method to use
jatropha oil and its methyl esters as a fuel in a CI
engine, International Journal of Biomass and Bio.
Ener., 25: 309-318.
5 Senthil Kumar, M.,A. Ramesh and B. Nagalingam,
2001. Investigation on the use of jatropha oil and its
methyl esters as a fuel in a compression ignition
engine, J. Institute of Ener., 74:24-28.
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