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IJESR/July 2013/ Vol-3/Issue-7/342-353 e-ISSN 2277-2685, p-ISSN 2320-9763
International Journal of Engineering & Science Research
CFD ANALYSIS AND EXPERIMENTAL VERIFICATION OF EFFECT OF MANIFOLD
GEOMETRY ON VOLUMETRIC EFFICIENCY AND BACK PRESSURE FOR MULTI-
CYLINDER SI ENGINE
KS Umesh*1, VK Pravin
2, K Rajagopal
3
1Dept. of Mech. Engg, Thadomal Shahani Engineering College, Mumbai , Maharastra, India
2Dept. of Mech. Engg, P.D.A. College of Engg., Gulbarga, Karnataka, India.
3Former Vice Chancellor, JNT University, Hyderabad (AP), India.
ABSTRACT
In internal combustion engines, volumetric efficiency is one of the prime factors in determining how much power output
an engine can generate as compared to its capacity. The purpose of this research work is to investigate using CFD
whether design of exhaust manifold has any impact on volumetric efficiency of the multi-cylinder SI engine and if any
verify those results obtained through CFD analysis via actual experiments. The scope of the research is further stretched
to investigate whether exhaust geometry has any impact on mechanical efficiency of the multi-cylinder SI engine. Flow
of the exhaust gases through exhaust manifold is simulated using ANSYS FLUENT V12.0 using pressure and velocity
parameters as boundary condition. The analysis has been carried out on two designs an existing one and a modified one
and results are subsequently compared. It was observed that the volumetric efficiency improved drastically upon
modification in exhaust geometry. Physical models of the same these two systems were subsequently manufactured and
exhaustive experiments were carried out on them. The results obtained through CFD analysis were experimentally
confirmed.
Keywords: Exhaust Manifold, Volumetric Efficiency, Multi-cylinder Engine, ANSYS FLUENT, Existing model.
1. INTRODUCTION
In any multi-cylinder IC engine, an exhaust manifold (also known as a header) collects the exhaust gases from multiple
cylinders into one pipe. It is attached downstream of the engine and is major part in multi‐ cylinder engines where there
are multiple exhaust streams that have to be collected into a single pipe.
When an engine starts its exhaust stroke, the piston moves up the cylinder bore, increasing the pressure. When the
exhaust valve opens, the high pressure exhaust gas enters into the exhaust manifold or header, creating an exhaust pulse
comprising three main parts: The high‐pressure head is created by the large pressure difference between the exhaust in
the combustion chamber and the atmospheric pressure outside of the exhaust system. As the exhaust gases equalize
between the combustion chamber and the atmosphere, the difference in pressure decreases and the exhaust velocity
decreases. This forms the medium‐pressure body component of the exhaust pulse. The remaining exhaust gas forms the
low‐pressure tail component. This tail component may initially match ambient atmospheric pressure, but the momentum
of the high‐ and medium‐ pressure components reduces the pressure in the combustion chamber to a
lower‐than‐atmospheric level. This relatively low pressure (known as back pressure) helps to extract all the combustion
products from the cylinder. Thus back pressure is one of the most critical parameter for exhaust system. Also lower back
pressure helps to induct the intake charge during the overlap period when both intake and exhaust valves are partially
open. The effect is known as scavenging. Scavenging efficiency is function of Length of the exhaust manifold,
cross‐sectional area, shaping of the exhaust ports and pipe‐works influences the degree of scavenging effect and the
engine speed range over which scavenging occurs. The magnitude of the exhaust scavenging effect is a direct function of
the velocity of the high and medium pressure components of the exhaust pulse. Headers are designed to increase the
exhaust velocity as much as possible. One technique is tuned‐length primary tubes. This technique attempts to time the
occurrence of each exhaust pulse, to occur one after the other in succession while still in the exhaust system. The lower
IJESR/July 2013/ Vol-3/Issue-7/342-353 e-ISSN 2277-2685, p-ISSN 2320-9763
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pressure tail of an exhaust pulse then serves to create a greater pressure difference between the high pressure head of the
next exhaust pulse, thus increasing the velocity of that exhaust pulse.
Exhaustive work has taken place already in this field. Scheeringa et al studied analysis of Liquid cooled exhaust
manifold using CFD. Detailed information of flow property distributions and heat transfer were obtained by him to
improve the fundamental understandings of manifold operation. A number of computations were performed by him to
investigate the parametric effects of operating conditions and geometry on the performance of manifolds. Seenikannan et
al analysed a Y section exhaust manifold system experimentally to improve engine performance. His paper investigates
the effect of using various models of exhaust manifold on CI engine performance and exhaust emission. Yasar Deger et
al did CFD-FE-Analysis for the Exhaust Manifold of a Diesel Engine aiming to determine specific temperature and
pressure distributions. The fluid flow and the heat transfer through the exhaust manifold were computed correspondingly
by CFD analyses including the conjugate heat transfer.
2. DISCUSSION
Model Description
Two different Models considered for this research work are shown in the figure 1 & 2 respectively.
Fig 1: Existing Model Fig 2: Modified Model
Both existing model and modified model has header length of 335mm. ID and OD of headers is 52.48 mm & 60.3 mm
respectively. In existing model the bend radius is 48 mm and exhaust is on one side as shown in the figure. Modified
model has bend radius of 100 mm and exhaust is at the centre of header. ID & OD of the bend & exhaust is 35.08mm and
42.2mm respectively for both models.
3. METHODOLOGY
Both the models considered for this work were prepared using SOLIDWORKS. These models were imported into
ANSYS CFX V12.0. The fluid body was subsequently generated from existing models using design Modular in ANSYS
and subsequently meshed as shown in figures.
Fig 3: Fluid Body (Existing Model) Fig 4: Existing Manifold (After Meshing)
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Fig 5: Fluid Body (Modified Model) Fig 6: Modified Manifold (After Meshing)
A steady state single‐species simulation will be carried out under isothermal conditions for exhaust gas. Turbulence will
be modeled by k-ε RNG turbulence model appropriate to account for high velocities and strong streamline curvature in
the flow domain. The reference pressure will be set at 1 atm and all pressure inputs and outputs will be obtained as gauge
values with respect to this.
4. MATERIAL FLUID PROPERTIES
Exhaust gas will be considered as an incompressible fluid operating at 230‐280 0C. The material properties under these
conditions are
Table 1: Material Fluid Properties
Material Air + Gasoline
Density (kg/m3) 1.0685
Viscosity (Pa-s) 3.0927 x 10‐5
Specific heat (J/kg-K) 1056.6434
Thermal conductivity (W/m-K) 0.0250
Boundary Conditions
The engine speed was maintained at 1500 RPM and results were obtained at different load Conditions viz. 2kg, 4kg, 6k,
8kg and 12 kg. The atmospheric gauge pressure was set at 0. And pressure distribution was obtained.
5. EXPERIMENTAL SET-UP
Two models considered for the work were manufactured. The material used for pipe was SA106 (Grade B). Flange
Material was IS 2062 (Grade B) . Elbows were manufactured using SA 234 WPB.
Fig 7: Existing model (left) and Modified Model (Right)
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The test was conducted on 4 stroke 4 cylinder Engine of Maruti-Suzuki make. Experimental set up consisted of:
(1) The engine & dynamometer fitted together on common channel frame
(2) Fuel Consumption measuring unit & temperature measuring units
(3) Exhaust gas Calorimeter
(4) Orifice Meter
The experimental set up is shown in the figure.
Fig 8: Experimental set up
(a) Temperatures were measured at
(b) Exhaust Gas inlet to the calorimeter
(c) Exhaust gas outlet to calorimeter
(d) Water inlet to calorimeter
(e) Water outlet from Calorimeter
(f) Water outlet from Engine
Also pressure and temperatures were measured in header at points where bends are attached and in the exhaust.
Engine Specifications
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Table 2: Engine Specification
Engine 4 Stroke 4 Cylinder SI engine
Make Maruti-Suzuki Wagon-R
Calorific Value of Fuel (Gasoline) 45208 KJ/Kg-K
Specific Gravity of Fuel 0.7 gm/cc
Bore and Stroke 69.05 mm X 73.40 mm
Swept Volume 1100 cc
Compression Ratio 7.2 :1
Dynamometer Constant 2000
Diameter of Orifice 29 mm
Coefficient of Discharge of orifice 0.65
6. RESULTS
CFD analysis was carried out on both the models at 6 different loads. 2kg, 4kg, 6kg, 8kg, 10kg and 12 kg. The resulting
pressure contour for 4 kg loading is shown in the figure for both the models. The experiments were conducted with same
loading conditions on same two models and results obtained after the calculation are enlisted in following table
Fig 9: Pressure contours for existing and Modified Models
The experiments were conducted with same loading conditions on same two models and results obtained after the
calculations are enlisted in following tables. Qs and Qa specify swept volume and air intake respectively. Thus their ratio
gives volumetric efficiency. Also morse test was conducted on engines to evaluate their Indicated power (I.P.). Brake
power (B.P.) was experimentally determined using dynamometer. Thus Mechanical efficiency was also evaluated as ratio
of B.P. to I.P. The pressures P1, P2, P3, P4, P5 and temperatures T1, T2, T3, T4, T5 were measured at exhaust manifold
and points where 4 inlet bends are attached to header. Velocity was calculated using ideal gas equation. These are
instantaneous velocities of exhaust gas at above mentioned points.
Table 3: Results of experiments conducted on existing Model
Column1
Unit 2 KG 4 KG 6 KG 8 KG 10 KG 12 KG
B.P. (kW) KW 1.119 2.238 3.357 4.476 5.595 6.71
Heat Equivalent Kj/min 67.14 134.2 201.4 268.5 335.7 402
Fuel Consumption cc/min 87.77 90.36 94.88 106.2 107.1 112
gm/min 61.43 63.25 66.41 74.34 74.97 78.8
Heat Supplied Kj/min 2777.5 2859.5 3002.5 3360.8 3389.2 3566
Heat Carried By water Kj/min 477.3 891 938.7 970.5 986.5 970.
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MgCpg Kj/Kg C 1.446 1.185 1.377 1.545 1.64 1.72
Heat Carried by Exhaust Kj/min 407.8 426.6 526 599.5 623.2 629
Unaccounted Heat Loss Kj/min 1825 1407 1336 1522 1443 1564
Qs *10-3
m3 13.75 13.75 13.75 13.75 13.75 13.7
Qa *10-3
m3 8.068 7.606 8.714 9.696 10.24 10.9
Volumetric Efficiency 58.67 55.32 63.37 70.52 74.47 79.4
Air : Fuel Ratio 9.454 8.658 9.447 9.391 9.834 9.97
B.S.F.C. Kg-Hr/ KW 3.294 1.695 1.187 0.996 0.804 0.70
p1 mm of water 90 131 169 196 198 223
p2 mm of water 121 168 213 251 261 289
p3 mm of water 102 142 186 222 225 255
p4 mm of water 122 163 210 252 265 296
p5 mm of water 126 167 216 255 265 296
t1 Celsius 303 381 403 409 401 385
t2 Celsius 335 423 449 456 451 441
t3 Celsius 540 630 630 661 665 690
t4 Celsius 344 424 425 432 418 403
t5 Celsius 284 371 389 390 381 370
v1 m/s 15.87 16.92 19.97 22.36 23.33 24.2
v2 m/s 4.176 4.487 5.310 5.945 6.229 6.53
v3 m/s 5.594 5.836 6.658 7.638 8.098 8.84
v4 m/s 4.237 4.496 5.135 5.749 5.943 6.18
v5 m/s 3.824 4.152 4.868 5.405 5.625 5.88
ma + mf (Kg/s) *10-3
kg/s 10.70 10.18 11.56 12.87 13.53 14.4
Morse test(All Cylinder) Kg 2 4 6 8 10 12
Morse test (1st cylinder) Kg 1.4 2.95 4.6 6.2 7.4 8.8
Morse test(2nd cylinder) Kg 1.4 2.90 4.6 6.15 7.35 8.8
Morse test (3rd cylinder) Kg 1.35 2.85 4.55 6.1 7.35 8.85
Morse test (4th cylinder) Kg 1.35 2.85 4.6 6.1 7.35 8.85
I.P. (1st) Kw 0.400 0.65 0.783 1.225 1.55 1.80
I.P. (2nd) Kw 0.400 0.605 0.783 1.15 1.485 1.80
I.P. (3rd) 0.375 0.575 0.811 1.15 1.485 1.85
I.P. (4th) Kw 0.375 0.575 0.783 1.225 1.485 1.85
IP Kw 1.45 2.5 3.65 4.985 6.225 7.55
Mechanical Efficiency Percentage 80 88.75 94.16 93.12 93 90.8
Frictional Power Kw 0.223 0.251 0.195 0.307 0.391 0.61
Table 4: Results of experiments conducted on modified Model
Column1 Unit 2 KG 4 KG 6 KG 8 KG 10 KG 12 KG
B.P. (kW) KW 1.119 2.238 3.357 4.476 5.595 6.714
Heat Equivalent Kj/min 67.14 134.28 201.42 268.56 335.7 402.87
Fuel Consumption cc/min 114.5 122.14 123.96 131.59 133.9 136.36
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gm/min 80.15 85.504 86.776 92.117 93.75 95.454
Heat Supplied Kj/min 3623.4 3865.4 3922.9 4164.4 4238 4315.2
Heat Carried By Water Kj/min 175.08 254.56 381.85 556.87 715.9 715.97
MgCpg Kj/Kg C 1.48 1.53 1.4248 1.6748 1.94 1.725
Heat Carried by
Exhaust
Kj/min 324.12 361.08 386.12 534.26 715.8 662.4
Unaccounted Heat Loss Kj/min 3057.0 3115.5 2953.5 2804.7 2470 2534.0
Qs *10-3
m3 13.75 13.75 13.75 13.75 13.75 13.75
Qa *10-3
m3 9.5 10.757 10.58 12.17 12.17 11.41
Volumetric Efficiency 69.090 78.232 76.945 88.509 88.50 82.981
Air : Fuel Ratio 8.534 9.0580 8.7784 9.5121 9.346 8.6064
B.S.F.C. Kg-Hr/ KW 4.2975 2.2923 1.5509 1.2348 1.005 0.8530
p1 mm of water 89 107 147 173 225 235
p2 mm of water 122 145 200 240 295 308
p3 mm of water 117 138 183 220 275 292
p4 mm of water 120 140 183 227 280 290
p5 mm of water 124 146 188 253 298 309
t1 Celsius 240 257 292 340 390 405
t2 Celsius 234 162 220 259 342 380
t3 Celsius 233 237 297 313 369 394
t4 Celsius 229 230 270 341 383 395
t5 Celsius 131 135 184 318 368 374
v1 m/s 16.646 19.440 20.306 25.281 27.21 26.065
v2 m/s 4.1001 3.9747 4.4079 5.4511 6.269 6.2339
v3 m/s 4.0939 4.6630 5.1044 6.0156 6.557 6.3770
v4 m/s 4.0604 4.5982 4.8626 6.2989 6.696 6.3877
v5 m/s 3.2665 3.7267 4.0906 6.0484 6.533 6.1761
ma + mf (Kg/s) *10-3
kg/s 12.735 14.333 14.142 16.139 16.16 15.282
Morse test(All Cylinder) Kg 2 4 6 8 10 12
Morse test (1st cylinder) Kg 1.4 2.95 4.6 6.2 7.4 8.8
Morse test(2nd cylinder) Kg 1.4 2.90 4.6 6.15 7.35 8.8
Morse test (3rd cylinder) Kg 1.4 2.85 4.55 6.1 7.35 8.85
Morse test (4th cylinder) Kg 1.35 2.85 4.6 6.1 7.35 8.85
I.P. (1st) Kw 0.400 0.65 0.783 1.225 1.55 1.80
I.P. (2nd) Kw 0.400 0.605 0.783 1.15 1.485 1.80
I.P. (3rd) 0.400 0.575 0.811 1.15 1.485 1.85
I.P. (4th) Kw 0.375 0.575 0.783 1.225 1.485 1.85
IP Kw 1.375 2.5 3.65 4.985 6.225 7.55
Mechanical Efficiency Percentage 77.5 90 90 91.25 93 90
Frictional Power Kw 0.25178 0.2238 0.3357 0.39165 0.3916 0.6714
Aim of the work was to verify all the results obtained through CFD analysis by experimentation. Thus the results
obtained through CFD analysis and experiments have been compared in following two tables for both the models at all
load conditions.
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Table 5: Comparison between theoretical results (Using CFD) and Experimental results For existing Model
LOAD :
2 Kg
Distance
from Exhaust
Pressure
(Theoretical al)
Pressure
( Experimental)
Pressure
(Experimental)
Velocity
(theoretical al)
Velocity
(Experimental) Temperature
(Pascal) (mm of water) (Pascal ) (m/s) (m/s) (Celsius)
-0.0425 1275.3 121 1187.01 4.225 4.176 335
0.0425 1079.1 102 1000.62 5.412 5.594 540
0.1275 1275.3 122 1196.82 4.225 4.237 344
0.2125 1324.35 126 1236.06 3.485 3.824 284
LOAD :
4 Kg
Distance
from Exhaust
Pressure
(Theoretical al)
Pressure
( Experimental) Pressure(Experimental)
Velocity
(theoretical al)
Velocity
(Experimental) Temperature
(Pascal) (mm of water) (Pascal ) (m/s) (m/s) (Celsius)
-0.0425 1579.41 168 1648.08 4.375 4.487 423
0.0425 1471.5 142 1393.02 5.45 5.836 630
0.1275 1579.41 163 1599.03 4.375 4.495 424
0.2125 1716.75 167 1638.27 4.02 4.152 371
LOAD :
6 Kg
Distance
from Exhaust
Pressure
(Theoretical al)
Pressure
( Experimental)
Pressure
(Experimental)
Velocity
(theoretical al)
Velocity
(Experimental) Temperature
(Pascal) (mm of water) (Pascal ) (m/s) (m/s) (Celsius)
-0.0425 1962 213 2089.53 5.125 5.31 449
0.0425 1765.8 186 1824.66 5.994 6.658 630
0.1275 1962 210 2060.1 5.125 5.135 425
0.2125 2207.25 216 2118.96 4.758 4.868 389
LOAD :
8 Kg
Distance from Exhaust
Pressure (Theoretical al)
Pressure ( Experimental)
Pressure (Experimental)
Velocity (theoretical al)
Velocity (Experimental) Temperature
(Pascal) (mm of water) (Pascal ) (m/s) (m/s) (Celsius)
-0.0425 2345.4 251 2462.31 5.485 5.945556 456
0.0425 2256.3 222 2177.82 6.987 7.637981 661
0.1275 2345.4 252 2472.12 5.485 5.749286 432
0.2125 2599.65 255 2501.55 5.585 5.405275 390
Load:
10 Kg
Distance from Exhaust
Pressure (Theoretical al)
Pressure (Experimental)
Pressure (Experimental)
Velocity (theoretical al)
Velocity (Experimental) Temperature
(Pascal) (mm of water) (Pascal ) (m/s) (m/s) (Celsius)
-0.0425 2648.7 261 2560.41 5.8742 6.229889 451
0.0425 2452.5 225 2207.25 7.945 8.098267 665
0.1275 2648.7 265 2599.65 5.8742 5.943732 418
0.2125 2795.85 265 2599.65 5.45 5.625472 381
LOAD : 12
Kg
Distance
from Exhaust
Pressure
(Theoretical al)
Pressure
( Experimental) Pressure(Experimental)
Velocity
(theoretical al)
Velocity
(Experimental) Temperature
(Pascal) (mm of water) (Pascal ) (m/s) (m/s) (Celsius)
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-0.0425 2943 289 2835.09 6.027 6.537302 441
0.0425 2646 255 2501.55 8.2125 8.844842 690
0.1275 2943 296 2903.76 6.027 6.185387 403
0.2125 3041.125 296 2903.76 5.628 5.883437 370
Table 6: Comparison between theoretical results (Using CFD) and Experimental results For Modified Model
Model
Column1 Column2 Column3 Column4 Column5 Column6 Column7
LOAD :
2 Kg
Distance
from
Exhaust
Pressure
(Theoretical al)
Pressure
( Experimental) Pressure (Experimental)
Velocity
(theoretical al)
Velocity
(Experimental) Temperature
(Pascal) (mm of water) (Pascal ) (m/s) (m/s) (Celsius)
-0.1275 1187.01 122 1196.82 3.96 4.100114 240
-0.0425 1177.2 117 1147.77 4.18 4.093944 234
0.0425 1177.2 120 1177.2 4.18 4.06044 233
0.1275 1187.01 124 1216.44 3.96 3.266541 229
LOAD :
4 Kg
Distance
from
Exhaust
Pressure
(Theoretical
al)
Pressure (
Experimental)
Pressure(Experimental
)
Velocity
(theoretical
al)
Velocity
(Experimental
)
Temperatur
e
(Pascal) (mm of water) (Pascal ) (m/s) (m/s) (Celsius)
-0.1275 1324.35 145 1422.45 4.15 3.97473 257
-0.0425 1314.54 138 1353.78 4.48 4.663078 162
0.0425 1314.54 140 1373.4 4.48 4.598215 237
0.1275 1324.54 146 1432.26 4.15 3.727674 230
LOAD :
6 Kg
Distance
from
Exhaust
Pressure
(Theoretical al)
Pressure
( Experimental) Pressure (Experimental)
Velocity
(theoretical al)
Velocity
(Experimental) Temperature
(Pascal) (mm of water) (Pascal ) (m/s) (m/s) (Celsius)
-0.1275 1863.9 200 1962 4.35 4.407936 292
-0.0425 1814.85 183 1795.23 5.025 5.104463 220
0.0425 1814.85 183 1795.23 5.025 4.862672 297
0.1275 1863.9 188 1844.28 4.35 4.090621 270
LOAD :
8 Kg
Distance
from
Exhaust
Pressure
(Theoretical al)
Pressure
( Experimental) Pressure (Experimental)
Velocity
(theoretical al)
Velocity
(Experimental) Temperature
(Pascal) (mm of water) (Pascal ) (m/s) (m/s) (Celsius)
-0.1275 2452.5 240 2354.4 5.5125 5.451164 340
-0.0425 2256.3 220 2158.2 6.125 6.01562 259
0.0425 2256.3 227 2226.87 6.125 6.298965 313
0.1275 2452.5 253 2481.93 5.5125 6.048429 341
LOAD :
10 Kg
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Copyright © 2013 Published by IJESR. All rights reserved 351
Distance
from Exhaust
Pressure (Theoretical al)
Pressure ( Experimental) Pressure (Experimental)
Velocity (theoretical al)
Velocity (Experimental) Temperature
(Pascal) (mm of water) (Pascal ) (m/s) (m/s) (Celsius)
-0.1275 2943 295 2893.95 5.9875 6.269705 390
-0.0425 2795.85 275 2697.75 6.235 6.557043 342
0.0425 2795.85 280 2746.8 6.235 6.696941 369
0.1275 2943 298 2923.38 5.9875 6.532959 383
LOAD :
12 Kg
Distance
from
Exhaust
Pressure
(Theoretical al)
Pressure
( Experimental) Pressure (Experimental)
Velocity
(theoretical al)
Velocity
(Experimental) Temperature
(Pascal) (mm of water) (Pascal ) (m/s) (m/s) (Celsius)
-0.1275 3139.2 308 3021.48 6.1245 6.233964 405
-0.0425 2992.05 292 2864.52 6.69545 6.377008 380
0.0425 2992.05 290 2844.9 6.69545 6.387746 394
0.1275 3139.2 309 3031.29 6.1245 6.176116 395
7. OBSERVATION
From table 5 and 6 it can be easily concluded that experimental results matches with the results of CFD analysis. Also
pressure, velocity and temperature distribution in header is more uniform for modified design as compared to existing
design. For making conclusions most important observations are enlisted below.
Table 7: Results obtained for existing Model
Load(kg) Volumetric Efficiency Mechanical Efficiency BSFC (Kg-hr/kW)
2 58.67636 80 3.294316
4 55.32073 88.75 1.695764
6 63.37818 94.167 1.18706
8 70.52073 93.125 0.996515
10 74.47273 93 0.803968
12 79.44727 90.83 0.705004
Table 8: Results obtained for modified Model
Load(kg) Volumetric Efficiency Mechanical Efficiency BSFC (Kg-hr/kW)
2 69.09091 77.5 4.297587
4 78.23273 90 2.29234
6 76.94545 90 1.55096
8 88.50909 91.25 1.234824
10 88.50909 93 1.005358
12 82.98182 90 0.85303
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Copyright © 2013 Published by IJESR. All rights reserved 352
Fig 10: Comparison between Volumetric Efficiency of two Models
Volumetric Efficiency VS Load
Fig 11: Comparison between Mechanical Efficiency of two models
8. CONCLUSION
From CFD analysis it was found that manifold geometry has a significant impact on the volumetric efficiency of the
engine. It was concluded that the modified design gives better volumetric efficiency. The results of CFD analysis were
subsequently proved by experimental analysis. Also more uniform pressure distribution and velocity distribution
obtained in modified model eases out the design procedure for the exhaust manifold. Also even though there was slight
variation in mechanical efficiency and brake specific fuel consumption (b.s.f.c.) the variation was found to be very small
and thus no conclusion can be drawn regarding effect of manifold geometry on mechanical efficiency and b.s.f.c. Thus
we conclude that Volumetric efficiency and thus power output of the engine can be improved significantly by
deployment of suggested modified design.
REFERENCES
[1] Muthaiah PLS, Kumar MS, Sendilvelan S. CFD Analysis of catalytic converter to reduce particulate matter and
achieve limited back pressure in diesel engine. Global journal of researches in engineering A: Classification (FOR)
091304,091399, 2010; 10(5).
[2] Kamble PR, Ingle SS. Copper Plate Catalytic Converter: An Emission Control Technique, SAE Number 2008-28-
0104.
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Volumetric Efficiency
(Modified Model)
Volumetric Efficiency
(Existing Model)
0
10
20
30
40
50
60
70
80
90
100
0 5 10 15
Mechanical Efficiency
(Modified Model)
Mechanical
Efficiency(Existing
Model)
IJESR/July 2013/ Vol-3/Issue-7/342-353 e-ISSN 2277-2685, p-ISSN 2320-9763
Copyright © 2013 Published by IJESR. All rights reserved 353
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