CFD analysis of IC engine exhaust manifold with … analysis of IC engine exhaust manifold with respect to the performance of a turbocharger 1P Sylvester Selvanathan, 2Dr. R. Sudhakaran,

ADVANCES in NATURAL and APPLIED SCIENCES

ISSN: 1995-0772 Published BYAENSI Publication EISSN: 1998-1090 http://www.aensiweb.com/ANAS

2017 April 11(4):pages 242-249 Open Access Journal

ToCite ThisArticle:P Sylvester Selvanathan, Dr. R. Sudhakaran, K Venkatesh, C Samuvel Tites, D Rajamanikandan.,CFD analysis of IC engine exhaust manifold with respect to the performance of a turbocharger.Advances in Natural and Applied Sciences. 11(4);Pages: 242-249

CFD analysis of IC engine exhaust manifold with respect to the performance of a turbocharger

1P Sylvester Selvanathan, 2Dr. R. Sudhakaran, 3K Venkatesh, 4C Samuvel Tites, 5D Rajamanikandan 2Head, Department of Mechanical Engineering, SNS College of Engineering, Coimbatore, India. 1,3,4,5Department of Mechanical Engineering, SNS College of Engineering, Coimbatore, India. Received 28 February 2017; Accepted 22 March 2017; Available online 25 April 2017

Address For Correspondence: Maruthamuthu

Copyright © 2017 by authors and American-Eurasian Network for Scientific Information (AENSI Publication). This work is licensed under the Creative Commons Attribution International License (CC BY). http://creativecommons.org/licenses/by/4.0/

ABSTRACT Turbocharger is a major contributor of both power and volumetric efficiency in internal combustion engines. Turbocharger is driven by exhaust gases collected using an exhaust manifold. Therefore the design of an exhaust manifold also plays an important role in improving the efficiency of the engine. Usually various factors are involved in designing an exhaust manifold and a computerized optimization would reduce the numerous technical and cost factors involved. This papers aims to analyze the design of an exhaust manifold to establish the significance of various factors involved in designing an exhaust manifold by comparing various existing designs using Computational Fluid Dynamics.

KEYWORDS:Computational Fluid Dynamics, Exhaust Manifold, Manifold Geometry, Exhaust Velocity

INTRODUCTION

The exhaust manifold in an internal combustion engine is a very vital component affecting the performance

of an engine. The engine’s volumetric efficiency is directly depended on its ability to push out the exhaust gases

effectively to suck in more air for combustion. To effectively expel the exhaust gases, a good manifold is

required and in cases of a turbocharged engine the manifold is even more important. The objective of this

project is to analyze existing designs of exhaust manifold to establish a better understanding of the significance

of various factors involved in its design process. The types of common manifolds include log type manifold and

tubular manifold. The main factors influencing the design of exhaust manifold includes runner length, runner

volume, collector, back pressure and exhaust pulses.

Literature Review:

Jafar M Hasan et al. [1] have discussed the importance of the geometry of the header and how it affects the

efficiency of the exhaust manifold. They considered headers with varying cross sections for different Re values

and found that a Tapered longitudinal header performed better than the conventional cross sectional header.

Marupilla Akhil Teja et al. [2] have presented a comprehensive study about analysis of exhaust manifold using

numerical method (CFD). Their paper gives detailed notes on the methodology to be followed while designing

an exhaust manifold. It also presents a sample analysis of an exhaust system modelled using CATIA V5R20 and

analyzed using Fluent solver. Mohd Sajig Ahemd et al. [3] have designed and analyzed 5 models of exhaust

manifold based on the manifold of a Maruti Suzuki Wagon R engine. They varied the cross section of the

243 P Sylvester Selvanathan et al., 2017/Advances in Natural and Applied Sciences. 11(4) April2017, Pages: 242-249

collector and studied them using commercial CFD software. In their study they have observed that Model 5 was

the optimum design having 0.845 bar back pressure and 12.5 m/s exhaust velocity. Model 5 is seen to have the

same convergent and divergent length. Nikhil Kanawade et al. [4] has submitted a literature review on the

methodologies used in the analysis of the exhaust system in internal combustion engines. They have discussed

about the methodologies used and various parameters involved in the design and analysis of the exhaust

manifold and system for automotive purposes. Rajesh Bisane et al. [5] has studied the significance of using

Computational Fluid Dynamic Techniques to study CI Engine Exhaust System by comparing conventional,

turbocharged and supercharged engines. He suggests that CFD proves as a valuable technique before proceeding

with experimental setup. K.S. Umesh et al. [6] studied eight variants of the exhaust manifold using for

parameters such as back pressure and exhaust velocity. They studied the models for every 2 kilogram mass flow

rate variation. The models they used are Short Bend Center Exit (SBCE), Short Bend Side Exit (SBSE), Long

Bend Center Exit (LBCE), Long Bend Side Exit (LBSE), Short Bend Center Exit with Reducer (SBCER), Short

Bend Side Exit with Reducer (SBSER), Long Bend Center Exit with Reducer (LBCER), and Long Bend Side

Exit with Reducer (LBSER). Based on their study hey concluded that LBCE variant had the better flow

characteristics. Vivekanand Navadagi et al. [7] analyzed two different geometries to reduce back pressure. They

analyzed the two models using CFX for mass flow rates of 3.143 m/s, 4.516 m/s, 4.981 m/s and 5.627 m/s

.They found that the model they designed achieved low back pressure and can improve volumetric efficiency.

Exhaust Velocity:

A turbocharger uses a radial in axial out turbine configuration which is influenced mainly by the exhaust

velocity. Higher the velocity the better will be the spooling of the turbocharger. The manifold must be designed

in a manner to give higher exhaust velocities even at lower engine rpms.

Design of Manifold:

There are 3 designs used for the purpose of this analysis. Two models is of log type and one model is of

tubular type. All models have 3 inlets with the same diameter. Due unavailability of experimental data, standard

dimensions have been assumed. The inlet diameter of the manifold is 44.45 mm. The first model has all 3

runners connected to a common stem as shown in Fig.1. The second model is characterized by joining the

second and third runner to the first runner while the third model is designed by joining all three runners into a

common collector as shown in Fig.2. and Fig.3. respectively.

Fig.1: Model 1 of the Exhaust Manifold




Methodology:

Steady state static analysis is done using Ansys Fluent. The analysis will be done with mass flow inlet and

pressure outlet assuming multiple reference frame technique to plot velocity vectors.

A. Boundary Conditions:

Three models along with a turbocharger are to be tested for the same mass flow rate. The following table

details the boundary conditions used for the analysis.

Table1: Boundary Conditions

S. No Parameter Value

1 Method Multiple Reference Frame

2 Inlet Type Mass Flow Inlet

3 Inlet Mass Flow Rate 0.0482 kg/s

4 Rotating Zone Type Moving Wall

5 Impeller RPM 60000 rpm

6 Outlet Type Pressure Outlet

7 Outlet Pressure 0 Pa

8 Working Fluid Air

B. Details of Mesh:

The cleanup of the geometry and meshing is done using ANSA 13.2. The cleanup involves extraction of the

fluid domain. The fluid domain under consideration in the manifold along with the turbine of the turbocharger.

The waste gate and the compressor are neglected. Surface mesh skewness of 0.6 (Fluent) is maintained using

triangular cells and volume mesh skewness of 0.9 (Fluent) is maintained using tetrahedral cells. Fig.4. Fig.5. and

Fig.6 shows the node conformity across the interfaces between the Rotating Zone and Outlet, Inlet and Rotating

Zone and the Inlet respectively.

Fig.4: Surface Mesh at the Interface of the Rotating Zone and the Outlet

Fig.5: Surface Mesh at the Interface of the Inlet and the Rotating Zone

Fig.6: Surface Mesh at the Inlet


Fig.7: Volume Mesh at the Interface of the Inlet and Rotating zone

Fig.7. shows the tetrahedral volume mesh generated at the Interface of the Inlet and the Rotating Zone.

RESULTS AND DISCUSSIONS

The analysis is carried out using Fluent and results are shown in colored contours obtained using CFD Post.

Fig.8: Velocity Vectors for Model 1

Fig.8. shows the velocity vector obtained near the impeller of the turbine. The maximum velocity obtained

is 191 (m/s).

Fig.9: Static Pressure Contours for Model 1


Fig.9. shows the static pressure contour obtained around the impeller of the turbine. Maximum static

pressure obtained is 15900 pascal.

Fig.10: Turbulent Kinetic Energy for Model 1

Fig.10. shows the turbulent kinetic energy contour. The maximum turbulent kinetic energy generated is 625

(m2/s2).



is 210 (m/s).







(m2/s2).



is 254 (m/s).







(m2/s2)

Fig.17: Comparison of Velocity Vectors

Fig.17. shows the comparison of velocity vectors of all three models. It shows that Model 3 has maximum

velocity 254 m/s.

Conclusions:

The 3 different models are analyzed using CFD software to obtain the velocity vector, static pressure and

turbulent kinetic energy along the manifold and the turbine housing. The simulation data was used to obtain the

necessary results using CFD Post. The following inferences were made:

• Apart from the runner length, runner volume, collector, back pressure and exhaust pulse, the physical

shape of the manifold also has significant impact on exhaust velocity.

• Unlike conventional design of manifold, the tubular design of the yield maximum velocity of 254 m/s.

REFERENCES

1. Jafar, M., Hasan, Wahid S. Mohammad, Thamer A Mohamed, Wissam H Alawee, 2014. ‘CFD Simulation

for Manifold with Tapered Longitudinal Section’, International Journal of Emerging Technology and

Advanced Engineering, 4: 2.

2. Marupilla Akhil Teja, Katari Ayyappa, Sunny Katam and Panga Anusha, 2016. ‘Analysis Of Exhaust

Manifold Using Computational Fluid Dynamics’, Fluid Mech Open Acc 3(1) 1000129 ISSN: FMOA, An

Open Access Journal

3. Mohd Sajid Ahmed, Kailash B A, Gowreesh, 2015. ‘Design And Analysis of a Multi-Cylinder Four Stroke

SI Engine Exhaust Manifold using CFD Technique’, International Research Journal Of Engineering And

Technology (IRJET) E-ISSN: 2395-0056 02(09) www.irjet.net P-ISSN: 2395-0072

0

50

100

150

200

250

300

1 2 3

Velocity Vector (m/s)


4. Nikhil Kanawade, Prof. Omkar Siras, 2016. ‘A Literature Review On Exhaust Manifold Design’,

International Journal of Scientific Research Engineering & Technology (IJSRET), ISSN 2278 – 0882 5(5).

5. Rajesh Bisane, Dhananjay Katpatal, 2014. ‘Experimental Investigation & CFD Analysis Of An Single

Cylinder Four Stroke C.I. Engine Exhaust System’, IJRET: International Journal of Research in

Engineering and Technology e ISSN: 2319-1163 | p ISSN: 2321-7308

6. Umesh, K.S., V.K. Pravin and K. Rajagopal, 2013. ‘CFD Analysis Of Exhaust Manifold Of Multi-Cylinder

SI Engine To Determine Optimal Geometry For Reducing Emissions’, International Journal of Automobile

Engineering Research and Development (IJAuERD) ISSN 2277-4785 3(4): 45-56 © TJPRC Pvt. Ltd.

7. Vivekanand Navadagi, Siddaveer Sangamad, 2014. ‘CFD Analysis of Exhaust Manifold of Multi - Cylinder

Petrol Engine for Optimal Geometry to Reduce Back Pressure’, International Journal of Engineering

Research & Technology (IJERT) ISSN: 2278-0181 3(3).

8. www.asia.donaldson.com/en/exhaust/support/datalibrary/1053747.pdf

9. https://www.turbobygarrett.com/turbobygarrett/sites/.../GT2860R_707160_7.pdf

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CFD analysis of IC engine exhaust manifold with … analysis of IC engine exhaust manifold with respect to the performance of a turbocharger 1P Sylvester Selvanathan, 2Dr. R. Sudhakaran,