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International Journal of Mechanical Engineering and Technology (IJMET) Volume 8, Issue 3, March 2017, pp. 269–278 Article ID: IJMET_08_03_030

Available online at http://www.iaeme.com/IJMET/issues.asp?JType=IJMET&VType=8&IType=3

ISSN Print: 0976-6340 and ISSN Online: 0976-6359

© IAEME Publication Scopus Indexed

THERMAL ANALYSIS OF SILENCER PIPE

A. S. Mate

Mechanical Engineering Department,

Pillai HOC College of Engineering & Technology,

Rasayani, Raigad - 410207, Maharashtra, India

V. Kumbhar

Mechanical Engineering Department,

Pillai College of Engineering & Technology,

New Panvel, Raigad - 410206, Maharashtra, India

ABSTRACT

Automotive and heavy machineries engines in industries have exhaust system which

is pivotal in rejecting the exhaust air, heat which increases air pollution, exhausting

speed increases noise pollution, human harmful atmospheric environment which may

be required to prevent and preserve harmful atmospheric gases. The silencer is required

to control air pollution, noise pollution, to filter (Catalytic converter) the chemical toxic

elements. The function of exhaust system to discharge the exhaust gases of the engines

which will not affect atmospheric environment.

This study deals with an investigation of hotspots or areas where the temperature

concentrations take place for example such as mating areas between two pipes.

Temperatures at different points on the silencer are determined by experimental setup

on a car further considering the results of temperatures geometric modelling is done on

the current model of silencer in ABAQUS and stress analysis is done on the same.

The main objective is to reduce the hotspots in the silencer thus improving the

efficiency of heat transfer and also improving the life span of the silencer. From this

report we can establish a relation between the exhaust gas temperatures and stresses

developed, modified design is proposed.

Key words: Silencer, Temperature Concentrations, Reduce Hotspots

Cite this Article: A. S. Mate and V. Kumbhar, Thermal Analysis of Silencer Pipe,

International Journal of Mechanical Engineering and Technology, 8(3), 2017, pp.269–

278.

http://www.iaeme.com/IJMET/issues.asp?JType=IJMET&VType=8&IType=3

Thermal Analysis of Silencer Pipe


1. INTRODUCTION

The hot gases from the combustion chamber pass through the automotive exhaust system and

come in contact with high temperatures. In order to increase the life of the exhaust system

components, the heat distribution should be uniform. To design the exhaust system it is very

important to understand the physical phenomenon which takes place in the exhaust system. By

controlling the exhaust gas temperature, normal operating conditions can be achieved and it

also enhances the performance of the engine. The heat transfer analysis of automotive exhaust

system is reviewed in this article. Dattatray Dilip Giripunje (2013) established that to reduce

the temperature and backpressure, silencer remodeling is suggested in such a way that the

transmission loss is reduced to 30 dB and there is also reduction of backpressure to 10. Mesut

Durat (2014) presents that by performing CFD analysis the optimal positioning of the catalyst

is determined. Mayuri Chourey (2014) suggested that from analysis that Carbon fibre material

can be used which demonstrates enormous non corrosive properties. Agron E. Gjinolli (2015)

developed a method to select and determine the optimal duct design that can be used along with

its shell thicknesses, mounting points, expansion joint locations /requirements, and loads on the

supporting structures can also be reviewed as well as the results of the final design. Mahesh S.

Vasava (2015) it can be concluded from the paper that exhaust gas temperature directly affects

the performance of engine and in order to improve the performance of the engine it is necessary

to control the exhaust temperature. S.Balamurugan (2015) mentioned that the baffle

arrangement is used in the muffler to eliminate tremendous amount of toxic exhaust that is

released from the engine as well as it also reduces the usage of fuel by 0.5%. Lakshminarayanan

(2015) established that the comparison of various factors affecting the muffler such as thermal

concentration, thermal stress and properties of material are taken in to account and analyzed in

the software and input is taken from experimental setup. Based on that optimal redesigning and

remodeling is made to the muffler. Silencer is an integral part of all the exhaust systems which

have hot gas discharges at relatively high velocities. The silencer is induced with several

stresses due to heat and other factors, such as vibration, fatigue which it has to withstand. The

enhancement of the function of the silencer is increased directly as we make improvements in

the silencer which also improves its effective life span.

Figure 1 Silencers

(Source: Complete Book on Production of Automobile Components & Allied Products NIIR

Publication)

A. S. Mate and V. Kumbhar


The exhaust system is also affected by factors such as backpressure and noise. The

maximum allowable engine backpressure is specified by the engine manufacturer. Increase in

backpressure gives rise to problems such as pumping work, reduced intake manifold boost

pressure, cylinder scavenging and turbocharger problems. The usage of silencers and mufflers

helps in reducing the engine exhaust noise. The function of the exhaust system is to carry the

harmful exhaust gases and discharge them quickly with reduced noise.

In context with the above the design considerations for the system are as follows:

1. To keep the backpressure within the specified limits as specified for the particular engine model

and to provide maximum efficiency we have to reduce the resistance to gas flow (backpressure).

2. Noise emission levels should not exceed the local regulations and application requirements.

3. To reduce the impact of high exhaust temperatures on engine components, an adequate

clearance should be provided.

4. To make sure that the life of the engine components is not reduced due to overstressing of engine

components such as turbocharger and manifolds with excess weight.

5. To select proper components for exhaust system that will reject heat as intended by the original

design.

The main Components in engine exhaust system are as follows:

Exhaust manifolds or EKE.

Catalytic converters.

Muffler (Silencer).

2. MAIN COMPONENTS OF SILENCER

2.1. Exhaust Manifold

The function of the exhaust manifold is to carry the hot exhaust gases and release them to the

environment through proper exhaust outlet. Backpressure and turbulence should be minimum

in the designed manifold. There are three types of manifolds such as dry, water-cooled and air

shielded water cooled manifold designs selected on the basis of application and design

requirements. Types of manifolds are as follows.

1. Dry Manifolds

2. Water-cooled Manifolds

3. Air Shielded Water-cooled Manifolds.

Figure 2 Manifolds

(Source: Performance Exhaust Systems, CarTech; 1publication)



2.2 Catalytic Converter

Catalytic converters are used to convert the harmful gases into harmless gases with the help of

catalyst. There are two types of catalytic converters available one is two way and three way

catalytic converter. Three way converters are used widely in diesel engines. Fig 1.3 shows the

chemical reaction that takes place in the tree way converters.

Figure 3 Chemical reaction in catalytic converter

(Source: A Text Book on Automobile Engineering, Laxmi Publication)

2.3. Mufflers

Mufflers are installed into the exhaust system to reduce the noise emission of the machine. It

also reduces back pressure and velocity of hot gases.

These are the following types of mufflers used in automobiles;

1. Reactive muffler

2. Absorptive muffler

3. Combination of absorptive and reactive muffler.

Figure 4 Muffler

(Source: Performance Exhaust Systems, Car Tech; 1publication)



3. DATA COLLECTION AND ANALYSIS

The methodology to find the solution for the current work adopted is as follows.By measuring

temperatures at the points using experimental set up on the silencer, then stress distribution for

those temperatures is found out by software. The steps followed to complete the project work

are in the form of flow chart.

Figure 5 Temperature at various points in the silencer.

Study of exhaust system and list out the Performance

parameters

Study of design of existing silencer

Analysis of existing silencer for `thermal’ (heat

dissipation)

Geometry modelling of existing silencer

Demonstrating a relation between exhaust gas

temperature and stress caused due to it.



Temperatures are recorded at critical locations of silencer .Muffler section are critical as

real-time temperatures are difficult to get. They are obtained by remote probe of temperature

recorder, with thermocouple at each of section of the silencer, approximately 4 locations are

fixed for temperatures and temperatures recorded. The temperatures are recorded at exhaust

manifolds, at middle of the silencer, before the muffler, at the muffler and at the exhaust of

silencer. The following table shows the recorded temperatures.

Table 1 Observation of temperature of exhaust system at different location and measurements of

temperature at those locations.

Sr .No Measuring Points T1 T2 T3 T4

Temperature at Starting of the Engine

1. Manifold 1 66 65 65 70

2. Manifold 2 70 71 70 70

3. Manifold 3 75 73 75 76

4. Manifold 4 75 76 74 75

5. Temperature at combination point of 4 manifolds 59 58 59 60

6. Temperature at middle of silencer 51 49 50 49

7. Temperature of silencer before muffler 46 47 47 46

8. Temperature of muffler 46 45 46 46

9. Temperature of silencer before exhaust to atmosphere 46 46 46 45

Temperature at Steady State

1. Manifold 1 85 86 86 87

2. Manifold 2 92 92 93 93

3. Manifold 3 97 97 98 99

4. Manifold 4 98 99 100 101

5. Temperature at combination point of 4 manifolds 82 82 83 84

6. Temperature at middle of silencer 65 64 64 64

7. Temperature of silencer before muffler 59 59 58 58

8. Temperature of muffler 56 55 55 54

9. Temperature of silencer before exhaust to atmosphere 53 53 52 51

The experimental data is then used with FEM package for creation of temperature field for

the silencer pipe, muffler pipe and muffler assembly. The analysis software used is ABAQUS.

The Flow of analysis is as follows:

The different material properties selected for silencer are as:

Young’s modulus of Elasticity E = 2e ^ 11 N\m2

Poisson ratio = 0.3, material density is = 7700 kg/m3,

Thermal conductivity=237 W\m k, coefficient of expansion =1.33e-005 and

The length of silencer is = 500 mm.

Materials used for silencer is alloy steel.



• Model and meshing of silencer pipe

Figure 6 Model of silencer pipe

The above figure shows model of silencer in solid works by selecting the tool circle then

create section and loft.

Figure 7 Meshing of silencer pipe

The above figure shows the meshing of the silencer pipe



• Analysis result of silencer pipe

Figure 8 Vonmises stress

The above figure shows the amount of von misses stress acting along the surface of the

silencer pipe.

Figure 9 Maximum principal stress

The above figure shows the magnitude of maximum principle stress along the surface of

silencer pipe.



Figure 10 Minimum principal stress

The above figure shows the magnitude of minimum principle stress along the surface of

silencer pipe.

Figure 11 Strain magnitude

4. CONCLUSION

Analysis is done for silencer pipe, muffler pipe and muffler assembly .From the analysis it is

observed that the stress concentration is at the periphery of the holes of the muffler. So we can

say that stress raising sections are dominant over muffler region because of holes, which are



mandatory now days due to which stress distributions are fluctuating and unsteady. To have

more life span of silencer stress concentration across the holes has to be minimized. Corrugated

construction of pipe with baffles should be used to prevent stress raisers .Same has to be

incorporated in muffler and that should be followed by automotive is outcome of study so far.

5. ACKNOWLEDGEMENTS

We express our gratitude to our professors for their unfailing inspiration. We take this

opportunity to thank our colleagues for their company during the course work and for useful

discussion we had with them.

REFERENCES

[1] Dattatray, D. G., Shinde, V. B., Kulkarni, S. S.,(2013) “Thermal analysis for motor bike

exhaust silencer for ensuring reduction in hot spots through design enhancement”,

International Journal of Advanced Engineering Research and Studies, Vol. II/ IV, pp.134-

137, 2013.

[2] Durat, M., Parlak, Z., Kapsiz, M., Parlak, A, (2013) “CFD and experimental analysis on

thermal performance of exhaust system of a spark ignition engine”, Journal of Thermal

Science and Technology, Vol. 33(2), pp.89-99, 2013.

[3] MayuriChourey, Dr.RohitRajvaidya, (2014) “Study and Comparison of Different Corrosion

Resistant Materials used in Aumotive Silencer”. Dept. of Product Design and Engineering,

Bhopal University.

[4] Agron E. Gjinolli, Elden F. Ray, Cary D. Bremigan and Bruce J. Morris.,(2015) “Offshore

Requirements for Turbine Exhaust System Analysis and Design” Universal Acoustic &

Emission Technologies Stoughton, Wisconsin, USA.

[5] Mahesh S. Vasava 1, P. V. Jotaniya.,(2015)“A Review on Heat Transfer Analysis in

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D. College of Engineering, Ahmedabad, Gujarat, India1 Assistant Professor, Department of

Mechanical Engineering, L. D. College of Engineering, Ahmedabad, Gujarat, India2.

[6] S.Balamurugan, N.Jeyaprakash, K.Manikandan.,(2015) “Design and Fabrication of Muffler

for Four Stroke Diesel Engine.”

[7] Lakshminarayanan.N, K.Surendrababu, Balamurugan.N.,(2015) “Design Modification and

Testing of CI Engine Muffler.”Dept. of Mechanical Engg, Aarupadai Veedu Institute of

Technology, Chennai.

[8] B. P Bhardwaj (Ed.), (2015), Complete Book on Production of Automobile Components &

Allied Products” NIIR Publication, pp 47.

[9] Mike Mavargian(Ed.), (2014),”Performance Exhaust Systems: How to Design, Fabricate,

and Install (Sa Design)” CarTech; 1publication, pp156

[10] R.K Rajput (Ed.), (2015), “A Text Book on Automobile Engineering” Laxmi Publication,

pp 47.

[11] Raj Kumar Yadav, Vikas Mukhraiya and Shwetank Soni, Thermal Analysis of Brake - A

Review. International Journal of Design and Manufacturing Technology 8(1), 2017, pp.08–

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[12] Nakka Sita Rama Raju, V Jaya Prasad, S Kamaluddin and A Sunny Kumar. Thermal

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Mechanical Engineering and Technology, 8(2), 2017, pp. 160–166.

[13] Mike Mavargian(Ed.), (2014),”Performance Exhaust Systems: How to Design, Fabricate,

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