Imperial Journal of Interdisciplinary Research (IJIR) Vol-3, Issue-2, 2017 ISSN: 2454-1362, http://www.onlinejournal.in
Diesel Engine Piston – Design and Thermal Analysis A.KrishnaPriya1, A.Gopichand2, V.S.Gangadhar3, Y.Tejo Ram Charan4, G.Sainath5 1,2
Student, Department of Automobile Engineering, Vignan University, 522213 Students, Department of Mechanical Engineering, K L University, 522502 5 Student, Department of Mechanical Engineering, G Pulla Reddy Engineering College, 518007 3,4,
Abstract: Piston is a moving component which is located in the cylinder and is made gas-tight by piston rings. It is a vital component in an engine. In this present work a piston is modelled in CATIA V5R17 and the same model was imported to ANSYS workbench and meshing was done and further analysis was carried out in the same ANSYS Workbench. The type of analysis that we had carried out here was thermal analysis, where we had found out the maximum temperature and total heat flux by applying average cycle temperature and adiabatic flame temperature on the piston. Here for carrying out the analysis three materials were selected and out of those the material which suits best for the stipulated condition was suggested. Keywords: Piston, Thermal analysis, adiabatic flame temperature, heat flux
Introduction Automobiles consists of various number of parts, out of which piston is one of the most vital component. Pistons are designed to perform specific functions during engine operations. Basically pistons are designed according to the procedures andh specification provided in the Machine Design data books or any other open literature which have valid approval. During the design of a piston various design considerations are to be taken care such as: It should have high strength to withstand the high pressure, it should have high speed reciprocation without noise, it should form effective oil sealing in the cylinder, and it should have minimum weight to withstand the inertia forces. In this present work three materials were selected for carrying out analysis, they are Aluminium, Grey Cast iron and Structural steel. The properties of the selected materials are as follows:
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Properties
Density Tensile Yield Strength Ultimate Yield Strength Young’s Modulus
Aluminium
2710 Kg/m3 280 MPa 330 MPa
71 GPa
Grey Cast iron 7200 Kg/m3 240 MPa 450 MPa
Structural Steel
140 GPa
210 GPa
7800 Kg/m3 250 MPa 460 MPa
Modelling The piston was modelled in CATIA and analysis was carried out in ANSYS workbench. For modelling, the basic profile is drawn in CATIA part drawing and then shaft operation is applied for 360o. Then for drawing Piston pin one of the face is selected and piston pin dimensions are given and pocket operation is carried out. Further, padding operation is done so that pin position is held correctly. The specifications are: 1. 2. 3. 4. 5. 6.
Thickness of piston head (th ) = 4.3mm Thickness of rib (tr ) = 2.4mm Piston ring radial width (b) = 2.916mm Piston barrel = 10.5mm (top end), 3.6mm (bottom end) The distance from the top of the piston to the first ring groove (h1) = 4.16mm The Distance between two consecutive ring grooves (h2) = 3.5mm
Fig.1 shows the completely modelled piston in CATIA.
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Imperial Journal of Interdisciplinary Research (IJIR) Vol-3, Issue-2, 2017 ISSN: 2454-1362, http://www.onlinejournal.in Fig.2 Meshed Piston Model.
Analysis
Fig.1 Completely Modelled Piston.
Meshing The component drawn in CATIA is imported to ANSYS and then meshing is done for the component. For meshing fine mesh is selected. Fig.2 shows meshing of the piston in ANSYS.
In this present work thermal analysis is carried out by applying average cycle temperature and adiabatic flame temperature. Here by applying them the maximum temperature distribution and total heat flux is calculated for all the three materials. In diesel engine piston, the average cycle temperature during suction, compression, combustion and exhaust process is between 1100 oC - 1200oC which is taken from open literature with convective heat transfer coefficient of 800 W/m2K. The adiabatic flame temperature ranges between 1800oC – 2000oC which is taken from open literature. These inputs are taken and applied to get the thermal analysis of the piston. Aluminium analysis: The maximum temperature distribution and total heat flux when the average cycle temperature is applied on the piston head as shown below in fig. 3
Fig.3 Temperature distribution at 1200o C The maximum temperature distribution and the total heat flux when the adiabatic flame temperature is applied on the piston head as shown in fig.4
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Imperial Journal of Interdisciplinary Research (IJIR) Vol-3, Issue-2, 2017 ISSN: 2454-1362, http://www.onlinejournal.in
Fig.4 Temperature distribution at 1900o C Grey Cast iron analysis: The maximum temperature distribution and the total heat flux when the average cycle temperature is applied on the piston head as shown in fig.5
Fig.5 Temperature distribution at 1200o C The maximum temperature distribution and the total heat flux when the adiabatic flame temperature is applied on the piston head as shown in fig.6
Fig.6 Temperature distribution at 1900o C Structural Steel analysis: The maximum temperature distribution and the total heat flux when the average cycle temperature is applied on the piston head as shown in fig.7
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Imperial Journal of Interdisciplinary Research (IJIR) Vol-3, Issue-2, 2017 ISSN: 2454-1362, http://www.onlinejournal.in
Fig.7 Temperature distribution at
ďż˝
C
The maximum temperature distribution and the total heat flux when the adiabatic flame temperature is applied on the piston head as shown in fig.8
Fig.8 Temperature distribution at 1900o C Table-1 shows the temperature and total heat flux when average cycle temperature is applied on piston head for all the three materials. Table-1: Average cycle temperature Materials Aluminium Grey cast iron Structural steel
Temperature (oC) 1200 1200 1200
Total heat flux (W/m2) 9.4524e+006 4.9338e+006 5.3091e+006
Table-2 shows the temperature and total heat flux when adiabatic flame temperature is applied on piston head for all the three materials. Table-2: Adiabatic flame temperature Materials Temperature (oC) Total heat flux (W/m2) Aluminium 1900 1.507e+007 Grey cast iron 1900 7.8656e+006 Structural steel 1900 8.4638e+006
Conclusion The main aim of this work was to design a piston and further by applying average cycle temperature and adiabatic flame temperature on three selected
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materials the temperature and total heat flux was to be determined and out of that which material suits best for the piston was to be investigated. And from the analysis carried out and the results we can
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Imperial Journal of Interdisciplinary Research (IJIR) Vol-3, Issue-2, 2017 ISSN: 2454-1362, http://www.onlinejournal.in conclude that Aluminium is efficient under stipulated conditions.
References [1]. A Textbook on “Internal Combustion Engines” by V. Ganesan. [2]. “Fundamentals of Internal Combustion Engines” by H.N.Gupta. [3]. “Internal Combustion Engine Fundamentals” by John B.Heywood. [4]. Mahdi Hamzehei, Manochehr Rashidi, “Determination of Piston and Cylinder Head Temperature Distribution in a 4-Cylinder Gasoline Engine at Actual Process”. [5]. Sachin Pente, Nitin Wankhade, Prasad Hatwalne, “Comparative investigation of vibration analysis of VCR diesel engine for different types of grey cast iron”. [6]. A.Krishnapriya, A.Gopichand, V.S.Gangadhar, B.B.Vasanth, Y.Tejo Ram Charan, Arun Peri, “Design and analysis of diesel engine piston”, volume-6, issue-9.
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