# On the basis of second consideration of heat transfer

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Unformatted text preview: on, 50 to 90 MPa for nickel cast iron and aluminium alloy and 60 to 100 MPa for forged steel. On the basis of second consideration of heat transfer, the thickness of the piston head should be such that the heat absorbed by the piston due combustion of fuel is quickly transferred to the cylinder walls. Treating the piston head as a flat ciucular plate, its thickness is given by H tH = 12.56k (T − T ) (in mm) ...(ii) C E where * The coefficient of thermal expansion for aluminium is 0.24 10–6 m / °C and for cast iron it is 0.1 × 10–6 m / °C. ** The heat conductivity for aluminium is 174.75 W/m/°C and for cast iron it is 46.6 W/m /°C. *** The density of aluminium is 2700 kg / m3 and for cast iron it is 7200 kg / m3. Internal Combustion Engine Parts n 1135 where H = Heat flowing through the piston head in kJ/s or watts, k = Heat conductivity factor in W/m/°C. Its value is 46.6 W/m/°C for grey cast iron, 51.25 W/m/°C for steel and 174.75 W/m/°C for aluminium alloys. TC = Temperture at the centre of the piston head in °C, and TE = Temperature at the edges of...
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## This note was uploaded on 09/30/2012 for the course MECHANICAL 403 taught by Professor A.thirumoorthy during the Spring '11 term at Anna University Chennai - Regional Office, Coimbatore.

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