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## Main Question or Discussion Point

I am building a mathematical model of a piston engine which calculates the pressure and temperature of the cylinder gas every 1° of crank angle.

I'm having some difficulty with the heat transfer to and from the cylinder wall (to when the Tg > Tw and from when Tg < Tw).

I found the heat transfer equation on EngineeringToolbox.com

http://www.engineeringtoolbox.com/conductive-heat-loss-cylinder-pipe-d_1487.html

Which gives me an heat loss in W. How do I convert the loss in W to a reduction in temperature in °K?

I'm having some difficulty with the heat transfer to and from the cylinder wall (to when the Tg > Tw and from when Tg < Tw).

I found the heat transfer equation on EngineeringToolbox.com

*q = 2 π k (ti - to) / ln(ro / ri) (1)*

where

q = heat transferred per unit time per unit length of cylinder or pipe (W/m, Btu/hr ft)

k = thermal conductivity of the material (W/m.K or W/m oC, Btu/(hr oF ft2/ft))

to = temperature outside pipe or cylinder (K or oC, oF)

ti = temperature inside pipe or cylinder (K or oC, oF)

ln = the natural logarithm

ro = cylinder or pipe outside radius (m, ft)

ri = cylinder or pipe inside radius(m, ft)where

q = heat transferred per unit time per unit length of cylinder or pipe (W/m, Btu/hr ft)

k = thermal conductivity of the material (W/m.K or W/m oC, Btu/(hr oF ft2/ft))

to = temperature outside pipe or cylinder (K or oC, oF)

ti = temperature inside pipe or cylinder (K or oC, oF)

ln = the natural logarithm

ro = cylinder or pipe outside radius (m, ft)

ri = cylinder or pipe inside radius(m, ft)

http://www.engineeringtoolbox.com/conductive-heat-loss-cylinder-pipe-d_1487.html

Which gives me an heat loss in W. How do I convert the loss in W to a reduction in temperature in °K?