Example 2: Radial heat transfer though a cylinder Consider heat is being transferred radially outwards in pipe from the inner surface, 1 , to the outer surface, 2 . The fluid in the pipe is stationary. Assuming steady state conditions with no heat source or sink within the plane and the heat transfer is in the r-direction, simplify the energy equation. Answer: T(r)=ln(R1/R2)Ts1Ts2ln(R2r)+Ts2