Effective thermal conductivity of composite pipe

[cbalsil]

I am using a specialized well bore anlysis program that calculates thermal profiles in down hole. The program requires a "k" thermal conductivity value for drill pipe as an input.

I am using a pipe that has insulation at different locations along its length. I would like to know how to calculate the effective "k" (thermal conductivity) of one pipe section "L". The pipe is basically steel with an insulation layer.

 

[corus]

Calculate it on the basis of the equivalent thermal resistance, so K = L/(x1/k1 + x2/k2. The problem is tht any boundary condition such k. dt/dx = h. (T-Ta) will be wrong using an equivalent K.

Tata

 

[zekeman]

Your question is too vague to get a proper answer.

Do you mean that the insulation around the steel pipe is different or non-existent at various positions and, if so, what are they? It is very problematical to develop a socalled equivalent K . Mpre realistically you might need a piecewise solution using a different program for this.

I would strongly suggest that you explain exactly what you are trying to do and give us a sense of thermal boundaries and flow conditions, if any.