Heat Losses From Underground Steam Pipelines

A new transient solution describing the heat transfer around a single buried steam pipe was developed. The solution technique uses Green’s functions and is particularly appropriate at distances greater than two or three pipe radii from the pipe. The solution models the pipe as a line heat source and considers a convective boundary condition at the soil surface. It was shown that for long time periods, the solution reduces to a steady-state expression that is believed to describe heat loss rates better than some current, commonly used steady-state relations. The solution was used with parameter estimation techniques to design an experimental procedure for determining buried steam pipe heat loss rates and depths from near-surface soil temperature measurements. Sensitivity coefficients derived from the solution were used to identify the linearly independent parameters and the optimum locations for the temperature measurements. An example of the use of this procedure is presented.