Modeling Meteorological Effects of Heat Transfer in a Pipe

For many heat loss models for a pipeline the ambient temperature is assumed to be constant in order to simplify the finite difference model. However, on longer pipe systems, such as the Trans Alaskan oil pipeline which spans 800 miles, assuming a constant ambient air temperature is a poor assumption. It was hypothesized that by using a PRISM (Parameter-elevation Regressions on Independent Slopes Model) temperature map of Alaska that a more accurate computer heat transfer model could be developed. To ensure that the ambient temperature values were as accurate as possible image processing was used to overlay the exact location of the pipeline on the PRIZM temperature map. A finite difference heat loss model was constructed in Matlab that accounted for the changing ambient temperature at each location on the pipe. The results were compared to two sets of experimental readings from April of 2001, and July of 2006. Significantly better results were obtained using changing ambient temperature values that correlated with the time of year and location on the pipe than assuming a constant average ambient air temperature. In the future, as alternative fuels are sought out, being able to accurately model the temperature values in an existing pipe, and thus the fluid properties, will be crucial in determining what new fluids can be used in the existing infrastructure.