Modelling of Natural Gas Pipe Flow with Rapid Transients-case Study of Effect of Ambient Model

The paper presents a study of gas pipeline to soil heat transfer. The effect of simplifications of the heat transfer model is investigated. Studied are steady, one dimensional unsteady and two dimensional unsteady models of the pipe wall and soil. Flow conditions at the pipeline inlet are varied. The effects of rapid changes in gas mass flow rate and temperature at the pipeline inlet are studied. The case presented is representative for export natural gas pipelines, containing offshore and buried sections along the route. Results are compared to experimental data from an existing export natural gas pipeline.