This example model shows the opposing effects of viscous warming and conductive cooling on the temperature of a buried pipeline segment for heated oil transportation. A requirement for these systems is for the crude oil to stay well above the pour point to provide a continuous steady flow. The system is modeled using the Thermal Liquid Foundation Library. Crude oil thermodynamic properties are stored in workspace matrices and are used to populate the Thermal Liquid Settings block mask parameters.
The model can be used to optimize the pipe diameter. In this example it is assumed that the outer diameter of the insulator is fixed, and it is the inner diameter that is to be optimized. An optimal design is where the heating and thermal loss terms balance so that the temperature stays constant through the segment. This model reproduces the study detailed in 'Optimal Pipeline Geometries and Oil Temperatures for Least Rates of Energy Expenditure During Crude-oil Transmission', S.D. Probert and C. Y. Chu, Applied Energy 14(1983) 1-31.