Approximate Mathematical Model of Heat Exchange in a Complex Thermal Engineering System of Several Product Pipelines Carrying a Motionless Isothermal Product within a Single Insulating Jacket

An approximate mathematical model was developed to describe the heat exchange in a complex thermal engineering system of several parallel product pipelines carrying an motionless isothermal product within a single insulating jacket. The model is distinguished by using a simplified mathematical model of the steady-state heat conduction on a circle (motionless product) and in an annulus (product pipeline wall) under the Robin boundary conditions using various approximating effective heat-transfer coefficients in different parts of the boundary of a heated product pipeline carrying the isothermal product with the air space and the insulation.