TECHNIQUE FOR PARAMETER IDENTIFICATION FOR MATHEMATICAL MODEL OF STEADY-STATE GAS FLOW BASED ON EXPERIMENTAL DATA

Abstract

The article substantiates the need to identify the parameters of a mathematical model of steady-state natural gas flow in a main gas pipeline using experimental data. It is established that using reference values for the hydraulic resistance coefficient and the gas-to-soil heat transfer coefficient without their identification leads to significant modeling errors. A methodology has been developed for identifying these coefficients as a single minimization problem in the space of two parameters, with an  objective function defined as the sum of squared normalized deviations of the calculated pressure and temperature values at the pipeline outlet from their experimentally measured values. Based on the minimization results, the formula for calculating the hydraulic resistance coefficient λ has been improved, and the heat transfer coefficient has been determined for the pipeline's laying conditions (3.71 W/(m²·K)). The adequacy of the model with identified parameters has been confirmed by comparing the calculated pressure and temperature at the pipeline outlet with the experimental data; the relative deviations do not exceed 0.38% for pressure and 0.01% for temperature. The developed technique is recommended for identifying model parameters for other gas pipelines, while the obtained pressure and temperature distributions can serve as boundary conditions for a mathematical model of non-steady gas flow.