Experimental and inverse numerical analysis of the thermal behavior of pantograph collector strips under natural and forced convection

The thermal behavior of pantograph collector strips significantly influences their wear performance. However, most existing numerical studies rely on generic thermal parameters and empirical convection conditions, which limit their applicability to actual operating conditions. This paper aims to investigate the thermal behavior of the collector strip and to identify its unknown critical parameters experimentally and numerically. A transient two-dimensional thermal model based on the finite difference method is developed for the collector strip, and full-scale temperature rise tests are conducted under natural and forced convection conditions. By employing the Levenberg-Marquardt inverse method with an explicit sensitivity matrix on experimental data obtained under natural convection, the unknown thermal parameters of the collector strip are identified. The identified parameters and the thermal model are further validated by reproducing temperature profiles under distinct experimental conditions. Furthermore, forced convective heat transfer coefficients are identified at various airflow speeds. Those coefficients exhibit a power-law relationship with airflow speed, consistent with classical correlations reported in the literature. Comparisons with other thermocouple data demonstrate acceptable relative errors, validating the applicability of the identified coefficients.