Numerical study of enhanced heat dissipation of OTR tire using rib structures on the sidewall

Temperature characteristics has a great influence on tire durability and rolling resistance, and heat dissipation from the tire’s outer surface is an important factor affecting the overall thermal balance of the tire. This study combines infrared thermography experiments with numerical simulations to investigate the convective heat transfer characteristics of off-the-road (OTR) tire surfaces, and evaluate the effects of sidewall mounted with rectangular rib on heat dissipation and thermal performance. Surface temperatures of the tire tread and sidewall are acquired via drum tests, and a three-dimensional numerical model is established. The SST k-ω turbulence model is adopted to compute the flow field around tire surface, and the numerical results are validated against experimental data. Rectangular ribs are designed on the tire sidewall, with varying rib thickness, spacing, and inclination angle. The convective heat transfer coefficient, temperature distribution and local flow-field features are analyzed under different rib configurations. The results show that the sidewall ribs significantly enhanced convective heat transfer. The optimal thermal performance is achieved with a spacing of 5 deg, an inclination angle of 0 deg and a thickness of 7 mm. For this configuration, the area-averaged convective heat transfer coefficient roses from 15.95 to 23.45 W·m ⁻² ·K ⁻¹ , representing an increase of approximately 47%, and the average sidewall temperature decreases by approximately 2.7 K. In contrast, the tread temperature varies by less than 0.7 K. The effects of different rib configurations on flow field characteristics, including turbulent kinetic energy and vortex structures, are analyzed to reveal the underlying heat transfer enhancement mechanisms.