In the bustling world of urban rail transit, where trains brake and accelerate countless times a day, a critical issue has been lurking in the shadows: the intense heat generated between the wheel and brake shoe during emergency stops. This heat can cause significant damage to the wheel treads, brake shoes, and even lead to thermal cracks. Enter SUN Ningyuan, a researcher from the School of Urban Rail Transportation at Shanghai University of Engineering Science, who has been tackling this very problem.
SUN and his team have developed a sophisticated three-dimensional transient temperature rise simulation model. This model takes into account crucial factors like contact thermal conductivity coefficients, material thermophysical parameters, and convective heat transfer coefficients. Using ABAQUS finite element software, they simulated the temperature field of the friction pair under various braking conditions.
The results are striking. Under a single emergency braking scenario, the surface temperature difference of the brake shoes considering and neglecting the contact thermal conductivity coefficient was a whopping 71.17 ℃. “This significant difference highlights the importance of considering contact thermal conductivity in our models,” SUN explained.
The study also revealed that axial temperatures of the brake shoes are concentrated in the central region, while radial temperatures are primarily distributed on the brake shoe surface, with significant temperature gradients. In three consecutive emergency braking events, the simulated temperatures of the brake shoes were 217.40 ℃, 245.78 ℃, and 270.70 ℃, respectively. The maximum error between the simulated and experimentally measured temperatures was a mere 3%, demonstrating the model’s high accuracy.
So, what does this mean for the future of urban rail transit? According to SUN, “Understanding the temperature field evolution of friction pairs is crucial for designing more efficient and durable braking systems.” This research could lead to significant improvements in the energy sector, particularly in the development of more heat-resistant materials and advanced braking technologies.
The study, published in ‘Chengshi guidao jiaotong yanjiu’ (translated to ‘Urban Rail Transit Research’), is a significant step forward in the quest to enhance the safety and efficiency of urban rail transit systems. As cities around the world continue to expand and invest in public transportation, this research could have far-reaching implications for the future of urban mobility.
In an era where energy efficiency and sustainability are paramount, SUN’s work serves as a reminder that even the smallest details, like the heat generated between a wheel and a brake shoe, can have a significant impact on the broader energy landscape. As we continue to push the boundaries of technology and innovation, it’s crucial that we also invest in the research that will shape the future of our cities and the way we move through them.