Methodology for conjugate heat transfer analysis of brake discs

Abstract

"Brakes are critical safety devices of any equipment in operation and for its control. Disc Brakes (DB) are ubiquitous with the present-day transportation industry for the many advantages it brings in through design, performance, operation, reliability, serviceability, and manufacturing. Many solutions that prove to work for the brake systems in other domains prove inefficient and cost constrained for implementation in the rail industry. Starting from a requirement of better thermal performance in both directions of rotation, the rail DB equipment establishes its own set of challenges. The thermal performance of the DB may have to be compromised by the design requirements of life and service, on account of the constraints, in applications such as the rail. The advent of new manufacturing methods, processes, assembly tools and materials, provide a path for improving the performance of the DB in question. Industry is accustomed to Computational Fluid Dynamics (CFD) as an efficient alternative to physical tests, detailed calculations, and one-dimensional simplifications. The rail industry solicits such an established practice in CFD to achieve standard, high-fidelity results for the development of the DB system. The design and performance parameters of system (Disc Brake System) like the calipers, actuators, braking fluid lines, layout and supporting equipment also require input from such simulations - for them work in unison. It is an established requirement hitherto, that the methods, models, assumptions, and differences of such simulations be documented and debated, which defines the scope of this publication. This effort is aimed at discussing a method of modelling a DB using Conjugate Heat Transfer (CHT) principles of CFD to accurately assess the heat transfer from the disc to the air that flows through. As solids and the fluid domains are coupled for heat transfer – the metal temperatures can be predicted more accurately. The models used for turbulence, the material properties, the geometric simplification in simulating the DB, help in predicting the local heat transfer coefficients, metal, and bulk fluid temperatures as primary output. "