Performance Comparison of Different Chamber designs for Ventilated Disk Brake 2017-36-0240
Environment concerns lead the automakers to invest resources and put research in engine downsize to reduce carbon emission. Turbo charge is a possibility due to its fuel consumption and emission reduction without compromise the performance. Nowadays, it is becoming common observe high performance small cars due to high torque and power available. In consequence, brake system need to dissipate more kinetic energy without adding mass or costs.
Modern passenger cars require a high-speed brake system. To achieve proper brake system cooling, the rotor must be ventilated and designed to optimize the energy dissipated, which is generated by friction between pad and disk.
Some approaches consider the rotor as a centrifugal air pump and the design rule is to improve the airflow inside the vanes. The approach considering a brake rotor similar to centrifugal air pump rotor may be considered as limited approach, once it simplifies the heat transfer phenomena inside chamber. The purpose of the rotor existence is not to pump air but, exchange energy with environment every time the braking process occurs.
There is one divergence with this approach once it indicates that higher mass flow rate inside vanes is the best for the cooling performance. Higher is the best, in this condition, focusing only on increasing Reynolds number to speed up turbulence flow condition, more adequate to exchange heat than laminar flow. This is done by optimization of rotor dimensions, that is limited by environment conditions (such as wheel rim diameter, hub bearings size, caliper dimensions), and could be enough to achieve required vehicle performance.
To improve the performance then, new designs and concepts of ventilated chamber for brake rotors are proposed to improve the convective heat transfer. This work will evaluate the alternatives for rotor chamber known as straight vane, currently most common at our market.
This study also evaluates the curves of rotor heating in a constant speed for all those concepts, in a range from 20 KPH to 80KPH.