The paper presents experimental investigation of the heat dissipation from stationary brake discs concentrated on four disc designs, a ventilated disc with radial vanes, two types of ventilated discs with curved vanes - a non-drilled and cross-drilled disc, and a solid disc. The experiments were conducted on a purpose built Thermal Spin Rig and provided repeatable and accurate temperature measurement and reliable prediction of the total, convective and radiative heat dissipation coefficients. The values obtained compare favourably with Computational Fluid Dynamics results for the ventilated disc with radial vanes and solid disc, though the differences were somewhat pronounced for the ventilated disc. The speeds of the hot air rising above the disc are under 1 m/s, hence too low to experimentally validate. However, the use of a smoke generator and suitable probe was very useful in qualitatively validating the flow patterns for all four disc designs. Convective heat transfer coefficients increase with temperature but the values are very low, typically between 3 and 5 W/m2K for the disc designs and temperature range analysed. As expected, from the four designs studied, the disc with radial vanes has highest convective heat dissipation coefficient and the solid disc the lowest, being about 30% inferior. Convective heat dissipation coefficient for the discs with curved vanes was about 20% lower than for the disc with radial vanes, with the cross drilled design showing marginal improvement at higher temperatures.

The paper compares heat dissipation characteristics of two interchangeable ventilated brake discs, a standard solid hub and a newly developed fingered hub version, both single piece cast designs. The tests were conducted on a specially developed Thermal Flow Rig, which enables disc induction heating to 450°C and cooling for a range of rotational and air speeds, in parallel and angular cross flow. The Rig facilitated very accurate and repeatable experiments to be conducted for numerous combinations of operating conditions. From the recorded cooling curves, average heat transfer coefficients for convection and radiation were extracted and the results also presented in a generic form, using Nusselt numbers. The fingered design demonstrated superior convective heat dissipation, with the improvements varying depending on the rotational speed, air cross flow velocity and angle, as well as disc temperature. The gains were ranging from 3.5% to over 20%. The fingered design is 8.5% lighter and being a single piece cast disc, it remains inexpensive to mass produce.

The article focuses on generating a monoblock fingered hub (top hat) disc design, aiming at reducing disc mass but maintaining rotor thermal capacity, whilst also improving heat dissipation characteristics. The analyses and tests demonstrated that such a design is possible to achieve, with mass reduction of just over 9%. The activities included research into cast iron modelling which gave very important insight into its limits of mechanical performance under bending. Initial Finite Element analyses enabled considerable progress towards establishing a baseline design but only through Shape Optimization and Topology Optimization procedures the full potential of the design have been accomplished. Shape optimization facilitated reduction of maximum principal stress by 32%, considerably improving disc torsional strength with practically no mass increase. The safety factor in torsion achieved the value of 3.57. Topology Optimization provided further, though small mass reduction (1.5%) whilst maintaining low stress levels.