Brake Rotor Thermal Flow Analysis
High temperature in a vehicle brake system could cause brake pad/caliper distortion, accelerated corrosion of the cast iron rotor, and excessive brake pad wear. All these problems would result in a shorter life span of the brake assembly and consequently more customer complaints.
The new brake rotor design is thus focused on the effective heat removal from braking. Current brake rotor design usually relies on expensive and time consuming experimental study for each new design.
Optimal CAE provides an integrated CFD thermal analysis technique that can assist the brake rotor designer to achieve the goal in a quicker turnaround time and a lower cost.
The steady state CFD results show that the maximum temperature on the rotor surface with 37 straight fins is much higher than that with 72 curved fins.
Results - Heat Transfer Coefficients
The "steady state" heat transfer coefficient resulted from the CFD analysis is used as boundary conditions in the FEA thermal stress analysis.
Results - Velocity Contours
The airflow through the 72 curved fin rotor is much higher than that for the 37 straight fin rotor.
The CFD/FEA analysis correctly predicts the temperature difference trends corresponding to rotor design changes, however, the temperature after 25 stops for CAE prediction is higher than the testing data.
The discrepancy between CAE prediction and test data could be attributed to the simplification of the model.
It was observed during field testing the mirror was vibrating excessively at certain speeds.
The vibration is due to the unsteady, flow-induced forces resulted from the vortex behind the mirror, which are close to the natural frequency of the mirror. The frequency of vortex shedding depends on the geometry of the mirror and the angle of impingement of the oncoming air. To avoid this resonance effect, an integrated CFD/FEA analysis could provide insight information in the mirror design process.
To investigate vortex shedding process in the baseline mirror design that will vibrate at high speed.
Based on the knowledge gained from the baseline design, modify the baseline design, conduct CFD simulation and compare to the baseline design.
Steady state velocity vector plots show that the modify mirror has a smaller re-circulation zone behind the side mirror.
Results - 3D Streamlines
The streamlines plots from the steady state flow analysis indicate that two recirculation zones can be found behind the mirror.
Results - Relative Pressure
The steady state pressure contour can be used as initial for structural dynamics analysis
The frequency of vortex shedding has been determined by using the cost-effective CFD/FEA model.
The modified design, a result of CFD and FEA analysis from the baseline design, increases the natural frequencies of the side view mirror. The increase of the natural frequency of the mirror have improved the vibration significantly.