Unsteady Flow Analysis Method for Automobile LED Headlamp based on Massively Parallel CFD considering the External Environment 2020-01-0636
The aim of this study is to understand the mechanism of dew condensation and try to prevent it on automobile headlamp. In this case, it is necessary to accurately reproduce the complicated shape of the headlamp as the computational model. In addition, the simulation framework for predicting the turbulent flow field accompanied by the high heat source and the wall heat transfer with high accuracy in the vehicle running environment is required.
Moreover, using CFD to understand the mechanism of the flow field inside the light emitting diode (LED) headlamp with a rotating fan to cool the light sources, is a challenging task because of the complicated internal structures and significant heat transfer.
In this paper, we report that we tried constructing the simulation method of compressible turbulence based on hierarchical Cartesian grid using the HPC (High Performance Computing) environment.
At first, we clarified the ventilation phenomenon through the vent holes in the uniform flow, and succeeded in obtaining the knowledge of ventilation control by changing the position and number of the vent holes. The calculation results by wind tunnel experiments were verified. This is to make it possible to consider the external environment of LED headlamps mounted on the vehicle in the future.
Next, we report about the construction of the calculation model for the rotating fan by adopting the moving boundary method based on the immersed boundary method (IBM) by using the HPC environment and then report comparing it with the particle image velocimetry (PIV). The numerical framework has been built and the result was in qualitatively good agreement with the experimental data using PIV.
Additionally, to simulate the real situation in the near future, where the extremely larger physical time (>10s) should be taken into consideration, the trade-off between the accuracy and the computational resource is investigated.