In this study, the optical sphere and the power analyzer were exploited to measure the optical and power parameters for the high-power LED lamps. The results, derived from the experimental data, were used as the power distribution inputs in the finite element analysis (FEA) for the determination of the temperature distribution for the printed circuit board assembly (PCBA) built in the LED lamp. In the finite element analysis, the conjugate heat transfer model was adapted for the calculation of the heat transfer, including thermal conductivity, convection and radiation. Applied on the power chips located on the PCBA, the graphene thermal interface material (TIMs) had been studied for its effects on the temperature distribution. For an accurate simulation about the LED lamp, the model with closed and compact space was built in the analysis. Compared to the experimental data, it showed that the simulation results had a deviation in the range of 3-5% around the main heating source, the light-emitting diodes. It proves the FEA model proposed in this study were well developed for the simulation of the temperature distribution for the high-power LED lamps which have mixed heat transfer mechanisms. The thermal radiation effects by TIMs with graphene were also investigated in this study and proven to be useful for the heat dissipation for the LED lamps. power input is high and the volume of the VR device is small, cooling the power chips will be very difficult. Obviously, the traditional TIMs or grease is not enough for the cooling requirements for the up-to-date electronic devices. There should be new heat sinkers or dissipators which are able to solve the over-heat problems for the powerful and compact electronic devices.In this study, the conjugate heat transfer model provided by the commercial finite volume method (FVM) software, FLUENT, will be used for the analysis about the temperature distribution for the electronic devices with high-power chips and compact volumes, such as LEDs and VRs. The values of power for the dominant chips on the PCBA will be derived experimentally by the optical sphere and the power analyzer. In the FEA model, the power chips will be simulated as heat sources. Heat by conduction will pass through the printed circuit board from the power chips. On the boundary between the PCBA and air, heat transfer by convection will happen. In addition, when the power chips are applied with TIMs of graphene, the heat transfer by radiation will be introduced in the analytic model. Finite space will be constructed to simulate the cases for LED lights. The results of simulation will be verified by those data obtained by the experiments, which confirms the validity of the proposed FEA model.
Literature ReviewThe parameters for the design of LED lights include luminous flux, chip temperature, input power and cooling mechanism, etc. An excessively high operating temperature will decrease the performance of LEDs. Generally, the higher the luminous flux is, the higher the operational temperature is. Precise measu...
