Study of an LED device with a honeycomb heat sink

Abstract

Previous studies show that the lighting quality of LED largely depends on operating temperature. LED without thermal management may fail early due to thermal runaway, epoxy degradation, and thermal stress under high-operating temperatures. In this study, the performance of a honeycomb heat sink was investigated by experimentation and three-dimensional numerical models. Two kinds of honeycomb models were proposed to demonstrate the performance of a heat sink with single and multiple heat sources for LED thermal management. The performances of innovative honeycomb heat sinks depend on the number of cells, aspect ratio, and the rib-space ratio. The simulated results indicated that the performance varies a little when the conductivity is over 50W/mK. Compared to the simulated heat flux ratio 0.95, the measured heat flux ratio 0.93 at θ=30° was slightly lower. The measured performance of the lump and stack (5 pieces) honeycomb heat sink can respectively keep 13.761W and 13.338W under the dummy heater at 67°C and the ambient temperature at 27°C. The innovative design with nine pieces of layers that are drilled to reduce their weight can effectively dissipate the heat by natural convection in the application of a high-power LED street lamp.