Heat transfer performance of the rectangular heat sinks with non-uniform height thermosyphons for high power LED lamps cooling

Abstract

The rectangular heat sinks with non-uniform height thermosyphons are proposed for high power light emitting diode (LED) lamps cooling in this study. The combined thermal resistance network and finite volume method is developed to reveal the heat transfer mechanism. The simulated results show good agreement with experimental data with relative errors of 2.14–2.69% at heating powers of 12–20 W. In comparison with type-a thermosyphon heat sink, the thermal resistance of type-b thermosyphon heat sink offers 8.47–9.91% higher due to thicker thermal boundary layer between air and thermosyphon fins in the intermediary region, whereas the thermal resistance of type-c thermosyphon heat sink offers 7.26–9.07% lower because of better free stream among thermosyphon fins in the intermediary region. The maximum heat transfer rate of type-a, type-b and type-c thermosyphon heat sinks are 19 W, 17 W and 22 W in regard to the temperature threshold of 85 °C, respectively. This paper provides guidelines for the design of high power LED lamps cooling.