INVESTIGATION OF BOILING IN HIGH-POWER LED COOLING SYSTEM

The technology of solid-state light source is associated with the future of a number of sectors of the economy. The duration of failure-free operation, optical radiation power and other output characteristics of the LEDs are closely linked with p-n junction temperature, which makes the development of the cooling systems an important step in creating LED systems. In this work, we have created a new experimental setup for studying heat transfer from a local heat source, modelling the LED chip. The boiling heat transfer on the local heaters with a diameter of 5 and 10 mm has been investigated at the saturation temperature in bulk liquid. It is shown that on the finned surfaces the overheating relative to the saturation temperature in comparison with a smooth surface decreases up to one and a half times for the heater with a diameter of 10 mm, and up to three times for the heater with a diameter of 5 mm. There is up to two times increase in heat transfer coefficient on finned surfaces as compared to the smooth ones. For finned surfaces on the heater with a diameter of 1 mm the surface overheating relative to the saturation temperature decreases four times. More than three times increase is observed for the heat transfer coefficient on finned surfaces as compared to the smooth ones.