Discrete Phase Analysis of Self Heating Particles Over an Immersion Liquid Cooled High Power Blue Light-Emitting Diode With Suspended Phosphor Particles

Abstract

In recent years, the interaction of unrestricted particles with dispersed multi-phase flows has been linked to a number of important engineering applications. Among these applications, the novel idea of immersion cooled phosphor particles, which has the potential of significantly increasing the thermal limits of phosphor converted white LEDs (Pc-WLEDs), has yet to be thoroughly investigated. With this objective, this research utilizes the discrete phase modeling (DPM) technique for the characterization of phosphor location and movements within a buoyancy-driven flow, which is the determining factor in the optical behavior of the newly proposed Pc-WLED configuration. Two-phase flow analysis is conducted to characterize particle movement. Heat transfer, flow, and energy paths of self-heating phosphor particles are extracted, and the influence of particle sizes is analyzed in detail. The results show that with immersion liquid cooling, the highest phosphor particle temperature is recorded to be under 420 K, while larger size particles introduce higher heat transfer rates to the Pc-WLED package for the same number of particles. Moreover, depending on the particle size and position, individual phosphor particles can follow a different trajectory that can affect the probability of obtaining white light emission.

LED Junction Temperature Measurement: From Steady State to Transient State

“…The temperatures of the junction and the phosphor layer (in phosphor-converted white LEDs) are the primary thermal issues for the next generation of high-power LED devices [23][24][25]. Precisely controlling LED temperatures is key to addressing these heat-induced issues [26,27]. Therefore, to provide suitable thermal management solutions, interpret photometric characteristics and packaging capabilities, and perform lifetime predictions, it is paramount that researchers can accurately determine both the steady-state and transient temperatures of LEDs across a wide range of conditions.…”

A Critical Review on the Junction Temperature Measurement of Light Emitting Diodes

“…The aging and degradation of LEDs, the majority of which is caused by high temperatures, has long been a topic of debate [ 44 , 45 , 46 , 47 ]. It is recognized that the temperature of the junction region and phosphor layer (in phosphor-converted white LEDs) are the two major thermal concerns for next generation, high power LED devices [ 48 , 49 , 50 ], and successful thermal management was found to be the key aspect to tackle thermal-induced problems [ 51 , 52 ]. However, to offer a suitable thermal management solution, interpreting photometric characteristics and package capabilities and making lifetime predictions, it is required to adopt a steady-state and transient temperature characterization in a large range of conditions.…”