Thermal Enhancement of LED Cooling Systems Using Passive Tesla Valves for Turbulence-Induced Convection

Summary

This work presents an experimental protocol to assess the thermal behavior of high-power Chip-on-Board (COB) LEDs using infrared thermography. A compact forced-convection cooling device was tested under variable power and airflow, demonstrating efficient heat dissipation and safe junction temperatures for compact applications such as smart lighting and embedded electronics.

Abstract

This study presents an experimental methodology for assessing the thermal behavior of high-power Chip-On-Board (COB) light-emitting diodes (LEDs) using infrared thermography, integrated with a novel compact forced-convection cooling device. The thermal performance was evaluated under varying power inputs and flow rates, revealing the system's ability to maintain LED junction temperatures below critical thresholds. Thermographic imaging enabled the spatially resolved temperature analysis of the LED surface under both natural and forced convection regimes. The proposed cooling device was specifically designed for compact integration, featuring a radial inlet/outlet configuration that minimizes space while maximizing heat dissipation efficiency. The simulation results generated were validated against experimental data, ensuring the reliability of the proposed cooling approach. This work demonstrates a feasible and replicable method for thermal management characterization in solid-state lighting applications, providing a scalable solution for integration in confined environments, such as LED luminaires, smart lighting systems, or embedded electronic modules.

Introduction

The escalating demand for high-power lighting solutions has propelled Chip-on-Board (COB) Light Emitting Diodes (LEDs) to the forefront of modern illumination technologies. COB LEDs, characterized by multiple LED chips mounted directly onto a thermally conductive substrate, offer superior luminous efficacy and compactness. However, their high power density and compact form factor pose significant thermal management challenges. Efficient heat dissipation is paramount to maintain performance, reliability, and longevity of these devices¹.

In COB LEDs, a substantial portion of the electrical energy is converted into heat....

Protocol

Geometry of the cooling device
The purpose of the project is to maintain a 50 W COB LED under a permissible temperature with the Tesla valve implementation. The COB used as a heat source is shown in Figure 2A, while Figure 2B shows 50 die chips turned on, indicating that each die has 1 W of power.

Results

Prototype manufacturing

The prototype was fabricated using CNC milling to create both the Tesla channels and the chambers. The machined Tesla channels are shown in Figure 8A, while the fabricated chambers are presented in Figure 8A. Subsequently, a drilling process was carried out to form the inlet and outlet ports on the chambers.

Discussion

Unlike conventional heat sinks^{9,10,11,12,13,14}, the system integrates a forced convection mechanism within a compact configuration that significantly enhances heat dissipation. Importantly, the integration of inlet and outlet ports in a radial configuration allows the system to occupy minimal space, making it ideal for confin.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
FreeCad Software	FreeCAD Community	https://forum.freecad.org/	Open-source software used for creating geometries and assemblies (RRID:SCR_066611).
Generic CNC Milling 3018 Pro Max	Generic (Sainsmart/Mostreprap)	3018 Pro Max	Desktop CNC milling machine used to manufacture the Tesla valve.
Infrared Camera	Unit-T	UTi260B / UTi720 Series	Infrared camera used to capture temperature distribution in the device.
Octave Software	GNU Project	https://octave.org/	Open-source software used for data processing and plot generation (RRID:SCR_014398).
OpenFoam	OpenCFD Ltd (ESI Group)	Open-source CFD software used to solve the numerical model (RRID:SCR_014876).
Paraview Software	Kitware Inc.	https://www.paraview.org/	Open-source software used for post-processing of the numerical solution (RRID:SCR_002516).
Termocouples	Unit-T	UT325/UT320 Series	Thermocouples used to capture the thermal behavior.