Comparison of junction temperature prediction methods through analysis of isolated 1-D thermal resistance model variables of an application utilizing forced convection of heat sinks

2018 ◽  
Author(s):  
N. A. Klitzke ◽  
S. C. Polzer ◽  
W. L. Wilkins ◽  
B. K. Gilbert ◽  
C. R. Haider
Keyword(s):  
Thermal Resistance ◽  
Forced Convection ◽  
Heat Sinks ◽  
Junction Temperature ◽  
Prediction Methods ◽  
Temperature Prediction ◽  
Resistance Model

Efficient Heat Dissipation Design of High-Power Multi-Chip Cob Package Led Modules

2012 ◽  
Vol 463-464 ◽  
pp. 1332-1340 ◽  
Author(s):  
Lei Wu ◽  
Xiao Yun Xiong ◽  
De Xing Wang
Keyword(s):  
Thermal Conductivity ◽  
Forced Convection ◽  
High Power ◽  
Heat Dissipation ◽  
Heat Sinks ◽  
Junction Temperature ◽  
Ir Camera ◽  
Chip Size ◽  
Computational Fluid Dynamics Cfd ◽  
Convection Cooling

In this study, the junction temperature (Tj) and thermal resistance (Rth) of five high-power multi-chip COB (chip-on-board) LED packages with different chip spacings were compared. The actual Tjwas measured by an IR camera and compared with the simulation results from a computational fluid dynamics (CFD) software. In addition, the effects of heat slugs with different thermal conductivity, heat sinks of various thicknesses, chip size, and forced convection cooling on the Tjand Rthof high-powered LED components were investigated. The experimental results show that smaller chip spacing resulted in higher Tjand Rth. The heat dissipation performance can be improved by using a heat slug with a high thermal conductivity; and increasing the thickness of the heat sink, or employing forced convection cooling.

Effect of Pin Fin Density of the Thermal Performance of Unshrouded Pin Fin Heat Sinks

1994 ◽  
Vol 116 (4) ◽  
pp. 306-309 ◽  
Author(s):  
Kaveh Azar ◽  
Carlo D. Mandrone
Keyword(s):  
Thermal Resistance ◽  
Surface Area ◽  
Forced Convection ◽  
Heat Sinks ◽  
Optimum Number ◽  
Base Temperature ◽  
Pin Fin ◽  
Pin Fins ◽  
Pattern Comparison ◽  
Temperature Constant

An experimental investigation was conducted to examine the effect of pin fin density on thermal resistance of unshrouded pin fin heat sinks. Six heat sinks with different number of round pin fins were constructed. Heat sink thermal resistance was calculated by maintaining its base temperature constant. For these experiments, air flow varied from natural to high velocity forced convection. The results showed that thermal resistance did not decrease with increase of number of pin fins. An optimum number of pin fins existed beyond which thermal resistance actually increased. The study also showed that thermal resistance was a function of air velocity and governing flow pattern. Comparison of the heat transfer coefficient (h) and pin fin surface area showed that h decreased dramatically as surface area increased. The results showed that pin fin heat sinks with small number of pins had the best performance at low and moderate forced convection cooling.

scholarly journals Influence of a Thermal Pad on Selected Parameters of Power LEDs

Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3732
Author(s):  
Krzysztof Górecki ◽  
Przemysław Ptak ◽  
Tomasz Torzewicz ◽  
Marcin Janicki
Keyword(s):  
Optical Properties ◽  
Thermal Resistance ◽  
Optical Power ◽  
Junction Temperature ◽  
Operating Parameters ◽  
Cold Plate ◽  
Optical Efficiency ◽  
Forward Current ◽  
Measurement Results ◽  
Set Up

This paper is devoted to the analysis of the influence of thermal pads on electric, optical, and thermal parameters of power LEDs. Measurements of parameters, such as thermal resistance, optical efficiency, and optical power, were performed for selected types of power LEDs operating with a thermal pad and without it at different values of the diode forward current and temperature of the cold plate. First, the measurement set-up used in the paper is described in detail. Then, the measurement results obtained for both considered manners of power LED assembly are compared. Some characteristics that illustrate the influence of forward current and temperature of the cold plate on electric, thermal, and optical properties of the tested devices are presented and discussed. It is shown that the use of the thermal pad makes it possible to achieve more advantageous values of operating parameters of the considered semiconductor devices at lower values of their junction temperature, which guarantees an increase in their lifetime.

scholarly journals Evaluation of Active Heat Sinks Design under Forced Convection—Effect of Geometric and Boundary Parameters

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2041
Author(s):  
Eva C. Silva ◽  
Álvaro M. Sampaio ◽  
António J. Pontes
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Additive Manufacturing ◽  
Pressure Drop ◽  
Forced Convection ◽  
Thermal Performance ◽  
Heat Sinks ◽  
Trapezoidal Shape ◽  
Computational Fluid Dynamics Simulations ◽  
Dynamics Simulations

This study shows the performance of heat sinks (HS) with different designs under forced convection, varying geometric and boundary parameters, via computational fluid dynamics simulations. Initially, a complete and detailed analysis of the thermal performance of various conventional HS designs was taken. Afterwards, HS designs were modified following some additive manufacturing approaches. The HS performance was compared by measuring their temperatures and pressure drop after 15 s. Smaller diameters/thicknesses and larger fins/pins spacing provided better results. For fins HS, the use of radial fins, with an inverted trapezoidal shape and with larger holes was advantageous. Regarding pins HS, the best option contemplated circular pins in combination with frontal holes in their structure. Additionally, lattice HS, only possible to be produced by additive manufacturing, was also studied. Lower temperatures were obtained with a hexagon unit cell. Lastly, a comparison between the best HS in each category showed a lower thermal resistance for lattice HS. Despite the increase of at least 38% in pressure drop, a consequence of its frontal area, the temperature was 26% and 56% lower when compared to conventional pins and fins HS, respectively, and 9% and 28% lower when compared to the best pins and best fins of this study.

Thermal Behaviors of Passively-Cooled Hybrid Fin Heat Sinks for Lightweight and High Performance Thermal Management

2015 ◽  
Author(s):  
Nico Setiawan Effendi ◽  
Kyoung Joon Kim
Keyword(s):  
Thermal Resistance ◽  
Heat Sink ◽  
High Performance ◽  
Heat Dissipation ◽  
Computational Study ◽  
Heat Sinks ◽  
Channel Diameter ◽  
Internal Channel ◽  
Study Results ◽  
Parametric Effects

A computational study is conducted to explore thermal performances of natural convection hybrid fin heat sinks (HF HSs). The proposed HF HSs are a hollow hybrid fin heat sink (HHF HS) and a solid hybrid fin heat sink (SHF HS). Parametric effects such as a fin spacing, an internal channel diameter, a heat dissipation on the performance of HF HSs are investigated by CFD analysis. Study results show that the thermal resistance of the HS increases while the mass-multiplied thermal resistance of the HS decreases associated with the increase of the channel diameter. The results also shows the thermal resistance of the SHF HS is 13% smaller, and the mass-multiplied thermal resistance of the HHF HS is 32% smaller compared with the pin fin heat sink (PF HS). These interesting results are mainly due to integrated effects of the mass-reduction, the surface area enhancement, and the heat pumping via the internal channel. Such better performances of HF HSs show the feasibility of alternatives to the conventional PF HS especially for passive cooling of LED lighting modules.

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