Improving the Thermal Performance of a Forced Convection Air Cooled Solution: Part 2 — Effect on System-Level Performance

2013 ◽  
Author(s):  
John Edward Fernandes ◽  
Saeed Ghalambor ◽  
Richard Eiland ◽  
Dereje Agonafer ◽  
Veerendra Mulay
Keyword(s):  
Power Consumption ◽  
Forced Convection ◽  
Thermal Performance ◽  
Heat Sink ◽  
Reducing Power ◽  
Junction Temperature ◽  
System Level ◽  
Parasitic Load ◽  
Convection Cooling ◽  
Level Performance

The heat sink assembly of an air cooled CPU is modified to improve thermal performance of the module-level solution. This modification is employed in a dual-socket server that relies on system fans to move air for forced convection cooling of all heat generating components on the motherboard. Currently, in the data center industry, the focus is on reducing power consumption through application of energy-efficient cooling solutions. Fans installed in the server operate as a function of CPU die temperatures and represent a parasitic load that must be minimized. Improvement in system-level performance can be quantified in terms of reduced fan and server power consumption. The server is subjected to varying CPU utilizations and corresponding average fan speeds and power consumption are reported. Similarly, reduction in CPU junction temperature and server power at a given utilization can be computed by operating the fans at a constant speed. Difference in thermal performance and power consumption between the baseline and modified heat sink configurations was found to negligible when a TIM is applied. However, in the absence of a TIM, the modified assembly delivered as much as 24.4% reduction in CPU die temperature and 6.2% reduction in server power consumption. In addition, there is indiscernible variation in server power consumption between the baseline (with employment of TIM) and modified (with and without TIM application) heat sink assemblies. Thus, the modified configuration has possible applications in systems where a TIM may be undesirable or difficult to apply.

Performance of Hybrid Fin Heat Sinks for Thermal Control of Light Emitting Diode Lighting Modules

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Kyoung Joon Kim
Keyword(s):  
Forced Convection ◽  
Thermal Performance ◽  
Heat Sink ◽  
Light Emitting Diode ◽  
Internal Flow ◽  
Thermal Control ◽  
Numerical Prediction ◽  
Light Emitting ◽  
Convection Condition ◽  
Pin Fins

In this paper we introduce a hybrid fin heat sink (HFH) proposed for the thermal control of light emitting diode (LED) lighting modules. The HFH consists of the array of hybrid fins which are hollow pin fins having internal channels and integrated with plate fins. The thermal performance of the HFH under either natural or forced convection condition is both experimentally and numerically investigated, and then its performance is compared with that of a pin fin heat sink (PFH). The observed maximum discrepancies of the numerical prediction to the measurement for the HFH are 7% and 6% for natural and forced convection conditions. The reasonable discrepancies demonstrate the tight correlation between the numerical prediction and the measurement. The thermal performance of the HFH is found to be 12–14% better than the PFH for the natural convection condition. The better performance might be explained by the enlarged external surface and the internal flow via the channel of the HF. The reference HFH is about 14% lighter than the reference PFH. The better thermal performance and the lighter weight of the HFH show the feasibility as the promising heat sink especially for the thermal control of LED street and flood lighting modules.

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.

Improving the Thermal Performance of a Forced Convection Air Cooled Solution: Part 1 — Modification of Heat Sink Assembly

2013 ◽  
Author(s):  
Saeed Ghalambor ◽  
John Edward Fernandes ◽  
Dereje Agonafer ◽  
Veerendra Mulay
Keyword(s):  
Pressure Distribution ◽  
Forced Convection ◽  
Thermal Performance ◽  
Heat Sink ◽  
Heat Sinks ◽  
Thermal Interface Material ◽  
Air Cooling ◽  
Interfacial Pressure ◽  
Interfacial Contact ◽  
Torque Analysis

Forced convection air cooling using heat sinks is one of the most prevalent methods in thermal management of microelectronic devices. Improving the performance of such a solution may involve minimizing the external thermal resistance (Rext) of the package. For a given heat sink design, this can be achieved by reducing the thermal interface material (TIM) thickness through promotion of a uniform interfacial pressure distribution between the device and heat sink. In this study, a dual-CPU rackmount server is considered and modifications to the heat sink assembly such as backplate thickness and bolting configuration are investigated to achieve the aforementioned improvements. A full-scale, simplified model of the motherboard is deployed in ANSYS Mechanical, with emphasis on non-linear contact analysis and torque analysis of spring screws, to determine the optimal design of the heat sink assembly. It is observed that improved interfacial contact and pressure distribution is achieved by increasing the number of screws (loading points) and positioning them as close to the contact area as possible. The numerical model is validated by comparison with experimental measurements within reasonable accuracy. Based on the results of numerical analysis, the heat sink assembly is modified and improvement over the base configuration is experimentally quantified through interfacial pressure measurement. The effect of improved interfacial contact on thermal performance of the solution is discussed.

scholarly journals Research on Cooling Method in Surfacing Repair Process of Aero Compressor Blade

2020 ◽  
Vol 2020 ◽  
pp. 1-19
Author(s):  
Shijie Dai ◽  
Miao Gong ◽  
Liwen Wang ◽  
Tao Wang
Keyword(s):  
Heat Transfer ◽  
Forced Convection ◽  
Heat Sink ◽  
Molten Pool ◽  
Cooling Effect ◽  
Modeling And Simulations ◽  
Cooling Method ◽  
Jet Impact ◽  
Convection Cooling ◽  
Vertical Jet

For the cooling method in surfacing repairing, most of the research focuses on the method based on the fixture structure. However, due to the low thermal conductivity and ultrathin alloy blade, the heat transfer speed from the molten pool to fixture is slow. When the heat is transferred to the fixture, most of the molten pool has solidified and absorbed or segregated out some impurities. Therefore, how to cool the welding area directly is more critical. For this reason, the thermal cycle characteristics of typical points of the blade and the heat transfer process of the key area of the fixture are analyzed, the original cooling time is calculated, and two innovative cooling methods based on lateral forced convection cooling and vertical jet impact forced convection cooling are proposed. For lateral forced cooling, with “AF-field” lateral convection cooling modeling, the cooling effects of characteristic points and sections under different flow velocities are calculated. For vertical jet impact cooling, the pressure, flow rate, and convective heat flux distribution on the wall under different impact heights and nozzle diameter are calculated. The influence of different inlet flow rates on cooling performance is influenced, based on the analysis results of impact modeling, the moving heat sink model is established, and the cooling effect under different heat sink-source distances is calculated. The heat transfer rules of two methods are analyzed in detail through modeling and simulations. The results show that both methods can improve the cooling effect and the vertical jet impact cooling method has an effect that is more obvious. When the nozzle radius is 2 mm, the impact height is 4d, the inlet flow velocity is 35 m/s, and the distance is 7 mm, and the cooling time under the vertical jet impact method is shortened by 12.5%, which can achieve better cooling effect. The experiment further validates the effectiveness of the modeling and simulations.

Energy Efficient Heat Sink Design: Natural Versus Forced Convection Cooling

2017 ◽  
Vol 32 (11) ◽  
pp. 8693-8704 ◽  
Author(s):  
Daniel Christen ◽  
Milos Stojadinovic ◽  
Juergen Biela
Keyword(s):  
Forced Convection ◽  
Heat Sink ◽  
Energy Efficient ◽  
Convection Cooling ◽  
Heat Sink Design

Effect of Flow Bypass on the Performance of Longitudinal Fin Heat Sinks

1994 ◽  
Vol 116 (3) ◽  
pp. 206-211 ◽  
Author(s):  
R. A. Wirtz ◽  
Weiming Chen ◽  
Ronghua Zhou
Keyword(s):  
Heat Transfer ◽  
Forced Convection ◽  
Thermal Performance ◽  
Heat Sink ◽  
Design Guidelines ◽  
Heat Sinks ◽  
Air Cooling ◽  
Regular Array ◽  
Electronic Package ◽  
And Performance

Heat transfer experiments are reported on the thermal performance of longitudinal fin heat sinks attached to an electronic package which is part of a regular array of packages undergoing forced convection air cooling. The effect of coolant bypass on the performance of the heat sink is assessed and performance correlations for reduced heat transfer due to this effect are developed. These correlations are used to develop design guidelines for optimal performance.

Effect of channel and fin geometries on a trapeze plate-fin heat sink performance

2021 ◽  
pp. 095440892110059
Author(s):  
Özgür Özdilli ◽  
Seyfi Şevik
Keyword(s):  
Heat Transfer ◽  
Thermal Performance ◽  
Heat Sink ◽  
Channel Model ◽  
Rectangular Channel ◽  
Heat Sinks ◽  
Junction Temperature ◽  
Base Temperature ◽  
Thermal Enhancement ◽  
Standard Plate

This study aims to achieve a minimum base temperature (or junction temperature) and hence better thermal performance. Trapezoidal curved plate-fin heat sink with dolphin fins and rectangular channel (Model-1) and trapezoidal curved plate-fin heat sink with dolphin fins, cut corner, and rectangular channel (Model-2) were designed and compared with a standard plate-fin heat sink. The effects of fins on the airflow and heat transfer in designed plate-fin heat sinks have been investigated numerically. The numeric results show that the use of fins and small changes in geometry significantly improve the heat transfer rate. Outcomes of the study showed 44–51% and 57–62% convective heat transfer enhancement compared with a standard plate-fin heat sink, without any overall mass augmentation, in Model-1 and Model-2, respectively. The presence of dolphin fins reduces the thermal resistance by up to 30%, which contributes to the overall thermal enhancement of the designed plate-fin heat sinks. Simulation results show that increasing the fins in areas close to the heat source and reducing the non-working areas significantly influence the thermal performance of heat sinks. The results also show that the trapeze plate-fin heat sinks with the different channel-fin geometries are superior to the standard trapeze plate-fin heat sink in thermal performance.

Sign in / Sign up

Export Citation Format

Share Document