Investigation of Cooling Performance of a Swirl Microchannel Heat Sink by Numerical Simulation

Author(s):  
Yanfeng Fan ◽  
Ibrahim Hassan

High heat fluxes have been created by the semiconductor devices due to the high power generation and shrank size. The large heat flux causes the circuit to exceed its allowable temperature and may experience both working efficiency loss and irreversible damage due to excess in their temperatures. In this paper, a swirl microchannel heat sink is designed to dissipate the large heat flux from the devices. The numerical simulation is carried out to investigate the cooling performance. Uniform heating boundary condition is applied and single phase water is selected as coolant. The present micro heat sink applies multiple swirl microchannels positioned in a circular flat plate to enhance the heat convection by creating the secondary flow at high Reynolds numbers. Copper is selected as the material of heat sink. The channel depth and width are fixed as 0.5 mm and 0.4 mm, respectively. The heat is injected into the system from the bottom of heat sink at the heat fluxes from 10 to 60 W/cm2. Flow is supplied from the top of micro heat sink through a jet hole with a diameter of 2 mm and enters swirl microchannels at the volume flow rates varying from 47 to 188 ml/min. The cooling performances of swirl microchannel heat sinks with different curvatures and channel numbers are evaluated based on the targets of low maximum temperature, temperature gradient and pressure drop.

Author(s):  
Yanfeng Fan ◽  
Ibrahim Hassan

A novel micro heat sink applying the jet-impingement and cross flow is proposed to dissipate the heat from the electrical devices. Six hotspots of 2 mm × 2 mm are positioned on a flat plate of 25.4 mm × 25.4 mm. The area of flat plate except the hotspots is provided a constant heat flux of 20 W/cm2 as background heating source among cases. Four heat fluxes from 40 to 100 W/cm2 on the hotspots are tested to simulate the different operation conditions. The cross flow is used to remove the background heat flux and jet flow is supplied into the swirl microchannel, located at the right top of hotspot, to dissipate the large heat flux from hotspots. The channel depth is 0.5 mm and the width of swirl microchannel is 0.38 mm. The cross flow and jet flow velocity vary from 0.1 m/s to 0.5 m/s and from 0.5 m/s to 2 m/s, respectively. The effects of cross flow and jet flow on the cooling performance are investigated by numerical simulation. The local heat transfer coefficient and Nusselt number are calculated to evaluate the cooling performance of proposed micro heat sink for the targets of low maximum temperature, temperature gradient and pressure drop. The results show that the maximum temperature of the proposed design occurred at the outlet is approximately 65 °C among tested cases. The corresponding pressure drop is 5.5 kPa. The overall thermal resistance reaches as small as 0.23 K/W.


2013 ◽  
Vol 455 ◽  
pp. 466-469
Author(s):  
Yun Chuan Wu ◽  
Shang Long Xu ◽  
Chao Wang

With the increase of performance demands, the nonuniformity of on-chip power dissipation becomes greater, causing localized high heat flux hot spots that can degrade the processor performance and reliability. In this paper, a three-dimensional model of the copper microchannel heat sink, with hot spot heating and background heating on the back, was developed and used for numerical simulation to predict the hot spot cooling performance. The hot spot is cooled by localized cross channels. The pressure drop, thermal resistance and effects of hot spot heat flux and fluid flow velocity on the cooling of on-chip hot spots, are investigated in detail.


2021 ◽  
Vol 1163 ◽  
pp. 73-88
Author(s):  
Md Tanbir Sarowar

Microchannel heat sink plays a vital role in removing a considerable amount of heat flux from a small surface area from different electronic devices. In recent times, the rapid development of electronic devices requires the improvement of these heat sinks to a greater extent. In this aspect, the selection of appropriate substrate materials of the heat sinks is of vital importance. In this paper, three boron-based ultra-high temperature ceramic materials (ZrB2, TiB2, and HfB2) are compared as a substrate material for the microchannel heat sink using a numerical approach. The fluid flow and heat transfer are analyzed using the finite volume method. The results showed that the maximum temperature of the heat source didn’t exceed 355K at 3.6MWm-2 for any material. The results also indicated HfB2 and TiB2 to be more useful as a substrate material than ZrB2. By applying 3.6 MWm-2 heat flux at the source, the maximum obtained surface heat transfer coefficient was 175.2 KWm-2K-1 in a heat sink having substrate material HfB2.


2015 ◽  
Vol 137 (4) ◽  
Author(s):  
Craig Green ◽  
Peter Kottke ◽  
Xuefei Han ◽  
Casey Woodrum ◽  
Thomas Sarvey ◽  
...  

Three-dimensional (3D) stacked electronics present significant advantages from an electrical design perspective, ranging from shorter interconnect lengths to enabling heterogeneous integration. However, multitier stacking exacerbates an already difficult thermal problem. Localized hotspots within individual tiers can provide an additional challenge when the high heat flux region is buried within the stack. Numerous investigations have been launched in the previous decade seeking to develop cooling solutions that can be integrated within the 3D stack, allowing the cooling to scale with the number of tiers in the system. Two-phase cooling is of particular interest, because the associated reduced flow rates may allow reduction in pumping power, and the saturated temperature condition of the coolant may offer enhanced device temperature uniformity. This paper presents a review of the advances in two-phase forced cooling in the past decade, with a focus on the challenges of integrating the technology in high heat flux 3D systems. A holistic approach is applied, considering not only the thermal performance of standalone cooling strategies but also coolant selection, fluidic routing, packaging, and system reliability. Finally, a cohesive approach to thermal design of an evaporative cooling based heat sink developed by the authors is presented, taking into account all of the integration considerations discussed previously. The thermal design seeks to achieve the dissipation of very large (in excess of 500 W/cm2) background heat fluxes over a large 1 cm × 1 cm chip area, as well as extreme (in excess of 2 kW/cm2) hotspot heat fluxes over small 200 μm × 200 μm areas, employing a hybrid design strategy that combines a micropin–fin heat sink for background cooling as well as localized, ultrathin microgaps for hotspot cooling.


Author(s):  
J. M. Wu ◽  
J. Y. Zhao

High power electronics are widely used in many different areas such as integrated circuit (IC) boards in nuclear reactor control system. Thermal management of electronic devices has been a topic of great interest among many researchers over the last few decades. Microchannel is one of several high-heat-flux removal techniques. Nanofluids with enhanced thermal conductivity and strong temperature- and size-dependent thermal properties are expected to be utilized in microchannels as coolants, which leads to a promising future for such high-heat-flux systems as cooling systems. The performance of the microchannel heat sink (MCHS) using water and Al2O3/water nanofluids, with consideration of different substrate materials, is numerically investigated and compared in the present paper to identify the combined effects of working fluids and substrate materials on the thermal resistance, pumping power and temperature distribution on the substrate surface of a heat sink.


Author(s):  
Chang-Nian Chen ◽  
Ji-Tian Han ◽  
Wei-Ping Gong ◽  
Tien-Chien Jen

High heat flux is very dangerous for electronic heat transfer, such as IGBT (Insulated Gate Bipolar Transistor) cooling. In order to explore and master the heat transfer and hydraulic characteristics for IGBT cooling, experiments have been carried out to study the situation mentioned above in a flat plate heat sink, which was designed for high heat flux IGBT cooling. The geometrical parameters of the test section are as follows: outline dimension 229 mm × 124 mm × 30 mm; flow channels of 229 mm × 3 mm × 4 mm in total of 20. The experiments performed at atmospheric pressure and with inlet temperatures of 25–35°C, heat fluxes of 3.5–18.9 kW/m2. The influence of temperatures, heat fluxes on IGBT surface temperature and the cooling effect of the liquid cold plate have been investigated under a range of flow rates of 280–2300 kg/m2s. It was found that the heat transfer enhancement was very obvious using this kind of small sized channel for IGBT cooling, which was tens of times of the effect than air cooling or triple of the effect than that in normal sized channels. And the heat transfer enhancement increases with increasing heat fluxes and flow rates, while it decreases with increasing inlet temperatures. Most of the experimental results show good cooling effect as expected. However, it is dangerous for the cooling system under high heat fluxes when the system starts or stops suddenly, when the Respond Time (RT) is less than 5 seconds to cut off heated power. Also, the cooling performance is bad when the heat fluxes increased greatly, which is considered as abnormal situation in operating. The effect on IGBT surface temperature of heat flux is more obvious when the average Nusselt Number is smaller. For hydraulic characteristics observed, it was found that the flow friction increased with flow rates increasing, but the pressure drops of heated flow channels ahead were slightly larger than those back, especially under large flow rates conditions. That is because the temperatures of flow heated in channels ahead are lower than those back, which causes the fluid viscosity to be higher. At last, this paper suggested a series of method for enhancing heat transfer in flat plate heat sink, and also gave some ways to avoid heat transfer dangerous situations for IGBT cooling, which can provide a basis for thermodynamic and hydraulic calculation of flat plate heat sink design and lectotype.


2006 ◽  
Vol 129 (7) ◽  
pp. 844-851 ◽  
Author(s):  
Ali Koşar ◽  
Yoav Peles

Critical heat flux (CHF) of R-123 in a silicon-based microchannel heat sink was investigated at exit pressures ranging from 227kPato520kPa. Critical heat flux data were obtained over effective heat fluxes ranging from 53W∕cm2to196W∕cm2 and mass fluxes from 291kg∕m2sto1118kg∕m2s. Flow images and high exit qualities suggest that dryout is the leading CHF mechanism. The effect of mass velocity, exit quality, and system pressure were also examined, and a new correlation is presented to represent the effect of these parameters.


2020 ◽  
Vol 18 ◽  
pp. 100587
Author(s):  
Essam M. Abo-Zahhad ◽  
Shinichi Ookawara ◽  
Ali Radwan ◽  
M.F. Elkady ◽  
A.H. El-Shazly

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