Hot-Spot Thermal Management With Flow Modulation in a Microchannel Heat Sink

2005 ◽  
Author(s):  
Poh-Seng Lee ◽  
Suresh V. Garimella
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Thermal Management ◽  
Heat Sink ◽  
Hot Spot ◽  
Microchannel Heat Sink ◽  
Transfer Enhancement ◽  
Local Enhancement ◽  
Flow Modulation ◽  
Flow And Heat Transfer

Recesses created in the lid of a microchannel heat sink can serve to modulate the flow, resulting in local and global heat transfer enhancement. Numerical analysis of laminar flow and heat transfer in such a modified microchannel heat sink has shown an augmentation of heat transfer without an added penalty of increased pressure drop. The presence of the recesses reduces the overall flow friction and thus pressure drop. The flow expansion into the recesses and the subsequent contraction into the downstream region causes significant local enhancement in heat transfer. Both the maximum and average wall temperatures are decreased as a result. The heat transfer is locally enhanced, by as much as 150% in the regions just downstream of the recesses due to the re-initialization of boundary layers as the flow re-enters the microchannels. The potential for hot-spot mitigation in microelectronics devices using this approach is discussed.

Heat Transfer Enhancement in a Microchannel Heat Sink with Trapezoidal Cavities on the Side Walls

2016 ◽  
Vol 819 ◽  
pp. 127-131
Author(s):  
Navin Raja Kuppusamy ◽  
N.N.N. Ghazali ◽  
Saidur Rahman ◽  
M.A. Omar Awang ◽  
Hussein A. Mohammed
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Sink ◽  
Heat Transfer Performance ◽  
Numerical Study ◽  
Flow Characteristics ◽  
Fluid Mixing ◽  
Microchannel Heat Sink ◽  
Transfer Enhancement ◽  
Side Walls

The present study focuses on the numerical study of thermal and flow characteristics in a microchannel heat sink with alternating trapezoidal cavities in sidewall (MTCS). The effects of flow rate and heat flux on friction factor and Nusselt are presented. The results showed considerable improvement heat transfer performance micro channel heat sink with alternating trapezoidal cavities in sidewall with an acceptable pressure drop. The heat transfer rate has improved in the cavity area due the greater fluid mixing in fluid vortices and thermal boundary layer disruption. The slipping over the reentrant cavities and pressure gain reduces pressure drop appears as the reason behind of only minor pressure drop due to the cavities.

Numerical Study of Fluid Flow and Heat Transfer in the Enhanced Microchannel With Oblique Fins

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Y. J. Lee ◽  
P. S. Lee ◽  
S. K. Chou
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Heat Transfer Enhancement ◽  
Heat Sink ◽  
Numerical Study ◽  
Leading Edge ◽  
Secondary Flows ◽  
Microchannel Heat Sink ◽  
Transfer Enhancement ◽  
Flow And Heat Transfer

Sectional oblique fins are employed in contrast to continuous fins in order to modulate flow in microchannel heat sink. The breakage of continuous fin into oblique sections leads to the reinitialization of both hydrodynamic and thermal boundary layers at the leading edge of each oblique fin, effectively reducing the thickness of boundary layer. This regeneration of entrance effect causes the flow to be always in a developing state thus resulting in better heat transfer. In addition, the presence of smaller oblique channels diverts a small fraction of flow into the adjacent main channels. The secondary flows thus created improve fluid mixing which serves to further enhance the heat transfer. Detailed numerical study on the fluid flow and heat transfer of this passive heat transfer enhancement technique provides insight to the local hydrodynamics and thermal development along the oblique fin. The uniquely skewed hydrodynamic and thermal profiles are identified as the key to the highly augmented and uniform heat transfer performance across the heat sink. The associated pressure drop penalty is much smaller than the achieved heat transfer enhancement, rendering it as an effective heat transfer enhancement scheme for single phase microchannel heat sink.

scholarly journals Effect of Taper Manifolds with Different Slopes in Microchannel Heat Sink

2019 ◽  
Vol 8 (12) ◽  
pp. 3988-3992
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Pressure Drop ◽  
Heat Sink ◽  
Microchannel Heat Sink ◽  
Micro Channel ◽  
Flow And Heat Transfer ◽  
Micro Channels ◽  
Upward Direction ◽  
Degree Slope

In this analysis, the liquid flow and heat transfer in micro channel heat sink (MCHS) to find the pressure drop are experimentally investigated by three degree slope in manifolds in addition to the arrangement of micro channels. This experimental analysis is executed with respect to the Nusselt Number and Heat transfer characteristics for three manifolds with different arrangement. We are working on this experiment at three different arrangement manifolds: Arrangement (A) is the three-degree slope in manifolds downward and upward, Arrangement (B) is the three-degree slope in manifolds upward and downward and Arrangement (C) is the three-degree slope in upward direction of the manifolds are selected. In this investigation we are using the Reynolds number ranging from 705-1411 for micro channel heat sink. The Arrangement (A) is the greater heat transfer coefficient within the increase Nusselt number and velocity and low pressure drop in comparison to Arrangement (B) and (C) type manifolds

Thermal Performance and Pressure Drop of Galinstan-Based Microchannel Heat-Sink for High Heat-Flux Thermal Management

2015 ◽  
Author(s):  
Yoshikazu Hayashi ◽  
Navid Saneie ◽  
Yoon Jo Kim ◽  
Jong-Hoon Kim
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Pressure Drop ◽  
Thermal Resistance ◽  
Specific Heat ◽  
Thermal Management ◽  
Heat Sink ◽  
Working Fluid ◽  
Microchannel Heat Sink ◽  
Pumping Power

We numerically investigated a novel galinstan-based microfluidic heat-sink. Galinstan is an eutectic alloys of gallium, indium, and tin. The thermal conductivity of galinstan is ∼27 times that of water, while the dynamic viscosity is only twice of water. Thus, heat transfer coefficient can be remarkably enhanced with a small penalty of pumping power. However, the specific heat of galinstan is significantly lower than that of water, which will inevitably undermine the cooling capability by increasing fluid outlet temperature (i.e., increase of caloric thermal management) and/or flow rate. As an alternative, therefore, galinstan/water heterogeneous mixture was proposed as a working fluid and the cooling performance was numerically explored with varying volume composition of galinstan. Effective medium theory for heterogeneous medium was used to evaluate the thermal conductivity of the mixture. The viscosity change with respect to the volume composition was also predicted considering both the viscosity of dispersed phase and interaction between the droplets. Classical models were used for the mixture density and specific heat calculations. Heat transfer and pressure drop characteristics of laminar flow through a silicon microchannel heat-sink was simulated using Fluent. The length and width of the channel array are 10 mm and 9.5 mm, respectively. The cross-sectional area of each channel is 300 μm × 300 μm and the spacing between channels is 100 μm. The heat dissipation was 50 W and the pumping power was fixed at 5 mW for the comparison between the varying galinstan/water compositions. The results showed that more than 30% of the thermal resistance enhancement was attainable using the novel working fluid. Due to the compromise between the convective thermal resistance (effect of thermal conductivity) and the caloric thermal resistance (effect of viscosity and specific heat), the lowest junction temperature was marked at the galinstan composition of ∼35% by volume.

scholarly journals Study on flow and heat transfer of liquid metal in a new top-slotted microchannel heat sink

2021 ◽  
Vol 621 ◽  
pp. 012054
Author(s):  
Zhiwei Chen ◽  
Peng Qian ◽  
Zizhen Huang ◽  
Chengyuan Luo ◽  
Minghou Liu
Keyword(s):  
Heat Transfer ◽  
Liquid Metal ◽  
Heat Sink ◽  
Microchannel Heat Sink ◽  
Flow And Heat Transfer

Compact Modeling of Fluid Flow and Heat Transfer in Straight Fin Heat Sinks

2004 ◽  
Vol 126 (2) ◽  
pp. 247-255 ◽  
Author(s):  
Duckjong Kim ◽  
Sung Jin Kim
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Fluid Flow ◽  
Pressure Drop ◽  
Heat Sink ◽  
Volume Averaging ◽  
Thermal Design ◽  
Heat Sinks ◽  
Compact Modeling ◽  
Flow And Heat Transfer

In the present work, a compact modeling method based on a volume-averaging technique is presented. Its application to an analysis of fluid flow and heat transfer in straight fin heat sinks is then analyzed. In this study, the straight fin heat sink is modeled as a porous medium through which fluid flows. The volume-averaged momentum and energy equations for developing flow in these heat sinks are obtained using the local volume-averaging method. The permeability and the interstitial heat transfer coefficient required to solve these equations are determined analytically from forced convective flow between infinite parallel plates. To validate the compact model proposed in this paper, three aluminum straight fin heat sinks having a base size of 101.43mm×101.43mm are tested with an inlet velocity ranging from 0.5 m/s to 2 m/s. In the experimental investigation, the heat sink is heated uniformly at the bottom. The resulting pressure drop across the heat sink and the temperature distribution at its bottom are then measured and are compared with those obtained through the porous medium approach. Upon comparison, the porous medium approach is shown to accurately predict the pressure drop and heat transfer characteristics of straight fin heat sinks. In addition, evidence indicates that the entrance effect should be considered in the thermal design of heat sinks when Re Dh/L>∼O10.

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