scholarly journals Evaluation and Optimization of a Cross-Rib Micro-Channel Heat Sink

Micromachines ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 132
Author(s):  
Haiying Chen ◽  
Chuan Chen ◽  
Yunyan Zhou ◽  
Chenglin Yang ◽  
Gang Song ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Aspect Ratio ◽  
Heat Sink ◽  
Heat Dissipation ◽  
Junction Temperature ◽  
Micro Channel ◽  
Test Chip ◽  
Thermal Test ◽  
Micro Channels ◽  
The Cross

This article presents a novel cross-rib micro-channel (MC-CR) heat sink to make fluid self-rotate. For a thermal test chip (TTC) with 100 w/cm2, the cross-ribs micro-channel were compared with the rectangular (MC-R) and horizontal rib micro-channel (MC-HR) heat sinks. The results show that, with the cross-rib micro-channel, the junction temperature of the thermal test chip was 336.49 K, and the pressure drop was 22 kPa. Compared with the rectangular and horizontal ribs heat sink, the cross-rib micro-channel had improvements of 28.6% and 14.3% in cooling capability, but the pressure drop increased by 10.7-fold and 5.5-fold, respectively. Then, the effects of the aspect ratio (λ) of micro-channel in different flow rates were studied. It was found that the aspect ratio and cooling performance were non-linear. To reduce the pressure drop, the inclination (α) and spacing (S) of the cross-ribs were optimized. When α = 30°, S = 0.1 mm, and λ = 4, the pressure drop was reduced from 22 kPa to 4.5 kPa. In addition, the heat dissipation performance of the rectangular, staggered fin (MC-SF), staggered rib (MC-SR) and cross-rib micro-channels were analyzed in the condition of the same pressure drop, MC-CR still has superior heat dissipation performance.

Effect of Inlet Plenum on Pressure Drop and Velocity in Fractal Micro Channels

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Gurjit Singh ◽  
S.S. Sehagal
Keyword(s):  
Reynolds Number ◽  
Pressure Drop ◽  
Aspect Ratio ◽  
Constant Velocity ◽  
Computational Analysis ◽  
Three Dimensional ◽  
Micro Channel ◽  
Ratio Model ◽  
Micro Channels ◽  
Inner Channel

The computational analysis for micro channel flow in a branched network was investigated by three dimensional CFD approach. The effect of the change of Inlet Plenum (IP) size at a constant Aspect Ratio (AR) of the outermost channel on pressure drop in a fractal branched micro channel was performed. The properties are compared along a particular path and it was observed that the pressure drop along a bifurcated path has considerably less effect when compared to that of the outer most straight branched channel for a constant aspect ratio model. Pressure does not change significantly if we change the IP radius even when all other parameters are constant. Velocity in the inner channel after a straight run has reduced significantly even for same AR and Reynolds Number (Re). This leads to the conclusion that the IP size affects the velocity after the bifurcation.

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

scholarly journals Impact of Channel Geometries and Flow Patterns On Micro-Channel Heat Sink Performance

2019 ◽  
Vol 8 (11) ◽  
pp. 331-336
Keyword(s):  
Heat Transfer ◽  
Heat Sink ◽  
Heat Dissipation ◽  
Volume Ratio ◽  
Nucleate Boiling ◽  
Flow Patterns ◽  
Micro Channel ◽  
Micro Channels ◽  
Extended Surface ◽  
Vapour Quality

Demand for greater capability of electronic devices in very small volume for compactness has affected huge augmentations in heat indulgence at all stages of device, electronic wrapping, test section and system. Latest cooling systems are hence needed to eliminate the released heat while maintaining compactness of the device. The micro-channel heat sink (MCHS) is ideal for this situation as it consists of channels of micron size which offers an extended surface area to volume ratio of approximately 15.294 m2 / m3 compared to 650 m2 / m3 for a typical heat compact exchanger. A comprehensive review has been done for consequence of heat flux (qo ), mass flux (G), vapour quality (x) and channel geometries at flow patterns and heat dissipation of MCHS. The study show that to increase the rate of heat transfer by using different channel geometries like converging-diverging, segmented etc. compared to conventional rectangular micro-channels has given better cooling effect The Flow patterns like bubbly, slug flow are associated with nucleate boiling dominated in low vapour quality and annular flow also given the significant effect on heat transfer in higher vapour quality region

scholarly journals Heat Dissipation Performance of Micro-channel Heat Sink with Various Protrusion Designs

2021 ◽  
Vol 20 ◽  
pp. 240-249
Author(s):  
Siyuan Bai ◽  
Khalil Guy ◽  
Yuxiang Jia ◽  
Weiyi Li ◽  
Qingxia Li ◽  
...  
Keyword(s):  
Porous Medium ◽  
Partial Differential Equations ◽  
Differential Equations ◽  
Heat Sink ◽  
Heat Dissipation ◽  
Volume Averaging ◽  
Micro Channel ◽  
Partial Differential ◽  
Micro Channels ◽  
Pin Fins

This research will focus on studying the effect of aperture size and shape of the micro-channel heat sink on heat dissipation performance for chip cooling. The micro-channel heat sink is considered to be a porous medium with fluid subject inter-facial convection. Derivation based on energy equation gives a set of governing partial differential equations describing the heat transfer through the micro-channels. Numerical simulation, including steady-state thermal analysis based on CFD software, is used to create a finite element solver to tackle the derived partial differential equations with properly defined boundary conditions related to temperature. After simulating three types of heat sinks with various protrusion designs including micro-channels fins, curly micro-channels fins, and Micro-pin fins, the result shows that the heat sink with the maximum contact area per unit volume will have the best heat dissipation performance, we will interpret the result by using the volume averaging theorem on the porous medium model of the heat sink.

Two-Phase Flow and Heat Transfer in Rectangular Micro-Channels

2003 ◽  
Author(s):  
Weilin Qu ◽  
Seok-Mann Yoon ◽  
Issam Mudawar
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Flow Pattern ◽  
Two Phase Flow ◽  
Flow Patterns ◽  
Heat Sinks ◽  
Phase Flow ◽  
Micro Channel ◽  
Two Phase ◽  
Micro Channels

Knowledge of flow pattern and flow pattern transitions is essential to the development of reliable predictive tools for pressure drop and heat transfer in two-phase micro-channel heat sinks. In the present study, experiments were conducted with adiabatic nitrogen-water two-phase flow in a rectangular micro-channel having a 0.406 × 2.032 mm cross-section. Superficial velocities of nitrogen and water ranged from 0.08 to 81.92 m/s and 0.04 to 10.24 m/s, respectively. Flow patterns were first identified using high-speed video imaging, and still photos were then taken for representative patterns. Results reveal that the dominant flow patterns are slug and annular, with bubbly flow occurring only occasionally; stratified and churn flow were never observed. A flow pattern map was constructed and compared with previous maps and predictions of flow pattern transition models. Annual flow is identified as the dominant flow pattern for conditions relevant to two-phase micro-channel heat sinks, and forms the basis for development of a theoretical model for both pressure drop and heat transfer in micro-channels. Features unique to two-phase micro-channel flow, such as laminar liquid and gas flows, smooth liquid-gas interface, and strong entrainment and deposition effects are incorporated into the model. The model shows good agreement with experimental data for water-cooled heat sinks.

Enhancement of Heat Transfer of Rectangular Saw Tooth Shaped Micro Channel Heat Sink with Water Nano Fluid/Aluminium Oxide

2015 ◽  
Vol 813-814 ◽  
pp. 685-689
Author(s):  
M. Vijay Anand Marimuthu ◽  
B. Venkatraman ◽  
S. Kandhasamy
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Nusselt Number ◽  
Pressure Drop ◽  
Heat Sink ◽  
Micro Channel ◽  
Performance Curve ◽  
Theoretical Level ◽  
Enhancement Of Heat Transfer ◽  
Nano Fluid

This paper investigates the performance and characteristics of saw tooth shape micro channel in the theoretical level. If the conduct area of the nano fluid increases the heat transfer also increases. The performance curve has drawn Reynolds number against nusselt number, heat transfer co efficient. Pressure drop plays an important role in this device. If pressure drop is high the heat transfer increases. The result in this experiment shows clearly that the heat transfer is optimized.

Optimized High-Aspect-Ratio Diffusional Micromixers

2008 ◽  
Author(s):  
Amit Maha ◽  
Vamsidhar Palaparthy ◽  
Steven A. Soper ◽  
Michael C. Murphy ◽  
Dimitris E. Nikitopoulos
Keyword(s):  
Pressure Drop ◽  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Optimization Procedure ◽  
Main Stream ◽  
Total Production ◽  
Production Time ◽  
Operating Condition ◽  
Micro Channels ◽  
Mixture Volume

This part of our work has been aimed at designing, manufacturing and characterizing effective micro-mixers which are cheap, durable and easily integrated on a variety of bio-chips with emphasis on those performing Polymerese Chain Reactions (PCR) and Ligase Detection Reactions (LDR). A key contribution is the development of an optimization procedure for the design of passive micro-mixers utilizing high-aspect-ratio micro-channels (HARMC). The optimization procedure identifies the optimum type of mixer on the basis of the flow rate proportions of the mixture constituents and provides for two optimum designs of the selected mixer type for an aspect ratio of choice in two ways: (a) for specified mixture volume and mixer pressure drop the optimum mixer dimensions and operating condition minimize the total production time and (b) for specified mixture volume and a total production time the optimum mixer dimensions and operating condition minimize the mixer pressure drop. The simplest and easiest to manufacture layout of an optimized mixer configuration (X2JC) with two inlet ports and three layers is shown in Figure 1. The injection of compound 1 into the compound 2 main stream is performed through two side-jets in a wider channel to further reduce the pressure loss overhead followed by a contraction into the main mixing channel.

The Effect of Parameter Changes to the Performance of a Triangular Shape Interrupted Microchannel Heat Sink

2012 ◽  
Vol 58 (2) ◽  
Author(s):  
Fudhail Abd Munir ◽  
Mohd Irwan Mohd Azmi ◽  
Nadlene Razali ◽  
Ernie Mat Tokit
Keyword(s):  
Contact Angle ◽  
Pressure Drop ◽  
Heat Sink ◽  
Heat Dissipation ◽  
Thermal Dissipation ◽  
Working Fluid ◽  
Uniform Heat Flux ◽  
Length Width ◽  
Fluent Software ◽  
Phase Water

The effect of parameter changes on triangular shaped interrupted microchannel performance was studied by simulation using FLUENT software. The parameters that were studied are total length, and the contact angle. On the other hand, the investigated effects were pressure drop and platinum film temperature. The flow in microchannel is laminar and single phase. Water was used as the working fluid and the interrupted microchannel is made of silicon. A thin platinum film plate was deposited to provide uniform heat flux. The geometry dimension of the heat sink is 30 mm in length, width of 7 mm and the thickness of 0.525 mm. From the simulation results, it is found that the improvement on heat dissipation may be achieved by increasing the microchannel length at the expense of increase in pressure drop. In addition to that, by reducing the contact angle will result to reduction in term of pressure drop and increases the improvement thermal dissipation.

Experimental Studies of Pressure Drop and Flow Instability in Evaporative Micro-Channels

2008 ◽  
Author(s):  
Hee Joon Lee ◽  
Dongyao Liu ◽  
Shi-Chune Yao
Keyword(s):  
Pressure Drop ◽  
Flow Instability ◽  
Experimental Studies ◽  
Bond Number ◽  
Effective Length ◽  
Instability Criterion ◽  
Micro Channel ◽  
Micro Channels ◽  
Wide Range ◽  
Channel Systems

Experiments were conducted on evaporative micro-channel systems of water, containing 48 parallel channels of 353 μm hydraulic diameter. The general correlation of two-phase pressure drop for an initial design purpose of evaporative micro-channel systems reported in [1] has been validated. For the water boiling in micro-channels, flow instability was observed. The instability criterion, proposed by Kandlikar [2], is able to predict the water experimental results. However, further examination of his criterion revealed that it can not predict the results of Brutin and Tadrist’s data of n-pentane. This is because the Bond number of water is 0.01, but 0.33 for n-pentane. As a result, the growing bubble of n-pentane may not cover the whole length of the micro-channel. A general expression of the effective length of squeezed bubbles in micro-channel was established for fluids at a wide range of Bond number. Using this proposed effective length, the Brutin and Tadrist’s experimental instability data can also be predicted satisfactorily.

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