scholarly journals The effectiveness of secondary channel on the performance of hybrid microchannel heat sink at low pumping power

2019 ◽  
Vol 469 ◽  
pp. 012032 ◽  
Author(s):  
W M A A Japar ◽  
N A C Sidik
Keyword(s):  
Heat Sink ◽  
Microchannel Heat Sink ◽  
Pumping Power ◽  
Secondary Channel

THERMAL AND HYDRODYNAMIC PERFORMANCE OF A MICROCHANNEL HEAT SINK COOLED WITH CARBON NANOTUBES NANOFLUID

2016 ◽  
Vol 78 (10-2) ◽  
Author(s):  
Nik Ahmad Faiz Nik Mazlam ◽  
Normah Mohd-Ghazali ◽  
Thierry Mare ◽  
Patrice Estelle ◽  
Salma Halelfadl
Keyword(s):  
Thermal Resistance ◽  
Heat Sink ◽  
Operating Temperature ◽  
Heat Removal ◽  
Hydrodynamic Performance ◽  
Spherical Particles ◽  
Microchannel Heat Sink ◽  
Pumping Power ◽  
Rectangular Microchannel ◽  
Aspect Ratios

The microchannel heat sink (MCHS) has been established as an effective heat removal system in electronic chip packaging. With increasing power demand, research has advanced beyond the conventional coolants of air and water towards nanofluids with their enhanced heat transfer capabilities. This research had been carried out on the optimization of the thermal and hydrodynamic performance of a rectangular microchannel heat sink (MCHS) cooled with carbon nanotube (CNT) nanofluid, a coolant that has recently been discovered with improved thermal conductivity. Unlike the common nanofluids with spherical particles, nanotubes generally come in cylindrical structure characterized with different aspect ratios. A volume concentration of 0.1% of the CNT nanofluid is used here; the nanotubes have an average diameter and length of 9.2 nm and 1.5 mm respectively. The nanofluid has a density of 1800 kg/m3 with carbon purity 90% by weight having lignin as the surfactant. The approach used for the optimization process is based on the thermal resistance model and it is analyzed by using the non-dominated sorting multi-objective genetic algorithm. Optimized outcomes include the channel aspect ratio and the channel wall ratio at the optimal values of thermal resistance and pumping power. The optimized results show that, at high operating temperature of 40°C the use of CNT nanofluid reduces the total thermal resistance by 3% compared to at 20°C and consequently improve the thermal performance of the fluid. In terms of the hydrodynamic performance, the pumping power is also being reduced significantly by 35% at 40°C compared to the lower operating temperature.  

Multi Objective Optimization of a Force Fed Microchannel Heat Sink

2009 ◽  
Author(s):  
Edvin Cetegen ◽  
Serguei Dessiatoun ◽  
Michael Ohadi
Keyword(s):  
Heat Transfer ◽  
Heat Sink ◽  
Microchannel Heat Sink ◽  
Pumping Power ◽  
Optimization Scheme ◽  
Pressure Drops ◽  
Multi Objective ◽  
Flow Parameters ◽  
Multi Objective Genetic Algorithm ◽  
Meta Modeling

An approximation assisted optimization (AAO) method was used to optimize the geometry and flow parameters of a Force Fed Microchannel Heat Sink (FFMHS). Numerical simulation solvers were combined with the chosen optimization scheme to obtain the design points. A Kriging meta-modeling was applied to optimize the problem using Multi Objective Genetic Algorithm. The optimum results were compared with optimum designs of a well known traditional microchannel heat sink for a 1 × 1 cm2 base heat transfer area. It is demonstrated that for a constant pumping power, force fed microchannel heat design sink can achieve 65% more heat transfer on average. For a given thermal performance, the pressure drops associated with FFMHS represent only a fraction of the pumping power required by a traditional microchannel heat sink.

Fluid Flow and Thermal Characteristics of a Microchannel Heat Sink Subject to an Impinging Air Jet

2004 ◽  
Vol 127 (7) ◽  
pp. 770-779 ◽  
Author(s):  
Seok Pil Jang ◽  
Sung Jin Kim
Keyword(s):  
Fluid Flow ◽  
Pressure Drop ◽  
Heat Sink ◽  
Thermal Characteristics ◽  
Impinging Jet ◽  
Microchannel Heat Sink ◽  
Pumping Power ◽  
Cooling Performance ◽  
Air Jet ◽  
Temperature Distributions

In the present study, fluid-flow and heat-transfer characteristics of a microchannel heat sink subject to an impinging jet are experimentally investigated. In order to evaluate the cooling performance of a microchannel heat sink subject to an impinging jet under the condition of fixed pumping power, the pressure drop across the heat sink and temperature distributions at its base are measured. Specifically, a microthermal sensor array is fabricated and used to accurately measure temperature distributions at the base of the heat sink. Based on these experimental results, a correlation for the pressure drop across a microchannel heat sink subject to an impinging jet and a correlation for its thermal resistance are suggested. In addition, it is shown that the cooling performance of an optimized microchannel heat sink subject to an impinging jet is enhanced by about 21% compared to that of the optimized microchannel heat sink with a parallel flow under the fixed-pumping-power condition.

scholarly journals A Computational Fluid Dynamic Study on Efficiency of a Wavy Microchannel/Heat Sink Containing Various Nanoparticles

Micromachines ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1192
Author(s):  
Yacine Khetib ◽  
Hala M. Abo-Dief ◽  
Abdullah K. Alanazi ◽  
S. Mohammad Sajadi ◽  
Mohsen Sharifpur ◽  
...  
Keyword(s):  
Heat Sink ◽  
Figure Of Merit ◽  
Fluid Dynamic ◽  
Reynolds Numbers ◽  
Microchannel Heat Sink ◽  
Pumping Power ◽  
Two Phase ◽  
Volume Percentage ◽  
The Common ◽  
Maximum Temperatures

In this paper, a common and widely used micro-heat sink (H/S) was redesigned and simulated using computational fluid dynamics methods. This H/S has a large number of microchannels in which the walls are wavy (wavy microchannel heat sink: WMCHS). To improve cooling, two (Al2O3 and CuO) water-based nanofluids (NFs) were used as cooling fluids, and their performance was compared. For this purpose, studies were carried out at three Reynolds numbers (Re) of 500, 1000, and 1500 when the volume percent (φ) of the nanoparticles (NPs) was increased to 2%. The mixture two-phase (T-P) model was utilized to simulate the NFs. Results showed that using the designed WMCHS compared to the common H/S reduces the average and maximum temperatures (T-Max) up to 2 °C. Moreover, using the Al2O3 NF is more suitable in terms of WMCHS temperature uniformity as well as its thermal resistance compared to the CuO NF. Increasing the φ is desirable in terms of temperature, but it enhances the pumping power (PP). Besides, the Figure of Merit (FOM) was investigated, and it was found that the value is greater at a higher volume percentage.

Performance Evaluation of Concentrated Photovoltaic System Using a Microchannel Heat Sink

2016 ◽  
Author(s):  
Ali Radwan ◽  
Mahmoud Ahmed ◽  
Shinichi Ookawara
Keyword(s):  
Solar Cell ◽  
Mass Flow Rate ◽  
Double Layer ◽  
Mass Flow ◽  
Flow Rate ◽  
Heat Sink ◽  
Single Layer ◽  
Microchannel Heat Sink ◽  
Pumping Power ◽  
Cell Temperature

The high incident heat flux on the concentrated photovoltaic (CPV) system causes a significant increase in the cell temperature and thus reduces the system efficiency. Therefore, using an efficient cooling technique is of great importance for those systems. In the present study, a new technology for concentrated photovoltaic systems is introduced using a truncated-double layer microchannel heat sink. A comprehensive three-dimensional thermo-fluid model for the photovoltaic layers integrated with a microchannel heat sink was developed. The proposed model was simulated numerically to estimate the solar cell temperature, temperature uniformity, cooling system pumping power, electrical efficiency and thermal efficiency of the CPV system. The numerical results were validated with the available experimental, analytical and numerical results in the literature. In the designed heat sink, various design parameters are investigated such as the truncation length, cooling mass flow rate, concentration ratio, and converging width ratio of the flow channel. Results indicate that increasing the truncated length leads to an increase of solar cell temperature at a constant coolant mass flow rate. The cell temperature varies between 80.1°C and 146.5°C as the truncation length ratio increases from 0 (i.e. single layer microchannel) to 1 respectively at a concentration ratio (CR) of 40 and a cooling mass flow rate (ṁ) of 26.6 g/min. Using the double layer microchannel reduces the consumed pumping power at the same total mass flow rate compared to the single layer microchannel. The Double layer configuration with a truncation length ratio (l/lsc) equal to unity achieves a lower pumping power and solar cell temperature uniformity in comparison to the single layer microchannel.

Numerical Modelling of Nanofluid Heat Transfer Inside a Microchannel Heat Sink

2012 ◽  
Author(s):  
Benjamin Rimbault ◽  
Cong Tam Nguyen ◽  
Nicolas Galanis
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Heat Sink ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Convective Heat Transfer Coefficient ◽  
Microchannel Heat Sink ◽  
Pumping Power ◽  
Particle Volume ◽  
Number Range

The problem of laminar flow and heat transfer of water-based nanofluids inside a 3D-microchannel heat sink was numerically investigated, considering temperature-dependent fluids properties. Results, obtained for the 250–2000 Reynolds number range, show that an important enhancement of surface convective heat transfer coefficient can be achieved by increasing the particle volume fraction. For given Reynolds number and particle fraction, a highest heat transfer enhancement is obtained using CuO-water nanofluid. However, the use of nanofluids considerably increases the wall friction and consequently the pumping power. The ‘heat transferred to fluid/pumping power’ ratio was calculated for nanofluids. For given Reynolds number and particle volume fraction, such a ratio was found lowest for CuO-water nanofluid, while alumina-water nanofluids provide similar results.

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