scholarly journals Numerical assessment on heat transfer performance of double-layered oblique fins microchannel heat sink with Al2O3 nanofluid

2021 ◽  
pp. 142-142
Author(s):  
Ji Choong ◽  
Kok Yu ◽  
Mohd Abdullah
Keyword(s):  
Heat Transfer ◽  
Thermal Resistance ◽  
Heat Sink ◽  
Heat Transfer Performance ◽  
Volume Fraction ◽  
Numerical Study ◽  
Al2o3 Nanoparticles ◽  
Microchannel Heat Sink ◽  
Transfer Performance ◽  
Primary Channel

This paper demonstrates a numerical study on heat transfer characteristics of laminar flow in a double-layered oblique finned heat sink using nanofluids with Al2O3 nanoparticles. Microchannel heat sink with primary channel width of 0.5 mm with aspect ratio of 3 is employed. Instead of having conventional straight fins, oblique fins with narrow secondary channels are used. In this numerical study, single-phase fluid model with conjugate heat transfer is considered. The numerical modelling was first validated with existing data for double-layered conventional microchannel heat sink having water (base fluid) as the working fluid. Numerical investigations on oblique finned microchannel heat sink were then conducted for flow rates ranging from 3?10-7 to 15?10-7 m3/s, equivalent to primary channel inlet velocity in between 0.2 and 1.0 m/s. It was found that double-layered oblique finned configuration yields better heat transfer performance, inferred by the lower overall thermal resistance obtained as compared with that of double-layered conventional heat sink. Employing double-layered oblique finned heat sink, the heat transfer performance could be further enhanced, by using nanoparticles that are added into water-based fluid. It is found that the reduction of overall thermal resistance is proportional to the volume fraction of nanoparticles. Using cross flow double-layered oblique finned configuration, the largest reduction in the overall thermal resistance can reach up to 25%, by using nanofluids with 4% volume fraction of Al2O3 nanoparticles.

Numerical Study of Forced Convection of Nanofluids in a Microchannel Heat Sink

2008 ◽  
Author(s):  
Parisa Vaziee ◽  
Omid Abouali
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Sink ◽  
Volume Fraction ◽  
Numerical Study ◽  
Heat Removal ◽  
Al2o3 Nanoparticles ◽  
Microchannel Heat Sink ◽  
Particle Volume ◽  
Volume Fractions

Effectiveness of the microchannel heat sink cooled by nanofluids with various particle volume fractions is investigated numerically using the latest theoretical models for conductivity and viscosity of the nanofluids. Both laminar and turbulent flows are considered in this research. The model of conductivity used in this research accounts for the fundamental role of Brownian motion of the nanoparticles which is in good agreement with the experimental data. The changes in viscosity of the nanofluid due to temperature variation are considered also. Final results are compared with the experimental measurements for heat transfer coefficient and pressure drop in microchannel. Enhancement in heat transfer is achieved for laminar flow with increasing of volume fraction of Al2O3 nanoparticles. But for turbulent flow an enhancement of heat removal was not seen and using higher volume fractions of nanoparticles increases the maximum substrate temperature. Pressure drop is increased with using nanofluids because of the augmentation in the viscosity and this increase is more noticeable in higher Reynolds numbers.

Effects of Al2O3-Water Nanofluid and Angular Orientation on Entropy Generation and Convective Heat Transfer of an Elliptical Micro-Pin-Fin Heat Sink

2014 ◽  
Author(s):  
Husam Rajab ◽  
Da Yin ◽  
Hongbin Ma
Keyword(s):  
Heat Transfer ◽  
Entropy Generation ◽  
Heat Sink ◽  
Heat Transfer Performance ◽  
Volume Fraction ◽  
Al2o3 Nanoparticles ◽  
Transfer Performance ◽  
Enhancement Of Heat Transfer ◽  
Pin Fin ◽  
Prandtl Numbers

This paper presents an investigation of the effect of nanofluid on the heat transfer performance in an elliptical micro-pin-fin heat sink including the influence of entropy generation and pin orientation. The orientation angle of pins is decreased with the number of pins in the array with a 90 degree angle for the first pin and a 0 degree angle for the last pin. To study the flow and heat transfer behaviors in a micro-pin-fin heat sink, steady Navier-Stokes and energy equations were discretized using a finite volume approach and were solved iteratively. Deionized (DI) water was used as a base coolant fluid while aluminum oxide (Al2O3) nanoparticles were used in the present study with mean diameters of 41.6 nm. The results showed that (1) changing the angular orientation of pins can cause significant enhancement in heat transfer, (2) a significant enhancement of heat transfer can be attained in the system due to the suspension of Al2O3 nanoparticles in the base fluid in comparison with pure water, (3) enhancement of heat transfer is intensified with increasing volume fraction of nanoparticles and Reynolds and Prandtl numbers, (4) increasing volume fraction of nanoparticles, which is responsible for higher heat transfer performance, leads to a higher pressure drop, (5) using nanofluids as coolant can cause lower heat transfer entropy generation due to their high thermal properties, and (6) with increasing volume fraction and Reynolds and Prandtl numbers, overall entropy generation rate decreases.

Numerical Study on Mitigation of Flow Maldistribution in Parallel Microchannel Heat Sink: Channels Variable Width Versus Variable Height Approach

2019 ◽  
Vol 141 (2) ◽  
Author(s):  
Ritunesh Kumar ◽  
Gurjeet Singh ◽  
Dariusz Mikielewicz
Keyword(s):  
Heat Transfer ◽  
Heat Sink ◽  
Heat Transfer Performance ◽  
Numerical Study ◽  
Heat Sinks ◽  
Computational Time ◽  
Microchannel Heat Sink ◽  
Transfer Performance ◽  
Parallel Microchannels ◽  
Flow Maldistribution

Microchannel heat sink on one hand enjoys benefits of intensified several folds heat transfer performance but on the other hand has to suffer aggravated form of trifling limitations associated with imperfect hydrodynamics and heat transfer behavior. Flow maldistribution is one of such limitation that exaggerates temperature nonuniformity across parallel microchannels leading to increase in maximum base temperature. Recently, variable width channels approach had been proposed by the current authors to mitigate the flow maldistribution in parallel microchannels heat sinks (MCHS), and in the current numerical study, variable height approach is opted for flow maldistribution mitigation. It is found that variable height microchannels heat sinks (VHMCHS) approach mitigates flow maldistribution rapidly in comparison to variable width microchannels heat sinks (VWMCHS) approach, almost 50% computational time can be saved by VHMCHS approach. Average fluid–solid interface temperature fluctuation across parallel microchannels reduces 3.3 °C by VHMCHS in comparison to VWMCHS approach. The maximum and average temperatures of the base of the heat sink are further reduced by 5.1 °C and 2.7 °C, respectively, for the VHMCHS. It is found that overall heat transfer performance of the heat sink improves further by 3.8% and 5.1% for the VWMCHS and VHMCHS, respectively. The pressure drop penalty of the VHMCHS is found to be 7.2% higher than VWMCHS.

scholarly journals Simulation analysis of heat transfer performance of heat sink with reduced material design

2020 ◽  
Vol 12 (5) ◽  
pp. 168781402092130
Author(s):  
Ya-Chu Chang
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Thermal Resistance ◽  
Heat Sink ◽  
Heat Transfer Performance ◽  
Electronic Device ◽  
Local Heating ◽  
Transfer Performance ◽  
Electronic Components ◽  
Thermal Reliability

The field of electronic device applications is becoming more and more extensive. With the development of science and technology and the improvement of the integration of electronic components, local heating is becoming more and more serious. If heat cannot be discharged immediately, it will cause heat to accumulate, causing the temperature of each component to exceed the limit. The reliability of electronic equipment is greatly reduced. Especially in important fields such as military and aerospace, the thermal reliability of electronic components is higher. The research results show that increasing the Reynolds number is helpful to reduce the overall temperature and thermal resistance of the heat sink, but the increase of the Reynolds number and the decrease of the thermal resistance value are gradually flat. The design concept of material reduction has a significant impact on processing and cost. The results of this article show that selecting the appropriate heat sink fins and matching the specific Reynolds number can effectively improve the heat transfer performance of the heat sink.

Optimization of Flow and Heat Transfer for a New Double-Layered Microchannel Heat Sink

2019 ◽  
Author(s):  
Huanling Liu ◽  
Bin Zhang
Keyword(s):  
Heat Transfer ◽  
Heat Sink ◽  
Heat Transfer Performance ◽  
Microchannel Heat Sink ◽  
Transfer Performance ◽  
Temperature Uniformity ◽  
Flow And Heat Transfer ◽  
Fluent Simulation ◽  
New Type ◽  
Improved Design

Abstract In this paper, we propose a new type of DL-MCHS to improve the substrate temperature uniformity of the microchannel heat sink, and conduct the optimization of the New DL-MCHS. The heat transfer and friction characteristics of the novel DL-MCHS are studied by numerical simulation. We compare the heat transfer performance the new DL-MCHS with the traditional TDL-MCHS (the DL-MCHS with truncated top channels λ = 0.38). The results prove the effectiveness of the improved design by FLUENT simulation. When the inlet velocity is kept constant and coolant is water, the heat transfer performance of the New DL-MCHS is higher than that of TDL-MCHS leading to an increase of the temperature uniformity. In order to achieving the best overall heat transfer performance, an optimization of New DL-MCHS is performed by GA (genetic algorithm).

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