Analysis of thermal characteristics of nanofluid Enriched Microchannel Heat Sink (original) (raw)

Investigation of Thermal Properties of Microchannel Heat Sink with Nanofluid

2017

Advancement in micro and nano fabrication technologies eases to manufacture compact heat exchanger devices. The compact heat exchanger and heat transfer devices performance can drastically improved by using microchannel arrays along with use of nanofluids. The parametric analysis of semicircular microchannel heat sink with distilled water and different concentrations of Multiwalled carbon nanotubes is carried out theoretically along with experimentation. The theoretical design is carried out for Minimum thermal resistance, maximum heat transfer coefficient, minimum friction factor and pressure drop along with minimum entropy generation. The microchannels with 200 μm hydraulic diameters are prototyped on accurate wire cut EDM. The effect of heat fluxes and Reynolds number is observed on heat transfer coefficient and pressure drop in laminar region. The performance of IC system is achieved best under Reynolds number 550 to 750. The heat transfer enhancement is observed 39 % over pure ...

Thermal and Hydrodynamic Performance of a Microchannel Heat Sink Cooled with Carbon Nanotubes Nanofluid

Jurnal Teknologi, 2016

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 op...

Optimization of thermal performances and pressure drop of rectangular microchannel heat sink using aqueous carbon nanotubes based nanofluid

Applied Thermal Engineering, 2014

The present work focuses on analytical optimization of a rectangular microchannel heat sink using aqueous carbon nanotubes based nanofluid as coolant. The particles weight concentration used in this study is 0.01%. The density, the thermal conductivity and the rheological behavior of the nanofluid are experimentally investigated in order to evaluate the thermal resistance and the pumping power in microchannel under laminar flow. An analytical approach of optimization scheme was applied; it is compiled from a systematic thermal resistance model as an analysis method and the elitist non-dominated sorting genetic algorithm (NSGA2). The effects of the temperature, the channel aspect ratio, the channel wall ratio and the use of aqueous carbon nanotubes based nanofluid on the thermal resistance and the pumping power are investigated. The optimized results showed that use of the nanofluid as a working fluid reduce the total thermal resistance and can enhance significantly the thermal performances of the working fluid at high temperatures.

Study of microchannel heat sink performance with expanded microchannels and nanofluids

2016

In this paper a microchannel heat sink with expanded microchannels and nanofluids is numerically investigated. The object of this paper is to study and improve the cooling performance of microchannel heat sink. Both the geometrical parameters and working fluids were studied and a comparison was made between them. Expanded microchannels (sudden expanded and diverging) were used instead of straight microchannels, also micro pin fins with square and triangular shapes were used for heat transfer enhancement. Sudden expanded microchannels were studied with different expansion ratios and expansion lengths. Three types of nanofluids (Cu-water, Al 2 O 3-water and Diamond-water) with volume concentration (1 – 5) % were studied as working fluids and their effects on overall performance of heat sink were compared with pure water. The results obtained shows that the overall performance of microchannel heat sink increased with increasing the expansion ratio or decreasing the expansion length. For the same expansion ratio the sudden expanded microchannels gives higher modification compared with diverging microchannels. Also using of nanofluids lead to enhance the heat transfer and the improvement got by geometric parameters such as using of expanded microchannels or fins is much larger than that obtained by using nanofluids for the same heat sink.

Heat Transfer and Numerical Analysis in Microchannel Heat Exchanger Using Nanofluids : A Review

Nanofluids are gaining lot of importance in thermal applications due to its excellent heat transfer characteristics. Micro-scale heat transfer devices are used on large scale in electronics industry which leads to the development of compact size heat exchanger with high heat transfer coefficient. Recent development in the field of nanotechnology involves the use of suspended nanoparticles in base fluids which leads to the improvement in the heat transfer coefficient of base fluids. This paper summarizes the articles published on enhancement of convective heat transfer in microchannel heat exchanger using nanofluids and effect of various thermophysical properties on heat transfer performance. Theoretical and experimental results for different geometries and effects on Nusselt number are reported in this paper. The results show outstanding increase in the importance of nanofluid application in microchannels. The effects of use of different nanofluids and their performance as compared to base fluids are shown.

Investigating the heat transfer performance and thermophysical properties of nanofluids in a circular micro-channel

International Communications in Heat and Mass Transfer, 2013

In this paper, the thermal performance of a circular shaped copper microchannel heat sink using three types of nanofluids is discussed analytically. Al 2 O 3-Water, TiO 2-water and CuO-water nanofluids were used in this analysis and the comparative thermal performance of these three nanofluids is also discussed. The hydraulic diameter of the circular channel is 400 μm and the total block dimension is 10 mm×10 mm× 4 mm. A steady, laminar and incompressible flow with constant heat flux is assumed in the circular channel. The analyses are done at various volume fractions ranging from 0.5 vol.% to 4 vol.% and at a constant inlet velocity of 1.5 m/s. The results showed that the thermal performance can be increased significantly by using CuO-water nanofluid as a coolant for cooling of electronic heat sink when Al 2 O 3-water and TiO 2-water nanofluids showed less improvement. Compared to pure water, the highest improvement (13.15%) in the heat flux occurred for 4 vol.% CuO-water nanofluid when Al 2 O 3-water and TiO 2-water nanofluids showed 6.80% and 6.20% improvements respectively. This improvement in heat flux is calculated without considering the additional required pumping power due to the increased viscosity of nanofluids. Therefore, CuO-water nanofluid can be recommended to obtain maximum heat transfer performance in a circular microchannel heat sink.

Experimental and Numerical Analysis of Micro-Scale Heat Transfer using Carbon based Nanofluid in Microchannel for Enhanced Thermal Performance

IOP Conference Series: Materials Science and Engineering

The existing heat transfer technologies suffer from numerous limitations and are poor in high performance and high heat dissipation. Liquid cooling using microchannels and nanofluids work with the increased surface area and minimum thermal resistance. Many researchers showed that nanofluids, particularly with carbon based materials, enhance heat transfer rate. In today era, in the case of microelectronics, small miniaturized heat sinks with high heat transfer are being developed, called micro-channel heat sinks (MCHS). The proposed work is concerned about the heat transfer behavior of aqueous suspensions of CNT nanofluids flowing through the triangular shaped microchannel. Significant enhancement of the convective heat transfer is observed and the enhancement depends on the flow conditions i.e. nusselt number, microchannel channel length, nanoparticles concentration. Particle rearrangement , shear induced thermal conduction enhancement, reduction of thermal boundary layer due to the presence of nanoparticles, as well as the very high aspect ratio of CNT nanofluids are proposed to be possible mechanisms. Results show that thermal boundary layers distorted due to use of carbon based nanofluids and heat transfer coefficient increases about three times as compared to water.

Three-Dimensional Heat Transfer Analysis of Microchannel Heat Sink Using Nanofluid

2015

A numerical simulation of three dimensional heat transfers in a silicon based microchannel heat sink has been conducted using nanofluid (TiO2-H2O) by SIMPLE method. Model of microchannel consists of trapezoidal channel. Dimensions of trapezoidal microchannel are 10 mm length, 280 μm channel top width, 225 μm channel bottom width, 431 μm channel hypotenuse and 430 μm channel height. Influence of properties of nanofluid on the heat transfer is investigated. Different parameters like heat transfer coefficient, Nusselt number, heat flux, outlet temperature are studied for different pressure drop. Pumping power depends upon pressure difference. So power consumption can be optimized by this study. Result shows that heat transfer coefficient is high in comparison to the water as a coolant in microchannel heat sink. Because of boundary layer, variation of Nusselt number decreases along the flow direction.

Numerical Modelling of Nanofluid Based Microchannel Heat Sink

Foundation of Computer Applications, 2019

The present paper describes the effect of heat transfer and fluid flow characteristics of rectangular microchannel under laminar flow conditions. Three dimensional model is created and simulated by applying suitable boundary conditions in the commercial CFD package ANSYS. Two microchannels with width 500 µm and 300 µm are considered for the present study. Water and nanofluid are chosen as working fluids. Two-phase mixture model is used for the modelling of microchannel working with nanofluid. Numerical model have been validated with the available experimental work in the literature. Then, the simulations were carried out for two different channels with nanofluid as working fluid. Heat transfer and flow characteristics of microchannels with nanofluid as working fluid have been obtained for different nanofluid volume concentrations. Finally, the comparison studies between water and nanofluid have been presented in order to understand the effective use of nanofluid as the heat transfer fluid.

Numerical Simulation of Nanofluids for Improved Cooling Efficiency in Microchannel Heat Sink

Applied Mechanics and Materials, 2014

Numerical simulation on 3-dimensional rectangular cross section of microchannel heat sink is conducted to investigate the effect of various type coolant consist of water and different type of nanofluids on the cooling performance of microchannel heat sink. FLUENT, a Computational Fluid Dynamic (CFD) is used as the solver of simulation. A rectangular microchannel with hydraulic diameter of 86um and length of 10mm under the boundary condition of constant heat flux and laminar flow with uniform inlet velocity with five sets of working fluid with different nanofluids. The defined model is validated with previous studies of numerical analysis. Results of present work show that using Diamond-H2O as cooling lead to higher efficiency of heat transfer in microchannel heat sink in comparison to others nanofluid and base fluid. Numerical results show that increasing the thermal conductivity of working fluid can enhanced heat transfer. Nusselt number follows the incremental in Reynolds number.