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Microchannel heat sink (MCHS) is an advanced cooling technique to fulfil the cooling demand for electronic devices installed with high-power integrated circuit packages (microchips). Various microchannel designs have been innovated to improve the heat transfer performance in an MCHS. Specifically, the utilisation of nanotechnology in the form of na...
Citations
... The numerical simulation of thermal performance through MCHS was studied by Farsad et al. [16] using nanofluids, and their study showed that metal nanofluids had better cooling performance than metal oxide nanofluids because of the metal nanofluids' thermal conductivity. The advantages and disadvantages of single and hybrid passive methods of MCHS were compared by Japar et al. [17]. They demonstrated that MCHS adopting the single passive technique was not as efficient at cooling as hybrid MCHS. ...
Microelectronic technologies are progressing rapidly. As devices shrink in size, they produce a substantial heat flux that can adversely affect performance and shorten their lifespan. Conventional cooling methods, such as forced-air heat transfer and essential heat sinks, are inadequate for managing the elevated heat flux generated by these devices. Consequently, microchannel heat sinks have been developed to address this challenge. The present research is intended to study forced flow convection and heat transfer in a cone–column combined microchannel heat sink (MCHS). This study examines a regularly shaped MCHS to evaluate its heat transfer rate. The heat transfer medium employed is a graphene–water nanofluid, and the heat sink’s base is assumed to maintain a constant heat flux. The Galerkin weighted finite element method solves the nanofluid’s governing partial differential equations. This thesis investigates the impact of varying intake velocities on the Reynolds number (100 ≤ Re ≤ 900), externally applied heat flux (10⁴ ≤ q ≤ 10⁶), and the volumetric ratio of nanoparticles (0.001 ≤ φ ≤ 0.04). The study conducts a mathematical analysis to explore how these parameters affect pressure drop, friction factor, average Nusselt number, average substrate temperature, and heat transfer enhancement. The findings are compared with those of a conventional MCHS as the Re increases. The results are analyzed and visually represented through isothermal lines for temperature contours and streamlines for velocity. An increase in the inlet velocity of the water–graphene nanofluid significantly enhances heat transfer and thermal efficiency, achieving improvements of approximately 27.00% and 21.21%, respectively. The research demonstrates that utilizing water–G as a smart coolant with the cone–column combined MCHS enhances thermal efficiency by 4.05% compared to standard water. A comparison of the hydraulic performance index at the substrate reveals that the cone–column combined MCHS is significantly more effective at dissipating heat than the traditional MCHS.
... A novel type of fluids known as nanofluids is made up of suspended nanoscale particles in the base fluid. Nanofluids have been extensively studied for a variety of applications, most notably microchannel heat sinks, due to their specific characteristics particularly their enhanced thermal conductivity [9][10][11][12][13]. There is also a lot of research being done on the use of nanofluids and nanoparticles in the fields of photovoltaic systems, solar stills, renewable energy sources, and biodiesel production [14,15]. ...
This study investigates the conjugate heat transfer performance of microchannel heat sinks (MCHS) cooled by alumina nanofluids, with a focus on mitigating back axial conduction at low Reynolds numbers (10 ≤ Re ≤ 50). Back axial conduction, a critical issue in laminar flows, impairs the cooling efficiency of microchannel systems. In this experimental work, a stainless steel heat sink with 18 circular microchannels was tested for alumina nanofluid efficacy under heat fluxes of 3750 and 6875 W m−2 at the top surface. Experimental results reveal that alumina nanofluids reduced back conduction by 51.54% compared to DI water, resulting in a 29% reduction in surface temperatures. Nanofluid concentrations ranging from 1 to 4% (m/m) improved the convective heat transfer performance by enhancing the bulk fluid temperature profiles along the microchannel. The study further explores the influence of Maranzana and Reynolds numbers, finding that increasing Re reduces back conduction while higher Maranzana numbers amplify axial conduction effects. Transient experiments revealed that nanofluids limit the inlet temperature rise to 86% compared to 140% for DI water at Re = 10, validating their superior thermal performance. Comprehensive experimental data validated the superior heat dissipation capabilities of nanofluids, highlighting their effectiveness in enhancing thermal performance. The findings demonstrate the viability of using alumina nanofluids for advanced thermal management in microelectronics, providing a scalable solution to improve cooling efficiency in high-heat-flux applications under low-Reynolds-number conditions.
Full paper can be read below:
https://rdcu.be/ecwD1
... Also, the powerful properties of nanofluid are mostly due to the large surface area of nanoparticles (NP), with copper (Cu) and aluminum oxide (Al 2 O 3 ) becoming the most favorable NP. Sidik et al., Japar et al., Loon et al., and Aziz et al., [13][14][15][16] extensively discussed the benefits of using nanofluid in numerous applications. Practically, the preparation of nanofluids which combine NP (with low concentration) and a base water can be done through the single and two-phase methods. ...
The research investigates the boundary layer flow and heat transfer of carbon nanotube (CNT) nanofluid over a stretching/shrinking sheet with the magnetohydrodynamic (MHD) effect. The purpose of constructing this model is to increase the understanding of CNT nanofluid flow and heat transfer characteristics, since numerous models use metallic nanoparticles. We conduct this study using numerical and response surface methodology (RSM) approaches in MATLAB and Minitab, respectively. We formulate the mathematical formula by applying the non-linear partial differential equations (PDE). Next, we transform the PDE into non-dimensional ordinary differential equations (ODE) by exploiting the similarity variables method. We show that the model produces multiple solutions in the shrinking region. The magnetic parameter can widen the solutions and delay the boundary layer separation. Both numerical and RSM methods reveal that the maximum value of the magnetic parameter maximizes the heat transfer coefficient. Additionally, both methods demonstrate that single-walled CNT nanofluid is better than multi-walled CNT nanofluid in transmitting heat.
... Conversely, the passive approach does not necessitate the use of external energy. Due to the inherent simplicity of designs without moving parts, the passive method offers a lower cost, making it the preferred choice in most cases [6]. Figure 2 demonstrates that each active and passive approach used in the published literature uses various methodologies. ...
Nanofluids in microchannels present a promising solution for enhancing heat dissipation across various engineering applications. This study provide an in-depth analysis of nanofluid role in improving heat transfer efficiency, focusing on critical factors such as nanoparticle concentration, type, and size. The influence of microchannel geometry—such as sinusoidal, square, and circular designs—and the addition of rib structures were also examined. A noticeable increase in the pressure drop was observed across the spectrum of microchannel investigations beyond a concentration threshold of 1 vol. %. Diverging-converging channels demonstrated potential for enhancing heat transfer with minimal pressure drop and pumping power. Most of the reviewed papers have used water and water-ethylene glycol mixtures (65% and 16%, respectively), along with the prevalent use of Al2O3 nanoparticles (37%), underscoring the need to explore alternative base fluids and nanoparticle combinations to achieve optimal performance. The focus on numerical simulations with 61% and 75% single-phase flow in numerical studies highlights the potential to expand research into multiphase flow phenomena. Furthermore, the limited exploration of nanoparticle shape effects and the reliance on simplistic thermal conductivity models point toward avenues for future investigation and model refinement.
... Apart from electronic devices, other applications of microchannel heat sinks include lasers, batteries, electric vehicles, avionics, photovoltaics, solar energy collectors, miniature fuel cells, condensers, evaporators, and reactors. [3][4][5] Furthermore, the heat removal capacity of flow boiling microchannels is enhanced by using the latent heat of the working fluid due to phase change. 6 Hence, substantial studies have been conducted on flow boiling in microchannels, emphasizing flow pattern transition, bubble dynamics, pressure drop, and heat transfer mechanism. ...
Flow boiling in microchannel heat sinks is an efficient way to dissipate high heat flux by utilizing the large surface-to-volume ratio and high latent heat. Previous studies of boiling heat transfer in microchannels mainly consider the fluid flow in channels only, but often neglect the conjugate effects of the heat conduction in the solid wall, which becomes important for microchannels because of the comparable sizes of the flow channel and the solid wall. In the present study, the effects of conjugate heat transfer on bubble growth during flow boiling in microchannels are examined by numerical simulation. The results indicate that the bubble growth is non-uniform for different bottom wall thicknesses or different solid materials even with the same heat flux at the wall. As the bottom wall thickness increases, the bubble growth rate increases because of the heat conduction in the solid wall along the channel direction. The increased bubble size also increases the perturbation to the flow field, and enhances the thermal convection between the fluid and the wall. For different solid materials, the high-thermal-diffusivity material possesses a higher heat transfer performance because of the quick diffusion of thermal energy from the heat source to the solid–fluid interface.
... It was mentioned within past study conducted by Japar et al., [5] that an improved cooling method called microchannel heat sink (MCHS) is used to meet the cooling needs of electronic devices that have high-power integrated circuit packages (microchips) installed. A variety of innovative microchannel designs have been developed to enhance an MCHS's heat transmission capability. ...
The increasing miniaturization of technology has intensified thermal challenges, particularly concerning the cooling of small components like ICs and CPUs. Microchannel heat sinks offer a common solution, but optimizing their configurations remains a subject of interest. This study addresses multiple thermal enhancing factors that is position of the inlet and outlet and integrating pin-fin configurations. The objectives of the study are to improve the thermal uniformity of the heat sink and to analyse the thermal performance across the different geometry of pin-fin using Ansys. The thermal performance parameters focused on this study are the maximum temperature and pressure drop. The results gathered that hexagon shaped pin fin yield better thermal performance as compared to the other geometry as it shows the lowest maximum temperature, lowest thermal resistance and lowest pressure drop. This proves the significance of geometry selection for the pin fin as it affected the thermal performance of the microchannel heat sink with cross flow effects.
... Flow boiling in microchannels is an efficient way to dissipate high heat flux by utilizing the high surfaceto-volume ratio and excellent cooling performance. Apart from electronic devices, other applications of microchannel heat sinks include lasers, batteries, electric vehicles, avionics, photovoltaics, solar energy collectors, miniature fuel cells, condensers, evaporators, and reactors [3][4][5] . Furthermore, the heat removal capacity of flow boiling microchannels is enhanced by using the latent heat of the working fluid due to phase change 6 . ...
Flow boiling in microchannel heat sinks is an efficient way to dissipate high heat flux by utilizing the large surface-to-volume ratio and high latent heat. Previous studies of boiling heat transfer in microchannels mainly consider the fluid flow in channels only, but often neglect the conjugate effects of the heat conduction in the solid wall, which becomes important for microchannels because of the comparable sizes of the flow channel and the solid wall. In the present study, the effects of conjugate heat transfer on bubble growth during flow boiling in microchannels are examined by numerical simulation. The results indicate that the bubble growth is non-uniform for different bottom wall thicknesses or different solid materials even with the same heat flux at the wall. As the bottom wall thickness increases, the bubble growth rate increases because of the heat conduction in the solid wall along the channel direction. The increased bubble size also increases the perturbation to the flow field, and enhances the thermal convection between the fluid and the wall. For different solid materials, the high-thermal-diffusivity material possesses a higher heat transfer performance because of the quick diffusion of thermal energy from the heat source to the solid-fluid interface.
... Active approaches involve integrating microchannels with additional techniques like vibration and electrostatic forces to boost heat transfer [8]. On the other hand, passive methods focus on altering the fundamental properties of microchannel heat sinks, applying techniques such as altering the microchannel structure [9,10], using different working fluids [11,12] such as nanofluids, and so on, and adjusting the coolant operating conditions [13]. Pin fin variations for microchannel heat sinks have been included in the design, like a higher area of convection, fluid mixing with an improved strategy, secondary flow, and disturbances of laminar flow, which are all benefits of micro pin-fin topologies [14,15]. ...
The ongoing trend of miniaturization of electronic devices, including computer processors, high-speed servers and micro-electro-mechanical system devices, should go hand in hand with their improved performance. However, managing heat remains a major challenge for these devices. In the present study, a numerical investigation was done on a micro-channel heat sink with an open-stepped micro-pin fin heat sink with various arrangements through ANSYS software. Pin fin was varied in a fashion of increasing and decreasing. The working fluid opted for was water in a single phase. The analysis takes into account varying thermo-physical properties of water. The operating parameters, i.e. the Reynolds number was taken as 100–350 and heat flux as 500 kW/m2. Arrangements selected were staggered and inline. Observations revealed that the staggered 2 arrangement has shown better thermal performance than other arrangements within the entire investigated range of Reynolds numbers because of the effective mixing of fluids. Furthermore, the inline configuration of micro pin fin heat sink has the worst performance. It is interesting to note that a very small difference was observed in the heat transfer capability of both staggered configurations, while the pressure drop in the staggered 2 arrangement has shown an elevated value at a higher Reynold number value compared to the staggered 1 arrangement.
... Several methods have been studied and developed, including microjet impingement, micro heat pipes, micro-electrohydrodynamics, and MCHSs. Among all these cooling methods, MCHSs are best for removing flux from microchips [7,8]. ...
... Active methods increase the thermal efficiency of smooth rectangular MCHSs by utilizing outside energy sources [8]. Go JS et al. [23] investigated the effects of vibration induced by flow on thermal performance in 2003 in a micro fin array. ...
... Using secondary channels in microchannel heat sinks presents several challenges in terms of fabrication, pressure loss, flow maldistribution, and thermal non-uniformity; therefore, the best design with secondary channels should consider these issues to achieve the best overall performance. Japar, W et al. [8] examined the effectiveness of the secondary channel numerically at a Reynolds number (Re) ranging from 100 to 450. A comparison analysis of related geometries was used to examine the efficiency of the suggested MCHS with rectangular ribs, triangular cavities, and microchannels with rectangular ribs and triangular cavities. ...
An efficient cooling system is necessary for the reliability and safety of modern microchips for a longer life. As microchips become smaller and more powerful, the heat flux generated by these chips per unit area also rises sharply. Traditional cooling techniques are inadequate to meet the recent cooling requirements of microchips. To meet the current cooling demand of microelectromechanical systems (MEMS) devices and microchips, microchannel heat sink (MCHS) technology is the latest invention, one that can dissipate a significant amount of heat because of its high surface area to volume ratio. This study provides a concise summary of the design, material selection, and performance parameters of the MCHSs that have been developed over the last few decades. The limitations and challenges associated with the different techniques employed by researchers over time to enhance the thermal efficiency of microchannel heat sinks are discussed. The effects on the thermal enhancement factor, Nusselt number, and pressure drop at different Reynold numbers in passive techniques (flow obstruction) i.e., ribs, grooves, dimples, and cavities change in the curvature of MCHSs, are discussed. This study also discusses the increase in heat transfer using nanofluids and how a change in coolant type also significantly affects the thermal performance of MCHSs by obstructing flow. This study provides trends and useful guidelines for researchers to design more effective MCHSs to keep up with the cooling demands of power electronics.
... To remove variability caused by structural variances, these materials were manufactured into heat sink prototypes with identical geometric patterns. With proportions suited for popular cooling arrangements, the heat sink design obtained a central water channel and parallel rectangular fins for effective heat dissipation [17]. ...
