Numerical optimization of thermal performance in V-shaped ribbed pin-fin heat sinks using porous media filled with radiative nanofluid

Effects of pin fin height, spacing and orientation to natural convection heat transfer for inline pin fin and plate heat sinks by experimental investigation

In the present work, a novel compact modeling method based on the volume-averaging technique and its application to the analysis of fluid flow and heat transfer in pin fin heat sinks are presented. The pin fin heat sink is modeled as a porous medium. The volume-averaged momentum and energy equations for fluid flow and heat transfer in pin fin heat sinks are obtained using the local volume-averaging method. The permeability, the Ergun constant and the interstitial heat transfer coefficient required to solve these equations are determined experimentally. To validate the compact model proposed in this paper, 20 aluminum pin fin heat sinks having a 101.43 mm × 101.43 mm base size are tested with an inlet velocity ranging from 1 m/s to 5 m/s. In the experimental investigation, the heat sink is heated uniformly at the bottom. Pressure drop and heat transfer characteristics of pin fin heat sinks obtained from the porous medium approach are compared with experimental results. Upon comparison, the porous medium approach is shown to predict accurately the pressure drop and heat transfer characteristics of pin fin heat sinks. Finally, surface porosities of the pin fin heat sink for which the thermal resistance of the heat sink is minimal are obtained under constraints on pumping power and heat sink size. The optimized pin fin heat sinks are shown to be superior to the optimized straight fin heat sinks in thermal performance by about 50% under the same constraints on pumping power and heat sink size.

Natural convection heat transfer enhancement in new designs of plate-fin based heat sinks

Heat transfer performance of the pin–fin heat sink filled with packed brass beads under a vertical oncoming flow

Experiments were performed on natural convection heat transfer from circular pin fin heat sinks subject to the influence of its geometry, heat flux and orientation. The geometric dependence of heat dissipation from heat sinks of widely spaced solid and hollow/perforated circular pin fins with staggered combination, fitted into a heated base of fixed area is discussed. Over the tested range of Rayleigh number, 3.8×106≤Ra≤1.65×107, it was found that the solid pin fin heat sink performance for upward and sideward orientations shows a competitive nature, depending on Rayleigh number and generally shows higher heat transfer coefficients than those of the perforated/ hollow pin fin ones in both arrangement. For all tested hollow/perforated pin fin heat sinks, however, the performance for sideward facing orientation was better than that for upward facing orientation. This argument is supported by observing that the augmentation factor was around 1.05–1.11, depending on the hollow pin diameter ratio, D i /D o . Meanwhile, the heat sink of larger hollow pin diameter ratio, D i /D o offered higher heat transfer coefficient than that of smaller D i /D o for upward orientation, and the situation was reversed for sideward orientation. The heat transfer performance for heat sinks with hollow/perforated pin fins was better than that of solid pins. The temperature difference between the base plate and surrounding air of these heat sinks was less than that of solid pin one and improved with increasing D i /D o

Natural convection heat transfer from a heat sink with hollow/perforated circular pin fins

In this study, a design of an aluminum alloy pin-fin heat sink with the passage divider and the packed brass beads was proposed. The effects of the passage divider and packed brass beads on the overall heat transfer performance of the pin-fin heat sink under forced convection with water cooling was investigated experimentally. The heat sink is made of an aluminum alloy square cavity with the in-line square pin fins as the basic configuration. Among them, the number of pin fins (4 × 4, 3 × 3, 2 × 2, 0 × 0) and the height of pin fins (H = 5, 10, 20 mm) are variables. The filled brass beads have three particle sizes (d = 4, 6 and 8 mm), and the passage divider designs are divided into 2 types, namely, left-and-right S-shape divider and up-and-down S-shape divider. The results indicate that for the heat sink with the passage divider but no filled with brass beads, the passage divider has a significant heat transfer enhancement for the 4 × 4 and 3 × 3 pin-fin heat sink. Especially for the 3 × 3 pin-fin heat sink added with the up-and-down S-shape divider, the heat transfer enhancement is up to 60%. For the heat sink with the passage divider and filled with brass beads, when adding the same passage divider, compared with the test case without filled with the brass beads, the filling of brass beads (d = 4 mm) has a significant heat transfer enhancement for the heat sink with H = 5 and 10 mm. It increases the heat transfer by an average of about 14%. Therefore, in the test case, the 3 × 3 pin-fin heat sink (H = 10 mm) added with the up-and-down S-shape divider and filled with brass beads (d = 4 mm) has the most significant heat transfer enhancement, and the overall Nusselt number increases by about 65% compared with the heat sink without the passage divider and brass beads.

Cooling of miniature size electronic components has become a challenge for designer in the development of integrated circuits. Micro pin fin heat sink and Micro channel pin fin heat sink are thermal management techniques for effective cooling. The paper presents comparison of fluid flow and heat transfer characteristics for micro pin fin heat sink and micro channel pin fin heat sink with unfinned micro channel heat sink. A three-dimensional heat sink with water as coolant subjected to constant heat flux 10 W/cm2, for Reynolds number ranging between 100 and 900 was considered for the study. Extended surfaces of different shapes namely, square and circular with staggered arrangement was considered for both micro pin fin heat sink and micro channel pin fin heat sink. Two non-dimensional parameters namely Nusselt number and thermal performance index were employed to access the performance of heat sink. Results indicate that the microchannel pin fin heat sink has highest nusselt number and friction factor over the whole Reynolds number range. Results also revealed that formation of secondary vortices enhances heat transfer in micro channel heat sink with square pin fin compared to micro channel heat sink with circular pin fin. However, pin fin heat sink has better thermal performance index compared to Micro channel pin fin heat sink and is more preferable when heat dissipation is compared with pressure drop penalty. The Governing equations for fluid and solid domain were solved using FLUENT to study flow and heat transfer characteristics.

An optimum design for a natural convection pin fin array with orientation consideration

Crucial for maintaining electronic device performance and longevity is effective thermal management. This study investigates two innovative heat sink configurations: the Square pin fin and the Slotted square pin fin. Assessed under varying conditions using Inventor 2018 and Autodesk Computational Fluid Dynamics (CFD) 2018, the Slotted square pin fin heat sink demonstrates a notable 18% increase in heat transfer area and a simultaneous 16% reduction in weight compared to the Square pin fin. Furthermore, a consistently lower base temperature is maintained, with an average reduction of around 10%. Importantly, 85% of total heat dissipation is contributed by the Slotted square pin fin, surpassing the Square pin fin configuration’s 80%. A commendable 19% reduction in thermal resistance is observed in the Slotted square pin fin compared to the Square pin fin. These insights underscore the advantages of the Slotted square pin fin heat sink in terms of heat transfer efficiency, weight reduction, lower temperatures and improved thermal resistance, contributing to advanced heat sink design and efficient thermal management strategies.

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Effect of pin fin configuration on thermal performance of plate pin fin heat sinks

Single-Phase Cryogenic Flow and Heat Transfer Through Microscale Pin Fin Heat Sinks

This paper demonstrates that the performance of natural-convection pin fin heat sinks can be improved up to 16% by actually removing pin fins from a conventional pin fin heat sink. Both numerical and experimental studies are performed on a commercially available pin fin heat sink suspended in mid-air and correlated well. Both natural convection and radiative heat transfer contributions are analysed. The individual contribution of each pin fin is studied, showing that 94% of heat transfer can be attributed to the heat sink baseplate and two outer rings of pin fins. A two-step optimization strategy was devised and applied leading to an optimal design with a thermal resistance of 3.35 K/W, compared to the original 4.0 K/W, for a 10 W heat load. Altogether, the advantages of computational modelling in combination with experimental testing are exploited leading to better, lighter and more cost effective thermal management solutions.

Influences of tip clearance on flow and heat transfer characterstics of open type micro pin fin heat sink