Cylindrical Heat Sink Research Articles

Thermal performance of center-cleared hollow cylindrical pin-fin heat sink for electronic cooling

Thermal performance of center-cleared hollow cylindrical pin-fin heat sink for electronic cooling

Influence of pin fins and channel geometry on the hydrothermal performance of hexagonal mini-channel heat sink for cooling cylindrical batteries

This study numerically and experimentally examined the effects of pin fin configuration and channel geometry on the performance of a hexagonal mini-channel heat sink (HMCHS) to cool cylindrical lithium-ion battery cells. Various configurations of HMCHS with circular pin fins are studied, including circular fins centrally positioned within flat channels, circular fins positioned within grooved channels, circular fins situated within hybrid channels transitioning between wavy and straight channels and circular fins placed within hybrid channels that incorporate secondary flow channels between the primary flow channels. This numerical study utilized the finite volume method to investigate the laminar water flow at Reynolds numbers below 800. Findings showed that the HMCHS exhibited superior thermal performance compared with the conventional cylindrical mini-channel heat sink design. Moreover, the incorporation of pin fins into the HMCHS design was more effective in enhancing the Nusselt number than simply increasing the Reynolds number across various configurations. Meanwhile, the hybrid channel design with secondary channels, combined with the addition of pin fins, achieved the optimal overall performance of the HMCHS, resulting in the highest performance index of 1.88.

3D transient numerical analysis of PCM dendritic cylindrical heat sinks designed by constructal theory

The phase change material (PCM) heat sink represents an important cooling tool for many applications. The presence of a heat sink in devices requires additional space to occupy it. This led to modeling this space to obtain the highest thermal performance with the smallest size. Among the modern modeling methods is constructal theory. This work presents a numerical modeling of the performance of cylindrical phase change material heat sinks with branched heat transfer fluid tubes in the manner of arterial and venous according to constructal theory. The aim of numerical simulations is to demonstrate the effect of growth in design by increasing the number of branches on thermal performance and melting time and the extent to which this is reflected in pressure drops. Several branching configurations are studied for comparison purpose. The governing continuity, momentum and energy equations were solved using the computational fluid dynamics method. Three-dimensional transient simulations of the melting process of phase change materials were performed using an enthalpy and porosity model. Four combinations of constructal dendritic tubes were considered. The results show that the proposed dendritic PCM heat sink significantly reduces the melting time of PCM compared to the traditional heat sink consisting of a shell and single tube up to 69.1 %. The drop in heat transfer fluid temperature at the outlet decreased by up to 51.7 %. The results proved also the heat transfer enhancement is governed with pressure drop increase because of changing branches configuration. Finally, this paper demonstrated the ability of constructal theory to provide promising solutions for cylindrical heat sinks of phase change materials in various applications.

Thermal enhancement of a constructal PCM cylindrical heat sink used for prosthetic cooling application

Thermal enhancement of a constructal PCM cylindrical heat sink used for prosthetic cooling application

Dynamic behavior of mixed convection heat transfer among horizontal co-axial fixed pipes at varying temperatures: Efficiency of cylindrical heat sink

The aim of the current research is to highlight the time-dependent properties of laminar convective thermal transmission inside a semi-infinite pipe, with an emphasis on flow frequencies that impact inter-fluid momentum and energy. The implicit finite difference approach is used to solve two-dimensional mathematical model composed of nonlinear partial differential equations. The research includes forecasting thermal performance of time-dependent flow in a pipe over several parameter ranges relevant to the flow model. The obtained forecasts were emphasized graphically. The numerical solutions were separated into steady and unsteady components, with the steady component yielding findings that were then used to determine the time dependent surface shearness and energy shearness in the time dependent phase. The stable component of the investigation revealed that raising the buoyancy force parameter and the impact of viscous dissipation significantly improved the flow velocity pattern and heat distributions throughout the flow domain. While the amplitude of time dependent surface shearness varied somewhat across various buoyancy force parameter values, the amplitude of time dependent heat transmission rates varied significantly. This study sheds light on the interaction of several characteristics, such as buoyancy force effects and internal energy loss, on time-dependent thermal energy flow inside a semi-infinite pipe subjected to laminar convective flow. It is worth noting that the amplitude of the time dependent rate of heat transmission shows more noticeable variations with different values of the buoyancy force parameter, in contrast to the minute change in the amplitude of the time dependent surface sheerness.

Constructal design of a PCM cylindrical heat sink with three‐branched, two‐stages dendritic tubes

AbstractAmputees who use prosthetic limbs suffer from the problem of high contact temperature between the socket of the prosthetic limb and the amputated part and lack of evaporation of sweat. These conditions lead to discomfort and failure to perform functions properly. In addition, these conditions help generate ulcers and accumulate harmful bacteria in this area. This paper presents a heatsink design to extract heat from the contact area. A cylindrical heat sink is designed for phase‐changing materials with three branched tubes in two stages. The current heat sink is used to cool the contact area between the amputated part and the socket in the lower prostheses. Three distributions of pipe branches are proposed. The distribution and pipe lengths were obtained using a constructal design method. In the constructal design, the lengths of the branched tubes were the degrees of freedom, the objective function was the minimization of the inlet temperature to the heat sink, and the constraint was the volume of the cylindrical heat sink. The metabolic heat transfer during exercise was estimated and its value was used to calculate the size of the cylindrical heatsink and the selection of the phase change material by testing three of them: water, tridecane, and dodecane. It was found that water gives the highest latent heat of melting and the lowest volume in addition to its availability. On the other hand, two cooling fluids were tested: water and air. It was found that water as a cooling fluid gave the lowest flow and the largest heat capacity. Constructal theory was used to design a cylindrical heat sink using branched tubes for the coolant in two steps: the first with three branches, and the second with nine branches. The degree of freedom for constructal theory was the length of the branches through the choice of their end locations. It was found that the branches of the highest length led to a reduction in temperature from 40°C to 15.48°C compared with the single tube, which reduced the temperature to 23.87°C. All tests recorded a pressure drop within the acceptable range of 3.1–5.43 Pa for the branches examined. The research demonstrated that using constructal theory achieved the best thermal dissipation within a restricted volume.

Numerical analysis of the effects of fins with orifices on hydrothermal and entropy generation characteristics in a cylindrical helical minichannel heat sink

Numerical analysis of the effects of fins with orifices on hydrothermal and entropy generation characteristics in a cylindrical helical minichannel heat sink

Thermal management of the central processing unit cooling system using a cylindrical metal foam heat sink under the influence of magnetohydrodynamic nanofluid flow

PurposeEfficient thermal management of central processing unit (CPU) cooling systems is vital in the context of advancing information technology and the demand for enhanced data processing speeds. This study aims to explore the thermal performance of a CPU cooling setup using a cylindrical porous metal foam heat sink.Design/methodology/approachNanofluid flow through the metal foam is simulated using the Darcy–Brinkman–Forschheimer equation, accounting for magnetic field effects. The temperature distribution is modeled through the local thermal equilibrium equation, considering viscous dissipation. The problem’s governing partial differential equations are solved using the similarity method. The CPU’s hot surface serves as a solid wall, with nanofluid entering the heat sink as an impinging jet. Verification of the numerical results involves comparison with existing research, demonstrating strong agreement across numerical, analytical and experimental findings. Ansys Fluent® software is used to assess temperature, velocity and streamlines, yielding satisfactory results from an engineering standpoint.FindingsInvestigating critical parameters such as Darcy number (10−4 ≤ DaD ≤ 10−2), aspect ratio (0.5 ≤ H/D ≤ 1.5), Reynolds number (5 ≤ ReD,bf ≤ 3500), Eckert number (0 ≤ ECbf ≤ 0.1) , porosity (0.85 ≤ ε ≤ 0.95), Hartmann number (0 ≤ HaD,bf ≤ 300) and the volume fraction of nanofluid (0 ≤ φ ≤ 0.1) reveals their impact on fluid flow and heat sink performance. Notably, Nusselt number will reduce 45%, rise 19.2%, decrease 14.1%, and decrease 0.15% for Reynolds numbers of 600, with rising porosity from 0.85 to 0.95, Darcy numbers from 10−4 to 10−2, Eckert numbers from 0 to 0.1, and Hartman numbers from 0 to 300.Originality/valueDespite notable progress in studying thermal management in CPU cooling systems using porous media and nanofluids, there are still significant gaps in the existing literature. First, few studies have considered the Darcy–Brinkman–Forchheimer equation, which accounts for non-Darcy effects and the flow and geometric interactions between coolant and porous medium. The influence of viscous dissipation on heat transfer in this specific geometry has also been largely overlooked. Additionally, while nanofluids and impinging jets have demonstrated potential in enhancing thermal performance, their utilization within porous media remains underexplored. Furthermore, the unique thermal and structural characteristics of porous media, along with the incorporation of a magnetic field, have not been fully investigated in this particular configuration. Consequently, this study aims to address these literature gaps and introduce novel advancements in analytical modeling, non-Darcy flow, viscous dissipation, nanofluid utilization, impinging jets, porous media characteristics and the impact of a magnetic field. These contributions hold promising prospects for improving CPU cooling system thermal management and have broader implications across various applications in the field.

The Thermal Analysis and Heat Dissipation Structure Optimization of a Propeller Driver System

The thermal performance of the propeller driver system is very important for underwater vehicles. A new kind of cylindrical heat sink is designed for a certain propeller driver system. The performances of the heat sink are analyzed, mainly using numerical methods. The thermal influences of structure parameters, such as base thickness, fins length, and fin number, are studied for the heat sink with an orthogonal experimental method. The results show that all three parameters have positive impacts on the heat dissipation of the driver. Compared with the fin numbers and the fin length, the base thickness has a relatively small impact on the working temperature of the driver. Compared to the initial design, the maximum temperature of the propeller driver drops by 22.3% with the designed novel cylindrical heat sink in the studied cases.

Cold plate performance enhancement based on parametric modeling of multiple structures

Power electronic equipment to miniaturization, high integration direction while facing the problem of high heat flow density and uneven temperature distribution. The large temperature fluctuations and uneven temperature distribution in the operation of power electronic equipment will lead to thermal stress, and excessive thermal stress or uneven distribution will cause fatigue failure of the packaging material, resulting in reduced reliability, module failure, and reduced life of power electronic equipment. In this paper, we propose two kinds of liquid-cooled flow channel non-linear reinforced heat transfer homogeneous liquid-cooled plate, which is theoretically derived to achieve the design requirement of uniform temperature on the heating side wall surface. The thermal design of the cold plate is carried out using ANSYS Workbench, and the indicators of various structures of the cold plate are analyzed and compared in terms of their ability to dissipate heat and maintain temperature uniformity. Based on the original runner structure, the heat dissipation performance of the rod structure and fin structure was evaluated, and the form of the internal heat dissipation structure of the runner was determined. The results show that the integrated liquid cooling plate temperature uniformity and flow resistance of both factors, the fin column heat sink is significantly better than the cylindrical fin column heat sink in the case of the same thermal resistance, the fin column heat sink flow resistance is significantly lower than the cylindrical fin column heat sink.

Multiple Phase Change Material-Based Heat Sink for Cooling of Electronics: A Combined Experimental and Numerical Study

Abstract This paper reports an investigation of the thermal performance of an energy storage heat sink incorporated with multiple phase change materials (PCMs). A six-cavity cylindrical heat sink heated at the base is chosen for the investigations with Docosane, n-Eicosane, and Tetracosane as candidate PCMs. The phase transition of PCMs has been visualized with a digital camera and three-dimensional numerical simulations. The results show that the latent heat exploitation process of PCMs in a heat sink with multiple PCMs is different from the single PCM heat sink, where the PCMs in all cavities melt distinctly rather at a time, thereby opening up windows for obtaining deeper insights that can lead to better performing heat sinks. A trained artificial neural network (ANN) with 78 representative heat sink configurations based on the arrangement of the PCMs in the cavities as input and charging and discharging times as output is used to swiftly drive the optimization engine. Finally, multi-objective optimization is performed using the artificial bee colony algorithm with simultaneous consideration of two conflicting objectives (i.e., maximizing charging cycle time and minimizing discharging cycle time) of the heat sink. From the optimization study, best performing nondominated Pareto optimal heat sink configurations are obtained and validated with the in-house experimental results. From the investigations, it is found that the heat sink configurations with multiple PCMs perform on par with the single PCMs in the charging process and show a superiority of up to 24% in discharging process over a heat sink with single PCMs in terms of time to reach set point temperature.

Sensitivity analysis of boehmite alumina nanofluid in a novel cylindrical heat sink with hybrid helical-straight minichannels using the taguchi method and statistical analysis

In the present study, heat transfer, fluid flow characteristics and entropy generation of boehmite alumina nanofluid in a cylindrical heat sink with hybrid helical-straight minichannels are simulated and examined numerically. Attention is focused to determine the influential design factors and the optimal levels for output parameters. The design factors are selected at four levels including the helix angle of minichannels, the Reynolds number, the helical length ratio, the nanoparticles shape and the volume fraction of nanoparticles. Sensitivity analysis of design factors was carried out using the Taguchi method with L16 orthogonal array and statistical analysis of variance (ANOVA). The Nusselt number (Nu), the Fanning friction factor (f), the total hydrothermal performance factor (JF), the rate of entropy generation (Sgen), and the entropy generation number (Ns), are selected as the output parameters. The obtained results revealed that the helix angle of minichannels and the Reynolds number play a vital role in Nu, JF, and Sgen, with the sum of the contribution ratios of the two factors 82.57%, 68.16%, and 81.97%, respectively. Also, the helix angle of minichannels has a 50.67% contribution in Ns. The optimized model is improved by 94.5%, 37.5%, 84%, 63.4%, and 64.1% for Nu, f, JF, Sgen, and Ns, respectively, compared with the original model. Two optimal combinations for JF and Sgen are acquired as A2B3C1D4E4 and A1B3C4D4E4, respectively. Overall, the hybrid helical-straight minichannel with boehmite alumina nanofluid can be beneficial as a preferred cooling for the cylindrical heat sources.

Performance Analysis of Central Processing Unit Heat Sinks Fitted With Perforation Technique and Splitter Inserts

Abstract The increase in the heat dissipation rate in heat sinks (HSs), the reduction of the occupied volume and mass, and the elimination of the lower heat transfer areas (LHTAs) behind the pins are the main parameters to be controlled in HSs design. For this purpose, this study is devoted to numerically investigating the effect of the combination between perforation technique and splitters inserts on the heat dissipation and turbulent fluid flow characteristics of pin fins heat sinks (PFHSs). The splitter is located in the back of the pin, and the cylindrical pin fins heat sinks (CPFHSs) are perforated with different pairs of hole numbers. These configurations are named PFHS-0 (without perforation) to PFHS-5. The results obtained for the PFHS-5 show an increase in Nusselt number by 34.91% and a reduction in the thermal resistance by 24.22%, compared with CPFHSs. For the same conditions, the occupied volume and mass of this case are also reduced by 70% and 47.5%, respectively. In addition, the PFHS-5 case ensures the highest hydrothermal performance factor (HTPF) of 1.42 at Re = 8,740.

Thermal Effect of Cylindrical Heat Sink on Heat Management in LED Applications

Light Emitting Diode (LED) applications are increasingly used in various microelectronic devices due to their efficient light generation. The miniaturisation of the LED and its integration into compact devices within the weight limit have resulted in excessive heat generation, and inefficient management of this heat could lead to the failure of the entire system. Passive and/or active heat sinks are used for dissipating heat from the system to the environment to improve performance. An ANSYS design modeller and transient thermal conditions were utilised in this study to design and simulate the LED system. The modeller performs its function by utilising the Finite Element Method (FEM) technique. The LED system considered in this work consists of a chip, thermal interface material, and a cylindrical heat sink. The thickness of the Cylindrical Heat Sink (CHS) fins used in the investigation is between 2 mm and 6 mm, whilst ensuring the mass of heat sinks is not more than 100 g. The input power of the LED chip is between 4.55 W and 25.75 W, as required by some original equipment manufacturers (OEMs). A mesh dependency study was carried out to ensure the results were synonymous with what can be obtained practically. The simulation results suggest that the power ratings did not affect the thermal resistance of the CHS. In addition, the thermal resistance increased with the increased thickness of the CHS fin. The efficiencies of the heat sink were found to increase with an increased thickness of the cylindrical fin and the accuracy between the calculated and simulated thermal efficiency ranges from 84.33% to 98.80%. Evidently, the CHS fin of 6 mm thickness is more efficient than the other CHS fins, as depicted in this study.

Investigation of the hydrothermal enhancement of grooved pin fins heat sinks

In this paper, a numerical investigation was conducted to analyse heat transfer and fluid flow on a new design of heat exchangers with grooved pin-fin heat sinks (G-PFHS), which included the optimisation of shape, size, and groove number (Ng ). The simulation results indicate that all-novel geometries have the highest heat dissipation rates compared to conventional geometry (Cylindrical pin fins heat sink, CPFHS). However, the configuration with semi-circular grooves exhibits the most design compared to other configurations (pin-fins heat sinks with a rectangle, triangular, trapezoidal grooves and CPFHS). Also, after optimisation of the size and number of grooves, the Nusselt number and thermal resistance are improved by 21.01% and 16.70%, respectively, with an increase in the pressure drop by 15.42% compared with the CPFHS at the highest Reynolds number. Therefore, this case provides the best hydrothermal performance factor (HTPF) of 1.18 at Re = 8740.

Objective oriented phase change material composite heat sink design

While phase change material based heat sinks have been shown to act as highly efficient transient cooling devices, the effective implementation of these components is prevented by a lack of design guidelines. Here, we develop an analytical framework for optimizing the design of rectangular and cylindrical phase change material composite heat sinks. This is accomplished through the definition of two design objectives: (1) maximize thermal buffering capacity at a given time, and (2) maximize the time the system can achieve a minimum thermal buffering capacity threshold. In this context, thermal buffering capacity can be quantified in terms of heat absorption rate or temperature, depending on the boundary condition applied. We demonstrate that, in finite volumes, there exist two design regimes where the thermal buffering capacity is either limited by the rate at which the system can absorb thermal energy or by the total thermal capacitance of the system. We present analytical expressions describing the optimal volume fraction for each combination of design objectives, form factors, and boundary conditions derived from appropriate analytical solutions for the melting problem. Analytically predicted optimal volume fractions are validated with numerical and experimental results from existing literature and original work. This collective toolbox enables thermal engineers to make rational decisions on architecture to optimize components under specific thermal loads and specific system constraints.

Design-expert aided thermohydraulic assessment of a nanofluid-cooled cylindrical microchannel heat sink: Possible application for thermal management of electric vehicle batteries

This work deals with experimental evaluation of thermo-hydraulic characteristics of silver-water nanofluids (at 0.1, 0.45, and 0.8 wt%) flow in a cylindrical microchannel heat sink under laminar flow regime. The experiments are performed at constant heat flux of 56.8 kW/m2 and Re is varied in a range between 400 and 1300. Furthermore, the nanofluid of 0.8 wt% at Re = 850 is found as the most efficient case with experimentally determined thermal performance factor (TPF) of about 1.35 where the Nusselt Number is predicted to enhance by approximately 67.1% compared to the base liquid. However, the pressure loss exerted by silver nanofluid at the optimum condition was found to be <0.2 bar. The results are statistically optimized based on response surface methodology (RSM) using a statistical software package (Design-Expert®) and it is clearly shown that Re has more dominant-positive effect on the local heat transfer coefficient in comparison with nanoparticle fraction. The optimized formula predicts the best thermal performance considering relative Nu and friction factor to be maximized and minimized, respectively. The optimum operating condition is found at Re≈848 and fraction of 0.8 wt% which is close to the above-mentioned experimental optimum point with an insignificant error of <3%.

Study on the flow and heat transfer characteristics of pin-fin manifold microchannel heat sink

In order to improve the heat transfer performance of the manifold microchannel, a cylindrical pin-fin manifold microchannel heat sink is designed on the basis of the manifold microchannel. The flow and heat transfer characteristics of the heat sink are numerically investigated. The results show that the heat transfer performance of the pin-fin manifold microchannel is better than that of the rectangular manifold microchannel at the same mass flux, but the pressure drop of the pin-fin manifold microchannel is higher. The heat transfer performance of the pin-fin manifold microchannel is better than that of the rectangular manifold microchannel at the same pressure drop, and the mass flux of the pin-fin manifold microchannel is less. The arrangement of pin fins is optimized in the ratio of the transverse length to the longitudinal length between 0.49 and 1.34 at the same pressure drop. The local optimal ratio is in the range of 0.8 to 0.9. The flow and heat transfer characteristics of the pin-fin manifold microchannel in subcooled flow boiling are numerically studied. The results show that the average chip temperature of the pin-fin manifold microchannel still fluctuates after the overall trend is stable.

Preparation of Cu-Cr-Zr Alloy by Laser Powder Bed Fusion: Parameter Optimization, Microstructure, Mechanical and Thermal Properties for Microelectronic Applications

Laser powder bed fusion (LPBF) technology is beneficial for the fabrication of thermal conductive materials, integrating with the predesigned structure, which shows a great potential for high heat dissipation applications. Here, a Cu–Cr–Zr alloy with relative density of 98.53% is successfully prepared by LPBF after process optimization. On this basis, microstructure, phase identification, precipitates, mechanical and thermal properties are investigated. The results demonstrate that the surface morphology of microstructure is affected by laser energy density, the α-Cu is the main phase of the LPBF sample and the virgin powder, the size of Cr spherical precipitates in some areas is about 1 μm, and the tensile fracture mode is a mixed ductile–brittle mode. Furthermore, the Vickers hardness of the LPBF Cu–Cr–Zr sample is 70.7 HV to 106.1 HV, which is higher than that of LPBF Cu and a wrought C11000 Cu, and the difference in Vickers hardness of different planes reflects the anisotropy. Ultimately, the two types of Cu–Cr–Zr alloy heat sinks are successfully fabricated, and their heat transfer coefficients are positively correlated with the volume flow. The heat dissipation performance of the cylindrical micro-needle heat sink is better, and its maximum heat transfer coefficient is 3887 W/(m2·K).

Experimental examination of the cooling performance of a cylindrical microchannel heat sink with straight and sinusoidal fins and alumina nanofluid coolant

Experimental examination of the cooling performance of a cylindrical microchannel heat sink with straight and sinusoidal fins and alumina nanofluid coolant