Zeitschriftenartikel: „Polymeric heat sinks“

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Marchetto, Daniel Borba, und Gherhardt Ribatski. „An experimental study on flow boiling heat transfer of HFO1336mzz(Z) in microchannels-based polymeric heat sinks“. Applied Thermal Engineering 180 (November 2020): 115815. http://dx.doi.org/10.1016/j.applthermaleng.2020.115815.

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Guzej, Michal, Martin Zachar, Jan Kominek, Petr Kotrbacek und Robert Brachna. „Importance of Melt Flow Direction during Injection Molding on Polymer Heat Sinks’ Cooling Efficiency“. Polymers 13, Nr. 8 (07.04.2021): 1186. http://dx.doi.org/10.3390/polym13081186.

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Polymers with highly conductive fillers could possibly replace standardly used materials, such as aluminum and copper alloys, for passive cooling purposes. The main problem of the composite polymer-based heat sinks is that their high thermal conductivity is uneven. The orientation of this anisotropy is set according to the position of the highly thermally conductive filler. Its orientation is influenced by the melt flow during the polymer heat sink molding process. This article shows that change of the melt flow inside the mold cavity can improve the overall cooling efficiency of a polymer heat sink, which leads to lower temperatures on the heat source used. Two polymer heat sinks of identical geometries were produced. Their high thermal conductivity was given by the use of graphite flakes as the filler. The only difference between the heat sinks was in the position of the fan gate during their production. Different temperatures of the heat source between the two heat sinks were observed for the same measurement conditions. The measurements were conducted at Heatlab, BUT.

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Kominek, Jan, Martin Zachar, Michal Guzej, Erik Bartuli und Petr Kotrbacek. „Influence of Ambient Temperature on Radiative and Convective Heat Dissipation Ratio in Polymer Heat Sinks“. Polymers 13, Nr. 14 (12.07.2021): 2286. http://dx.doi.org/10.3390/polym13142286.

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Miniaturization of electronic devices leads to new heat dissipation challenges and traditional cooling methods need to be replaced by new better ones. Polymer heat sinks may, thanks to their unique properties, replace standardly used heat sink materials in certain applications, especially in applications with high ambient temperature. Polymers natively dispose of high surface emissivity in comparison with glossy metals. This high emissivity allows a larger amount of heat to be dissipated to the ambient with the fourth power of its absolute surface temperature. This paper shows the change in radiative and convective heat transfer from polymer heat sinks used in different ambient temperatures. Furthermore, the observed polymer heat sinks have differently oriented graphite filler caused by their molding process differences, therefore their thermal conductivity anisotropies and overall cooling efficiencies also differ. Furthermore, it is also shown that a high radiative heat transfer leads to minimizing these cooling efficiency differences between these polymer heat sinks of the same geometry. The measurements were conducted at HEATLAB, Brno University of Technology.

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Barba, Alessandro, Barbara Musi und Marco Spiga. „Performance of a polymeric heat sink with circular microchannels“. Applied Thermal Engineering 26, Nr. 8-9 (Juni 2006): 787–94. http://dx.doi.org/10.1016/j.applthermaleng.2005.10.015.

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Liang, C., J. R. Arias und A. Velazquez. „Tip Clearance Effects on Microchannel-Based Heat Sink with Polymeric Fluid“. Journal of Thermophysics and Heat Transfer 30, Nr. 2 (April 2016): 350–58. http://dx.doi.org/10.2514/1.t4592.

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Arayanarakool, Rerngchai, Hian See, Samuel Marshall, Niven Virik, Heng Wang, Poh Lee und Peter Chen. „Rapid Prototyping of Polymer-Based Rolled-Up Microfluidic Devices“. Micromachines 9, Nr. 10 (13.10.2018): 516. http://dx.doi.org/10.3390/mi9100516.

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This work presents the simple and rapid fabrication of a polymer-based microfluidic prototype manufactured by rolling up thin films of polymer. The thin films were fabricated via a casting method and rolled up around a center core with the aid of plasma activation to create a three-dimensional (3D) spiral microchannel, hence reducing the time and cost of manufacture. In this work, rolled-up devices with single or dual fluidic networks fabricated from a single or two films were demonstrated for heat sink or heat exchanger applications, respectively. The experimental results show good heat transfer in the rolled-up system at various flow rates for both heat sink and heat exchanger devices, without any leakages. The rolled-up microfluidic system creates multiple curved channels, allowing for the generation of Dean vortices, which in turn lead to an enhancement of heat and mass transfer and prevention of fouling formation. These benefits enable the devices to be employed for many diverse applications, such as heat-transfer devices, micromixers, and sorters. To our knowledge, this work would be the first report on a microfluidic prototype of 3D spiral microchannel made from rolled-up polymeric thin film. This novel fabrication approach may represent the first step towards the development of a pioneering prototype for roll-to-roll processing, permitting the mass production of polymer-based microchannels from single or multiple thin films.

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Bég, O. Anwar, Atul Kumar Ray, Rama S. R. Gorla, Henry J. Leonard, Ali Kadir, T. A. Bég und B. Vasu. „Homotopy Simulation of Dissipative Micropolar Flow and Heat Transfer from a Two-Dimensional Body with Heat Sink Effect“. Chemical & biochemical engineering quarterly 34, Nr. 4 (2021): 257–75. http://dx.doi.org/10.15255/cabeq.2020.1849.

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Non-Newtonian flow from a wedge constitutes a fundamental problem in chemical engineering systems and is relevant to processing of polymers, coating systems, etc. Motivated by such applications, the homotopy analysis method (HAM) was employed to obtain semi-analytical solutions for thermal convection boundary layer flow of incompressible micropolar fluid from a two-dimensional body (wedge). Viscous dissipation and heat sink effects were included. The non-dimensional boundary value problem emerges as a system of nonlinear coupled ordinary differential equations, by virtue of suitable coordinate transformations. The so-called Falkner-Skan flow cases are elaborated. Validation of the HAM solutions was achieved with earlier simpler models, as well as with a Nakamura finite difference method for the general model. The micropolar model employed simulates certain polymeric solutions quite accurately, and features rotary motions of micro-elements. Primary and secondary shear stress, wall couple stress, Nusselt number, microrotation velocity, and temperature were computed for the effect of vortex viscosity parameter (micropolar rheological), Eckert number (viscous dissipation), Falkner-Skan (pressure gradient) parameter, micro-inertia density, and heat sink parameter. The special cases of Blasius and stagnation flow were also addressed. It was observed from the study that the temperature and thermal boundary layer thickness are both suppressed with increasing wedge parameter and wall heat sink effect, which is beneficial to temperature regulation in polymer coating dynamics. Further, strong reverse spin was generated in the microrotation with increasing vortex viscosity, which resulted in increase in angular momentum boundary layer thickness. Also, both primary and secondary skin friction components were reduced with increasing wedge parameter. Nusselt number was also enhanced substantially with greater wedge parameter.

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Awais, Muhammad, Saeed Awan, A. Aqsa, Nimra Muqaddass, Saeed Rehman und Muhammad Raja. „Numerical and analytical approach for Sakiadis rheology of generalized polymeric material with magnetic field and heat source/sink“. Thermal Science 24, Nr. 2 Part B (2020): 1183–94. http://dx.doi.org/10.2298/tsci180426284a.

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In this analysis, Sakiadis rheology of the generalized polymeric material has been presented with magnetic field and heat source/sink. Convective heating process with thermal radiations have been incorporated. Mathematical modeling has been performed for the conversion of physical problem into set of non-linear equations. Suitable transformations have been employed in order to convert the derived PDE into set of non-linear ODE. Analytical as well as finite difference method based numerical solutions for the velocity and temperature profiles are computed. Graphical and numerical illustrations have been presented in order to analyze the behavior of involved physical quantities. Error analysis for the non-linear system has been presented in order to show the validity of the obtained results. Bar charts have been plotted to present the heat flux analysis. Tabular values of local Nusselt number are computed for the involved key parameters. Heat transfer rates against magnetic and porosity effects found to be decreased since magnetic field and porosity retard the molecular movement of the fluid particles. This controlling property of magnetic field and porosity effects have application in MHD power generation, electromagnetic casting of metals, MHD ion propulsion, etc. Moreover internal heat generation and absorption effects have opposite effects on the fluid temperature.

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Prasher, Ravi S. „Surface Chemistry and Characteristics Based Model for the Thermal Contact Resistance of Fluidic Interstitial Thermal Interface Materials“. Journal of Heat Transfer 123, Nr. 5 (27.02.2001): 969–75. http://dx.doi.org/10.1115/1.1388301.

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Microprocessor powers are increasing at a phenomenal rate, which requires very small thermal resistance between the die (chip) and the ambient, if the current economical methods of conduction and convection cooling are to be utilized. A typical thermal solution in flip chip technology utilizes two levels of thermal interface materials: between the die and the heat spreader, and between the heat spreader and the heat sink. Phase change materials and thermal greases are among the most prominent interstitial thermal interface materials (TIM) used in electronic packaging. These TIMs are typically polymeric matrix loaded with highly conducting filler particles. The dwindling thermal budget has necessitated a better understanding of the thermal resistance of each component of the thermal solution. Thermal conductivity of these particle-laden materials is better understood than their contact resistance. A careful review of the literature reveals the lack of analytical models for the prediction of contact resistance of these types of interstitial materials, which possess fluidic properties. This paper introduces an analytical model for the thermal contact resistance of these types of interstitial materials. This model is compared with the experimental data obtained on the contact resistance of these TIMs. The model, which depends on parameters such as, surface tension, contact angle, thermal conductivity, roughness and pressure matches very well with the experimental data at low pressures and is still within the error bars at higher pressures.

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Tang, L. Q., K. Pochiraju, C. Chassapis und S. Manoochehri. „A Computer-Aided Optimization Approach for the Design of Injection Mold Cooling Systems“. Journal of Mechanical Design 120, Nr. 2 (01.06.1998): 165–74. http://dx.doi.org/10.1115/1.2826955.

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A methodology is presented for the design of optimal cooling systems for injection mold tooling which models the mold cooling as a nonlinear constrained optimization problem. The design constraints and objective function are evaluated using Finite Element Analysis (FEA). The objective function for the constrained optimization problem is stated as minimization of both a function related to part average temperature and temperature gradients throughout the polymeric part. The goal of this minimization problem is to achieve reduction of undesired defects as sink marks, differential shrinkage, thermal residual stress built-up, and part warpage primarily due to non-uniform temperature distribution in the part. The cooling channel size, locations, and coolant flow rate are chosen as the design variables. The constrained optimal design problem is solved using Powell’s conjugate direction method using penalty function. The cooling cycle time and temperature gradients are evaluated using transient heat conduction simulation. A matrix-free algorithm of the Galerkin Finite Element Method (FEM) with the Jacobi Conjugate Gradient (JCG) scheme is utilized to perform the cooling simulation. The optimal design methodology is illustrated using a case study.

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McBride, Daniel, und Chin Su. „Near-field scanning optical microscopy probes with heat sinks for higher power operations“. Materials Research Express 2, Nr. 10 (16.10.2015): 105202. http://dx.doi.org/10.1088/2053-1591/2/10/105202.

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Mora, Mario, Hippolyte Amaveda, Luis Porta-Velilla, Germán F. de la Fuente, Elena Martínez und Luis A. Angurel. „Improved Copper–Epoxy Adhesion by Laser Micro- and Nano-Structuring of Copper Surface for Thermal Applications“. Polymers 13, Nr. 11 (24.05.2021): 1721. http://dx.doi.org/10.3390/polym13111721.

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The objective of this work is the enhancement of metal-to-metal bonding to provide high thermal conductivity together with electrical insulation, to be used as heat sinks at room and cryogenic temperatures. High thermal conductive metal (copper) and epoxy resin (Stycast 2850FT) were used in this study, with the latter also providing the required electrical insulation. The copper surface was irradiated with laser to induce micro- and nano-patterned structures that result in an improvement of the adhesion between the epoxy and the copper. Thus, copper-to-copper bonding strength was characterized by means of mechanical tensile shear tests. The effect of the laser processing on the thermal conductivity properties of the Cu/epoxy/Cu joint at different temperatures, from 10 to 300 K, is also reported. Using adequate laser parameters, it is possible to obtain high bonding strength values limited by cohesive epoxy fracture, together with good thermal conductivity at ambient and cryogenic temperatures.

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Zhang, Xin, Ru-Chun Li und Qi Zheng. „Analysis and simulation of high-power LED array with microchannel heat sink“. Advances in Manufacturing 1, Nr. 2 (Juni 2013): 191–95. http://dx.doi.org/10.1007/s40436-013-0027-0.

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Ernst, G. K. „Influence of Compound Heat Conductivity on the Temperature Distribution in Rotor Type Curemeters“. Tire Science and Technology 19, Nr. 2 (01.04.1991): 68–78. http://dx.doi.org/10.2346/1.2141710.

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Abstract The effective temperature in rotor type curemeters is — according to DIN 53529 — controlled using an unfilled EPDM compound with dicumylperoxide as cross-linking agent. The rate of DCP decomposition has a well-known temperature dependence. This rate is also in all practical cases the same as the rate of cross-linking. Therefore, the measured rate of cross-linking indicates the effective temperature in the reaction cavity. The rotor in common curemeters is clamped. Because it can not be heated directly, this rotor is a heat sink in the cavity. The effect is a temperature gradient in the cavity depending on the heat conductivity of the tested compound. This temperature gradient in rotor type curemeters is compared to rotorless curemeters. It is shown that using the unfilled EPDM/DCP compound for temperature calibration leads to a too high effective temperature for filled compounds.

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Hong, Jung-Pyo, Sung-Woon Yoon, Taeseon Hwang, Joon-Suk Oh, Seung-Chul Hong, Youngkwan Lee, Jae-Do Nam, Md Mainul Hossain Bhuiya und Kwang J. Kim. „High-performance heat-sink composites incorporating micron-sized inorganic fillers and Sn/In metal particles“. Polymer Engineering & Science 52, Nr. 11 (12.05.2012): 2435–42. http://dx.doi.org/10.1002/pen.23190.

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Al-Salem, S. M., A. Y. Al-Nasser, M. H. Behbehani, H. H. Sultan, H. J. Karam, M. H. Al-Wadi, A. T. Al-Dhafeeri, Z. Rasheed und M. Al-Foudaree. „Thermal Response and Degressive Reaction Study of Oxo-Biodegradable Plastic Products Exposed to Various Degradation Media“. International Journal of Polymer Science 2019 (30.04.2019): 1–15. http://dx.doi.org/10.1155/2019/9612813.

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In this work, three plastic film products commonly used as commodity thermoplastic articles were analysed with the aim of characterizing their thermal behaviour and stability. The test specimens were subjected to a series of analytical tests to confirm their biodegradable nature. The specimens ranged between 30 and 70 μm in thickness and showed high concentrations of regulated metals, namely, lead (Pb), postchemical analysis which can lead to its migration to natural sinks. The specimens were also exposed to degressive media, namely, accelerated (UV induced) weathering and soil burial field testing. The weight loss measured exceeded 58% after soil burial indicating deterioration under natural environmental stressors. In addition, the thermal characterization campaign executed with the aim of determining the product’s thermal response followed internationally recognised experimental protocols for the determination of thermal stability. The methodology used followed the International Confederation for Thermal Analysis and Calorimetry (ICTAC) recommendation for thermal stability and the computation of kinetic parameters. The degradation reaction kinetics were also determined postexposure to degressive media. Thermogravimetric analysis coupled with differential scanning calorimetry heat flow analysis and Fourier infrared spectroscopy results was also used in studying the degradation behaviour of the specimens. Analytical kinetic estimation methods relying on model free solutions enabled the determination of the apparent activation energy (Ea) of the specimens postexposure to degradation media. A shift in the degradation mechanism was also detected after studying the kinetic parameters which showed a range of Ea between 86.64 and 226.90 kJ mol-1 depending on the type of specimens and exposure media. It can be concluded that the oxo-biodegradable films are well suited for thermal treatment in the future as discarded plastic solid waste (PSW) articles. This work also paves the way for developing national standards and future plans for societies burdened with PSW accumulation.

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Siegel, Edward, A. Smith, E. Dinn, E. Zeller und G. Dreschoff. „Hydrocarbon polymeric quantum-confinement quantum-wires embedded in diamond via proton-lithography ion-implantation chemical-reaction di… poly-acetylene: nano-electronics & nano-photonics interconnects embedded in optimal heat-sink alternative to gigascale si integration? very-high-tc hyper-(if not super)-conductivity???“ Applied Superconductivity 1, Nr. 10-12 (Oktober 1993): 1949–59. http://dx.doi.org/10.1016/0964-1807(93)90342-y.

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Schartel, Bernhard, und Ulrike Braun. „Comprehensive fire behaviour assessment of polymeric materials based on cone calorimeter investigations“. e-Polymers 3, Nr. 1 (01.12.2003). http://dx.doi.org/10.1515/epoly.2003.3.1.177.

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Abstract Bench scale performance based cone calorimeter investigations were conducted on glass fibre reinforced polyamide 66 (PA-66) and high impact polystyrene (HIPS) materials. Red phosphorus and magnesium hydroxide were used as fire retardants. Dilution, heat sink, barrier and charring mechanisms are considered to be active in the condensed phase. Dilution, cooling and flame poisoning mechanisms are discussed for the gas phase. Cone calorimeter data are used to give a comprehensive fire behaviour assessment in terms of the propensity to cause a quick growing fire and of the propensity to cause a fire of long duration. The external heat flux is varied between 30 and 75 kW/m2 so that the results for combustion behaviour and flame retardancy, respectively, are valid for different fire scenarios and fire tests. Results on the intrinsic contribution of the steady heat release rate per unit area reveal information about the flammability behaviour. UL 94 results are predicted in close correspondence to UL 94 experiments.

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Waqas, Hassan, Umar Farooq, Aqsa Ibrahim, M. Kamran Alam, Zahir Shah und Poom Kumam. „Numerical simulation for bioconvectional flow of burger nanofluid with effects of activation energy and exponential heat source/sink over an inclined wall under the swimming microorganisms“. Scientific Reports 11, Nr. 1 (12.07.2021). http://dx.doi.org/10.1038/s41598-021-93748-x.

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AbstractNanofluids has broad applications such as emulsions, nuclear fuel slurries, molten plastics, extrusion of polymeric fluids, food stuffs, personal care products, shampoos, pharmaceutical industries, soaps, condensed milk, molten plastics. A nanofluid is a combination of a normal liquid component and tiny-solid particles, in which the nanomaterials are immersed in the liquid. The dispersion of solid particles into yet another host fluid will extremely increase the heat capacity of the nanoliquid, and an increase of heat efficiency can play a significant role in boosting the rate of heat transfer of the host liquid. The current article discloses the impact of Arrhenius activation energy in the bioconvective flow of Burger nanofluid by an inclined wall. The heat transfer mechanism of Burger nanofluid is analyzed through the nonlinear thermal radiation effect. The Brownian dispersion and thermophoresis diffusions effects are also scrutinized. A system of partial differential equations are converted into ordinary differential equation ODEs by using similarity transformation. The multi order ordinary differential equations are reduced to first order differential equations by applying well known shooting algorithm then numerical results of ordinary equations are computed with the help of bvp4c built-in function Matlab. Trends with significant parameters via the flow of fluid, thermal, and solutal fields of species and the area of microorganisms are controlled. The numerical results for the current analysis are seen in the tables. The temperature distribution increases by rising the temperature ratio parameter while diminishes for a higher magnitude of Prandtl number. Furthermore temperature-dependent heat source parameter increases the temperature of fluid. Concentration of nanoparticles is an decreasing function of Lewis number. The microorganisms profile decay by an augmentation in the approximation of both parameter Peclet number and bioconvection Lewis number.

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Zeitschriftenartikel zum Thema „Polymeric heat sinks“

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