Showing papers on "Electronics cooling published in 2021"
TL;DR: In this article, a tree-like structure heat sink was proposed to improve the thermal performance of a phase change material (PCM)-based heat sink, which was fabricated by selective laser melting (SLM), a metal additive manufacturing (AM) technique.
47 citations
TL;DR: In this article, a ground-based experimental investigation of the gas-atomized spray cooling using various micro-structured surfaces and a flat surface is provided and discussed, and a cooling correlation of gas-atomic spray cooling upon micro-structure surfaces is provided with a relative error within ±9%.
47 citations
TL;DR: In this article, the authors focused on passive thermal management of electronic devices using heat sinks embedded with single or multiple phase change materials (PCMs) RT58, RT44 and n-Eicosane.
Abstract: The present study focuses on passive thermal management of electronic devices using heat sinks embedded with single or multiple phase change materials (PCMs) RT58, RT44 and n-Eicosane are used as PCMs, while aluminium fins are used as thermal conductivity enhancer (TCE) Single PCM cases are investigated independently while multiple PCMs pairs are studied through their filling in alternate enclosures separately Three constant heat fluxes of 15, 25 and 35 kW/m2 are applied to the heat sinks to investigate PCMs’ thermal performance The numerical model is validated against available experimental results where an acceptable 29% difference in the transient temperature is achieved High values of Nusselt number were discovered at the beginning of melting and the end of solidification stages The RT44 shows the lowest peak temperature and longest melting duration among single PCM cases, due to its high latent heat of fusion When n-Eicosane and RT44 are paired in a heat sink, the best overall thermal performance is achieved where its operational time is increased by 33–12% comparing to single n-Eicosane or RT44 The results show that the multiple PCMs pair of n-Eicosane/RT44 is feasible for high critical temperature devices due to its longer operating time and also lowest average transient temperature
43 citations
TL;DR: In this paper, a review summarizes the significant outcomes with respect to the improvement in the nanofluids for theoretical and experimental results, and some fascinating angles about utilizing nanof-luids in electronic components cooling are introduced.
40 citations
TL;DR: In contrast to pool boiling, flow boiling heat transfer is a more applied mode of heat transfer and has been most widely used in high heat flux cooling systems as mentioned in this paper, and there are two general approaches for improving Flow Boiling heat transfer: active and passive methods.
37 citations
TL;DR: In this article, the authors developed an AI-based method to estimate the pool boiling heat transfer coefficient for sintered porous surfaces, which can handle the complex nature of the coating characteristics such as porosity, coating thickness, and particle size.
Abstract: Owing to the high nucleation site density and relatively robust behavior, sintered coated surfaces are of great interest for thermal management via pool boiling in many industries/applications such as desalination, electronics cooling, petrochemical, and power sector. The coated surfaces have been extensively used to improve the performance of the pool boiling process over the years. Regardless of a large amount of experimental data on the pool boiling of coated surfaces, no accurate mathematical/empirical approaches have been developed to estimate the heat transfer coefficient of these surfaces. The present study develops an AI-based method to estimate the pool boiling heat transfer coefficient for coated porous surfaces. The proposed AI method can handle the complex nature of the coating characteristics such as porosity, coating thickness, and particle size. Via using deep neural networks, the proposed method is applicable for highly wetting fluids (dielectric liquids), refrigerants, and low-wetting liquid (water). Correlation matrix analysis confirms that porosity, coating thickness, particle size, wall superheat, and surface inclination as well as the thermophysical properties of the working fluids are the best independent variables to estimate the considered parameter. Different deep neural networks are designed and evaluated to find the optimized model in terms of its predictive accuracy by experimental data (373 points). The best model with an input layer, three hidden layers, and an output layer (11–30–15–1–1) was able to predict the heat transfer coefficient with overall R2 = 0.976 and (mean absolute error) MAE% = 5.74. The proposed approach is simple and can be employed to optimize the sintered coated surfaces for different cooling applications.
26 citations
TL;DR: In this article, the performance of a spiral liquid block made from nickel is compared with those of the base-plate liquid block and the serpentine liquid block in terms of cooling efficiency.
25 citations
21 citations
TL;DR: In this article, a phase change material (PCM) based heat sink was used to reduce the discharge time of the heat sink in the discharging cycle using baffles, and the performance of the BS was evaluated with different fill ratios and orientations.
19 citations
TL;DR: In this article, the effect of the operating conditions on the performance of passive electronic thermal management systems based on phase change materials is explained, and the main outcome is that the use of the enhanced surface does not always lead to an improvement of the heat transfer performance especially during fast intermittent operations and thus the maximum effective thermal conductivity cannot always be considered the main design objective.
18 citations
TL;DR: In this paper, the heat transfer and entropy generation in electroosmotic flow of two-power-law nanofluids considering viscous dissipation and Joule heating effect are studied.
TL;DR: In this paper, a microbial bio-coating surface modification technique for phase change cooling applications was developed, which was implemented using a facile dip coating method on different metallic and non-metallic surfaces.
TL;DR: In this article, a variable density alternating obliquely truncated microchannel combined with oblique fin enhancement is proposed to improve the temperature uniformity of microchannels with liquid coolants in high heat flux electronics cooling due to their enhanced heat dissipation capacity.
TL;DR: In this article, the feasibility of the proposed thermal management technique has been numerically inspected following the volume-averaging approach of porous media considering a local thermal nonequilibrium to prevail between the solid foam and liquid coolant flowing through.
TL;DR: In this paper, a numerical model was developed to study the behavior of conventional heat sink and phase change material (PCM) heat sink for electronics cooling applications, and the results showed that the PCM heat sink achieved base temperature equivalent to the conventional heat sinks with the heat transfer coefficient between 30 and 40 W/m2-K under constant and variable heat flux conditions.
Abstract: In this study, a numerical model is developed to study the behaviour of conventional heat sink and phase change material (PCM) heat sink for electronics cooling applications. Two different PCMs, RT35HC (ΔTm = 34–36 °C and ΔH = 240 kJ/kg) and RT44HC (ΔTm = 41–44 °C and ΔH = 250 kJ/kg), are selected for the analysis. A comparison has been made between conventional heat sink and PCM-based heat sink under constant and variable heat flux conditions. Further, four different hybrid heat sink design configurations are studied during the cooling period (solidification) and compared with PCM-based heat sink. During the heating period, the conventional heat sink is subjected to different convective cooling environments (h = 10–50 W/m2-K). The results showed that the PCM heat sink achieved base temperature equivalent to the conventional heat sink with the heat transfer coefficient between 30 and 40 W/m2-K under the constant heat flux condition. Under the variable heat flux condition, the base temperature of the PCM heat sink is very much less than the conventional heat sink subjected to 50 W/m2-K. During the cooling period, hybrid heat sinks reduced the heat transfer coefficient by ten times less than that of the PCM heat sink.
TL;DR: In this article, performance studies of heat pipes with deposition of nanoparticles and suitable coating made on the wick structure are reviewed, and various heat transfer mechanisms in heat pipes while using a nanofluid and a porous coating in the evaporator are summarized.
Abstract: Heat pipes are silent heat transfer devices that work on the motion of boiling and condensation process. They have been used in space crafts, heat recovery and ventilation, power conversion, energy, and electronics cooling applications. Over the past few eras, several necessary upgradations in heat pipe technologies have happened to implement new advanced fluids, design modification, and modified wick structures. Heat transfer enhancement due to these upgradations/implementations has been deliberated in many studies. In this paper, performance studies of heat pipes with deposition of nanoparticles and suitable coating made on the wick structure are reviewed. Various heat transfer mechanisms involved in heat pipes with nanoparticles deposition on the evaporator are summarized. Also, the various heat transfer mechanisms in heat pipes while using a nanofluid and a porous coating in the evaporator are summarized. This review shall offer a superior comprehension of the improvement required in cooling devices and help future research fraternity to develop advanced cooling gadgets.
TL;DR: In this article, the exact solution of the temperature field is established for a fully developed forced convection in a parallel plate channel saturated with a porous medium, subjected to uniform heating at one boundary.
20 Jan 2021
TL;DR: In this paper, the authors numerically study the heat transfer and hydrodynamic performance of a graphene-based hybrid nanofluid flowing through a microchannel for electronics cooling applications.
Abstract: The objective of this paper is to numerically study the heat transfer and hydrodynamic performance of a graphene-based hybrid nanofluid flowing through a microchannel for electronics cooling applic...
TL;DR: In this article, the structural regularity of copper inverse opals (IO) is exploited to develop capillary structures with unprecedented fidelity, enabling a detailed study of the impacts of architectural design variables on boiling critical heat flux (CHF) as well as liquid and vapor transport properties.
23 Jan 2021
TL;DR: In this paper, the authors present a review of the latest experimental and theoretical studies on enhancing boiling/evaporative heat transfer using nanofabricated porous coatings, with potential applications in the fields of electronics thermal management.
Abstract: This paper presents a review of the latest experimental and theoretical studies on enhancing boiling/evaporative heat transfer using nanofabricated porous coatings, with potential applications in the fields of electronics thermal management. It is proposed that the key to enhanced heat transfer lies in optimal design of nanostructures that can activate a reduced/negative pressure through nanoscale evaporation, allow continuous liquid microflow through the porous nanostructures, and facilitate bubble release from the coating. In this point of view, a multiscale predictive approach that covers a wide size range from nanoscale to the system size is critical. We propose this can be achieved by combing Molecular Dynamics (MD) simulations, the Lattice Boltzmann Method (LBM), and Two-Fluid Model (TFM) in a coupled way, with the MD addressing the generation of negative pressure, LBM modelling the liquid microflow, and TFM simulating the two-phase coolant flows. The comprehensive modelling strategy will provide a mechanistic all-in-one simulation of the complex multiscale process, and greatly boost the design of optimal nanostructures.
TL;DR: This review paper looks at different actuation methods (electromagnetic, piston cylinder, piezoelectric, etc.) to generate synthetic jet cooling and proposes an empirical correlation based on available data using non-linear regression via computational tools.
Abstract: Effective removal of excess heat from electronics equipment is the key to its intended functionality. A Defense Advanced Research Projects Agency (DARPA) hard problem is proposed in microtechnologies for the air-cooled heat exchangers (MACE) program that posed challenges to reduce the heat sink size fourfold while using only 50% of the current power budget. While numerous heat removal techniques have been proposed over the last several decades, synthetic jet actuator (SJA) is one of the leading candidates to create a game-changing cooling performance. This is due to its inherent advantages, such as size, low power consumption, ease of use, and affordability. This review article looks at different actuation methods (electromagnetic, piston cylinder, piezoelectric, and so on) to generate synthetic jet cooling. The performances of these approaches vary and need a procedure to unify the predictive capability. The performances are evaluated based on actuation (stroke length, operating frequency, and jet-to-heater spacing) and geometric parameters (shape and size of the cavity and the orifice). The flow characteristics and jet formation criterion are also discussed methods, and a critical commentary is added to normalize previous findings. Available correlations for predicting Nu numbers are evaluated and summarized through data sets for a possible unification. Finally, an empirical correlation is proposed based on available data using nonlinear regression via computational tools. To conclude, the challenges and research gaps are enumerated covering the fundamental and applied aspects of those jets for the implementation in electronics thermal management.
TL;DR: In this paper, a two-sensor 3ω-2ω method with a novel experimental procedure design is proposed, which can well address those deficiencies in the conventional 3ω method.
Abstract: Thermal boundary resistance (TBR), which measures an interface's resistance to the thermal flow, is of critical importance among various areas, such as electronics cooling and thermoelectric materials As for measuring TBR, electrical techniques are generally less sensitive compared to optical ones, but they are easily operable and compatible with the measurement of other electric properties; thus, it is highly desirable to develop electrical methods with higher accuracy and larger measurement range Here, a two-sensor 3ω-2ω method with a novel experimental procedure design is proposed, which can well address those deficiencies in the conventional 3ω method Two parallel metal sensors are fabricated, with one of them being wide and the other being narrow The temperature changes of these two sensors are measured by detecting the 3ω and 2ω signals, respectively The measurement includes three steps: (1) obtain thin film's thermal conductivity from the wide sensor's 3ω thermal response; (2) obtain substrate thermal conductivity from the narrow sensor's 2ω thermal response; and (3) derive an effective TBR from the narrow sensor's 3ω thermal response Moreover, it is found the TBRs of metal/dielectric and dielectric/substrate interfaces are distinguishable due to the considerable difference between their contact areas, which enables us to separate these two TBRs by varying the contact area (heater's width) Then, our method is employed to probe the TBRs between the Al2O3 nanofilm and Si as well as SiC substrates at room temperature and good agreement with the previous measurements is achieved, verifying its feasibility Our present scheme will be helpful for the experimental study of interfacial thermal transport
TL;DR: In this article, the effects of perforation shape and size on various parameters, e.g., total drag force, average Nusselt number, perforated fin efficiency (PFE), heat transfer performance enhancement (HTPE), and fin optimization factor (η), were evaluated.
09 Oct 2021
TL;DR: In this paper, a comprehensive review on the effect of various geometrical and actuation parameters on the flow dynamics and heat transfer behavior of synthetic jet cooling is presented, including orifice geometry, excitation frequency, amplitude, etc.
Abstract: Extensive research has been carried out to meet the cooling demand of high heat flux electrical and electronic devices. Among the emerging cooling technologies, synthetic jet (SJ) cooling has proved to be an efficient and compact candidate. This paper presents a comprehensive review on the effect of numerous geometrical and actuation parameters on the flow dynamics and heat transfer behaviour of synthetic jet cooling. The parameters studied include orifice to surface spacing, stroke length, frequency of excitation, orifice shape, orifice plate thickness, cavity shape, jet vectoring, and the acoustic aspect. The present studies also extended the discussion on a novel dual synthetic jet (DSJ) and SJ embedded heat sink. Furthermore, the flow and heat transfer characteristics of the SJ are compared with the baseline case of the continuous jet. Among the studied parameters, it is found that orifice geometry, excitation frequency, amplitude, etc. play a vital role in SJ's thermal performance. Also, careful selection of the multi-orifice jet parameters can be employed for mitigating the recirculation effects of a single orifice SJ. New research areas have been identified to enable the effective implementation of SJ for high heat flux electronics cooling.
01 May 2021
TL;DR: In this article, two novel micro-jet impingement vapor chamber configurations, including separated micro-board vapor chamber (SJVC) and integrated micro-joint vapor chambers (IJVC), were designed and tested.
TL;DR: In this article, experimental tests in steady-state are carried out using R1233zd(E) and R1224yd(Z) as a working fluid to investigate the respective influences and resulting design requirements.
Abstract: Two-phase loop thermosyphon (TPLT) is a promising technology looking at highly effective electronics cooling. Due to strong coupling between the internal and external parameters, in this study experimental tests in steady-state are carried out using R1233zd(E) and R1224yd(Z) as a working fluid to investigate the respective influences and resulting design requirements. The relationship between the governing thermal and flow equations is presented to facilitate the interpretation of the test results. The study shows a stable flow and cooling performance over a wide range of heat loads and recooling temperatures. The refrigerant charge is identified as one of the main influencing factors, with an optimum being between excessive subcooling and beginning dry-out. Both tested refrigerants lead to basically similar results, showing minor differences regarding thermal performance and system stability.
01 Oct 2021
TL;DR: In this paper, the thermal conductivity of 2H-Germanium carbide (2H-GeC) using first principles calculations was reported. And the authors also analyzed the phonon group velocities, phonon scattering rates and mode contribution from acoustic and optical phonons.
Abstract: Designing and searching for a high thermal conductivity material in both bulk and nanoscale is highly demanding for electronics cooling. In this work, we studied the thermal conductivity of 2H-Germanium Carbide(2H-GeC) using first principles calculations. At 300 K, we are reporting a high thermal conductivity of 1350 Wm-1K-1 and 1050 Wm-1K-1 along a-axis and c-axis respectively for pure 2H-GeC. These values are 130% higher than the thermal conductivity of 2H-silicon carbide and 20% lower than cubic germanium carbide(c-GeC). We analyzed the phonon group velocities, phonon scattering rates and mode contribution from acoustic and optical phonons. We also studied the thermal conductivity of nanostructured 2H-GeC for heat dissipation in nanoelectronics. At room temperature, thermal conductivity of 2H-GeC is ~65 Wm-1K-1 at nanometer length scales(L) of 100 nm is equal to that of the c-GeC. This result suggests that, 2H- GeC will be a promising material for thermal management applications in micro/nano electronics.