CPU Heat Sink Research Articles

Numerical study optimation design of CPU cooling system analysis using CFD method

Computers often experience damage to the CPU, especially the mainboard and processor, due to several factors, including human error or excessive use and environmental conditions. Component placement is frequently utilized to improve the CPU room conditions to keep it cool. This research numerically investigates desktop PC processors and heatsink configurations for mechanical engineering vocational learning. The kind of metal material, number of fans, and fan arrangement were all tested at three levels. The computer components in this research are the CPU, heatsink, fan, and processor—a 65-watt Thermal Design Power (TDP) CPU with a constant air intake speed of 5 m/s. The criteria investigated include metal type (steel, aluminum, and copper), cooling design (horizontal, vertical, and mixed), and fan count (2-4-8). The methods used in this research are the Computational Fluid Dynamics (CFD) method and the Taguchi method to examine fluid flow characteristics and temperature. Numerical results show the maximum temperature is 123 °C in the vertical, eight-fan, and steel configurations. Minimum temperature 39.22 °C in mixed configuration, eight fans, and copper. These findings reveal that the kind of metal material, number of fans, and fan arrangement all impact the CPU cooler and heatsink configuration. However, the Taguchi method can provide a more detailed understanding of configuration.

Design of a CPU Heat Sink with Minichannel-Fins & its Thermal Analysis

Abstract In this paper, the design and the thermal analysis of a tribled microprocessor cooler combining the advantages of strong swirl flow and minichannel-fins and CuO nanofluid, have been presented. It is thought that the results will contribute to the understanding of the effects of parameters on the cooling flux of the heat sink and the decline at the microprocessor temperature, as Reynolds number in the minichannels and CuO % volume fraction. The results have exhibited that the total performance of the heat sink cooled with the mixture of water–CuO-EG nanofluids increases with the increase of Re number and the %load of nanoparticles in the coolant. It has been determined that the energy withdrawn from the microprocessor was 241 times higher than the energy generated for maximum CuO load and Re number conditions. Besides, the highest temperature decrease has been measured at the maximum CuO load value and maximum Re number.

Heat transfer and thermal analysis in a semi-spherical fin with temperature-variant thermal properties: an application of Probabilists’ Hermite collocation method

Finned surfaces are utilized in several industrial and technological applications including radiators in cars, air conditioning systems, and computer CPU heat sink to dissipate heat through convection or radiation. In this regard, the heat transfer enhancement utilizing the fins has received more attention in the scientific field. Motivated by this, the present research explicates temperature variation through a convective-radiative semi-spherical fin (SSF) with internal heating by taking into consideration of linear and nonlinear temperature-dependent heat transfer coefficient and thermal conductivities. Furthermore, the efficiency and heat transfer aspects of the fin are elaborated. The Rosseland approximation is used in this study to analyze radiation heat exchange. The developed energy equation is converted to a nonlinear ordinary differential equation (ODE) using dimensionless terms, and the probabilists’ Hermite collocation method (PHCM) is used to solve this problem. The governing parameters have been varied in their appropriate ranges to illustrate their impact on the thermal profile, and the results have been portrayed graphically. Some notable key findings of the current analysis are that as the scale of the convection–conduction and the radiation number upsurges, the thermal distribution through SSF drops. On the other hand, thermal distribution escalates for heat generation and thermal conductivity parameters.

Design parameter optimization of a CPU heat sink using numerical simulation for steady-state thermal analysis and CFD-modeling

This paper deals with the design of a CPU cooling system using a novel numerical modelling approach based on automatic calculation in a commercial software. A research object is an aluminium CPU heat sink with a thermal design power of 50 W with a new fin design. A numerical model of the cooling process has been developed, and the heat sink efficiency has been investigated. The main goal of optimization was to get the minimum temperature of the CPU processor at the minimum mass of the heat sink. The comparative analysis of the results that obtained via three methods (screening, adaptive multiple-objective, multi-objective genetic algorithm) was performed. This analysis showed that screening was the least time-consuming method, but it did not provide the required solution. Adaptive multiple-objective and multi-objective genetic algorithm solutions show similar results but significantly differ in time. It was established that the adaptive multiple-objective method is the best method for the heat sink optimization task. At the determined optimal design parameter, the CPU temperature is in the range 304–307 K, while the mass was 81–87 g. In comparison, the heat sink mass before optimization of the design parameters was 93 g at the CPU temperature of 309–311 K.

Stochastic heat transfer analysis and reliability assessment under non-stationary random thermal load using the explicit time-domain method

Efficient and accurate reliability assessment is of utmost importance for a safe and economical design of engineering equipment involving stochastic heat transfer. However, the stochastic analysis of large-scale heat transfer problems under non-stationary random thermal loads is still a challenging task due to the heavy computational burden. This paper extends the explicit time-domain method (ETDM), an efficient method initially developed for random structural vibration, to stochastic heat transfer problems. In ETDM, the underlying physical law driving the uncertainty propagation is first converted to a discrete and algebraic form through deterministic impulse analyses, resulting in the explicit expressions of concerned responses in the time domain. Using the explicit expressions, the statistics of the random system responses can be efficiently evaluated. With the deterministic impulse analyses serving as a bridge, the physical mechanism is treated separately from the stochastic evolution mechanism. Thus, ETDM can be deemed a general method for stochastic problems governed by various physical laws. Its capability is demonstrated by solving large-scale heat transfer problems subjected to non-stationary random thermal loads. The efficiency and accuracy of the method are highlighted by the reliability assessment of a CPU heat sink discretized by a very fine finite element mesh.

Numerical Optimization of a CPU Heat Sink Geometry

During its operation CPU dissipates undesirable heat. Therefore, heat sink is very essential in modern computing system to absorb extra heat dissipated by the CPU. Forced convection air cooling is common approach. In the present work, a steady-state convective heat transfer process is analyzed for CPU cooling. A rectangular fin heat sink equipped in a computer chassis is numerically investigated and simulated using the software ANSYS CFX. A two-equation based turbulence model is chosen to capture the turbulence of the flow inside the domain. The overall dimension of the heat sink is optimized for three different parameters of the heat sink such as fin quantity, fin height and baseplate thickness. An optimum fin quantity, fin height and baseplate thickness are found, and, respectively. Two different orientations of fins are also compared. Better thermal performance is achieved when the fin channel is perpendicular to the surface parallel to the outlet. The average temperature of the heat sink is found. It is also predicted that the heat sink studied here is capable to keep the CPU temperature underthat is reasonably acceptable.

Parametric Study of the Radiated Emission From the Plate-Fin CPU Heatsink at 2–8 GHz

This study proposes an approach to minimize the electromagnetic radiated emissions (RE) from the plate-fin type heatsinks, and the proposed approach is based on the parametric analysis using measurement and simulation results. In the parametric analysis, width, length, height, number of fins, base height, and fin thickness on electromagnetic interference effects are taken into account in the range of 2–8 GHz (S-C band). Simulations are held as a first step, and that is followed by the production of them. The next step is conducting regular standard measurements in an anechoic chamber to validate the simulation results. According to the results, first, parameters such as length, fin height and width are more effective on radiated emission than the others with an amount of change in RE of 1–6 dBmV/m. Second, these three parameters are effective in 52%, 73%, and 38% of the 2–8 GHz band, respectively. The length of the heatsink is recommended in the widest frequency band (73%). Lastly, when the effects of these three parameters on RE are examined, width is the most efficient with 5–6 dBmV/m.

Analysis of Thermal Performance Metrics—Application to CPU Cooling in HPC Servers

Optimization of heatsinks has a critical importance for the energy-efficient cooling of high-performance computing (HPC) servers to meet reliability, performance, and cost targets. This article provides a detailed application of the effectiveness as a performance metric to provide a qualitative comparison of the CPU heatsink solutions. First, the use of effectiveness as a metric to provide an absolute performance of heatsinks on a simple scale of 0–1 is highlighted. Then, the effectiveness and thermal resistances are compared to explore the limits of air cooling and the relative merits of liquid cooling. Second, a response surface method (RSM) for the heatsink optimization is presented. Furthermore, a response surface optimization (RSO) based on the design of experiments (DOE) is performed on the numerical models of the heatsink and cold plates using FloTHERM computational fluid dynamics (CFD) software. The simulation results obtained at 45 °C inlet are used to provide an objective comparison among the optimum heatsink and cold plates. The simulations show that heatsinks have the effectiveness of 0.65–0.75 and a cooling capability of 150–250 W. The cold plates have an effectiveness of 0.25–0.30 and a cooling capability of 325–425 W. Furthermore, the simulation results are compared with benchmark validation studies. Counterintuitively, the higher effectiveness obtained for the air-cooled heatsinks indicates limited scope for further improvement, whereas the cold plates (with lower effectiveness) provide great scope for further improvements to meet future cooling challenges.

Narrowband Polaritonic Thermal Emitters Driven by Waste Heat.

There are a broad range of applications for narrowband long-wave infrared (LWIR) sources, especially within the 8–12 μm atmospheric window. These include infrared beacons, free-space communications, spectroscopy, and potentially on-chip photonics. Unfortunately, commercial light-emitting diode (LED) sources are not available within the LWIR, leaving only gas-phase and quantum cascade lasers, which exhibit low wall-plug efficiencies and in many cases require large footprints, precluding their use for many applications. Recent advances in nanophotonics have demonstrated the potential for tailoring thermal emission into an LED-like response, featuring narrowband, polarized thermal emitters. In this work, we demonstrate that such nanophotonic IR emitting metamaterials (NIREMs), featuring near-unity absorption, can serve as LWIR sources with effectively no net power consumption, enabling their operation entirely by waste heat from conventional electronics. Using experimental emissivity spectra from a SiC NIREM device in concert with a thermodynamic compact model, we verify this feasibility for two test cases: a NIREM device driven by waste heat from a CPU heat sink and one operating using a low-power resistive heater for elevated temperature operation. To validate these calculations, we experimentally determine the temperature-dependent NIREM irradiance and the angular radiation pattern. We purport that these results provide a first proof-of-concept for waste heat-driven thermal emitters potentially employable in a variety of infrared application spaces.

Experimental and numerical investigations on heat transfer and fluid flow characteristics of integrated U-shape micro heat pipe array with rectangular pin fins

A novel air-cooled CPU heat sink integrated U-shape micro heat pipe array with rectangular pin fins (U-MHPA-RPF) is proposed. The heat transfer and friction characteristics of U-MHPA-RPF were investigated by the wind tunnel experimental set up systematically. The results show that the operating temperature can be reduced easily below 75 °C when the input power reached 130 W. The simplified three-dimensional model was established in ANSYS ICEM, the conjugate heat transfer from the CPU to the air were computed numerically in ANSYS Fluent for a range of air flow at different heating powers. Verified by the experimental results, the thermal resistance of each part of the heat sink is discussed. The contact thermal resistance is the major component, the advantage of the U-MHPA-RPF heat sink is proved by the lower values of the thermal resistance of the heat sink. By changing the Reynolds number, it is found that the cooling device could be operated at small air flow rates to reduce fan power consumption and noise.

Modelling of the Temperature Difference Sensors to Control the Temperature Distribution in Processor Heat Sink.

This paper has three main purposes. The first is to investigate whether it is appropriate to use a planar thick-film thermoelectric sensor to monitor the temperature difference in a processor heat sink. The second is to compare the efficiency of two heat sink models. The third is to compare two kinds of sensors, differing in length. The model of the CPU heat sink sensor system was designed for numerical simulations. The relations between the CPU, heat sink, and the thermoelectric sensor were modelled because they are important for increasing the efficiency of fast processors without interfering with their internal structure. The heat sink was mounted on the top of the thermal model of a CPU (9.6 W). The plate fin and pin fin heat sinks were investigated. Two planar thermoelectric sensors were mounted parallel to the heat sink fins. These sensors monitored changes in the temperature difference between the CPU and the upper surface of the heat sink. The system was equipped with a cooling fan. Switching on the fan changed the thermal conditions (free or forced convection). The simulation results showed the temperature gradient appearing along the sensor for different heat sinks and under different thermal conditions. Comparison of the results obtained in the simulations of the CPU heat sink sensor systems proves that changes in the cooling conditions can cause a strong, step change in the response of the thermoelectric sensor. The results suggest that usage of the pin fin heat sink model is a better solution for free convection conditions. In the case of strong forced convection the heat sink type ceases to be significant.

Investigation of a computer CPU heat sink under laminar forced convection using a structural stability method

In the present study, the thermal performance of an air-cooled, flat-plate heat sink in forced convection was performed using a three-dimensional analytical model. To validate the present model, this solution is compared with numerical and experimental results that agree. This research studies the influence of heat sink thermal performance and of environmental parameters on the heat sink’s stability against thermal stress, which is essential for manufacturers’ goals. The effective parameters on heat transfer rate from the surface of heat sink were investigated. Reynolds and Nusselt numbers, heat transfer coefficient, fins height, and fins number were studied under various air flow velocities. In addition, the thermal stress (structural stability method) was investigated. Enhancement of the airflow velocity caused the Nusselt number value to incline, which increases the heat transfer coefficient. Increasing the Reynolds number from 3.80*103 to 2.28*104 leads to less thermal stress by 47.36%, less deformation by 50%, less surface temperature by 28.57%, and, consequently, less geometry failure. Results depicted that pure convection has less heat transfer by 1.66% compared with convection-radiation heat transfer, and enhancing the fins number and fins height reduces the surface temperature by 25% and 20%, respectively. As a result, the chosen range of the Reynolds number is totally suitable for this high-temperature device that does not allow thermal stress to deform the fins of the heat sink.

Effects of the location of the inlet and outlet on heat transfer performance in pin fin CPU heat sink

A numerical analysis is performed for heat sinks with varied inlet and outlet layouts. The traditional model (heat sink A), has its inlet and outlet located on opposing sides. For heat sinks B-D, the coolant flows vertically into the heat sink from the center of the top wall. These models have either one, two, or four outlets near the sides of the top wall. The corresponding temperature fields, flow fields, pressure drop, and thermal characteristics are presented based upon a verified computational model. The numerical results indicate that the Nu number of the heat sink with four outlets is lower than that of the heat sink with one outlet. However, the four-outlet model presents a lower flow resistance and a higher comprehensive coefficient. The same thermal performance can be obtained with lower energy consumption when four-outlet heat sink D is used. This paper demonstrates that utilizing the proper layout can improve the comprehensive coefficient of a heat sink.

Experimental study on influences of cylindrical grooves on thermal efficiency, exergy efficiency and entropy generation of CPU cooled by nanofluids

An experiment set for researching the flow and heat transfer characteristics of nanofluids flowing through CPU is established and validated. The influences of groove depths (1 mm, 2 mm, 3 mm) and arrangement modes (aligned and staggered arrangements) on thermo-hydraulic performances of CPU cooled by TiO2-water nanofluids are explored. In addition, the influences of nanoparticle mass fractions (0.0, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%) and Reynolds numbers (472–1198) are studied. It is found that there is a most appropriate nanoparticle mass fraction (0.3%) and groove depth (2 mm) for the lowest CPU temperature. Heat transfer augmentation of CPU heat sink is more sensitive to staggered arrangement grooves and high Reynolds number. Nanofluids (0.3%) in CPU heat sink with staggered arrangement grooves (2 mm) show the best heat transfer performances. Lastly, thermal efficiency, exergy efficiency and entropy generation are applied to analyze the cooling performance of enhanced structure. Results show that the thermal efficiency decreases with mass fraction when Reynolds number is less than 791, but increases with the depth of groove. Exergy efficiency of the groove structure can be obviously strengthened under the same pumping power and mass flow rate. From entropy generation analysis, it is found that the aligned arrangement shows lower entropy generation performance than aligned arrangement.

Experimental study on thermo-hydraulic performance of nanofluids in CPU heat sink with rectangular grooves and cylindrical bugles based on exergy efficiency

An experiment system for CPU cooling based on nanofluids is set up. The flow and heat transfer characteristics of TiO2-water nanofluids in CPU heat sink are experimentally investigated. The influences of rectangular groove depths (1 mm, 2 mm) and cylindrical bulge arrangement modes (aligned and staggered arrangements) on thermo-hydraulic performances of CPU cooled by TiO2-water nanofluids are analyzed. In addition, the influences of nanoparticle mass fractions (0.0%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%) and Reynolds numbers (472-1198) are studied. The thermal efficiency and exergy efficiency evaluation plots are developed and are applied to evaluate the thermo-hydraulic performance of nanofluids. It is found that large depth rectangular groove and staggered arrangement cylindrical bulges are beneficial to heat transfer enhancement. Nanofluids with mass fraction of 0.3% and 0.4% show the best cooling performance for rectangular grooves structure and cylindrical bulges structure respectively. CPU with rectangular grooves and cylindrical bugles shows higher exergy efficiency than that with smooth surfaces under the same pump power. The exergy efficiency is sensitive to deep grooves, aligned arrangement bulges, small Reynolds number. Nanofluids with low mass fraction (0.1%) show the highest exergy efficiency.

Experimental study on thermo-hydraulic performances of CPU cooled by nanofluids

Stable Al2O3-water and TiO2-water nanofluids are prepared, and the morphology of nanoparticles and the stability of nanofluids are analyzed. An experimental set for heat transfer characteristics of CPU cooled by nanofluids is established in this paper. The heat transfer and flow characteristics of nanofluids in the CPU heat sink are experimentally studied. The effects of nanoparticle mass fractions (Al2O3-water: 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 1%, 1.5% and 2%; TiO2-water: 0.1%, 0.2%, 0.3%, 0.4%, 0.5% and 1%) and Reynolds numbers (Re: 146, 275, 406, 479, 541, 593, 707 and 812) on the heat transfer and flow characteristics are discussed. In addition, the comprehensive evaluation for thermo-hydraulic performance of nanofluids is investigated. It is found that the nanofluids with the highest nanoparticle mass fraction have not the best heat transfer performance, and Nusselt number firstly increases and then decreases with nanoparticle mass fraction, and the critical nanoparticle mass fractions for the best heat transfer performance of Al2O3-water and TiO2-water nanofluids are ω=1.0% and ω=0.4% respectively. It is also found that Al2O3-water and TiO2-water nanofluids can reduce the temperature of CPU by 23.2% and 14.9% at best compared with water respectively.

Experimental and Transient Thermal Analysis of Heat Sink Fin for CPU processor for better performance

The advancement of the digital computer and its utilization day by day is rapidly increasing. But the reliability of electronic components is critically affected by the temperature at which the junction operates. The designers are forced to shorten the overall system dimensions, in extracting the heat and controlling the temperature which focus the studies of electronic cooling. In this project Thermal analysis is carried out with a commercial package provided by ANSYS. The geometric variables and design of heat sink for improving the thermal performance is experimented. This project utilizes thermal analysis to identify a cooling solution for a desktop computer, which uses a 5 W CPU. The design is able to cool the chassis with heat sink joined to the CPU is adequate to cool the whole system. This work considers the circular cylindrical pin fins and rectangular plate heat sink fins design with aluminium base plate and the control of CPU heat sink processes.

Experimental investigations on solar flat plate collector by changing geometry of fin using CFD - a review

Fins are extended surface which increase the heat transfer rate. It is most commonly used in heat exchanger device such as car radiator, computer CPU heat sink and hydrogen fuel cell, etc. Fins increase area of heat transfer in cooling and heating application. Our ultimate aim is to reduce losses present in flat plate collector by conduction, convection and re-radiation. Lots of experimentation has been done to improve the heat transfer rate of solar water heater by adding fins of helical, rectangle, circular, trapezoidal section as well as twisted shape. This paper makes summary of the all previous work on solar FPC with number of geometrical shapes of fins and their effect on efficiency of flat plate collector. As surface area increases heat transfer from fins also increases. So implementation of fin in solar FPC is also a most promising technique that enhances the heat transfer rate through absorber.

EMC Computer Modeling Techniques for CPU Heat Sink Simulation

This paper presents finite-element frequency domain results for electromagnetic radiation emitted from high power microelectronic circuits connected to a heat sink. The heat sink model associated with one of the IEEE EMC challenging problems has been used to investigate three different grounding configurations. A new simulation model for the Intel P4 CPU heat sink is proposed and analyzed. A resonant frequency of 2.6 GHz with a reflection coefficient of 8.3 dB was found for the CPU heat sink. This is close to the IEEE and Bluetooth wireless communication system's operating frequency of 2.4 GHz. An optimal design of the CPU heat sink design should be performed in order to minimize the radiated emission from the CPU heat sink

Elastic Buckling Analysis of Die Fins during Extrusion

In this study, elastic buckling criteria for die fins during extrusion of complex-shaped parts are analytically derived. In this analytical model, the fins of the extrusion die are regarded as cantilever beams with a narrow rectangular cross section. The load intensity acting on each fin is assumed to be distributed uniformly, which is quite similar to the actual distribution. The elastic critical load intensity of buckling is successfully obtained by solving simultaneously the moment equilibrium differential equations. A commercial finite element package “DEFORM 3D" is also employed to simulate the flow pattern of the billet inside the die in extrusion of a CPU heat sink. The stress distribution pattern on the fins of the extrusion die is discussed.