scholarly journals An Analytical and Experimental Evaluation of a Heat Sink Under Constant Heat Flow and Forced Convection Heat Transfer

2021 ◽  
Vol 53 (4) ◽  
pp. 210405
Author(s):  
Ehsan Fadhil Abbas
Keyword(s):  
Exact Solution ◽  
Heat Flow ◽  
Heat Sink ◽  
Experimental Result ◽  
Maximum Temperature ◽  
Average Error ◽  
Airflow Rate ◽  
Convection Heat ◽  
Constant Heat ◽  
Error Ratio

In this study, the exact transient differential equation was used to calculate the convection heat loss in a heat sink with a rectangular cross section fin. The result of the analytic solution was compared to the result from experiments conducted on a standard heat sink. The experiments were performed at a constant heat flow of 9000 W/m2 and a low airflow rate ranging from 12 to 100 cm3/s in seven steps. The comparative results showed that while there was good agreement between the experimental result and the exact solution, the average error ratio increased with an increase of the airflow rate. However, the maximum average error ratio between the experimental result and the exact solution did not exceed 6.4%. The maximum temperature distribution in the heat sink was obtained at a time of 900 s in all experiments.

Thermal Behaviors in a Square Duct with U-Ribbed Tape Inserts

2014 ◽  
Vol 931-932 ◽  
pp. 1208-1212
Author(s):  
Chitakorn Khanoknaiyakarn ◽  
Sompol Skullong ◽  
Pongjet Promvonge ◽  
Nuthvipa Jayranaiwachira
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Performance Enhancement ◽  
Thermal Characteristics ◽  
Longitudinal Vortex ◽  
Experimental Result ◽  
Airflow Rate ◽  
Constant Heat ◽  
Square Duct ◽  
The One

This paper presents an experimental study on thermal characteristics in a constant heat-fluxed square-duct heat exchanger with U-ribbed tape inserts. The experiments are carried out by varying airflow rate for Reynolds number ranging from 4000 to 38,000. The insertion of the U-ribbed tape is performed with an axial rib-pitch set to four times duct-height (4H) at a single attack angle, α=45° and the ribbed tape is diagonally inserted in the square duct in order to generate longitudinal vortex flows. Effects of five blockage ratios (e/H=0.1, 0.15, 0.2, 0.25 and 0.3) on heat transfer and friction loss are experimentally investigated. The experimental result shows that the insertion of the U-ribbed tape at e/H=0.3 provides the highest heat transfer and friction factor values but the one at e/H=0.25 yields the highest thermal performance enhancement.

Thermal Performance of a Phase Change Material-Based Heat Sink Subject to Constant and Power Surge Heat Loads: A Numerical Study

2020 ◽  
Vol 13 (3) ◽  
Author(s):  
Rajesh Akula ◽  
C. Balaji
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Heat Sink ◽  
Heat Load ◽  
Numerical Study ◽  
Heat Sinks ◽  
Superior Performance ◽  
Maximum Temperature ◽  
Constant Heat ◽  
Change Material

Abstract A power surge is a frequent phenomenon that occurs in electronics. Inadequate and improper cooling during power surges results in a rapid increase in operating temperatures that may lead to failure of the electronics. In the present investigation, the thermal characteristics of a phase change material (PCM)-based heat sinks, having different configurations and orientations of fins, subject to (i) constant heat load and (ii) heat load with a power surge, are studied numerically. Preliminary investigations showed that a heat sink with PCM gets heated at a much lower temperature than an air cooled heat sink. Following this, four finned heat sinks are considered for further investigations. The heat sink with PCM, sans fins, is used for baseline comparison. The orientation of fins in the other four heat sinks is either vertical or horizontal with square and rectangular cross sections. The heat sink and fins are made of aluminum, and the PCM used is n-eicosane (C20 H42). The enthalpy-porosity method is used to model the solid–liquid phase change in the PCM. All the transient three-dimensional numerical simulations are carried out using ansys fluent 15.0. For a constant heat load of 5 W and power surges of various magnitudes at different time instants, the heat sink with vertical square fins shows superior performance. However, the performance variation among the heat sinks with different fin configurations is insignificant for constant heat load. Even so, for power surges, the location and the configuration of fins have a significant effect on the heater temperature. Cases with high power surge and shorter duration of the surge were also considered to critically examine the effect of fins in controlling the maximum temperature in the heat sink. The numerical results of the best-performing heat sink, i.e., the heat sink with vertical square fins, are finally validated against in-house experiments.

scholarly journals Study of Mini Channel Heat Sink with Different Internal Configuration

2020 ◽  
Vol 319 ◽  
pp. 02004
Author(s):  
Muhammad Akif Rahman ◽  
Md Badrath Tamam ◽  
Md Sadman Faruque ◽  
A.K.M. Monjur Morshed
Keyword(s):  
Nusselt Number ◽  
Thermal Performance ◽  
Heat Sink ◽  
Rectangular Channel ◽  
Three Dimensional ◽  
Heat Sinks ◽  
Maximum Temperature ◽  
Rectangular Channels ◽  
Flow Through ◽  
Internal Configuration

In this paper a numerical analysis of three-dimensional laminar flow through rectangular channel heat sinks of different geometric configuration is presented and a comparison of thermal performance among the heat sinks is discussed. Liquid water was used as coolant in the aluminum made heat sink with a glass cover above it. The aspect ratio (section height to width) of rectangular channels of the mini-channel heat sink was 0.33. A heat flux of 20 W/cm2 was continuously applied at the bottom of the channel with different inlet velocity for Reynold’s number ranging from 150 to 1044. Interconnectors and obstacles at different positions and numbers inside the channel were introduced in order to enhance the thermal performance. These modifications cause secondary flow between the parallel channels and the obstacles disrupt the boundary layer formation of the flow inside the channel which leads to the increase in heat transfer rate. Finally, Nusselt number, overall thermal resistance and maximum temperature of the heat sink were calculated to compare the performances of the modified heat sinks with the conventional mini channel heat sink and it was observed that the heat sink with both interconnectors and obstacles enhanced the thermal performance more significantly than other configurations. A maximum of 36% increase in Nusselt number was observed (for Re =1044).

scholarly journals Thermogravimetric analysis of empty fruit bunch

2018 ◽  
Vol 225 ◽  
pp. 02002 ◽  
Author(s):  
Girma T. Chala ◽  
Ying P. Lim ◽  
Shaharin A. Sulaiman ◽  
Chin L. Liew
Keyword(s):  
Thermogravimetric Analysis ◽  
Heat Flow ◽  
Loss Rate ◽  
Renewable Energy Sources ◽  
Thermal Reaction ◽  
Maximum Temperature ◽  
Empty Fruit Bunch ◽  
Weight Loss Rate ◽  
Minimum Heat ◽  
Maximum Weight Loss

This paper presents the characteristics of empty fruit bunch (EFB) using thermogravimetric analysis (TGA) and shows its potential as a renewable energy sources. A set of data were collected from the thermal reaction and plotted in mass or percentage of the initial mass against either temperature or time, respectively. In the thermogravimetric analysis, mass, temperature and time were considered as base measurements and important data for derivative thermogravimetric (DTG) curve were analysed while many additional measures could be derived from these three base measurements. It was observed that heating rate of 8.5°C/min and air flow rate of 85mL/min provided a maximum weight loss rate of 0.209%/°C at the temperature of 313.5°C and the derivative weight peak of -0.1895mg/°C at 292°C. The time taken to reach the maximum temperature of 899.9°C was 46.74 minutes, and ΔT endo-up reflected minimum point of -0.2°C at 15.82 minutes and maximum ΔT endo-up of 888°C at 42 minutes. Heat flow endo-up also showed that the minimum heat flow was 15.39mW at 15.85 minutes and reaching the peak heat flow endo-up of 47.73mW at 43.27 minutes.

scholarly journals Simulation of Nanofluid Flow in a Micro-Heat Sink With Corrugated Walls Considering the Effect of Nanoparticle Diameter on Heat Sink Efficiency

2021 ◽  
Vol 9 ◽  
Author(s):  
Yacine Khetib ◽  
Hala M. Abo-Dief ◽  
Abdullah K. Alanazi ◽  
Goshtasp Cheraghian ◽  
S. Mohammad Sajadi ◽  
...  
Keyword(s):  
Heat Sink ◽  
Figure Of Merit ◽  
Reynolds Numbers ◽  
Constant Heat Flux ◽  
Maximum Temperature ◽  
Nanofluid Flow ◽  
Numerical Work ◽  
Volume Percentage ◽  
Flow And Heat Transfer ◽  
20 Nm

In this numerical work, the cooling performance of water–Al2O3 nanofluid (NF) in a novel microchannel heat sink with wavy walls (WMH-S) is investigated. The focus of this article is on the effect of NP diameter on the cooling efficiency of the heat sink. The heat sink has four inlets and four outlets, and it receives a constant heat flux from the bottom. CATIA and CAMSOL software were used to design the model and simulate the NF flow and heat transfer, respectively. The effects of the Reynolds number (Re) and volume percentage of nanoparticles (Fi) on the outcomes are investigated. One of the most significant results of this work was the reduction in the maximum and average temperatures of the H-S by increasing both the Re and Fi. In addition, the lowest Tmax and pumping power belong to the state of low NP diameter and higher Fi. The addition of nanoparticles reduces the heat sink maximum temperature by 3.8 and 2.5% at the Reynolds numbers of 300 and 1800, respectively. Furthermore, the highest figure of merit (FOM) was approximately 1.25, which occurred at Re=1800 and Fi = 5%. Eventually, it was revealed that the best performance of the WMH-S was observed in the case of Re=807.87, volume percentage of 0.0437%, and NP diameter of 20 nm.

Performance Comparison of Microchannel Heat Sink Using Boron-Based Ceramic Materials

2021 ◽  
Vol 1163 ◽  
pp. 73-88
Author(s):  
Md Tanbir Sarowar
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Sink ◽  
Electronic Devices ◽  
Ceramic Materials ◽  
Substrate Material ◽  
Heat Sinks ◽  
Maximum Temperature ◽  
Microchannel Heat Sink ◽  
Small Surface

Microchannel heat sink plays a vital role in removing a considerable amount of heat flux from a small surface area from different electronic devices. In recent times, the rapid development of electronic devices requires the improvement of these heat sinks to a greater extent. In this aspect, the selection of appropriate substrate materials of the heat sinks is of vital importance. In this paper, three boron-based ultra-high temperature ceramic materials (ZrB2, TiB2, and HfB2) are compared as a substrate material for the microchannel heat sink using a numerical approach. The fluid flow and heat transfer are analyzed using the finite volume method. The results showed that the maximum temperature of the heat source didn’t exceed 355K at 3.6MWm-2 for any material. The results also indicated HfB2 and TiB2 to be more useful as a substrate material than ZrB2. By applying 3.6 MWm-2 heat flux at the source, the maximum obtained surface heat transfer coefficient was 175.2 KWm-2K-1 in a heat sink having substrate material HfB2.

Design and Optimization of a Composite Heat Spreader to Improve the Thermal Management of a 3D Integrated Circuit

2021 ◽  
Author(s):  
Andisheh Tavakoli ◽  
Kambiz Vafai
Keyword(s):  
Thermal Conductivity ◽  
Heat Sink ◽  
Variable Temperature ◽  
Heat Removal ◽  
High Conductivity ◽  
High Thermal Conductivity ◽  
Maximum Temperature ◽  
Optimal Distribution ◽  
Heat Spreader ◽  
The Impact

Abstract The present study analyzes the optimal distribution of a limited amount of high thermal conductivity material to enhance the heat removal of circular 3D integrated circuits, IC. The structure of the heat spreader is designed as a composite of high thermal conductivity (Boron Arsenide) and moderate thermal conductivity (copper) materials. The volume ratio of high-conductivity inserts to the total volume of the spreader is set at a fixed pertinent ratio. Two different boundary conditions of constant and variable temperature are considered for the heat sink. To examine the impact of adding high-conductivity inserts on the cooling performance of the heat spreader, various patterns of the single and double ring inserts are studied. A parametric study is performed to find the optimal location of the rings. Moreover, the optimal distribution of the high-conductivity material between the inner and outer rings is found. The results show that for the optimal conditions, the maximum temperature of the 3D IC is reduced up to 10%; while the size of the heat sink, and heat spreader can be diminished by as much as 200%.

Relating Semiconductor Heat Sink Local and Non-Local Experimental and Simulation Data to Upper Scale Design Goals

2001 ◽  
Author(s):  
V. S. Travkin
Keyword(s):  
Heat Sink ◽  
Solid Phase ◽  
Physical Characteristics ◽  
Heat Sinks ◽  
Maximum Temperature ◽  
Pin Fin ◽  
Three Samples ◽  
Non Local ◽  
Scale Design ◽  
Research And Design

Abstract The primary difficulty in semiconductor heat sink (and many other types of heat exchangers) research and design is not a lack of interest or money, but rather confusion with what being looked for and adequacy of the tools used for the search. As recently shown, there are few meaningful parameters (apart from sizes and weight) or physical characteristics of interest in semiconductor cooler design are local values. Even the maximum temperature of the base Tmax or semiconductor temperature are not local. In this work outlined the description in detail of arguments on how, and for what reasons, the measured data are to be simulated or measured and represented in a way that allows design goals to be formulated primarily with bulk physical characteristics. We demonstrate why studies of only averaged local integrated variables are not enough. Four sample semiconductor heat sinks of two morphologies (three samples of round pin fin and one sample of longitudinal rib fin sinks) were studied by different techniques and models. There were changes in by-pass values, external heat flux and flow rate. The results are depicted with using new parameters that better represent the needs of a design process as well as the usual parameters used in the past. Characteristics reported are the heat transfer rate in solid phase, relative fin effectiveness, and influence of only morphology features among others. Some suggestions for heat sink design are discussed.

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