Numerical study of TiO2-based nanofluids flow in microchannel heat sinks: Effect of the Reynolds number and the microchannel height

2019 ◽  
Vol 161 ◽  
pp. 114130 ◽  
Author(s):  
Víctor A. Martínez ◽  
Diego A. Vasco ◽  
Claudio M. García-Herrera ◽  
Roberto Ortega-Aguilera
Keyword(s):  
Reynolds Number ◽  
Numerical Study ◽  
Heat Sinks ◽  
Microchannel Heat Sinks

scholarly journals Temperature Uniformity in Cross-Flow Double-Layered Microchannel Heat Sinks

Fluids ◽  
2020 ◽  
Vol 5 (3) ◽  
pp. 143
Author(s):  
Carlo Nonino ◽  
Stefano Savino
Keyword(s):  
Numerical Study ◽  
Cross Flow ◽  
Bottom Layer ◽  
Heat Sinks ◽  
Temperature Uniformity ◽  
Counter Flow ◽  
Microchannel Heat Sinks ◽  
Unequal Number ◽  
Flow Configurations ◽  
Header Design

An in-house finite element method (FEM) procedure is used to carry out a numerical study on the thermal behavior of cross-flow double-layered microchannel heat sinks with an unequal number of microchannels in the two layers. The thermal performance is compared with those yielded by other more conventional flow configurations. It is shown that if properly designed, i.e., with several microchannels in the top layer smaller than that in the bottom layer, cross-flow double-layered microchannel heat sinks can provide an acceptable thermal resistance and a reasonably good temperature uniformity of the heated base with a header design that is much simpler than that required by the counter-flow arrangement.

Natural Patterns Applied to the Design of Microchannel Heat Sinks

2009 ◽  
Author(s):  
Carlos Alberto Rubio-Jimenez ◽  
Abel Hernandez-Guerrero ◽  
Jose Cuauhtemoc Rubio-Arana ◽  
Satish Kandlikar
Keyword(s):  
Heat Flux ◽  
Reynolds Number ◽  
Heat Sink ◽  
Heat Sinks ◽  
Temperature Fields ◽  
Channel Inlet ◽  
Cooling Fluid ◽  
Microchannel Heat Sinks ◽  
Natural Forms ◽  
Hydrodynamic Behaviors

The present work shows a study developed of the thermal and hydrodynamic behaviors present in microchannel heat sinks formed by non-conventional arrangements. These arrangements are based on patterns that nature presents. There are two postulates that model natural forms in a mathematical way: the Allometric Law and the Biomimetic Tendency. Both theories have been applied in the last few years in different fields of science and technology. Using both theories, six models were analyzed (there are three cases proposed and both theories are applied to each case). Microchannel heat sinks with split channels are obtained as a result of applying these theories. Water is the cooling fluid of the system. The inlet hydraulic diameter is kept in each model in order to have a reference for comparison. The Reynolds number inside the heat sink remains below the transition Reynolds number value published by several researchers for this channel dimensions. The inlet Reynolds number of the fluid at the channel inlet is the same for each model. A heat flux is supplied to the bottom wall of the heat sink. The magnitude of this heat flux is 150 W/cm2. The temperature fields and velocity profiles are obtained for each case and compared.

scholarly journals Numerical Study of Double-Layered Microchannel Heat Sinks with Different Cross-Sectional Shapes

Entropy ◽  
2018 ◽  
Vol 21 (1) ◽  
pp. 16 ◽  
Author(s):  
Daxiang Deng ◽  
Guang Pi ◽  
Weixun Zhang ◽  
Peng Wang ◽  
Ting Fu
Keyword(s):  
Pressure Drop ◽  
Thermal Resistance ◽  
Thermal Performance ◽  
Numerical Study ◽  
Heat Sinks ◽  
High Heat Flux ◽  
Pumping Power ◽  
Cross Sectional ◽  
Prime Concern ◽  
Microchannel Heat Sinks

This work numerically studies the thermal and hydraulic performance of double-layered microchannel heat sinks (DL-MCHS) for their application in the cooling of high heat flux microelectronic devices. The superiority of double-layered microchannel heat sinks was assessed by a comparison with a single-layered microchannel heat sink (SL-MCHS) with the same triangular microchannels. Five DL-MCHSs with different cross-sectional shapes—triangular, rectangular, trapezoidal, circular and reentrant Ω-shaped—were explored and compared. The results showed that DL-MCHS decreased wall temperatures and thermal resistance considerably, induced much more uniform wall temperature distribution, and reduced the pressure drop and pumping power in comparison with SL-MCHS. The DL-MCHS with trapezoidal microchannels performed the worst with regard to thermal resistance, pressure drop, and pumping power. The DL-MCHS with rectangular microchannels produced the best overall thermal performance and seemed to be the optimum when thermal performance was the prime concern. Nevertheless, the DL-MCHS with reentrant Ω-shaped microchannels should be selected when pumping power consumption was the most important consideration.

Experimental and Numerical Study of Transient Electronic Chip Cooling by Liquid Flow in Microchannel Heat Sink

2010 ◽  
Author(s):  
Jingru Zhang ◽  
Tiantian Zhang ◽  
Yogesh Jaluria
Keyword(s):  
Liquid Flow ◽  
Heat Sink ◽  
Single Channel ◽  
Numerical Study ◽  
Numerical Models ◽  
Heat Removal ◽  
Heat Fluxes ◽  
Heat Sinks ◽  
Chip Cooling ◽  
Microchannel Heat Sinks

Cooling of electronic chips has become a critical aspect in the development of electronic devices. Overheating may cause the malfunction or damage of electronics and the time needed for heat removal is important. In this paper, an experimental setup and numerical model was developed to test the effects of different parameters and their influence on the transient electronic chip cooling by liquid flow in microchannel heat sinks. The temperature change with time of the system for different heat fluxes at different flow was determined, from which the response time can be obtained. Three different configurations of multi-microchannel heat sinks were tested during the experiment. Numerical models were then developed to simulate the transient cooling for two of the configurations. A good agreement between the experimental data and numerical results showed that single-channel models are capable of simulating the thermal behavior of the entire heat sink by applying appropriate assumptions and boundary conditions.

A Three-Dimensional Simulation Analysis of Fluid Flow and Heat Transfer in Microchannel Heat Sinks with Different Structures

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Jienan Shen ◽  
Xiuxiu Li ◽  
Yongsheng Zhu ◽  
Boya Zhang ◽  
Hang Guo ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Fluid Flow ◽  
Heat Sink ◽  
Simulation Analysis ◽  
Heat Sinks ◽  
Mixing Efficiency ◽  
Microchannel Heat Sink ◽  
Flow And Heat Transfer ◽  
Microchannel Heat Sinks

Abstract Numerical studies have been performed to analyze the fluid flow and heat transfer characteristics of nine microchannel heat sinks (MCHS) with different shapes and different arrangements of the ribs and cavities on the sidewalls, using three common shapes (square, triangle, and circular) of ribs or cavities as the basic structure in this work. The boundary conditions, governing equations, friction factor (f), Nusselt number (Nu), and performance evaluation criteria (ξ) were considered to determine which design was the best in terms of the heat transfer, the pressure drop, and the overall performance. It was observed that no matter how the circular ribs or cavities were arranged, its heat sink performance was better than the other two shapes for Reynolds number of 200–1000. Therefore, circular ribs or cavities can be considered as the best structure to improve the performance of MCHS. In addition, the heat sink performance of the microchannel heat sink with symmetrical circular ribs (MCHS-SCR) was improved by 31.2 % compared with the conventional microchannel heat sink at Re = 667. This was because in addition to the formation of transverse vortices in the channel, four symmetrical and reverse longitudinal vortices are formed to improve the mixing efficiency of the central fluid (low temperature) and the near-wall fluid (high temperature). Then, as the Reynolds number increases, the heat sink performance of MCHS-SCR dropped sharply. The heat sink performance of microchannel heat sinks with staggered ribs and cavities (MCHS-SCRC, MCHS-STRC, and MCHS-SSRC) exceeded that of MCHS-SCR. This indicated that the microchannel heat sink with staggered ribs and cavities was more suitable for high Reynolds number (Re > 800).

A Parametric Numerical Study in Cylindrical Oblique Fin Minichannel

2013 ◽  
Author(s):  
Yan Fan ◽  
Poh Seng Lee ◽  
Li-Wen Jin ◽  
Beng Wah Chua ◽  
Na-Si Mou ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Heat Sink ◽  
Numerical Study ◽  
Three Dimensional ◽  
Numerical Data ◽  
Channel Structure ◽  
Heat Sinks ◽  
Secondary Channel ◽  
Oblique Angle

A novel cylindrical oblique fin minichannel heat sink was proposed to cool cylindrical heat sources using forced convection scheme. In this paper, parametric numerical study was employed to understand the importance of the various dimensions of the oblique fin heat sinks and their heat transfer performance and pressure drop. Three dimensional conjugated heat transfer simulations were carried out using Computational Fluid Dynamics (CFD) method based on laminar flow to determine its performance in the oblique fin heat sink. 214 parametric studies were performed by varying the oblique angle from 20° to 45°, secondary channel gap from 1mm to 5mm and Reynolds number from 200 to 900. Their thermal performance was compared for a constant heat flux of 1 W/cm2. The results show that the flow is main channel directed in shorter secondary channel structure while the flow becomes secondary channel directed in longer secondary channel structure. Secondary flow becomes more effective in heat transfer when increasing the secondary channel gap. When the oblique angle increases, more flow will be diverted into secondary channel and improve flow mixing to enhance the heat transfer. The best configuration in this paper was suggested based on the numerical data point. The overall performance can be improved up to 110% at Reynolds number of 900 compared with conventional straight fin minichannel. Therefore, this is the attractive candidate for future cylindrical heat sinks.

Impinging Jet Cooled Plate Fin Heat Sinks With Turbulators Enhancement

2009 ◽  
Author(s):  
Ganesh Subbuswamy ◽  
Xianchang Li
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Heat Sink ◽  
Numerical Study ◽  
Turbine Blades ◽  
Jet Impingement ◽  
Impinging Jet ◽  
Impinging Jets ◽  
Heat Sinks ◽  
Internal Cooling

Extended surfaces (fins) and impinging jets have been used to enhance heat transfer in many applications. In electronic thermal management, heat sinks can be designed to take advantage of the combined effect of fins and jet impingement such as jets impinging on an array of pin fins or plate fins. Significant studies have been focused on the thermal resistance, pressure drop, and the parametric effect of Reynolds number, fin thickness, density, and height. To further improve the heat sink performance, ribs/turbulators, which are widely employed in internal cooling of gas turbine blades, can be integrated into the plate fins, especially close to the surface area with low heat transfer coefficient. Numerical study is performed in this paper to examine the flow and heat transfer behavior of plate fin heat sinks cooled by an impinging jet and enhanced by the ribs. The height and shape of the turbulators are investigated to achieve the best performance. Parametric studies also include the flow Reynolds number and the spacing between the ribs. Heat transfer mechanism is explored for the confined turbulence jet with and without turbulators. It is expected that the rib enhancement can lead to a more cost-effective heat sink for cooling of electronic components. Further enhancement and optimization are discussed in this paper.

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