Fluid Flow and Heat Transfer in a Novel Microchannel Heat Sink Partially Filled With Metal Foam Medium

2014 ◽  
Vol 6 (2) ◽  
Author(s):  
E. Farsad ◽  
S. P. Abbasi ◽  
M. S. Zabihi
Keyword(s):  
Heat Transfer ◽  
Thermal Resistance ◽  
Metal Foam ◽  
Three Dimensional ◽  
Numerical Data ◽  
Flow And Heat Transfer ◽  
Cooling Devices ◽  
Volume Method ◽  
Steady Laminar ◽  
Good Agreement

Performance of microchannel heatsink (MCHS) partially filled with foam is investigated numerically. The open cell copper foams have the porosity and pore density in the ranges of 60–90% and 60–100 PPI (pore per inch), respectively. The three-dimensional steady, laminar flow, and heat transfer governing equations are solved using finite volume method. The performance of microchannel heatsink is evaluated in terms of overall thermal resistance, pressure drop, and heat transfer coefficient and temperature distribution. It is found that the results of the surface temperature profile are in good agreement with numerical data. The results show the microchannel heatsink with insert foam appears to be good candidates as the next generation of cooling devices for high power electronic devices. The thermal resistance for all cases decreases with the decrease in porosity. The uniformity of temperature in this heatsink is enhanced compared the heatsink with no foam. The thermal resistance versus the pumping power is depicted, it is found that 80% is the optimal porosity for the foam at 60 PPI with a minimum thermal resistance 0.346 K/W. The results demonstrate the microchannel heatsink partially filled with foam is capable for removing heat generation 100 watt over an area of 9 × 10−6 m2 with the temperature of heat flux surface up to 59 °C.

Effects of Intersection Angles on Flow and Heat Transfer in Corrugated-Undulated Channels With Sinusoidal Waves

2006 ◽  
Vol 128 (8) ◽  
pp. 819-828 ◽  
Author(s):  
Jixiang Yin ◽  
Guojun Li ◽  
Zhenping Feng
Keyword(s):  
Heat Transfer ◽  
Cross Section ◽  
Three Dimensional ◽  
Computational Domain ◽  
Straight Channel ◽  
Flow Area ◽  
Contact Points ◽  
Flow And Heat Transfer ◽  
Different Characteristics ◽  
Steady Laminar

This paper reported three-dimensional numerical simulations of the steady laminar flow and heat transfer in corrugated-undulated channels with sinusoidal waves, aiming to investigate the effects of intersection angles (θ) between corrugated and undulated plate and Reynolds number (Re) on the flow and heat transfer. The simulations are conducted by using multi-channel computational domain for three different geometries. The code is validated against experimental results and then data for Nusselt number (Nu) and friction factor (f) are presented in a Re range of 100-1500, and intersection angle range of 30-150deg. The simulation confirms the changes of Nuu (averaged over undulated plate) and Nuc (averaged over corrugated plate) with θ representing different characteristics. As θ increases, Nu (Nuu or Nuc) is about 2–16 times higher for the corrugated-undulated configurations CP-UH1 and CP-UP1 and the concomitant f is about 4–100 higher, when compared to a straight channel having square cross section. The minimum of local Nu ( Nuu or Nuc ) is situated at the four contact points where the top plate touches the bottom one, and the high Nu is located upstream of the crest of the conjugate duct. Performance evaluation for the CP-UH1 channel shows that the goodness factors (G) are larger than 1 with the straight channel having a square cross section as a reference, and the 30deg geometry channel has optimal flow area goodness.

Buoyancy Effect on Developing Turbulent Flow and Heat Transfer in a Helical Pipe With Finite Pitch

2000 ◽  
Author(s):  
B. Zheng ◽  
C. X. Lin ◽  
M. A. Ebadian
Keyword(s):  
Heat Transfer ◽  
Turbulent Flow ◽  
Control Volume ◽  
Three Dimensional ◽  
Boussinesq Approximation ◽  
Buoyancy Effect ◽  
Constant Wall Temperature ◽  
Flow And Heat Transfer ◽  
Helical Pipe ◽  
Volume Method

Abstract Numerical modeling was performed to investigate the buoyancy effect on developing turbulent flow and the heat transfer characteristics of saturated water in a helical pipe with finite pitch. The renormalization group (RNG) κ–ε model was used to account for the turbulent flow and heat transfer in the helical pipe at a constant wall temperature with or without buoyancy force effect. A control volume method with second-order accuracy was used to numerically solve the three-dimensional full elliptic governing equations for this problem. The O-type nonuniform structured grid system was adopted to discretize the computation domain. The Boussinesq approximation was applied to deal with the buoyancy. This study explored the influence of buoyancy on the developing heat transfer along the helical pipe. Based on the results of this research, the velocity, temperature, and Nusselt number are presented graphically and analyzed.

Aspects of Flow and Heat Transfer in Louver-Fin Round-Tube Heat Exchangers

2005 ◽  
Author(s):  
Hailing Wu ◽  
Ying Gong ◽  
Xiaobo Zhu
Keyword(s):  
Heat Transfer ◽  
Heat Exchangers ◽  
Three Dimensional ◽  
Flow Region ◽  
Recirculation Region ◽  
Round Tube ◽  
Flow And Heat Transfer ◽  
Representative Cell ◽  
Conjugated Heat Transfer ◽  
Good Agreement

Experimental and numerical investigations on flow and heat transfer were conducted for louver-fin round-tube two-row heat exchangers. The airflow velocity ranged from 1 m/s to 3 m/s. A three-dimensional numerical method was developed by modeling representative cell units with fluid-solid conjugated heat transfer. Results of three-dimensional numerical simulations were in good agreement with the experimental data. A stagnant flow region exists behind the round tubes, and results in diminished local convective heat transfer. For two-row heat exchangers operating at Reynolds number, Re<300, the first row dominates the heat transfer rate. With Re increasing, the heat transfer contribution of both rows tends to be more uniform. The flow pattern shows a recirculation region downstream of the heat exchanger at higher Re flows, which may be induced by a vortex-shedding instability from the tube and louver bank.

Natural Convection Cooling of an Array of Flush Mounted Discrete Heaters Inside a 3D Cavity

2017 ◽  
Vol 9 (3) ◽  
pp. 698-721 ◽  
Author(s):  
V. P. M. Senthil Nayaki ◽  
S. Saravanan ◽  
X. D. Niu ◽  
P. Kandaswamy
Keyword(s):  
Heat Transfer ◽  
Aspect Ratio ◽  
Vertical Wall ◽  
Three Dimensional ◽  
Heat Removal ◽  
Simple Algorithm ◽  
Nusselt Numbers ◽  
Flow And Heat Transfer ◽  
Cold Walls ◽  
Volume Method

AbstractAn investigation of natural convective flow and heat transfer inside a three dimensional rectangular cavity containing an array of discrete heat sources is carried out. The array consists of a row and columnwise regular arrangement of identical square shaped isoflux discrete heaters and is flush mounted on a vertical wall of the cavity. A symmetrical isothermal sink condition is maintained by cooling the cavity uniformly from either the opposite wall or the side walls or the top and bottom walls. The other walls of the cavity are maintained adiabatic. A finite volume method based on the SIMPLE algorithm and the power law scheme is used to solve the conservation equations. The parametric study covers the influence of pertinent parameters such as the Rayleigh number, the Prandtl number, side aspect ratio of the cavity and cavity heater ratio. A detailed fluid flow and heat transfer characteristics for the three cases are reported in terms of isothermal and velocity vector plots and Nusselt numbers. In general it is found that the overall heat transfer rate within the cavity for Ra=107 is maximum when the side aspect ratio of the cavity lies between 1.5 and 2. A more complex and peculiar flow pattern is observed in the presence of top and bottom cold walls which in turn introduces hot spots on the adiabatic walls. Their location and size are highly sensitive to the side aspect ratio of the cavity and hence offers more effective ways for passive heat removal.

scholarly journals Hybrid lattice Boltzmann and finite volume method for fluid flow and heat transfer simulations

2015 ◽  
Author(s):  
◽  
Zheng Li
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Numerical Methods ◽  
Hybrid Method ◽  
Three Dimensional ◽  
Multiscale Methods ◽  
Tracking Method ◽  
Flow And Heat Transfer ◽  
Interface Location ◽  
Volume Method

The fluid flow and heat transfer problems encountered in industry applications span into different scales and there are different numerical methods for different scales problems. Multiscale methods are needed to solve problems involving multiple scales. In this dissertation, multiscale methods are developed by combining various single scale numerical methods, including lattice Boltzmann method (LBM), finite volume method (FVM) and Monte Carlo method. Two strategies exist in combing these numerical methods. For the first one, the whole domain is divided into multiple subdomains and different domains use various numerical methods. Message passing among subdomains decides the accuracy of this type of multiscale numerical method. For the second one, various parameters are solved with different numerical methods. These two types of multiscale methods are both discussed in this dissertation. In Chapters 3 and 4, the whole domain is divided into two subdomains and they are solved with LBM and FVM respectively. This LBM-FVM hybrid method is verified with lid driven flows and natural convections. In Chapter 5, a LBM-FVM hybrid method is proposed to take both advantages of LBM and FVM: velocity field and temperature file are solved with LBM and FVM respectively. MCM has advantages in solving radiative heat transfer, and LBM-MCM hybrid method is proposed in Chapter 6. Numerical investigation for melting problems are carried on in this dissertation. The key point in solving the melting problem is how to obtain the interface location. To overcome the disadvantages in the now existing numerical methods, an interfacial tracking method is advanced to calculate the interface location. In Chapter 7, low Prandtl fluid natural convections are solved with LBM to discuss the oscillation results. Based on these results, low Prandtl number melting problems are solved using LBM with interfacial tracking method in Chapter 8. High Prandtl number melting problems in a discrete heated enclosure are solved using FVM with interfacial tracking method in Chapter 9. To take both advantages of LBM and FVM, melting problems are solved with LBM-FVM hybrid method in chapter 10, while interfacial tracking method is advanced by porous media assumptions in fluid flow field simulation process. Problems in Chapters 3-10 are all in two-dimensional and three-dimensional problems are more general than them in the realistic applications. Double LBM-MRT model for three-dimensional fluid flow and heat transfer is proposed and three types of natural convections in a cubic cavity are discussed in Chapter 11. For the first two types of cubic natural convections, the present results agreed very well with the benchmark solutions or experimental results in the literature. The results from the third type exhibited more general three-dimensional characters. Three-dimensional melting problems are solved with the proposed double LBM-MRT model with interfacial tracking method in Chapter 12. Numerical results in three conduction melting problems agree with the analytical results well. Taking Chapter 11 results in consideration, the double LBM-MRT model with interfacial tracking method is valid to solve three-dimensional conduction or convection controlled melting problems. Two convection melting problems in a cubic cavity are also solved. With a lower Rayleigh number, the convection effects are weaker; side wall effects are smaller; melting process carries on slower.

scholarly journals Internal Passage Heat Transfer Prediction Using Multiblock Grids and a k-ω Turbulence Model

1996 ◽  
Author(s):  
David L. Rigby ◽  
A. A. Ameri ◽  
E. Steinthorsson
Keyword(s):  
Heat Transfer ◽  
Turbulence Model ◽  
Three Dimensional ◽  
Reynolds Numbers ◽  
Three Dimensional Flow ◽  
Flow And Heat Transfer ◽  
Aspect Ratios ◽  
Single Block ◽  
Multiblock Grid ◽  
Good Agreement

Numerical simulations of the three-dimensional flow and heat transfer in a rectangular duct with a 180° bend were performed. Results are presented for Reynolds numbers of 17,000 and 37,000 and for aspect ratios of 0.5 and 1.0. A k-ω turbulence model with no reference to distance to a wall is used. Direct comparison between single block and multiblock grid calculations are made. Heat transfer and velocity distributions are compared to available literature with good agreement. The multi-block grid system is seen to produce more accurate results compared to a single-block grid with the same number of cells.

Flow and Heat Transfer of the Cu-Water Nanofluid in a Corrugated Channel

2021 ◽  
Vol 8 (9) ◽  
pp. 507-517
Author(s):  
Rahima Benchabi ◽  
Ahsene Lanani
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Numerical Simulations ◽  
Metallic Nanoparticles ◽  
Volume Fraction ◽  
Corrugated Channel ◽  
Flow And Heat Transfer ◽  
Fluent Software ◽  
Volume Method ◽  
Good Agreement

This paper is devoted to study the influence of the Cu-water nanofluid on a two-dimensional laminar and incompressible flow and heat transfer in a corrugated triangular-based channel filled with homogeneous mixture of water and metallic nanoparticles. The equations governing the problem were solved using the finite volume method. ANSYS 15.0 FLUENT software was used to perform the numerical simulations. These numerical simulations were carried out for different values of the Reynolds number ranging from 100 to 1000 and for metallic nanoparticles of diameter with volume fractions of and. The effect of the Reynolds number, the nature of the nanofluid on the flow field and the heat transfer were studied. Note that the obtained results are in good agreement with the results existing in the literature. Keywords: Cu-water nanofluid, Fluent, forced convection, Reynolds number, volume fraction.

Thermal Performance Analysis of Bi-Porous Metal Foam Heat Sink

2016 ◽  
Author(s):  
Yongtong Li ◽  
Liang Gong ◽  
Minghai Xu ◽  
Yogendra Joshi
Keyword(s):  
Heat Transfer ◽  
Thermal Performance ◽  
Heat Sink ◽  
Metal Foam ◽  
Three Dimensional ◽  
Porous Metal ◽  
Bottom Layer ◽  
Momentum Equation ◽  
Flow And Heat Transfer ◽  
Foam Thickness

The three-dimensional forced convective heat transfer in a bi-porous metal foam heat sink is numerically investigated. Each of the metal foam layers has a distinct thickness, porosity, and pore density. The effects of these geometrical and morphological parameters on fluid flow and heat transfer are analyzed by employing the Forchheimer-Brinkman extended Darcy momentum equation and local thermal non-equilibrium energy equation. The numerical results show that the thermal resistance of the bi-porous metal foam heat sink is decreased with reduction in top layer metal foam porosity, as well as the bottom layer metal foam thickness, for a fixed bottom metal foam porosity of 0.9. The best thermal performance is achieved by employing a 30PPI metal foam at the bottom layer, and a 50PPI metal foam at the top layer. The optimal thickness of the bottom foam layer is about 1mm.

Effect of Inclination Angle on Three-Dimensional Combined Convective Heat Transfer of Nanofluids in Rectangular Channels

2013 ◽  
Vol 388 ◽  
pp. 176-184
Author(s):  
Hussein A. Mohammed ◽  
Nur Irmawati Om ◽  
Mazlan A. Wahid
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Inclination Angle ◽  
Pure Water ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Flow And Heat Transfer ◽  
Rectangular Channels ◽  
Energy Equations ◽  
Volume Method

Combined convective nanofluids flow and heat transfer in an inclined rectangular duct is numerically investigated. Three dimensional, laminar Navier-Stokes and energy equations were solved using the finite volume method. Pure water and four types of nanofluids such as Au, CuO, SiO2 and TiO2with volume fractions range of 2% φ 7% are used. This investigation covers the following ranges: 2 × 106 Ra 2 × 107, 100 Re 1000 and 30° Θ 60°. The results revealed that the Nusselt number increased as Rayleigh number increased.SiO2nanofluid has the highest Nusselt number while Au nanofluid has the lowest Nusselt number. An increasing of the duct inclination angle decreases the heat transfer.

scholarly journals Computations of Flow and Heat Transfer in a Channel With Rows of Hemispherical Cavities

1999 ◽  
Author(s):  
Y.-L. Lin ◽  
T. I-P. Shih ◽  
M. K. Chyu
Keyword(s):  
Heat Transfer ◽  
Computational Study ◽  
Three Dimensional ◽  
Reynolds Numbers ◽  
Navier Stokes ◽  
Wall Functions ◽  
Time Stepping ◽  
Flow And Heat Transfer ◽  
A Cell ◽  
Volume Method

Computations were performed to investigate the three-dimensional flow and heat transfer in a high aspect ratio channel in which one or two wall are lined with four rows of hemispherical cavities arranged in a staggered fashion with two Reynolds numbers (23,000 and 46,000). The focus is on understanding the flow induced by cavities and how that flow affects surface heat transfer. Computed results were compared with available experimental data. This computational study is based on the ensemble-averaged conservation equations of mass, momentum (compressible Navier-Stokes), and energy closed by the low Reynolds number shear-stress transport k-ω turbulence model (wall functions were not used). Solutions were generated by a cell-centered finite-volume method that uses third-order accurate flux-difference splitting of Roe with limiters, multigrid acceleration of a diagonalized ADI scheme with local time stepping, and patched/overlapped structured grids.

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