Experimental Study of Pressure Drop and Heat Transfer in a Single-Phase Micropin-Fin Heat Sink

2007 ◽  
Vol 129 (4) ◽  
pp. 479-487 ◽  
Author(s):  
Abel Siu-Ho ◽  
Weilin Qu ◽  
Frank Pfefferkorn
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Pressure Drop ◽  
Friction Factor ◽  
Heat Sink ◽  
Single Phase ◽  
Tip Clearance ◽  
Hydrodynamic Performance ◽  
Pin Fin ◽  
Heat Transfer Correlations

The pressure drop and heat transfer characteristics of a single-phase micropin-fin heat sink were investigated experimentally. Fabricated from 110 copper, the heat sink contained an array of 1950 staggered square micropin fins with 200×200μm2 cross section by 670μm height. The ratios of longitudinal pitch and transverse pitch to pin-fin equivalent diameter are equal to 2. De-ionized water was employed as the cooling liquid. A coolant inlet temperature of 25°C, and two heat flux levels, qeff″=50W∕cm2 and qeff″=100W∕cm2, defined relative to the platform area of the heat sink, were tested. The inlet Reynolds number ranged from 93 to 634 for qeff″=50W∕cm2, and from 127 to 634 for qeff″=100W∕cm2. The measured pressure drop and temperature distribution were used to evaluate average friction factor and local averaged heat transfer coefficient/Nusselt number. Predictions of the previous friction factor and heat transfer correlations that were developed for low Reynolds number (Re<1000) single-phase flow in short pin-fin arrays were compared to the present micropin-fin data. Moores and Joshi’s friction factor correlation (2003, “Effect of Tip Clearance on the Thermal and Hydrodynamic Performance of a Shrouded Pin Fin Array,” ASME J. Heat Transfer, 125, pp. 999–1006) was the only one that provided acceptable predictions. Predictions from the other friction factor and heat transfer correlations were significantly different from the experimental data collected in this study. These findings point to the need for further fundamental study of single-phase thermal/fluid transport process in micropin-fin arrays for electronic cooling applications.

Pressure Drop and Heat Transfer in a Single-Phase Micro-Pin-Fin Heat Sink

2006 ◽  
Author(s):  
Abel M. Siu Ho ◽  
Weilin Qu ◽  
Frank Pfefferkorn
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Pressure Drop ◽  
Friction Factor ◽  
Heat Sink ◽  
Single Phase ◽  
Fluid Transport ◽  
Heat Sinks ◽  
Inlet Temperature ◽  
Pin Fin

The pressure drop and heat transfer characteristics of a single-phase micro-pin-fin heat sink were investigated experimentally. Fabricated from 110 copper, the heat sink consisted of 1950 staggered micro-pins with 200×200 μm2 cross-section by 670 μm height. Deionized water was employed as the cooling liquid. A coolant inlet temperature of 25°C, and two heat flux levels, q" eff = 50 W/cm2 and q" eff = 100 W/cm2, defined relative to the planform area of the heat sink, were tested. The inlet Reynolds number ranged from 93 to 634 for q" eff = 50 W/cm2, and 127 to 634 for q" eff = 100 W/cm2. The measured pressure drop and temperature distribution were used to evaluate average friction factor and local averaged heat transfer coefficient/Nusselt number. Predictions of the Moores and Joshi friction factor correlation and the Chyu et al. heat transfer correlation that were developed using macro-size pin-fin arrays were compared to micro-pin-fin heat sink data. While the Moores and Joshi correlation provide acceptable predictions, the Chyu et al. correlation overpredicted local Nusselt number data by a fairly large margin. These findings point to the need for further study of single-phase thermal/fluid transport process in micro-pin-fin heat sinks.

scholarly journals Experimental Investigation of Embedded Micropin-Fins for Single-Phase Heat Transfer and Pressure Drop

2018 ◽  
Vol 140 (2) ◽  
Author(s):  
Chirag R. Kharangate ◽  
Ki Wook Jung ◽  
Sangwoo Jung ◽  
Daeyoung Kong ◽  
Joseph Schaadt ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Friction Factor ◽  
Integrated Circuit ◽  
Single Phase ◽  
Absolute Error ◽  
Heat Fluxes ◽  
Operating Conditions ◽  
Working Fluid ◽  
Pin Fin

Three-dimensional (3D) stacked integrated circuit (IC) chips offer significant performance improvement, but offer important challenges for thermal management including, for the case of microfluidic cooling, constraints on channel dimensions, and pressure drop. Here, we investigate heat transfer and pressure drop characteristics of a microfluidic cooling device with staggered pin-fin array arrangement with dimensions as follows: diameter D = 46.5 μm; spacing, S ∼ 100 μm; and height, H ∼ 110 μm. Deionized single-phase water with mass flow rates of m˙ = 15.1–64.1 g/min was used as the working fluid, corresponding to values of Re (based on pin fin diameter) from 23 to 135, where heat fluxes up to 141 W/cm2 are removed. The measurements yield local Nusselt numbers that vary little along the heated channel length and values for both the Nu and the friction factor do not agree well with most data for pin fin geometries in the literature. Two new correlations for the average Nusselt number (∼Re1.04) and Fanning friction factor (∼Re−0.52) are proposed that capture the heat transfer and pressure drop behavior for the geometric and operating conditions tested in this study with mean absolute error (MAE) of 4.9% and 1.7%, respectively. The work shows that a more comprehensive investigation is required on thermofluidic characterization of pin fin arrays with channel heights Hf < 150 μm and fin spacing S = 50–500 μm, respectively, with the Reynolds number, Re < 300.

Cryogenic Single-Phase Heat Transfer in a Microscale Pin Fin Heat Sink

2013 ◽  
Author(s):  
Eric D. Truong ◽  
Erfan Rasouli ◽  
Vinod Narayanan
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Sink ◽  
Single Phase ◽  
Flow Direction ◽  
Heat Sinks ◽  
Variable Cross ◽  
Transfer Coefficients ◽  
Pin Fin ◽  
Heat Transfer Coefficients

A combined experimental and computational fluid dynamics study of single-phase liquid nitrogen flow through a microscale pin-fin heat sink is presented. Such cryogenic heat sinks find use in applications such as high performance computing and spacecraft thermal management. A circular pin fin heat sink in diameter 5 cm and 250 micrometers in depth was studied herein. Unique features of the heat sink included its variable cross sectional area in the flow direction, variable pin diameters, as well as a circumferential distribution of fluid into the pin fin region. The stainless steel heat sink was fabricated using chemical etching and diffusion bonding. Experimental results indicate that the heat transfer coefficients were relatively unchanged around 2600 W/m2-K for flow rates ranging from 2–4 g/s while the pressure drop increased monotonically with the flow rate. None of the existing correlations in literature on cross flow over a tube bank or micro pin fin heat sinks were able to predict the experimental pressure drop and heat transfer characteristics. However, three dimensional simulations performed using ANSYS Fluent showed reasonable (∼7 percent difference) agreement in the average heat transfer coefficients between experiments and CFD simulations.

scholarly journals Effect of Pin Diameter Degressive Gradient on Heat Transfer in a Microreactor with Non-Uniform Pin-Fin Array under Low Reynolds Number Conditions

Energies ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2702
Author(s):  
Miao Qian ◽  
Jie Li ◽  
Zhong Xiang ◽  
Chao Yan ◽  
Xudong Hu
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Nusselt Number ◽  
Pressure Drop ◽  
Friction Factor ◽  
Low Reynolds Number ◽  
Hydrodynamic Characteristics ◽  
Pin Fin ◽  
Low Reynolds ◽  
Pin Fin Array

To improve the efficiency of hydrogen-producing microreactors with non-uniform pin-fin array, the influence of the pin diameter degressive gradient of the non-uniform pin-fin array (NPFA) on heat transfer and pressure drop characteristics is analyzed in this study via numerical simulation under low Reynolds number conditions. Because correlations in prior studies cannot be used to predict the Nusselt number and pressure drop in the NPFA, new heat transfer and friction factor correlations are developed in this paper to account for the effect of the pin diameter degressive gradient, providing a method for the optimized design of the pin diameter degressive gradient for a microreactor with NPFA. The results show that the Nusselt number and friction factor under a low Reynolds number are quite sensitive to the pin diameter degressive gradient. Based on the new correlations, the exponents of the pin diameter degressive gradient for the friction factor and Nusselt number were 6.9 and 2.1, respectively, indicating the significant influence of the pin diameter degressive gradient on the thermal and hydrodynamic characteristics in the NPFA structure.

Heat Transfer in Thin, Compact Heat Exchangers With Circular, Rectangular, or Pin-Fin Flow Passages

1992 ◽  
Vol 114 (2) ◽  
pp. 373-382 ◽  
Author(s):  
D. A. Olson
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Nusselt Number ◽  
Pressure Drop ◽  
Friction Factor ◽  
Heat Exchangers ◽  
Rectangular Channel ◽  
Fluid Temperature ◽  
Compact Heat Exchangers ◽  
Pin Fin

We have measured heat transfer and pressure drop of three thin, compact heat exchangers in helium gas at 3.5 MPa and higher, with Reynolds numbers of 450 to 36,000. The flow geometries for the three heat exchanger specimens were: circular tube, rectangular channel, and staggered pin fin with tapered pins. The specimens were heated radiatively at heat fluxes up to 77 W/cm2. Correlations were developed for the isothermal friction factor as a function of Reynolds number, and for the Nusselt number as a function of Reynolds number and the ratio of wall temperature to fluid temperature. The specimen with the pin fin internal geometry had significantly better heat transfer than the other specimens, but it also had higher pressure drop. For certain conditions of helium flow and heating, the temperature more than doubled from the inlet to the outlet of the specimens, producing large changes in gas velocity, density, viscosity, and thermal conductivity. These changes in properties did not affect the correlations for friction factor and Nusselt number in turbulent flow.

Numerical Analysis of Convective Heat Transfer From an Elliptic Pin Fin Heat Sink With and Without Metal Foam Insert

2010 ◽  
Vol 132 (7) ◽  
Author(s):  
Hamid Reza Seyf ◽  
Mohammad Layeghi
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Nusselt Number ◽  
Numerical Analysis ◽  
Pressure Drop ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Heat Sink ◽  
Metal Foam ◽  
Pin Fin

A numerical analysis of forced convective heat transfer from an elliptical pin fin heat sink with and without metal foam inserts is conducted using three-dimensional conjugate heat transfer model. The pin fin heat sink model consists of six elliptical pin rows with 3 mm major diameter, 2 mm minor diameter, and 20 mm height. The Darcy–Brinkman–Forchheimer and classical Navier–Stokes equations, together with corresponding energy equations are used in the numerical analysis of flow field and heat transfer in the heat sink with and without metal foam inserts, respectively. A finite volume code with point implicit Gauss–Seidel solver in conjunction with algebraic multigrid method is used to solve the governing equations. The code is validated by comparing the numerical results with available experimental results for a pin fin heat sink without porous metal foam insert. Different metallic foams with various porosities and permeabilities are used in the numerical analysis. The effects of air flow Reynolds number and metal foam porosity and permeability on the overall Nusselt number, pressure drop, and the efficiency of heat sink are investigated. The results indicate that structural properties of metal foam insert can significantly influence on both flow and heat transfer in a pin fin heat sink. The Nusselt number is shown to increase more than 400% in some cases with a decrease in porosity and an increase in Reynolds number. However, the pressure drop increases with decreasing permeability and increasing Reynolds number.

Liquid Single-Phase Flow in an Array of Micro-Pin-Fins—Part II: Pressure Drop Characteristics

2008 ◽  
Vol 130 (12) ◽  
Author(s):  
Weilin Qu ◽  
Abel Siu-Ho
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Friction Factor ◽  
Single Phase ◽  
Cast Aluminum ◽  
Pin Fin ◽  
Pin Fins ◽  
Friction Factor Correlation ◽  
Micro Pin Fins ◽  
Pin Fin Arrays

This Technical Brief is Part II of a two-part study concerning water single-phase pressure drop and heat transfer in an array of staggered micro-pin-fins. This brief reports the pressure drop results. Both adiabatic and diabatic tests were conducted. Six previous friction factor correlations for low Reynolds number (Re<1000) flow in conventional and micro-pin-fin arrays were examined and found underpredicting the adiabatic data except the correlation by Short et al. (2002, “Performance of Pin Fin Cast Aluminum Coldwalls, Part 1: Friction Factor Correlation,” J. Thermophys. Heat Transfer, 16(3), pp. 389–396), which overpredicts the data. A new power-law type of correlation was developed, which showed good agreement with both adiabatic and diabatic data.

Enhancement of Heat Transfer of Rectangular Saw Tooth Shaped Micro Channel Heat Sink with Water Nano Fluid/Aluminium Oxide

2015 ◽  
Vol 813-814 ◽  
pp. 685-689
Author(s):  
M. Vijay Anand Marimuthu ◽  
B. Venkatraman ◽  
S. Kandhasamy
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Nusselt Number ◽  
Pressure Drop ◽  
Heat Sink ◽  
Micro Channel ◽  
Performance Curve ◽  
Theoretical Level ◽  
Enhancement Of Heat Transfer ◽  
Nano Fluid

This paper investigates the performance and characteristics of saw tooth shape micro channel in the theoretical level. If the conduct area of the nano fluid increases the heat transfer also increases. The performance curve has drawn Reynolds number against nusselt number, heat transfer co efficient. Pressure drop plays an important role in this device. If pressure drop is high the heat transfer increases. The result in this experiment shows clearly that the heat transfer is optimized.

Assessment of heat transfer and pressure drop of metal foam-pin-fin heat sink

2021 ◽  
Vol 170 ◽  
pp. 107109
Author(s):  
Mohanad A. Alfellag ◽  
Hamdi E. Ahmed ◽  
Mohammed Gh. Jehad ◽  
Marwan Hameed
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Sink ◽  
Metal Foam ◽  
Pin Fin
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