Validation of Analytical Methods for Parallel Plate Fin Heat Sinks

2004 ◽  
Author(s):  
Guoping Xu ◽  
Henry Jung
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Pressure Drop ◽  
Test Data ◽  
Analytical Methods ◽  
Parallel Plate ◽  
Heat Sinks ◽  
Analytical Models ◽  
Experimental Investigations ◽  
Duct Flow

Several analytical models to predict heat transfer and pressure drop performance for parallel plate fin heat sinks are available in the literature. However, the experimental data to validate these models are very limited especially for high fin density heat sinks. In this paper, a new method is proposed to predict thermal performance in both laminar flow and turbulent flow. This method and other models selected from the literature have been compared to the test data. Experimental investigations were conducted with fully-duct flow for parallel plate fin heat sinks to measure overall thermal resistance and pressure drop. Three heat sinks with different fin materials and fin configurations are tested. We conclude by recommending some of the analytical methods for engineering applications by comparing the test data with predictions.

Pressure Drop and Heat Transfer in Turbulent Duct Flow: A Two-Parameter Variational Method

1995 ◽  
Vol 117 (2) ◽  
pp. 289-295 ◽  
Author(s):  
N. Ghariban ◽  
A. Haji-Sheikh ◽  
S. M. You
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Pressure Drop ◽  
Variational Method ◽  
Turbulent Flow ◽  
Turbulent Shear ◽  
Duct Flow ◽  
Turbulent Shear Stress ◽  
Fully Developed Turbulent Flow ◽  
Two Parameter

A two-parameter variational method is introduced to calculate pressure drop and heat transfer for turbulent flow in ducts. The variational method leads to a Galerkin-type solution for the momentum and energy equations. The method uses the Prandtl mixing length theory to describe turbulent shear stress. The Van Driest model is compared with experimental data and incorporated in the numerical calculations. The computed velocity profiles, pressure drop, and heat transfer coefficient are compared with the experimental data of various investigators for fully developed turbulent flow in parallel plate ducts and pipes. This analysis leads to development of a Green’s function useful for solving a variety of conjugate heat transfer problems.

High Dense Plate Fin Heat Sinks Characterization and Validation

2005 ◽  
Author(s):  
Guoping Xu ◽  
Chakravarthy Akella ◽  
Lee Follmer
Keyword(s):  
Heat Transfer ◽  
Laminar Flow ◽  
Turbulent Flows ◽  
Heat Sink ◽  
Analytical Methods ◽  
Parallel Plate ◽  
Electronics Cooling ◽  
Heat Sinks ◽  
Laminar And Turbulent Regimes ◽  
Laminar And Turbulent Flows

Plate fin heat sinks are commonly used in electronics cooling including high end processors. A number of empirical and analytical methods are available to predict their performance but most of the models are valid for fin pitch larger than 3 mm heat sinks in laminar flow. The present work is to investigate high dense plate fin heat sink in both laminar and turbulent regimes. Thermal and hydraulic performance of several dense plate-fin heat sinks were characterized for high end processors in a fully-ducted wind tunnel. All the three heat sinks tested have the same dimensions of 89 mm (L) × 56 mm (W) × 50 mm (H), and fin number varied between 23 and 33. Heat sink base for all heat sinks was made of solid copper, while different fin materials of Aluminum and Copper are used. Several analytical methods for laminar flow from literature were reviewed in this study. A new heat transfer analytical method was proposed for both laminar and turbulent flows. The characterization data from these three parallel plate heat sinks were compared with the analytical methods. Finally, empirical heat transfer correlations were developed for both laminar and turbulent flows.

Fluid Flow Characteristics for Partially-Confined Compact Plain-Plate-Fin Heat Sinks

2005 ◽  
Author(s):  
M. P. Wang ◽  
T. Y. Wu ◽  
J. T. Horng ◽  
C. Y. Lee ◽  
Y. H. Hung
Keyword(s):  
Experimental Data ◽  
Fluid Flow ◽  
Pressure Drop ◽  
Heat Sink ◽  
Flow Behavior ◽  
Flow Characteristics ◽  
Heat Sinks ◽  
Experimental Investigations ◽  
Channel Height ◽  
Fluid Flow Characteristics

A series of experimental investigations with a stringent measurement method on the study of the fluid flow behavior for confined compact heat sinks in forced convection have been successfully conducted. In the present study, a theoretical model to effectively predict the velocity and pressure drop for partially-confined heat sinks has been successfully developed. The air velocities flowing into heat sink Us through side bypass U1 and top bypass U2 for various 0.47<H/Hc<1 ratios are evaluated, where H/Hc is the ratio of the heat sink height to channel height. The maximum and average deviations of the velocities predicted by the present model from the experimental data are less than 20.31% and 13.13%, respectively, for confined compact heat sinks. Besides, the results show a good agreement between the predicted results and the experimental data of the pressure drop for the cases of H/Hc = 1. Nevertheless, the relative deviation of the predictions from the experimental data becomes more significant with decreasing H/Hc ratio, i.e., increasing the top bypass of confined compact heat sink. A new modified correlation of pressure drop including the H/Hc effect is presented. The maximum and average deviations of the results predicted by the new correlation from the experimental data are 14.48% and 7.72%, respectively.

Pressure Drop and Heat Transfer Characteristics for Partially-Confined Heat Sinks in Ducted Flow

2006 ◽  
Author(s):  
H. T. Chen ◽  
T. Y. Wu ◽  
P. L. Chen ◽  
S. F. Chang ◽  
Y. H. Hung
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Nusselt Number ◽  
Pressure Drop ◽  
Heat Sink ◽  
Average Nusselt Number ◽  
Heat Sinks ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics ◽  
Effective Friction

The pressure drop and heat transfer characteristics for partially-confined heat sinks with different fin types, including plain-plate fin, pin-fin array and strip-fin array, in ducted flow are investigated. The main focus of the experimental results is on pressure drop and heat transfer characteristics of generalized heat sink in ducted flow with considering the flow top- and side-bypass effects. The parameters controlled in the study are the heating load (Qt), inlet flow velocity (Ui), the ratio of heat sink height to duct height (Hs/Hc), and the ratio of heat sink width to duct width (Ws/Wc). The ranges of parameters studied are Ui=2~12m/s, Qt=10~30W, Ws/Wc = 0.6~1, and Hs/Hc = 0.5~1. In the present study, an effective friction factor related to the overall pressure drop is defined; and a new experimental correlation for the effective friction factor for generalized heat sinks in ducted flow with top- and side-bypass effects is presented. A satisfactory agreement between the experimental data and the theoretical predictions is achieved with the maximum and average deviations of 17.2% and 9.6%, respectively. As for convective heat transfer performance, the average Nusselt number is not significantly affected by Grashof number; while, it increases significantly with increasing Reynolds number. Furthermore, the thermal performance increases with increasing top or side confinement ratio (Hs/Hc or Ws/Wc). The best thermal performance occurred at the fully-confined condition, i.e., Hs/Hc=1, Ws/Wc = 1. Based on all the experimental data for three types of partially-confined heat sinks, a generalized correlation of average Nusselt number for partially-confined heat sinks in ducted flow in terms of Re, Hs/Hc and Ws/Wc is presented. The maximum and average deviations of the results obtained by the experimental data from the theoretical prediction are 12.4% and 7.5%, respectively.

Two-Phase Flow and Heat Transfer in Rectangular Micro-Channels

2003 ◽  
Author(s):  
Weilin Qu ◽  
Seok-Mann Yoon ◽  
Issam Mudawar
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Flow Pattern ◽  
Two Phase Flow ◽  
Flow Patterns ◽  
Heat Sinks ◽  
Phase Flow ◽  
Micro Channel ◽  
Two Phase ◽  
Micro Channels

Knowledge of flow pattern and flow pattern transitions is essential to the development of reliable predictive tools for pressure drop and heat transfer in two-phase micro-channel heat sinks. In the present study, experiments were conducted with adiabatic nitrogen-water two-phase flow in a rectangular micro-channel having a 0.406 × 2.032 mm cross-section. Superficial velocities of nitrogen and water ranged from 0.08 to 81.92 m/s and 0.04 to 10.24 m/s, respectively. Flow patterns were first identified using high-speed video imaging, and still photos were then taken for representative patterns. Results reveal that the dominant flow patterns are slug and annular, with bubbly flow occurring only occasionally; stratified and churn flow were never observed. A flow pattern map was constructed and compared with previous maps and predictions of flow pattern transition models. Annual flow is identified as the dominant flow pattern for conditions relevant to two-phase micro-channel heat sinks, and forms the basis for development of a theoretical model for both pressure drop and heat transfer in micro-channels. Features unique to two-phase micro-channel flow, such as laminar liquid and gas flows, smooth liquid-gas interface, and strong entrainment and deposition effects are incorporated into the model. The model shows good agreement with experimental data for water-cooled heat sinks.

Compact Modeling of Fluid Flow and Heat Transfer in Straight Fin Heat Sinks

2004 ◽  
Vol 126 (2) ◽  
pp. 247-255 ◽  
Author(s):  
Duckjong Kim ◽  
Sung Jin Kim
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Fluid Flow ◽  
Pressure Drop ◽  
Heat Sink ◽  
Volume Averaging ◽  
Thermal Design ◽  
Heat Sinks ◽  
Compact Modeling ◽  
Flow And Heat Transfer

In the present work, a compact modeling method based on a volume-averaging technique is presented. Its application to an analysis of fluid flow and heat transfer in straight fin heat sinks is then analyzed. In this study, the straight fin heat sink is modeled as a porous medium through which fluid flows. The volume-averaged momentum and energy equations for developing flow in these heat sinks are obtained using the local volume-averaging method. The permeability and the interstitial heat transfer coefficient required to solve these equations are determined analytically from forced convective flow between infinite parallel plates. To validate the compact model proposed in this paper, three aluminum straight fin heat sinks having a base size of 101.43mm×101.43mm are tested with an inlet velocity ranging from 0.5 m/s to 2 m/s. In the experimental investigation, the heat sink is heated uniformly at the bottom. The resulting pressure drop across the heat sink and the temperature distribution at its bottom are then measured and are compared with those obtained through the porous medium approach. Upon comparison, the porous medium approach is shown to accurately predict the pressure drop and heat transfer characteristics of straight fin heat sinks. In addition, evidence indicates that the entrance effect should be considered in the thermal design of heat sinks when Re Dh/L>∼O10.

Experimental Investigation of Heat Transfer in Impingement Air Cooled Plate Fin Heat Sinks

2005 ◽  
Vol 128 (4) ◽  
pp. 412-418 ◽  
Author(s):  
Zhipeng Duan ◽  
Y. S. Muzychka
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Thermal Resistance ◽  
Thermal Performance ◽  
Heat Transfer Model ◽  
Heat Sinks ◽  
Transfer Model ◽  
Transfer Coefficients ◽  
Developing Flow ◽  
Rectangular Channels

Impingement cooling of plate fin heat sinks is examined. Experimental measurements of thermal performance were performed with four heat sinks of various impingement inlet widths, fin spacings, fin heights, and airflow velocities. The percent uncertainty in the measured thermal resistance was a maximum of 2.6% in the validation tests. Using a simple thermal resistance model based on developing laminar flow in rectangular channels, the actual mean heat transfer coefficients are obtained in order to develop a simple heat transfer model for the impingement plate fin heat sink system. The experimental results are combined into a dimensionless correlation for channel average Nusselt number Nu∼f(L*,Pr). We use a dimensionless thermal developing flow length, L*=(L∕2)∕(DhRePr), as the independent parameter. Results show that Nu∼1∕L*, similar to developing flow in parallel channels. The heat transfer model covers the practical operating range of most heat sinks, 0.01<L*<0.18. The accuracy of the heat transfer model was found to be within 11% of the experimental data taken on four heat sinks and other experimental data from the published literature at channel Reynolds numbers less than 1200. The proposed heat transfer model may be used to predict the thermal performance of impingement air cooled plate fin heat sinks for design purposes.

Heat Transfer Performance of Aluminum Foams

2011 ◽  
Vol 133 (6) ◽  
Author(s):  
Simone Mancin ◽  
Claudio Zilio ◽  
Luisa Rossetto ◽  
Alberto Cavallini
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Pressure Drop ◽  
Fluid Dynamic ◽  
Foam Core ◽  
Aluminum Foams ◽  
Experimental Heat ◽  
High Heat Transfer ◽  
Experimental Heat Transfer ◽  
Core Height

Because of their interesting heat transfer and mechanical properties, metal foams have been proposed for several different applications, thermal and structural. This paper aims at pointing out the effective thermal fluid dynamic behavior of these new enhanced surfaces, which present high heat transfer area per unit of volume at the expense of high pressure drop. The paper presents the experimental heat transfer and pressure drop measurements relative to air flowing in forced convection through four different aluminum foams, when electrically heated. The tested aluminum foams present 5, 10, 20 and 40 PPI (pores per inch), porosity around 0.92–0.93, and 0.02 m of foam core height. The experimental heat transfer coefficients and pressure drops have been obtained by varying the air mass flow rate and the electrical power, which has been set at 25.0 kW m−2, 32.5 kW m−2, and 40.0 kW m−2. The results have been compared against those measured for 40 mm high samples, in order to study the effects of the foam core height on the heat transfer. Moreover, predictions from two recent models are compared with heat transfer coefficient and pressure drop experimental data. The predictions are in good agreement with experimental data.

Experimental Study of Heat Transfer to Supercritical Pressure Water Flowing in a 2×2 Rod Bundle

2014 ◽  
Author(s):  
Han Wang ◽  
Qincheng Bi ◽  
Linchuan Wang ◽  
Haicai Lv ◽  
Laurence K. H. Leung
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Heat Flux ◽  
Pressure Drop ◽  
Wall Temperature ◽  
Mass Flux ◽  
Heat Fluxes ◽  
Outer Diameter ◽  
Square Channel ◽  
Rod Bundle

An experiment has recently been performed at Xi’an Jiaotong University to study the wall temperature and pressure drop at supercritical pressures with upward flow of water inside a 2×2 rod bundle. A fuel-assembly simulator with four heated rods was installed inside a square channel with rounded corner. The outer diameter of each heated rod is 8 mm with an effective heated length of 600 mm. Experimental parameters covered the pressure of 23–28 MPa, mass flux of 350–1000 kg/m2s and heat flux on the rod surface of 200–1000 kW/m2. According to the experimental data, it was found that the circumferential wall temperature distribution of a heated rod is not uniform. The temperature difference between the maximum and the minimum varies with heat flux and/or mass flux. Heat transfer characteristics of supercritical water in bundle were discussed with respect to various heat fluxes. The effect of heat flux on heat transfer in rod bundles is similar with that in tubes or annuli. In addition, flow resistance reflected in the form of pressure loss has also been studied. Experimental results showed that the total pressure drop increases with bulk enthalpy and mass flux. Four heat transfer correlations developed for supercritical pressures water were compared with the present test data. Predictions of Jackson correlation agrees closely with the experimental data.

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