Single Phase Liquid Cooling of High Heat Flux Devices with Local Hotspot in a Micro-Gap with Non-Uniform Fin Array

2020 ◽  
Author(s):  
Yuanchen Hu ◽  
Tom Sarvey ◽  
Muhannad Bakir ◽  
Yogendra Joshi
Keyword(s):  
Heat Flux ◽  
Thermal Performance ◽  
Single Phase ◽  
Heat Fluxes ◽  
Thermal Design ◽  
Liquid Cooling ◽  
Cooling Performance ◽  
Pin Fin ◽  
Phase Liquid ◽  
Pin Fin Array

Abstract Single-phase liquid cooling in micro-channels and micro-gaps has been successfully demonstrated for heat fluxes of ~1 kW/cm2 for silicon chips with maximum temperature below 100 °C. However, effectively managing localized hotspots in heterogeneous integration, which refers to the integration of various components that achieve multiple functionalities, entails further thermal challenges. To address these, we use a non-uniform pin-fin array. Single-phase liquid-cooling performance of four silicon test chips, thermal design vehicles (TDVs), each with a non-uniform pin-fin array, are experimentally examined. We evaluate multiple combinations of hotspot and background heat fluxes using four background heaters aligned upstream to downstream, and one additional hotspot heater located in the center. We examine the thermal performance of cylindrical fin-enhanced TDVs and hydrofoil fin-enhanced TDVs, both with two designs: one with increased fin density around the hotspot only, and another with increased fin density spanning the entire width of the channel. The resulting heat flux ratio of the localized hotspot to background heaters varies from 1 to 5. TDVs with spanwise increased hydrofoil fin density (spanwise hydrofoil) exhibit the best thermal performance with 6%-14% lower hotspot temperature than others. TDVs with spanwise increased cylindrical fin (cylindrical spanwise) maintain a balance between hotspot cooling performance and pressure drops. In general, as the temperature of the hotspot remains around 70? with a heat flux of 625 W/cm2, the non-uniform fin-enhanced micro-gaps appears to be a promising hotspot thermal management approach.

Experimental Research on Phase-Change Cooling for High-Power Chip

2014 ◽  
Vol 628 ◽  
pp. 306-310
Author(s):  
Long Sheng Wu ◽  
Xu Zhang ◽  
Cheng Jian Wang ◽  
Zhen Long Wang
Keyword(s):  
Heat Flux ◽  
Phase Change ◽  
Single Phase ◽  
Experimental System ◽  
Temperature Uniformity ◽  
Pumping Power ◽  
Liquid Cooling ◽  
Chip Temperature ◽  
Phase Liquid ◽  
Cooling Technology

Phase change cooling technology is based on the boiling of refrigerating medium to absorb the heat generated by the electronic chip. It provides higher heat flux dissipation, reduces the refrigerating medium flux and consumes a lower pumping power, compared with single-phase liquid cooling. It also has good temperature uniformity and higher working temperature, which is ideal for energy reuse. Experimental system was designed for phase change cooling of R123 to analyze the basic conditions required for boiling vaporization. The chip temperature was 70 °C or less when the heat flux was 100 W·cm-2, with the 0.6 mm rectangular micro-channel evaporator. Experiments were conducted to analyze the effects of heat flux, channel dimension, throttling action on the heat transfer effect.

Single-Phase and Boiling Cooling of Small Pin Fin Arrays by Multiple Nozzle Jet Impingement

1996 ◽  
Vol 118 (1) ◽  
pp. 21-26 ◽  
Author(s):  
David Copeland
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Critical Heat Flux ◽  
Single Phase ◽  
Jet Impingement ◽  
Transfer Coefficients ◽  
Pin Fin ◽  
Heat Transfer Coefficients ◽  
Aspect Ratios ◽  
Pin Fin Arrays

Experimental measurements of multiple nozzle submerged jet array impingement single-phase and boiling heat transfer were made using FC-72 and 1 cm square copper pin fin arrays, having equal width and spacing of 0.1 and 0.2 mm, with aspect ratios from 1 to 5. Arrays of 25 and 100 nozzles were used, with diameters of 0.25 to 1.0 mm providing nozzle area from 5 to 20 mm2 (5 to 20% of the heat source base area). Flow rates of 2.5 to 10 cm3/s (0.15 to 0.6 l/min) were studied, with nozzle velocities from 0.125 to 2 m/s. Single nozzles and smooth surfaces were also evaluated for comparison. Single-phase heat transfer coefficients (based on planform area) from 2.4 to 49.3 kW/m2 K were measured, while critical heat flux varied from 45 to 395 W/cm2. Correlations of the single-phase heat transfer coefficient and critical heat flux as functions of pin fin dimensions, number of nozzles, nozzle area and liquid flow rate are provided.

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.

Thermal Design Analysis of 2.5-D Packages With Analytical TSV Submodels

2015 ◽  
Author(s):  
H. Y. Zhang ◽  
Xiao Yan ◽  
W. H. Zhu ◽  
Leon Lin
Keyword(s):  
Thermal Performance ◽  
Heat Sink ◽  
Power Dissipation ◽  
High Current Density ◽  
Hot Spot ◽  
Thermal Design ◽  
Good Prediction ◽  
Excessive Heat ◽  
Pin Fin ◽  
Power Application

2.5-D package with through silicon vias (TSVs) on interposer has been envisioned as the most viable way in heterogeneous integration. In this work, several design approaches are considered in the thermal analysis and enhancements of a 2.5-D package with multi chips on through silicon interposer (TSI), which include overmolding materials, metal slug, lid attachment, pin fin heat sink and fan-driven heat sink cooling. The analysis models consist of two dummy flip chips on a silicon interposer to represent the logic die and memory die, respectively. Package submodels, especially the TSV ones, are analyzed with good modeling accuracy. Package thermal modeling indicates that the thermal conductivity of the epoxy overmolding has minimal effect on the thermal performance of copper slug package. Lid attachment further enhances the thermal performance through peripheral substrate attachment. Both designs largely rely on thermally conductive PCB (4L) to maximize power dissipation. Pin-fin heat sink, made of aluminum, can be mounted on the package top to further minimize thermal resistance and extend the power dissipation beyond 10W. For high power application, fan cooled heat sink is used to reduce excessive heat. Copper based aluminum heat sink can remove the heat of 120W from the bare-die package. Self heating due to high current density through the TSV is analyzed. The proposed analytical expression gives good prediction on the local TSV hot spot. It is demonstrated that a distributed TSV network design provides lower temperature rise, which shall have lower risk of failures and is preferred in practice.

scholarly journals Experimental Investigation of Compact Evaporators for Ultralow Temperature Refrigeration of Microprocessors

2007 ◽  
Vol 129 (3) ◽  
pp. 291-299 ◽  
Author(s):  
Robert Wadell ◽  
Yogendra K. Joshi ◽  
Andrei G. Fedorov
Keyword(s):  
High Heat ◽  
Heat Fluxes ◽  
Junction Temperature ◽  
High Heat Flux ◽  
Base Line ◽  
Vapor Compression ◽  
Pin Fin ◽  
Slit Flow ◽  
Strong Motivation ◽  
Pin Fin Array

Microprocessor performance can be significantly improved by lowering the junction temperature, especially down to the deep subambient levels. This provides the strong motivation for the current study, which focuses on the design and thermohydraulic performance evaluation of high heat flux evaporators suitable for interfacing the microprocessor chip with a cascaded R134a∕R508b vapor compression refrigeration system at −80°C. Four compact evaporator designs are examined—a base line slit-flow structure with no microfeatures, straight microchannels, an inline pin fin array, and an alternating pin fin array—all fitting the same size envelope. Pressure drop and heat transfer measurements are reported and discussed to explain the performance of the various evaporator geometries for heat fluxes ranging between 20W∕cm2 and 100W∕cm2.

Numerical Study of the Endwall Effects on Water Single-Phase Pressure Drop Across a Circular Micro-Pin-Fin Array

2011 ◽  
Author(s):  
Jonathan R. Mita ◽  
Weilin Qu ◽  
Frank E. Pfefferkorn
Keyword(s):  
Pressure Drop ◽  
Single Phase ◽  
Numerical Study ◽  
Circular Cross Section ◽  
Reynolds Numbers ◽  
Pin Fin ◽  
Pin Fins ◽  
Micron Diameter ◽  
Micro Pin Fins ◽  
Pin Fin Array

This paper presents a numerical study of pressure drop associated with water liquid single-phase flow across an array of staggered micro-pin-fins having circular cross-section. The numerical simulations were validated against previously obtained experimental results using an array of staggered circular micro-pin-fins having the following dimensions: 180 micron diameter and 683 micron height. The longitudinal pitch and transverse pitch of the micro-pin-fins are equal to 399 microns. The effects of endwalls on pressure drop characteristics were then explored numerically. Six different micro-pin-fin height to diameter ratios were studied with seven different Reynolds numbers. All simulations were performed at room temperature (23°C). It was seen that for any given Reynolds number, as the pin height to diameter ratio increased, the pressure drop and resulting non-dimensional friction factor decreased.

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