Numerical Investigation of Flow Boiling in a Manifold Microchannel Heat Sink With Conjugate Heat Transfer

2019 ◽  
Author(s):  
Zhichuan Sun ◽  
Yang Luo ◽  
Junye Li ◽  
Wei Li ◽  
Jingzhi Zhang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Numerical Investigation ◽  
Heat Sink ◽  
Conjugate Heat Transfer ◽  
Flow Boiling ◽  
High Heat Flux ◽  
Microchannel Heat Sink ◽  
Two Phase ◽  
Boiling Process ◽  
Manifold Microchannel

Abstract The manifold microchannel heat sink receives an increasing number of attention lately due to its high heat flux dissipation. Numerical investigation of boiling phenomena in manifold microchannel (MMC) heat sinks remains a challenge due to the complexity of fluid route and the limitation of numerical accuracy. In this study, a computational fluid dynamics (CFD) approach including subcooled two-phase flow boiling process and conjugate heat transfer effect is performed using a MMC unit cell model. Different from steady-state single phase prediction in MMC heat sink, this type of modeling allows for the transient simulation for two-phase interface evolution during the boiling process. A validation case is conducted to validate the heat transfer phenomenon among three phases. Besides, this model is used for the assessment of the manifold dimensions in terms of inlet and outlet widths at the mass flux of 1300 kg/m2·s. With different ratios of inlet-to-outlet area, the thermal resistances remain nearly stable.

A Comparative Numerical Study on Two-Phase Boiling Fluid Flow and Heat Transfer in the Microchannel Heat Sink With Different Manifold Arrangements

2020 ◽  
Author(s):  
Yang Luo ◽  
Jingzhi Zhang ◽  
Wei Li
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Sink ◽  
Numerical Study ◽  
Flow Boiling ◽  
High Surface ◽  
Volume Ratio ◽  
High Heat Flux ◽  
Two Phase ◽  
Flow Maldistribution

Abstract The manifold microchannel (MMC) heat sink system has been widely used in high-heat-flux chip thermal management due to its high surface-to-volume ratio. Two-phase, three-dimensional numerical methods for subcooled flow boiling have been developed using a self-programming solver based on OpenFOAM. Four different types of manifold arrangements (Z-type, C-type, H-type and U-type) have been investigated at a fixed operational condition. The numerical results evaluate the effects of flow maldistribution caused by different manifold configurations. Before simulating the two-phase boiling flow in MIMC metamodels, single-phase liquid flow fields are performed at first to compare the flow maldistribution in microchannels. It can be concluded from the flow patterns that H-type and U-type manifolds provide a more even and a lower microchannel void fraction, which is conducive to improving the temperature uniformity and decreasing the effective thermal resistance. The simulation results also show that the wall temperature difference of H-type (0.471 K) is only about 10% of the Z-type (4.683 K). In addition, the U-type manifold configuration show the lowest average pressure drop at the inlet and outlet of the MIMC metamodel domain. However, H-type manifold also shows an impressive 59.9% decrease in pressure loss. Results indicate that both the H-type and the U-type manifolds for flow boiling in microchannels are recommended due to their better heat transfer performance and lower pressure drop when compared with Z-type and C-type.

Flow Boiling in a Microchannel Heat Sink

2005 ◽  
Author(s):  
Dong Liu ◽  
Suresh V. Garimella
Keyword(s):  
Heat Transfer ◽  
Heat Sink ◽  
Boiling Heat Transfer ◽  
Flow Boiling ◽  
Transfer Model ◽  
Microchannel Heat Sink ◽  
Transfer Coefficients ◽  
Two Phase ◽  
Convective Boiling ◽  
Saturated Boiling

Flow boiling heat transfer in a microchannel heat sink is experimentally investigated. The microchannels considered are 275 μm wide and 636 μm deep, and the experiments are conducted at inlet water temperatures in the range of 66 to 95°C and mass fluxes of 341 to 936 kg/m2s. Convective boiling heat transfer coefficients are measured and compared to predictions from correlations proposed for larger channels. While an existing correlation was found to provide satisfactory prediction of the heat transfer coefficient in subcooled boiling in the microchannels, saturated boiling was not well predicted by the correlations for macrochannels. A new heat transfer model is developed to correlate the data in the saturated boiling regime. Good agreement with the experimental measurements indicates that this correlation is suitable for use in the design of two-phase microchannel heat sinks.

Simulation of Subcooled Flow Boiling in Manifold Microchannel Heat Sink

2020 ◽  
Author(s):  
Yang Luo ◽  
Jingzhi Zhang ◽  
Wei Li
Keyword(s):  
Phase Change ◽  
Heat Sink ◽  
Flow Boiling ◽  
High Heat Flux ◽  
Phase Flow ◽  
Interfacial Resistance ◽  
Two Phase ◽  
Lee Model ◽  
Resistance Model ◽  
Manifold Microchannel

Abstract The manifold microchannel (MMC) heat sink has become the most popular one among emerging technologies for high heat flux thermal management because of its high surface-to-volume ratio. Even though numerous numerical studies have been performed for the single-phase flow in the MMC heat sink, researches on two-phase flow boiling/condensation in this type of microchannel is seldomly reported because of its issues with flow pattern prediction. In the present work, a numerical approach involving two-phase interface capturing, phase change and solid heat conduction is conducted for the simplified MMC unit cell model. Heat and mass transfers of Lee model and interfacial heat resistance model for phase change are validated by the single bubble growth problem. Besides, both phase-change models are shown to provide good predictions against the experimental temperature database, with all of the data points falling within −5% to +20% and −5% to +10% error bands for Lee model and interfacial resistance model, respectively. Furthermore, a liquid-vapor interface region with thin thickness and accurate interface temperature can be obtained by the interfacial resistance model coupled with homogeneous nucleation-site model.

Integrate Monolithic Nanostructures in Microchannels to Enhance Flow Boiling Heat Transfer of HFE-7000

2015 ◽  
Author(s):  
Fanghao Yang ◽  
Xiaochuan Li ◽  
Wenming Li ◽  
Chen Li
Keyword(s):  
Heat Transfer ◽  
Heat Sink ◽  
Boiling Heat Transfer ◽  
Flow Boiling ◽  
Working Fluid ◽  
Microchannel Heat Sink ◽  
Two Phase ◽  
Dielectric Fluids ◽  
Flow Boiling Heat Transfer ◽  
Two Phase Heat Transfer

Two-phase microchannel heat sink is promising in cooling high power electronics with dielectric fluids. Compared to water, dielectric fluids can assure system safety in case of working fluid leakage. However, two-phase heat transfer of these hydrofluorocarbon refrigerants is restricted by their relatively low thermal conductivities and low latent heats. Numerous nanoscale/submicron structures have been developed to enhance the single and two-phase heat transfer in microchannels; but these techniques usually require nanoparticle seeds in multi-step wet processes or nanolithography to integrate these nanostructures. Therefore, most of these techniques were time-consuming and costly. In this study, we present a plasma etching method using a modified Bosch process to create silicon tips with nanoscale scallops in microchannels. This is a rapid and cost-effective method to integrate large density of nucleation sites without involving nanolithography method or using nanoparticle seeds. Then, these silicon tip arrays were aligned with side walls of microchannels. As a result, flow boiling heat transfer of a dielectric refrigerant, HFE-7000, is substantially enhanced in a microchannel heat sink (five parallel channels: 10 mm L × 220 μm W × 250 μm H). Compared to plain-wall microchannels, the average junction temperature can be reduced up to 10 °C at a heat flux of 55 W/cm2 and the equivalent thermal resistance of microchannel heat sink is reduced up to 31% at a mass flux of 1018 kg/m2·s.

The Effects of Hybrid Sandblasting Patterns on the Heat Transfer Performance in a Single-Phase Microchannel Heat Sink

2017 ◽  
Author(s):  
Saad K. Oudah ◽  
Ruixian Fang ◽  
Amitav Tikadar ◽  
Karim Egab ◽  
Chen Li ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Sink ◽  
Single Phase ◽  
Heat Transfer Performance ◽  
Bottom Surface ◽  
High Heat Flux ◽  
Microchannel Heat Sink ◽  
Transfer Performance ◽  
Two Phase ◽  
Number Range

An experimental investigation was conducted on a single phase microchannel heat sink, in which the bottom surface of the microchannel was modified with hybrid micro-sandblasting of elliptical patterns (HSEP) and fully sandblasting (FS) to passively enhance the microchannel heat transfer performance. The dimension of the microchannel is measured as 26 mm (L) × 5mm (W) × 0.35 mm (H), which results in a hydraulic diameter of 654 μm. Deionized water was used as the coolant, and the Reynolds number range between 85 to 650 was tested. The experimental results show that fully sandblasting (FS) bottom surface of the microchannel only slightly improved the heat transfer performance. However, the modified surface with HSEP enhanced the heat transfer performance substantially, compared to the benchmark results obtained with the bare surface (BS) microchannel. The pressure drops of the HSEP increased slightly compared to the BS and FS, due to the flow resistance of the microstructures. The proposed surface for enhancement of heat transfer will be useful in many high heat flux engineering applications. In the future, this study will be further extended to two-phase microchannel heat transfer.

scholarly journals A hierarchical manifold microchannel heat sink array for high-heat-flux two-phase cooling of electronics

2018 ◽  
Vol 117 ◽  
pp. 319-330 ◽  
Author(s):  
Kevin P. Drummond ◽  
Doosan Back ◽  
Michael D. Sinanis ◽  
David B. Janes ◽  
Dimitrios Peroulis ◽  
...  
Keyword(s):  
Heat Flux ◽  
Heat Sink ◽  
High Heat ◽  
High Heat Flux ◽  
Microchannel Heat Sink ◽  
Two Phase ◽  
Cooling Of Electronics ◽  
Two Phase Cooling ◽  
Manifold Microchannel

Two-Phase Flow in Microchannels

2001 ◽  
Author(s):  
G. Hetsroni ◽  
A. Mosyak ◽  
Z. Segal
Keyword(s):  
Heat Sink ◽  
High Speed ◽  
Single Phase ◽  
Flow Boiling ◽  
Electronics Cooling ◽  
Working Fluid ◽  
Microchannel Heat Sink ◽  
Two Phase ◽  
Infrared Radiometry ◽  
Phase Water

Abstract Experimental investigation of a heat sink for electronics cooling is performed. The objective is to keep the operating temperature at a relatively low level of about 323–333K, while reducing the undesired temperature variation in both the streamwise and transverse directions. The experimental study is based on systematic temperature, flow and pressure measurements, infrared radiometry and high-speed digital video imaging. The heat sink has parallel triangular microchannels with a base of 250μm. According to the objectives of the present study, Vertrel XF is chosen as the working fluid. Experiments on flow boiling of Vertrel XF in the microchannel heat sink are performed to study the effect of mass velocity and vapor quality on the heat transfer, as well as to compare the two-phase results to a single-phase water flow.

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