On jet impingement and thin film breakup on a horizontal superhydrophobic surface

In this paper, the results of a series of heat transfer experiments conducted on a compact electronics cooling device based on single phase jet impingement techniques are reported. Deionized-water is propelled into four microchannels of inner diameter 685 μm which are used as nozzles and located at a nozzle to surface distance of 2.5mm. The generated jet impingement is targeted through these channels towards the surface of a nanostructured plate. This plate of size 20mmx20mm consisted of ∼600 nm long copper nanorod arrays with an average nanorod diameter of ∼150 nm, which were integrated on top of a silicon wafer substrate coated with a copper thin film layer (i.e. Cu-nanorod/Cu-film/Silicon-wafer). Heat removal characteristics induced through jet impingement are investigated using the nanostructured plate and compared to results obtained from a flat plate of copper thin film coated on silicon wafer surface. Enhancement in heat transfer up to 15% using the nanostructured plate has been reported in this paper. Heat generated by small scale electronic devices is simulated using a thin film heater placed on an aluminum base. Surface temperatures are recorded by a data acquisition system with the thermocouples integrated on the surface at various locations. Constant heat flux provided by the film heater is delivered to the nanostructured plate placed on top of the base. Volumetric flow rate and heat flux values were varied in order to better characterize the potential enhancement in heat transfer by nanostructured surfaces.

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Deformation and removal of viscous thin film by submerged jet impingement

AIChE Journal ◽

10.1002/aic.16745 ◽

2019 ◽

Vol 66 (1) ◽

Author(s):

Jiakai Lu ◽

Carlos M. Corvalan ◽

Jen‐Yi Huang

Keyword(s):

Thin Film ◽

Jet Impingement ◽

Submerged Jet

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Rapid transformation of transparent conducting films into superhydrophobic conductive films

RSC Advances ◽

10.1039/c7ra00931c ◽

2017 ◽

Vol 7 (28) ◽

pp. 17173-17177

Author(s):

Jong Seok Woo ◽

Geon-Woong Lee ◽

Soo-Young Park ◽

Joong Tark Han

Keyword(s):

Thin Film ◽

Electromagnetic Interference ◽

Superhydrophobic Surface ◽

Electromagnetic Interference Shielding ◽

Conductive Films ◽

Transparent Conducting Films ◽

Transparent Conducting ◽

Self Cleaning ◽

Conductive Plastics ◽

Rapid Transformation

A smart multifunctional surface of conductive plastics with a superhydrophobic surface can potentially be very useful for electrostatic dissipation, electromagnetic interference shielding, and thin film heater with self-cleaning properties.

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Supersonic Two-Phase Impinging Jet Heat Transfer

Journal of Heat Transfer ◽

10.1115/1.4007408 ◽

2012 ◽

Vol 135 (2) ◽

Cited By ~ 6

Author(s):

Richard R. Parker ◽

James F. Klausner ◽

Renwei Mei

Keyword(s):

Thin Film ◽

Heat Transfer ◽

Heat Transfer Coefficient ◽

Transfer Coefficient ◽

Heat Removal ◽

Jet Impingement ◽

Impinging Jet ◽

High Heat Flux ◽

Two Phase ◽

Air Jet

The experimental heat transfer rates from a supersonic two-phase impinging air jet with disperse droplets are presented. The experimental configuration consists of an expanding disperse mixture of air and water through a converging–diverging nozzle, designed for Mach 3.26 with a liquid to air mass flow ratio ranging from 1.28% to 3.83%, impinging upon a thin film heater constructed of nichrome. The spatially varying heat transfer coefficient is measured, and peak values are on the order of 200,000 W/m2K. Two distinct regions of heat transfer are identified, one dominated by the jet impingement flow and another dominated by thin film heat transfer. The heat transfer coefficient of an impinging jet with dry air and no droplets is measured during the investigation as well. The heat transfer results are compared, and it is demonstrated that the addition of disperse water droplets to the jet significantly increases the heat removal capability of the jet as well as smoothing the spatial temperature distribution of the heater surface. As much as an order of magnitude increase in heat transfer coefficient is observed near the centerline of the jet and a factor of 3–5 increase is seen at a distance of approximately 4 nozzle diameters from the jet. The fundamental heat transfer coefficient measurements should benefit applications involving supersonic two-phase jets for high heat flux thermal management.

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Improved performance of Mg–Y alloy thin film switchable mirrors after coating with a superhydrophobic surface

Applied Surface Science ◽

10.1016/j.apsusc.2017.01.106 ◽

2017 ◽

Vol 403 ◽

pp. 23-28 ◽

Cited By ~ 10

Author(s):

Mao La ◽

Huaijuan Zhou ◽

Ning Li ◽

Yunchuan Xin ◽

Ren Sha ◽

...

Keyword(s):

Thin Film ◽

Superhydrophobic Surface ◽

Alloy Thin Film ◽

Improved Performance

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Formation of AlOOH and silica composite hierarchical nanostructures thin film by sol–gel dip-coating for superhydrophobic surface with high adhesion force

Journal of Sol-Gel Science and Technology ◽

10.1007/s10971-014-3466-6 ◽

2014 ◽

Vol 72 (3) ◽

pp. 511-517 ◽

Cited By ~ 7

Author(s):

Zhijie Wang ◽

Weiwei Ji ◽

Hong Du ◽

Xiangyu Li ◽

Jinghua Gong ◽

...

Keyword(s):

Thin Film ◽

Superhydrophobic Surface ◽

Adhesion Force ◽

Sol Gel ◽

Dip Coating ◽

Hierarchical Nanostructures ◽

Silica Composite ◽

High Adhesion

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Gas Assisted Thin-Film Evaporation for Hotspot Thermal Management

2010 14th International Heat Transfer Conference, Volume 3 ◽

10.1115/ihtc14-23015 ◽

2010 ◽

Author(s):

Shankar Narayanan ◽

Andrei G. Fedorov ◽

Yogendra K. Joshi

Keyword(s):

Thin Film ◽

Phase Change ◽

Jet Impingement ◽

High Heat ◽

Heat Fluxes ◽

Air Cooling ◽

Transfer Coefficients ◽

Evaporation Surface ◽

Operation Conditions ◽

Overall Performance

Presence of hotspots in microprocessors requires localized dissipation of high heat fluxes. While typical background cooling solutions (e.g. air cooling with heat sinks/spreaders, heat pipes etc.) fail to address hotspots, aggressive fluidic cooling with liquid to vapor phase change can potentially meet this goal. In particular, we have been successful in cooling hotspots with a micro-fabricated device providing evaporative cooling. Fundamentally different from boiling, the device takes advantage of evaporation from the free surface of a very thin film of coolant enhanced by flow of dry sweeping gas. Heat transfer coefficients close to 0.1 MW/m2K have already been demonstrated exceeding the performance of other contemporary phase change cooling solutions. This development can potentially play a very important role in designing effective thermal solutions for next generation microprocessors, with application in 3D stacked chips, cooling on-chip optical devices and power electronics, among others. In this paper, we briefly describe the various components constituting the device and the experimental procedure employed for testing the device under different operation conditions. In particular, we investigate the effect of flow configuration of the sweep gas on the overall performance of the system. Jet impingement of air is characterized by varying two operating parameters: (1) the separation between the jet’s nozzle and the evaporation surface, and (2) the inclination of the jet with respect to the evaporation surface (i.e., oblique jet impingement). The results from these experiments help elucidate the importance of these two factors in determining the overall performance of the device.

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Supersonic Two Phase Impinging Jet Heat Transfer

2010 14th International Heat Transfer Conference, Volume 5 ◽

10.1115/ihtc14-22836 ◽

2010 ◽

Author(s):

Richard R. Parker ◽

James F. Klausner ◽

Renwei Mei

Keyword(s):

Thin Film ◽

Heat Transfer ◽

Heat Transfer Coefficient ◽

Transfer Coefficient ◽

Heat Removal ◽

Jet Impingement ◽

Impinging Jet ◽

High Heat Flux ◽

Two Phase ◽

Air Jet

The experimental heat transfer rates from a supersonic two-phase impinging air jet with disperse droplets is presented. The experimental configuration consists of an expanding disperse mixture of air and water through a converging-diverging nozzle, designed for Mach 3.26 with a liquid to air mass flow ratio ranging from 1.28 to 3.83%, impinging upon a thin film heater constructed of nichrome. The spatially varying heat transfer coefficient was measured, and peak values are on the order of 200,000 W/m2 − K. Two distinct regions of heat transfer are identified, one dominated by the jet impingement flow and another dominated by thin film heat transfer. The heat transfer coefficient of an impinging jet with dry air and no droplets was measured during the investigation as well. The heat transfer results are compared, and it is demonstrated that the addition of disperse water droplets to the jet significantly increases the heat removal capability of the jet as well as smoothing the spatial temperature distribution of the heater surface. As much as a ten fold increase in heat transfer rate is observed. These results demonstrate the usefulness of supersonic two-phase jets for high heat flux thermal management applications.

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