Hydrophobic Surface Effect on Heat Transfer Performance in an Oscillating Heat Pipe

Ji, Yulong; Chen, Hsiu-hung; Kim, Young Jo; Yu, Qingsong; Ma, Xuehu; B., H.

doi:10.1115/1.4006111

Cited by 47 publications

(9 citation statements)

References 15 publications

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“…frequency domain which has been generally emloyed for signal processing in hydrualic machinery (e.g., hydraulic turbines [35][36][37], pumps [38] and propellers [39,40]), will provide further inside for the analysis. For further enhancement of OHP, employment of hydrophobic surface is currently being intensively explored [41][42][43] due to the distinguishable characteristics of bubble dynamics on the surface [44]. …”

Section: Discussionmentioning

confidence: 99%

Experimental investigations of dynamic fluid flow in oscillating heat pipe under pulse heating

Xian

Zhang

et al. 2015

Applied Thermal Engineering

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Section: Discussionmentioning

confidence: 99%

Experimental investigations of dynamic fluid flow in oscillating heat pipe under pulse heating

Xian

Zhang

et al. 2015

Applied Thermal Engineering

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“…Previous work showed that the thermal resistance o f the OHP with the superhydrophobic surface was higher than that with the hydrophilic surface [16]. 11-13.…”

Section: S U P E R H Y D R O P H O B Ic S U R Fa C E O N (A ) H E a Tmentioning

confidence: 95%

“…The flow pattern and slug motion is affected by the surface wettability and the heat transfer performance of OHP depends on the oscillating motion of the slugs. Ji et al [16] studied the heat transfer performance of OHPs with superhydrophobic surface and found that the thermal resistance of the superhydrophobic surface OHP was higher than that with the hydrophilic inner sur face. Khandekar et al [15] found the surface having negligible dynamic contact angle hyster esis should be preferred in the OHPs in order to reduce the capil lary resistance under slug flow conditions.…”

Section: Introductionmentioning

confidence: 99%

Effects of Superhydrophobic and Superhydrophilic Surfaces on Heat Transfer and Oscillating Motion of an Oscillating Heat Pipe

Hao

Lan

et al. 2014

Journal of Heat Transfer

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E ffects of S u p e rh y d ro p h o b ic and S u p e rh y d ro p h ilic S u rfa c e s on H e a t T ra n s fe r and O s c illa tin g M o tio n of an O s c illa tin g H e a t P ip eThe effects o f superhydrophobic surface and superhydrophobic and superhydrophilic hybrid surface on the fluid flow and heat transfer of oscillating heat pipes (OHPs) were investigated in the paper. The inner surfaces of the OHPs were hydrophilic sutface (copper), hybrid surface (superhydrophilic evaporation and superhydrophobic condensa tion section), and uniform superhydrophobic surface, respectively. De-ionized water was used as the working fluid. Experimental results showed that superhydrophobic sutface influenced the slug motion and thermal performance of OHPs. Visualization results showed that the liquid-vapor interface was concave in the OHP with copper surface. A thin liquid film existed between the vapor plug and the wall o f the OHP. On the contrary, the liquid-vapor interface took a convex profile in the OHP with superhydrophobic sur face and the liquid-vapor interface contact line length in the hybrid surface OHP was longer than that in the uniform superhydrophobic surface OHP. The liquid slug move ments became stronger in the hybrid surface OHPs as opposed to the copper OHP, while the global heat transfer performance of the hybrid surface OHPs increased by 5-20%. Comparing with the copper OHPs, the maximum amplitude and velocity o f the liquid slug movements in the hybrid surface OHPs increased by 0-127% and 0-185%, respectively. However, the maximum amplitude and velocity of the liquid slug movements in the uni form superhydrophobic OHPs was reduced by 0-100% and 0-100%, respectively. The partial dryout phenomenon took place in OHPs with uniform superhydrophobic surface. The liquid slug movements became weaker and the thermal resistance was increased by 10-35% in the superhydrophobic surface OHPs. Covered by PC plate for visualization F ig . 1 S c h e m a t ic o f t h e e x p e r im e n t a l s e t u p 0 8 2 0 0 1 -2 / Vol. 136, AUGUST 2014Transactions of the ASME

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“…On the other side, different researchers showed that the surface wettability influences the vapor and liquid slug motion and so, the thermal performance of PHP [9] [10] [11]. Actually, the presence of thin films over internal surfaces, surrounding the vapor plugs, is related to the surface wettability.…”

Section: Introductionmentioning

confidence: 99%

Experimental study of thermal performance in a closed loop pulsating heat pipe with alternating superhydrophobic channels

Betancur

Mangini

Mantelli

et al. 2020

Thermal Science and Engineering Progress

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A Pulsating Heat Pipe (PHP) with alternating hydrophilic/superhydrophobic channels was tested at vertical position, bottom heat mode and different heat power inputs. The device consists in a copper tube (internal/external diameters of 3.18/4.76 mm), bent into a planar serpentine of ten channels and five U-turns. The tube is partially functionalized with a superhydrophobic coating, in such a way to create an alternation of hydrophilic and superhydrophobic surfaces on the straight tubes along the loop, in the condenser zone. The aim is to investigate how the alternated wettability affects the startup, the fluid motion along the tubes and the overall thermal performance of the device, which is compared to another PHP, having the same geometry and under the same working conditions, but completely hydrophilic. Distilled water, at 50% filling ratio is the working fluid. Power inputs varying from 20 to up to 350W, in a stepwise increasing and decreasing fashion, are applied to the PHP. The condenser temperature is kept constant, at 20°C. The device is monitored by sixteen thermocouples and one pressure transducer, mounted in contact to the fluid in the condenser region. Data analysis shows that the alternating wettability of tube sections strongly affects the flow motion, the start-up and the overall performance. In general, the alternating PHP presents a worse overall thermal performance: the thermal resistance is always higher and the start-up is achieved at higher heating power levels. Temperature at superhydrophobic surfaces exhibit a flat trend, suggesting that the flow was blocked in the functionalized area surface, while, for the hydrophilic inserts, more pronounced temperature fluctuations are observed. It is believed that the superhydrophobic coating hinders the liquid film formation, decreasing locally the flow motion. On the other hand, the enhancement of the inner wettability improves the flow motion, as the liquid film that covers the inner surface acts as lubricant.

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Hydrophobic Surface Effect on Heat Transfer Performance in an Oscillating Heat Pipe

Cited by 47 publications

References 15 publications

Experimental investigations of dynamic fluid flow in oscillating heat pipe under pulse heating

Experimental investigations of dynamic fluid flow in oscillating heat pipe under pulse heating

Effects of Superhydrophobic and Superhydrophilic Surfaces on Heat Transfer and Oscillating Motion of an Oscillating Heat Pipe

Experimental study of thermal performance in a closed loop pulsating heat pipe with alternating superhydrophobic channels

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