TRANSIENT POOL BOILING HEAT TRANSFER FROM SMOOTH SURFACE DUE TO EXPONENTIAL STEP HEAT INPUT

2018 ◽  
Author(s):  
Avdhoot A. Walunj ◽  
Alangar Sathyabhama
Author(s):  
Zan Wu ◽  
Anh Duc Pham ◽  
Zhen Cao ◽  
Cathrine Alber ◽  
Peter Falkman ◽  
...  

This work aims to investigate pool boiling heat transfer enhancement by using nanostructured surfaces. Two types of nanostructured surfaces were employed, gold nanoparticle-coated surfaces and alumina nanoparticle-coated surfaces. The nanostructured surfaces were fabricated by an electrophoretic deposition technique, depositing nanoparticles in a nanofluid onto smooth copper surfaces under an electric field. N-pentane and acetone were tested as working fluids. Compared to the smooth surface, the pool boiling heat transfer coefficient has been increased by 80% for n-pentane and acetone. Possible mechanisms for the enhancement in heat transfer are qualitatively provided. The increase in active nucleation site density due to multiple micro/nanopores on nanoparticle-coated surfaces is likely the main contributor. The critical heat flux on nanostructured surfaces are approximately the same as that on the smooth surface because both smooth and modified surfaces show similar wickability for the two working fluids.


1996 ◽  
Vol 118 (3) ◽  
pp. 662-667 ◽  
Author(s):  
J. P. O’Connor ◽  
S. M. You ◽  
J. Y. Chang

The effects of surface treatments and “gassy-subcooling” on pool boiling heat transfer are quantified by testing both smooth and treated surfaces at gassy-subcooling levels from O°C to 40°C (1 atm) and 40°C to 85°C (3 atm). Incipient and nucleate boiling wall superheats decrease over this range of gassy-subcooling. At gassy-subcooling levels greater than 20°C, the boiling curves for the smooth surface indicate two distinct regions governed by different heat transfer mechanisms, one in which the boiling process is influenced by the presence of dissolved gas, the other by boiling of the pure liquid. The critical heat flux (CHF) for each surface continually increases with increased levels of gassy-subcooling and the CHF sensitivity to gassy-subcooling is higher for the treated surface. The CHF increase due to combined surface treatment and gassy-subcooling (85°C) is ~400 percent (78 W/cm2).


1998 ◽  
Vol 29 (1-3) ◽  
pp. 196-207
Author(s):  
Haruhiko Ohta ◽  
Koichi Inoue ◽  
Suguru Yoshida ◽  
Tomoji S. Morita

1970 ◽  
Author(s):  
V. I. Subbotin ◽  
D. N. Sorokin ◽  
A.A, Tsiganok

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