Interfacial wicking dynamics and its impact on critical heat flux of boiling heat transfer

2014 ◽  
Vol 105 (19) ◽  
pp. 191601 ◽  
Author(s):  
Beom Seok Kim ◽  
Hwanseong Lee ◽  
Sangwoo Shin ◽  
Geehong Choi ◽  
Hyung Hee Cho
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Critical Heat Flux ◽  
Boiling Heat Transfer

scholarly journals Critical Heat Flux and Boiling Heat Transfer to Water in a 3-mm-Diameter Horizontal Tube

2001 ◽  
Author(s):  
Wenhua Yu ◽  
Martin W. Wambsganss ◽  
John R. Hull ◽  
David M. France
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Critical Heat Flux ◽  
Boiling Heat Transfer ◽  
Horizontal Tube

Boiling Heat Transfer and Critical Heat Flux Enhancement of Upward- and Downward-Facing Heater in Nanofluids

2013 ◽  
Vol 135 (7) ◽  
Author(s):  
Muhamad Zuhairi Sulaiman ◽  
Masahiro Takamura ◽  
Kazuki Nakahashi ◽  
Tomio Okawa
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Critical Heat Flux ◽  
Boiling Heat Transfer ◽  
Pool Boiling ◽  
Nucleate Boiling ◽  
Flux Enhancement ◽  
Optimum Configuration ◽  
Wall Superheat ◽  
Nucleate Boiling Heat Transfer

Boiling heat transfer (BHT) and critical heat flux (CHF) performance were experimentally studied for saturated pool boiling of water-based nanofluids. In present experimental works, copper heaters of 20 mm diameter with titanium-oxide (TiO2) nanocoated surface were produced in pool boiling of nanofluid. Experiments were performed in both upward and downward facing nanofluid coated heater surface. TiO2 nanoparticle was used with concentration ranging from 0.004 until 0.4 kg/m3 and boiling time of tb = 1, 3, 10, 20, 40, and 60 mins. Distilled water was used to observed BHT and CHF performance of different nanofluids boiling time and concentration configurations. Nucleate boiling heat transfer observed to deteriorate in upward facing heater, however; in contrast effect of enhancement for downward. Maximum enhancements of CHF for upward- and downward-facing heater are 2.1 and 1.9 times, respectively. Reduction of mean contact angle demonstrate enhancement on the critical heat flux for both upward-facing and downward-facing heater configuration. However, nucleate boiling heat transfer shows inconsistency in similar concentration with sequence of boiling time. For both downward- and upward-facing nanocoated heater's BHT and CHF, the optimum configuration denotes by C = 400 kg/m3 with tb = 1 min which shows the best increment of boiling curve trend with lowest wall superheat ΔT = 25 K and critical heat flux enhancement of 2.02 times.

Study on Subcooled-Forced Flow Boiling Heat Transfer and Critical Heat Flux of Solid-Water Two-Phase Mixture

1999 ◽  
Author(s):  
Yasuo Koizumi ◽  
Hiroyasu Ohtake ◽  
Manabu Mochizuki
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Critical Heat Flux ◽  
Liquid Layer ◽  
Boiling Heat Transfer ◽  
Flow Boiling ◽  
Nucleate Boiling ◽  
Forced Flow ◽  
Superheated Liquid ◽  
Flow Boiling Heat Transfer

Abstract The effect of solid particle introduction on subcooled-forced flow boiling heat transfer and a critical heat flux was examined experimentally. In the experiment, glass beads of 0.6 mm diameter were mixed in subcooled water. Experiments were conducted in a range of the subcooling of 40 K, a velocity of 0.17–6.7 m/s, a volumetric particle ratio of 0–17%. When particles were introduced, the growth of a superheated liquid layer near a heat trasnsfer surface seemed to be suppressed and the onset of nucleate boiling was delayed. The particles promoted the condensation of bubbles on the heat transfer surface, which shifted the initiation of a net vapor generation to a high heat flux region. Boiling heat trasnfer was augmented by the particle introduction. The suppression of the growth of the superheated liquid layer and the promotion of bubble condensation and dissipation by the particles seemed to contribute that heat transfer augmentation. The wall superheat at the critical heat flux was elevated by the particle introduction and the critical heat flux itself was also enhanced. However, the degree of the critical heat flux improvement was not drastic.

scholarly journals Characteristics of Flow Boiling Heat Transfer and Critical Heat Flux in a Vertical Tube with a Wire Coil.

2001 ◽  
Vol 67 (653) ◽  
pp. 128-134
Author(s):  
Keishi TAKESHIMA ◽  
Terushige FUJII ◽  
Nobuyuki tAKENAKA ◽  
Hitoshi ASANO ◽  
Takamitsu KONDO
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Critical Heat Flux ◽  
Boiling Heat Transfer ◽  
Flow Boiling ◽  
Vertical Tube ◽  
Flow Boiling Heat Transfer ◽  
Wire Coil

Boiling Heat Transfer and Critical Heat Flux

2016 ◽  
pp. 315-346
Author(s):  
Hajime Akimoto ◽  
Yoshinari Anoda ◽  
Kazuyuki Takase ◽  
Hiroyuki Yoshida ◽  
Hidesada Tamai
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Critical Heat Flux ◽  
Boiling Heat Transfer

Study on Boiling Heat Transfer and Critical Heat Flux in Mist Cooling: Effect of Droplet Size on Heat Transfer Characteristics

2004 ◽  
Author(s):  
Hiroyasu Ohtake ◽  
Tomoyasu Tanaki ◽  
Yasuo Koizumi
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Critical Heat Flux ◽  
Droplet Size ◽  
Flow Rate ◽  
Mass Flux ◽  
Boiling Heat Transfer ◽  
Heat Transfer Characteristics ◽  
Liquid Mass ◽  
Mist Cooling

Boiling heat transfer and critical heat flux—CHF—in mist cooling were investigated experimentally and analytically. Especially, the heat transfer in the mist cooling was examined focusing on the effects of droplet size and droplet velocity on the heat transfer characteristics. Steady state experiments of heat transfer were conducted using a pure copper cylinder and mist flow of water-air at room temperature. Liquid flow rate was 0.3, 0.9, 1.8, 4 and 8 l/hr, respectively; each air flow rate on normal condition was 0, 40, 75 and 120 lN/min. Furthermore, liquid mass flux on the heater surface for each experimental condition was measured by using a cylinder with a scale and the same diameter as the heater. Distribution of air velocity, average velocity of droplets and average diameter of droplets were measured by using a fine Pitot tube, laser doppler anemometry and immersion method, respectively. Three correlations of the mist cooling rate for non-boiling, evaporation of droplets and evaporation of the liquid film were developed by using the measured liquid mass flux, characteristic droplet velocity and wall superheat. A CHF model was presented by focusing on maximum evaporation rate of the liquid mass flux on a heater. A droplet evaporation model was proposed by using the transient heat conduction in a sphere. Finally, three dimensionless correlations for the mist cooling were presented.

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