A Theoretical Critical Heat Flux Model for Low-Pressure, Low-Mass-Flux, and Low-Steam-Quality Conditions

1993 ◽  
Vol 103 (3) ◽  
pp. 332-345 ◽  
Author(s):  
Wei-Hsiao Ho ◽  
Kuan-Chywan Tu ◽  
Bau-Shei Pei ◽  
Chin-Jang Chang
Keyword(s):  
Heat Flux ◽  
Critical Heat Flux ◽  
Mass Flux ◽  
Low Pressure ◽  
Steam Quality ◽  
Flux Model ◽  
Low Mass ◽  
Heat Flux Model

Critical heat flux in non-uniformly heated tube under low-pressure and low-mass-flux condition

2005 ◽  
Vol 35 (1) ◽  
pp. 47-60 ◽  
Author(s):  
Hisashi Umekawa ◽  
Tetsuo Kitajima ◽  
Mio Hirayama ◽  
Mamoru Ozawa ◽  
Kaichiro Mishima ◽  
...  
Keyword(s):  
Heat Flux ◽  
Critical Heat Flux ◽  
Mass Flux ◽  
Low Pressure ◽  
Heated Tube ◽  
Flux Condition ◽  
Low Mass

A New Mechanistic Critical Heat Flux Model at Low-Pressure and Low-Flow Conditions

1998 ◽  
Vol 124 (3) ◽  
pp. 243-254 ◽  
Author(s):  
Kuan-Chywan Tu ◽  
Chien-Hsiung Lee ◽  
Shih-Jen Wang ◽  
Bau-Shei Pei
Keyword(s):  
Heat Flux ◽  
Critical Heat Flux ◽  
Low Pressure ◽  
Low Flow ◽  
Flow Conditions ◽  
Flux Model ◽  
Heat Flux Model

scholarly journals Critical Heat Flux in Non-uniformly Heated Tube under Low-Pressure and Low-Mass-Flux Condition

2005 ◽  
Vol 71 (703) ◽  
pp. 939-946
Author(s):  
Hisashi UMEKAWA ◽  
Tetsuo KITAJIMA ◽  
Mio HIRAYAMA ◽  
Mamoru OZAWA ◽  
Kaichiro MISHIMA ◽  
...  
Keyword(s):  
Heat Flux ◽  
Critical Heat Flux ◽  
Mass Flux ◽  
Low Pressure ◽  
Heated Tube ◽  
Flux Condition ◽  
Low Mass

Effect of Inlet Restriction on Flow Boiling Heat Transfer in a Horizontal Microtube

2013 ◽  
Vol 135 (2) ◽  
Author(s):  
YanFeng Fan ◽  
Ibrahim Hassan
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Pressure Drop ◽  
Critical Heat Flux ◽  
Mass Flux ◽  
Boiling Heat Transfer ◽  
Flow Boiling ◽  
Mass Fluxes ◽  
Flow Boiling Heat Transfer ◽  
Low Mass

Flow boiling heat transfer in a horizontal microtube with inlet restriction (orifice) under uniform heating condition is experimentally investigated using FC-72 as working fluid. A stainless steel microtube with an inner diameter of 889 μm is selected as main microtube. Two microtubes with smaller diameters are assembled at the inlet of main microtube to achieve the restriction ratios of 50% and 20%. The experimental measurement is carried out at mass fluxes ranging from 160 to 870 kg/m2·s, heat fluxes varying from 6 to 170 kW/m2, inlet temperatures of 23 and 35 °C, and saturation pressures of 10 and 45 kPa. The effects of the orifices on two-phase pressure drop, critical heat flux (CHF), and flow boiling heat transfer coefficient are studied. The results show that the pressure drop caused by the orifice takes a considerable portion in the total pressure drop at low mass fluxes. This ratio decreases as the vapor quality or mass flux increases. The difference of normal critical heat flux in the microtubes with different orifice sizes is negligible. In the aspect of flow boiling heat transfer, the orifice is able to enhance the heat transfer at low mass flux and high saturation pressure, which indicates the contribution of orifice in the nucleate boiling dominated regime. However, the effect of orifice on flow boiling heat transfer is negligible in the forced convective boiling dominated regime.

Critical Heat Flux in Horizontal Tube Bundles in Vertical Crossflow of R113

1992 ◽  
Vol 114 (1) ◽  
pp. 179-184 ◽  
Author(s):  
K. M. Leroux ◽  
M. K. Jensen
Keyword(s):  
Heat Flux ◽  
Critical Heat Flux ◽  
Mass Flux ◽  
Horizontal Tube ◽  
High Mass ◽  
Intermediate Mass ◽  
Average Value ◽  
Mass Fluxes ◽  
Local Quality ◽  
Low Mass

The critical heat flux (CHF) on a single tube in a horizontal bundle subject to an upward crossflow of R113 has been studied in three bundle geometries. Effects of local quality, mass flux, pressure, and bundle geometry on the CHF were investigated. The shapes of the CHF-quality curves display three distinct patterns, which progress from one to another as mass flux increases. At low mass fluxes, the CHF data monotonically decreased with increasing quality. At intermediate mass fluxes with increasing quality, the CHF data initially decreased to a relative minimum, then increased to a relative maximum, and finally began to decrease again as the higher qualities were reached. At high mass fluxes, as quality increased, the CHF rose gradually from the zero quality value to a maximum and then began to decrease. For all mass fluxes, the zero-quality CHF points clustered around an average value, which varied slightly with test section geometry. Mechanisms for the CHF condition are suggested.

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