Critical Heat Flux of Steady Boiling for Subcooled Water Jet Impingement on the Flat Stagnation Zone

2004 ◽  
Vol 126 (2) ◽  
pp. 179-183 ◽  
Author(s):  
Zhen-Hua Liu ◽  
Tie-Feng Tong ◽  
Yu-Hao Qiu
Keyword(s):  
Experimental Data ◽  
Heat Flux ◽  
Critical Heat Flux ◽  
Jet Impingement ◽  
Nucleate Boiling ◽  
Water Jet ◽  
Stagnation Zone ◽  
Subcooled Water ◽  
Nozzle Size ◽  
Jet Nozzle

An experimental investigation was carried out for predicting the critical heat flux (CHF) of steady boiling for a round subcooled water jet impingement on the flat stagnation zone. The experimental data were measured in a steady nucleate boiling state. Three main influencing parameters, i.e., subcooling, impact velocity and jet nozzle size were widely changed and their effects on the critical heat flux were systemically studied. An empirical correlation was obtained using the experimental data over a wide experimental range for predicting the critical heat flux of steady boiling for a round subcooled water jet impingement on the flat stagnation zone.

Prediction of Critical Heat Flux for Convective Boiling of Saturated Water Jet Impinging on the Stagnation Zone

2002 ◽  
Vol 124 (6) ◽  
pp. 1125-1130 ◽  
Author(s):  
Zhen-Hua Liu ◽  
Qun-Zhi Zhu
Keyword(s):  
Experimental Data ◽  
Heat Flux ◽  
Experimental Investigation ◽  
Critical Heat Flux ◽  
Correlation Factor ◽  
Water Jet ◽  
Stagnation Zone ◽  
Helmholtz Instability ◽  
Convective Boiling ◽  
Saturated Water

A theoretical analysis and an experimental investigation were carried out for predicting the critical heat flux (CHF) of convective boiling for a round saturated water jet impinging on the jet stagnation zone. The model of the maximum liquid subfilm thickness based on the Helmholtz instability is used to derive a semi-theoretical equation and the correlation factor was determined from the experimental data. Finally, a semi-theoretical correlation was proposed for predicting CHF of convective boiling for saturated water jet impinging on the jet stagnation zone.

Critical Heat Flux During Submerged Jet Impingement Boiling of Saturated Water at Sub-Atmospheric Conditions

2011 ◽  
Author(s):  
Ruander Cardenas ◽  
Vinod Narayanan
Keyword(s):  
Experimental Data ◽  
Heat Flux ◽  
Critical Heat Flux ◽  
Jet Impingement ◽  
Atmospheric Conditions ◽  
Predictive Tool ◽  
Submerged Jet ◽  
Fluid Saturation ◽  
Saturated Water ◽  
Jet Impingement Boiling

Experimental data for critical heat flux (CHF) during submerged jet impingement boiling of saturated water at sub-atmospheric conditions is presented. Experiments are performed at three sub-atmospheric pressures of 0.176 bar, 0.276 bar, and 0.477 bar with corresponding fluid saturation temperatures of about 57.3 °C, 67.2 °C, and 80.2 °C. Jet exit Reynolds numbers ranging from 0 to 14,000 are considered for two different heater surface finishes at a fixed nozzle to surface spacing of six nozzle diameters. CHF correlations from literature on jet impingement boiling are compared against the experimental data and found to poorly predict CHF under the conditions considered. A CHF correlation that captures the entire experimental data set within an average error of ±3 percent and a maximum error of ±13 percent is developed to serve as a predictive tool for the range of conditions examined.

Critical Heat Flux of Steady Boiling for Water Jet Impingement in Flat Stagnation Zone on Superhydrophilic Surface

2005 ◽  
Vol 128 (7) ◽  
pp. 726-729 ◽  
Author(s):  
Zhenhua Liu ◽  
Yuhao Qiu
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Boiling Heat Transfer ◽  
Jet Impingement ◽  
Nucleate Boiling ◽  
Stagnation Zone ◽  
Heat Transfer Characteristics ◽  
Nucleate Boiling Heat Transfer ◽  
The Common ◽  
Superhydrophilic Surface

The nucleate boiling heat transfer characteristics of a round water jet impingement in a flat stagnation zone on the superhydrophilic surface were experimentally investigated. The superhydrophilic heat transfer surface was formed by a TiO2 coating process. The experimental results were compared with those on the common metal surface. In particular, the quantificational effects of the flow conditions, heating conditions, and the coating methods on the critical heat flux (CHF) were systemically investigated. The experimental data showed that the nucleate boiling heat transfer characteristics on the superhydrophilic surface are significantly different from those on the common metal surface. The CHF of boiling on the superhydrophilic surface is greatly increased by decreasing of the solid-liquid contact angle.

Critical Heat Flux Modeling in Forced Convection Boiling During Power Transients

1990 ◽  
Vol 112 (4) ◽  
pp. 1058-1062 ◽  
Author(s):  
K. O. Pasamehmetoglu ◽  
R. A. Nelson ◽  
F. S. Gunnerson
Keyword(s):  
Experimental Data ◽  
Heat Flux ◽  
Theoretical Prediction ◽  
Forced Convection ◽  
Critical Heat Flux ◽  
Nucleate Boiling ◽  
Convective Boiling ◽  
New Model ◽  
Semi Empirical

In this paper, a theoretical prediction of critical heat flux (CHF) during power transients in forced convective boiling is presented. The analysis is restricted to departure from nucleate boiling (DNB) type of CHF at low qualities. The developed theory is compared with the experimental data available in the literature. The agreement is exceptionally good. The new model also is compared with the semi-empirical transient CHF model in the literature.

Hotspot Cooling Performance for Submerged Confined Two-Phase Jet Impingement Cooling

2021 ◽  
Author(s):  
Tanvir Ahmed Chowdhury ◽  
Shawn A. Putnam
Keyword(s):  
Heat Flux ◽  
Single Phase ◽  
Heated Surface ◽  
Jet Impingement ◽  
Nucleate Boiling ◽  
Heat Fluxes ◽  
Nozzle Outlet ◽  
Two Phase ◽  
Impingement Cooling ◽  
Jet Nozzle

Abstract Jet impingement can be particularly effective for removing high heat fluxes from local hotspots. Two-phase jet impingement cooling combines the advantage of both the nucleate boiling heat transfer with the single-phase sensible cooling. This study investigates two-phase submerged jet impingement cooling of local hotspots generated by a diode laser in a 100 nm thick Hafnium (Hf) thin-film on glass. The jet/nozzle diameter is ∼1.2 mm and the normal distance between the nozzle outlet and the heated surface is ∼3.2 mm. Novec 7100 is used as the coolant and the Reynolds numbers at the jet nozzle outlet range from 250 to 5000. The hotspot area is ∼ 0.06 mm2 and the applied hotspot-to-jet heat flux ranges from 20 W/cm2 to 220 W/cm2. This heat flux range facilitates studies of both the single-phase and two-phase heat transport mechanisms for heat fluxes up to critical heat flux (CHF). The temporal evolution of the temperature distribution of the laser heated surface is measured using infrared (IR) thermometry. This study also investigates the nucleate boiling regime as a function of the distance between the hotspot center and the jet stagnation point. For example, when the hotspot center and the jet are co-aligned (x/D = 0), the CHF is found to be ∼ 177 W/cm2 at Re ∼ 5000 with a corresponding heat transfer coefficient of ∼58 kW/m2.K. While the CHF is ∼ 130 W/cm2 at Re ∼ 5000 with a jet-to-hotspot offset of x/D ≈ 4.2.

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