Transition Boiling Curves in Saturated Pool Boiling From Horizontal Cylinders

1996 ◽  
Vol 118 (3) ◽  
pp. 654-661 ◽  
Author(s):  
E. K. Ungar ◽  
R. Eichhorn
Keyword(s):  
High Speed ◽  
Pool Boiling ◽  
Nucleate Boiling ◽  
Heat Fluxes ◽  
Film Boiling ◽  
High Speed Flow ◽  
Wall Superheat ◽  
Speed Flow ◽  
Single Transition ◽  
Horizontal Cylinders

Pool boiling heat flux versus wall superheat boiling curves were obtained for horizontal 3.18-mm-dia thin-walled brass tubes heated by an internal high-speed flow of ethylene glycol. The boiling liquids were saturated n-pentane, R-113, acetone, methanol ethanol, benzene, and isopropanol. Boiling results include nucleate and transition boiling in all the test liquids, but film boiling was achieved only with methanol. The measured peak heat fluxes are well correlated by available predictions. The methanol experiments clearly display two transition boiling curves, one obtained on increasing the cylinder temperature from nucleate boiling, the other on decreasing the cylinder temperature from film boiling. For the cases in which the highest cylinder temperature reached only into the transition regime, a single transition boiling curve resulted.

Numerical Simulation of Pool Boiling: A Review

2013 ◽  
Vol 135 (6) ◽  
Author(s):  
Vijay K. Dhir ◽  
Gopinath R. Warrier ◽  
Eduardo Aktinol
Keyword(s):  
Numerical Simulation ◽  
Conjugate Heat Transfer ◽  
Numerical Models ◽  
Pool Boiling ◽  
Nucleate Boiling ◽  
Film Boiling ◽  
Gravity Level ◽  
Designed Experiments ◽  
Wall Superheat ◽  
Multiple Bubbles

A review of numerical simulation of pool boiling is presented. Details of the numerical models and results obtained for single bubble, multiple bubbles, nucleate boiling, and film boiling are provided. The effect of such parameters such as wall superheat, liquid subcooling, contact angle, gravity level, noncondensables, and conjugate heat transfer are also included. The numerical simulation results have been validated with data from well designed experiments.

Subcooled Flow Boiling on Micro-Porous Structured Copper Surface in a Vertical Mini-Gap Channel

2019 ◽  
Author(s):  
Junye Li ◽  
Kan Zhou ◽  
Wei Li
Keyword(s):  
Heat Transfer ◽  
High Speed ◽  
Flow Boiling ◽  
Copper Surface ◽  
Heat Fluxes ◽  
High Speed Flow ◽  
Subcooled Flow Boiling ◽  
Mass Fluxes ◽  
Speed Flow ◽  
Subcooled Flow

Abstract An experimental investigation of subcooled flow boiling in a large width-to-height-ratio, one-sided heating rectangular mini-gap channel was conducted with deionized water as the working fluid. The super-hydrophobicity micro-porous structured copper surface was utilized in the experiments. High speed flow visualization was conducted to illustrate the effects of heat flux and mass rate on the heat transfer coefficient and flow pattern on the surfaces. The mass fluxes were in the range of 200–500 kg/m2s, the wall heat fluxes were spanned from 40–400 kW/m2. With increments of imposed heat flux, the slopes of boiling curves for superhydrophobic micro-porous copper surfaces increased rapidly, indicating the Onset of Nucleate Boiling. Heat transfer characteristics were discussed with variation of heat fluxes and mass fluxes, the trends of which were analyzed with the aid of high speed flow visualization.

Transient Pool Boiling CHF in FC-72

2008 ◽  
Author(s):  
P. F. Sutopo ◽  
Katsuya Fukuda ◽  
Qiusheng Liu
Keyword(s):  
Pool Boiling ◽  
Heat Fluxes ◽  
Current Work ◽  
Film Boiling ◽  
Wide Range ◽  
Horizontal Cylinders

In the current work, critical heat fluxes (CHFs) and related boiling phenomena due to transient heat inputs, Q0exp(t/τ), to horizontal finite heaters were investigated in a pool of FC-72. Investigations were made on 1.0 mm diameter horizontal cylinders and a horizontal vertically oriented ribbon (4.0 mm × 0.1 mm × 31.5 mm) under a wide range of pressures ranged from 79.5 kPa up to 1278.1 kPa and liquid subcoolings ranged from saturated up to 140 K. The CHFs obtained from each heater with their dependency on pressure and liquid subcooling, and the typical ones against exponential period, τ, were observed and compared. The transition boiling processes to film boiling including mechanisms of incipient boiling and CHF, and vapor and bubble behaviors were also derived.

Dynamics of Pool Boiling on Plain and Nanotube Coated Silicon Surfaces

2010 ◽  
Author(s):  
Vijaykumar Sathyamurthi ◽  
Debjyoti Banerjee
Keyword(s):  
Heat Flux ◽  
Surface Temperature ◽  
Chaotic Dynamics ◽  
Pool Boiling ◽  
Deterministic Chaos ◽  
Nucleate Boiling ◽  
High Heat ◽  
Heat Fluxes ◽  
Film Boiling ◽  
Test Fluid

Saturated pool boiling experiments are conducted over silicon substrates with and without Multi-walled Carbon Nanotubes (MWCNT) with PF-5060 as the test fluid. Micro-fabricated thin film thermocouples located on the substrate acquire surface temperature fluctuation data at 1 kHz frequency. The high frequency surface temperature data is analyzed for the presence of chaotic dynamics. The shareware code, TISEAN© is used in analysis of the temperature time-series. Results show the presence of low-dimensional deterministic chaos, near Critical Heat Flux (CHF) and in some parts of the Fully Developed Nucleate Boiling (FDNB) regime. Some evidence of chaotic dynamics is also obtained for the film boiling regimes. Singular value decomposition is employed to generate pseudo-phase plots of the attractor. In contrast to previous studies involving multiple nucleation sites, the pseudo-phase plots show the presence of multi-fractal structure at high heat fluxes and in the film boiling regime. An estimate of invariant quantities such as correlation dimensions and Lyapunov exponents reveals the change in attractor geometry with heat flux levels. No significant impact of surface texturing is visible in terms of the invariant quantities.

Transient Pool Boiling Critical Heat Flux of FC-72 Under Saturated Conditions

2006 ◽  
Author(s):  
Sutopo P. Fitri ◽  
Katsuya Fukuda ◽  
Qiusheng Liu ◽  
Jongdoc Park
Keyword(s):  
Steady State ◽  
Hydrodynamic Instability ◽  
Pool Boiling ◽  
Nucleate Boiling ◽  
Heat Fluxes ◽  
Cylinder Surface ◽  
Empirical Correlations ◽  
Direct Transition ◽  
Spontaneous Nucleation ◽  
Horizontal Cylinders

In this study, the steady-state and transient critical heat fluxes (CHFs) in pool boiling were measured on 1.0 mm diameter horizontal cylinders of gold and platinum heaters under saturated conditions due to transient heat inputs, Q0exp(t/τ), in a pool of Fluorinert FC-72. Heaters were heated by electric current with the periods, τ, ranged from 10 ms to 20 s, and the pressures ranged from atmospheric up to around 1.2 MPa. The steady-state CHFs measured are dependent on pressure and almost agree with the values obtained by Kutateladze’s correlation based on hydrodynamic instability (HI) model. It was considered that the boiling inception and the direct transition during the steady-state period occur by the pre-pressure of ∼1.2 MPa. The trend of typical transient CHFs were clearly divided into the first, second, and third groups for long, short, and intermediate periods, respectively. The direct transition processes to film boiling without nucleate boiling for the short periods obtained from both heaters were confirmed due to the heterogeneous spontaneous nucleation (HSN) in flooded cavities on the cylinder surface. The empirical correlations to express each of corresponding CHFs measured on both heaters for the short periods are presented in this paper.

Visualization of High Speed Flow in a Pipe with Cavity

1997 ◽  
Vol 17 (Supplement2) ◽  
pp. 113-116
Author(s):  
Kenji HOSOI ◽  
Masaaki KAWAHASHI ◽  
Hiroyuki HIRAHARA ◽  
Kouju SHIOZAKI ◽  
Kenichirou SATOH
Keyword(s):  
High Speed ◽  
High Speed Flow ◽  
Speed Flow
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