Film Boiling Heat Transfer From an Oscillating Sphere

1969 ◽  
Vol 91 (2) ◽  
pp. 267-271 ◽  
Author(s):  
L. G. Rhea ◽  
R. G. Nevins
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Boiling Heat Transfer ◽  
Correlation Equation ◽  
Heat Transfer Surface ◽  
Film Boiling ◽  
Maximum Deviation ◽  
Coated Surface ◽  
Good Agreement ◽  
Oscillating Sphere

An experimental investigation has been undertaken to determine the effect of oscillation of the heat transfer surface on turbulent film boiling heat transfer. A transient technique was used to calculate the heat flux from copper spheres of 1 in., 3/4 in., and 1/2 in. dia. In all tests, saturated liquid nitrogen at atmospheric pressure was used as the boiling fluid. The data obtained were found to be in good agreement with published theory at zero frequency. The range of frequencies studied was from zero to approximately 12 cps at peak-to-peak amplitudes of 2 in. and 1 in., i.e., at amplitude-to-diameter ratios of 1.00, 1.34, 2.00, 2.67, and 4.00. It was determined that oscillation of the heat transfer surface considerably increases the heat flux for a given temperature difference over that for natural convection film boiling. The results were correlated with a maximum deviation of +35, −17 percent. The correlation equation Nu=0.14gd3ρvf(ρl−ρvf)μvf2(Pr)vfhfgCpvfΔT+0.5ag+X2F2gd1/3 showed that the Nusselt number was proportional to the vibrational Fronde number to the 2/3 power. Tests were conducted with spheres having a corroded surface, a glass-bead-peened surface and a Teflon-coated surface. The results show that the turbulent film boiling from an oscillating sphere is independent of the condition of the heat transfer surface over the range of frequencies and amplitudes tested.

Steady State Film Boiling Heat Transfer Simulated With TRACE V4.160

2006 ◽  
Author(s):  
Audrius Jasiulevicius ◽  
Rafael Macian-Juan
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Mass Flux ◽  
Boiling Heat Transfer ◽  
High Mass ◽  
Film Boiling ◽  
Experimental Database ◽  
Boiling Heat Transfer Coefficient

This paper presents the results of the assessment and analysis of TRACE v4.160 heat transfer predictions in the post-CHF (critical heat flux) region and discusses the possibilities to improve the TRACE v4.160 code predictions in the film boiling heat transfer when applying different film boiling correlations. For this purpose, the TRACE v4.160-calculated film boiling heat flux and the resulting maximum inner wall temperatures during film boiling in single tubes were compared with experimental data obtained at the Royal Institute of Technology (KTH) in Stockholm, Sweden. The experimental database included measurements for pressures ranging from 30 to 200 bar and coolant mass fluxes from 500 to 3000 kg/m2s. It was found that TRACE v4.160 does not produce correct predictions of the film boiling heat flux, and consequently of the maximum inner wall temperature in the test section, under the wide range of conditions documented in the KTH experiments. In particular, it was found that the standard TRACE v4.160 underpredicts the film boiling heat transfer coefficient at low pressure-low mass flux and high pressure-high mass flux conditions. For most of the rest of the investigated range of parameters, TRACE v4.160 overpredicts the film boiling heat transfer coefficient, which can lead to non-conservative predictions in applications to nuclear power plant analyses. Since no satisfactory agreement with the experimental database was obtained with the standard TRACE v4.160 film boiling heat transfer correlations, we have added seven film boiling correlations to TRACE v4.160 in order to investigate the possibility to improve the code predictions for the conditions similar to the KTH tests. The film boiling correlations were selected among the most commonly used film boiling correlations found in the open literature, namely Groeneveld 5.7, Bishop (2 correlations), Tong, Konkov, Miropolskii and Groeneveld-Delorme correlations. The only correlation among the investigated, which resulted in a significant improvement of TRACE predictions, was the Groeneveld 5.7. It was found, that replacing the current film boiling correlation (Dougall-Rohsenow) for the wall-togas heat transfer with Groeneveld 5.7 improves the code predictions for the film boiling heat transfer at high qualities in single tubes in the entire range of pressure and coolant mass flux considered.

Flow Behavior and Flow Boiling Heat Transfer in Thin-Rectangular Mini-Channels

2008 ◽  
Author(s):  
Yasuo Koizumi ◽  
Hiroyasu Ohtake ◽  
Tomonari Yamada
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Flow Pattern ◽  
Critical Heat Flux ◽  
Boiling Heat Transfer ◽  
Annular Flow ◽  
Flow Channel ◽  
Heat Transfer Surface ◽  
Liquid Slug ◽  
Flux Condition

Boiling heat transfer of thin-rectangular channels of the width of 10 mm has been examined. The height of the flow channel was in a range from 0.6 mm to 0.4 mm. Experimental fluid was water. Bubbly flow, slug flow, semi annular flow and annular flow were observed. The flow pattern transition agreed well with the Baker flow pattern map for the usual sized flow path. The critical heat flux was lower than the value of the usual sized flow channel. The Koizumi and Ueda method predicted well the trend of the critical heat flux of the present experiments. At the critical heat flux condition, the heat transfer surface was covered by liquid slug, a large bubble pushed away the liquid slug, a dry area was formed on the heat transfer surface and then liquid slug came around to cover the heat transfer surface again. This process repeated rapidly. Following this observation, a heat transfer surface temperature calculation model at the critical heat flux condition was proposed. The calculated result re produced the experimental result.

scholarly journals ELETRIC FIELD ENHANCEMENT AND DETERIORATION OF BOILING HEAT TRANSFER AND CRITICAL HEAT FLUX IN DIELECTRIC FLUIDS

2001 ◽  
Vol 1 (1) ◽  
pp. 32
Author(s):  
P. M. Carrica ◽  
V. Masson
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Critical Heat Flux ◽  
Electric Fields ◽  
Boiling Heat Transfer ◽  
Nucleate Boiling ◽  
Film Boiling ◽  
Two Phase ◽  
Boiling Regime ◽  
Dielectric Fluids

We present the results of an experimental study of the effects of externally imposed electric fields on boiling heat transfer and critical heat flux (CHF) in dielectric fluids. The study comprises the analysis of geometries that, under the effects of electric fields, cause the bubbles either to be pushed toward the heater or away from it. A local phase detection probe was used to measure the void fraction and the interfacial impact rate near the heater. It was found that the critical heat flux can be either augmented or reduced with the application of an electric field, depending on the direction of . In addition, the heat transfer can be slightly enhanced or degraded depending on the heat flux. The study of the two-phase flow in nucleate boiling, only for the case of favorable dielectrophoretic forces, reveals that the application of an electric field reduces the bubble detection time and increases the detachment frequency. It also shows that the two-phase flow characteristics of the second film boiling regime resemble more a nucleate boiling regime than a film boiling regime.

The Critical Heat Flux in Nucleate Boiling Heat Transfer: Part I—The Chemical Actuator Mechanism

2009 ◽  
Author(s):  
M. R. Reda
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Phase Change ◽  
Grain Boundaries ◽  
Recent Work ◽  
Boiling Heat Transfer ◽  
Nucleate Boiling ◽  
Passive Layer ◽  
Nucleate Boiling Heat Transfer ◽  
Good Agreement

Nucleate boiling heat transfer is first introduced and the literature is reviewed. It was concluded that the passive layer and the grain boundaries are responsible for the transfer to the nucleate boiling regime. Based on the recent work of Biener and his collaborators (Nature Material 2008) and the Gibbs rule of thermodynamics, a possible mechanism was outlined. The mechanism assumes that each grain in the passive layer act as a chemical actuator which is driven by microstructure phase change. The new mechanism agrees well with the experimental results, in good agreement with previous models and can explain why and how CHF occurs.

Study on Nucleate Boiling Heat Transfer by Measuring Detailed Surface Temperature Distribution and Variation With Infrared Radiation Camera

2014 ◽  
Author(s):  
Kazuki Takahashi ◽  
Yasuo Koizumi
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Temperature Distribution ◽  
Surface Temperature ◽  
Infrared Radiation ◽  
Boiling Heat Transfer ◽  
Pool Boiling ◽  
Heat Transfer Surface ◽  
Bubble Generation ◽  
Test Vessel

Pool boiling heat transfer experiments were performed for water at 101 kPa to examine elementary process of nucleate pool boiling. The heat transfer surface was made from a copper printed circuit board. The size of the heat transfer surface was 10 mm × 10 mm. Direct current was supplied to the heat transfer surface to heat it up. The Bakelite plate of the backside of the copper layer was taken off at the center portion of the heat transfer surface. The test vessel was a closed 200-mm cube container made of duralumin. It has transparent view windows on opposing side walls made of a Polycarbonate plate to observe a boiling state. Heat transfer surface was placed at the bottom of the test vessel. Distilled water was used for the experiments. The instantaneous variation of the backside temperature of the heat transfer surface was measured with an infrared radiation camera. Bubble behavior was recorded with a high speed video camera. The time and the space resolution of the infrared radiation cameras used in present experiments were 60 Hz and 0.1 mm × 0.1 mm, and 120 Hz and 0.315 mm × 0.315 mm, respectively. When the heat flux was increased, the instantaneous surface temperature variation explain the pattern. In the isolated bubble region, surface temperature was uniform during waiting time. When boiling bubble generation started, a large dip in the surface temperature was formed under the bubble. After the bubble left from the heat transfer surface, the surface temperature returned to former uniform temperature distribution. Surface temperature was not affected by the bubble generation beyond 1.8 mm from the center of the bubble. In the intermediate and high heat flux region, the variation of surface temperature and heat flux were small. Rather the heat flux variation range was close to that at the isolated boiling region.

Study on Nucleate Boiling Heat Transfer by Measuring Spatially Instantaneous Local Surface Temperature and Observing Instantaneous Bubble/Liquid Fluid Behavior

2013 ◽  
Author(s):  
Yasuo Koizumi ◽  
Kenta Hayashi
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Surface Temperature ◽  
Critical Heat Flux ◽  
Boiling Heat Transfer ◽  
Nucleate Boiling ◽  
Heat Transfer Surface ◽  
Bubble Generation ◽  
Three Phase ◽  
Nucleate Boiling Heat Transfer

Pool nucleate boiling heat transfer experiments were performed for water at 0.101 MPa to examine the elementary process of the nucleate boiling. Heat transfer surface was made from a copper printed circuit board. Direct current was supplied to heat it up. The Bakelite plate of the backside of a copper layer was taken off at the center portion of the heat transfer surface. The instantaneous variation of the backside temperature of the heat transfer surface was measured with an infrared radiation camera. Bubble behavior was recorded with a high speed video camera. In the isolated bubble region, surface temperature was uniform during waiting time. When boiling bubble generation started, a large dip in the surface temperature was formed under the bubble. After the bubble left from the heat transfer surface, the surface temperature returned to former uniform temperature distribution. Surface temperature was not affected by the bubble generation beyond 1.6 mm from the center of the bubble. In the isolated bubble region, a convection term was approximately 80 % in total heat transfer rate. The importance of the three-phase interface line in the heat transfer should be checked carefully. In the intermediate and high heat flux region, the variation of surface temperature and heat flux were small. Rather those were close to their average values even at critical heat flux condition. It seemed that the large part of the heat transfer surface was covered with water even at the critical heat flux condition. The heat flux at the area that appeared to be the three-phase contact line was not so high and close to the average heat flux.

scholarly journals ELETRIC FIELD ENHANCEMENT AND DETERIORATION OF BOILING HEAT TRANSFER AND CRITICAL HEAT FLUX IN DIELECTRIC FLUIDS

2002 ◽  
Vol 1 (1) ◽  
Author(s):  
P. M. Carrica ◽  
V. Masson
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Critical Heat Flux ◽  
Electric Fields ◽  
Boiling Heat Transfer ◽  
Nucleate Boiling ◽  
Film Boiling ◽  
Two Phase ◽  
Boiling Regime ◽  
Dielectric Fluids

We present the results of an experimental study of the effects of externally imposed electric fields on boiling heat transfer and critical heat flux (CHF) in dielectric fluids. The study comprises the analysis of geometries that, under the effects of electric fields, cause the bubbles either to be pushed toward the heater or away from it. A local phase detection probe was used to measure the void fraction and the interfacial impact rate near the heater. It was found that the critical heat flux can be either augmented or reduced with the application of an electric field, depending on the direction of . In addition, the heat transfer can be slightly enhanced or degraded depending on the heat flux. The study of the two-phase flow in nucleate boiling, only for the case of favorable dielectrophoretic forces, reveals that the application of an electric field reduces the bubble detection time and increases the detachment frequency. It also shows that the two-phase flow characteristics of the second film boiling regime resemble more a nucleate boiling regime than a film boiling regime.

Comparison and Improvements of Correlations for Film Boiling in Tubes

2009 ◽  
Author(s):  
E.-L. Pelletier ◽  
L. K. H. Leung ◽  
A. Teyssedou ◽  
R. Girard
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Wall Temperature ◽  
Boiling Heat Transfer ◽  
Prediction Accuracy ◽  
Film Boiling ◽  
Independent Parameter ◽  
Maximum Temperature

Two methodologies to predict film boiling heat-transfer coefficient have been assessed against experimental wall-temperature measurements obtained under steady-state conditions with water flow inside vertical tubes. One of these methodologies employs heat flux as the independent parameter while the other uses wall temperature as the independent parameter. The film boiling heat transfer consists of developing and fully developed film-boiling regions. Film boiling heat-transfer coefficients are predicted using the film boiling look-up tables for fully developed flow. Developing film-boiling effect is accounted for using modification factors to the fully developed heat-transfer coefficient. Wall-temperature distributions along uniformly heated tubes were established using a semi-analytical scheme and compared against measurements. Both methodologies have provided good predictions. However, the overall prediction accuracy for the heat-flux-based correlation is slightly better than that for the wall-temperature-based correlation. Wall temperatures predicted with the heat-flux-based correlation follow closely measurements at the developing post-dryout region. The wall superheat correlation predicts a sharp temperature rise once the critical heat flux is exceeded, resulting in discrepancies between predictions and measurements of wall temperature and overpredictions of the maximum temperature. The wall-temperature-based modification factor for the developing film-boiling region has been revised using the tube heat-transfer database to improve the prediction accuracy of the wall temperature.

Sign in / Sign up

Export Citation Format

Share Document