Experimental Investigation of Wall Nucleation Characteristics in Flow Boiling

2015 ◽  
Vol 137 (5) ◽  
Author(s):  
Caleb S. Brooks ◽  
Nicolás Silin ◽  
Takashi Hibiki ◽  
Mamoru Ishii
Keyword(s):  
Flow Boiling ◽  
Bulk Liquid ◽  
Poor Agreement ◽  
Experimental Database ◽  
System Pressure ◽  
Boiling Flow ◽  
Vertical Annulus ◽  
Forced Convective Flow ◽  
Departure Size ◽  
Current Database

Wall nucleation experiments have been performed in a vertical annulus test section for investigation of the bubble departure diameter and bubble departure frequency. The experimental data in forced convective subcooled boiling flow is presented as a parametric study of the effect of wall heat flux, local bulk liquid subcooling, liquid flow rate, and system pressure. The data are shown to extend the database currently available in literature to a wider range of system conditions. Along with the current database in forced convective flow, the available models for bubble departure size and frequency are reviewed and compared with the existing database. The prediction of the bubble departure frequency is shown to require accurate modeling of the bubble departure diameter which has poor agreement with the experimental database.

Experimental Investigation of Bubble Departure Diameter and Bubble Departure Frequency in Subcooled Flow Boiling in a Vertical Annulus

2013 ◽  
Author(s):  
Caleb S. Brooks ◽  
Nicolás Silin ◽  
Takashi Hibiki ◽  
Mamoru Ishii
Keyword(s):  
Flow Boiling ◽  
Bulk Liquid ◽  
Subcooled Flow Boiling ◽  
Experimental Database ◽  
System Pressure ◽  
Subcooled Flow ◽  
Boiling Flow ◽  
Vertical Annulus ◽  
Forced Convective Flow ◽  
Departure Size

Wall nucleation experiments have been performed in a vertical annulus test section for investigation of the bubble departure diameter and bubble departure frequency. The experimental data in forced convective subcooled boiling flow is presented as a parametric study of the effect of wall heat flux, local bulk liquid sub-cooling, liquid flow rate, and system pressure. The data is shown to extend the database currently available in literature to a wider range of system conditions. Along with the current database in forced convective flow, the available models for bubble departure size and frequency are reviewed and compared with the new data. The prediction of the bubble departure frequency is shown to require accurate modeling of the bubble departure diameter which has poor agreement with the experimental database.

Thermal Design Correlations for Single- and Two-Phase Flow of R-407C in Meso-Scale Heat Exchangers

2004 ◽  
Author(s):  
Yasir M. Shariff ◽  
T. S. Ravigururajan
Keyword(s):  
Flow Boiling ◽  
Thermal Design ◽  
Design Parameters ◽  
Two Phase ◽  
Channel Diameter ◽  
Experimental Database ◽  
Boiling Flow ◽  
Flow Variables ◽  
Saturated Boiling ◽  
Meso Scale

The paper presents correlation development for an experimental database done on R-407C flow in meso-scale horizontal channels. Single-phase, two-phase subcooled, and two-phase saturated boiling flow correlations were developed. The variables considered in this study including essential design parameters, such as, channel diameter, coils pitch and diameter. For flow variables considered are the Reynolds number and the Prandtl number. The purpose of this study is to present new design correlations for flow boiling in a ternary refrigerant mixture at a meso-scale size. The relative influences of enhancement design parameters on friction factor and heat transfer were carried in this parametric analysis of the flow boiling correlations. The resulted correlations developed in this study are compared to available published correlations.

Numerical Analysis of Water Flow Boiling Characteristics within Vertical Rectangular Thin Channels

2013 ◽  
Vol 655-657 ◽  
pp. 154-157
Author(s):  
Yan Chen ◽  
Shu Sheng Zhang ◽  
Ye Lu
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Water Flow ◽  
Stream Flow ◽  
Flow Boiling ◽  
System Pressure ◽  
Thin Channel ◽  
Boiling Flow ◽  
The Heat Transfer Coefficient

In this paper, water flow boiling characteristics within vertical rectangular thin channels were numerical analyzed. By the method of numerical simulation, the isolation bubbly stream flow patterns adapt to the non-restricted and restricted thin channel were obtained and the influence of channel-scale on the boiling flow pattern characteristics are analyzed. Study shown that the system pressure drop is increased with the decrease of the channel width; the heat transfer coefficient shows a decreasing trend after the first increase along with the increasing dryness; the decline of channel scale will lead to increasing of the average heat transfer coefficient.

Effect of Bubble Contact Diameter on Bubble Departure Size in Flow Boiling

2014 ◽  
Vol 29 (1) ◽  
pp. 37-52 ◽  
Author(s):  
P. Guan ◽  
L. Jia ◽  
L. Yin ◽  
Z. Tan
Keyword(s):  
Flow Boiling ◽  
Departure Size ◽  
Contact Diameter

Vapor Bubble Condensation Characteristics of Subcooled Flow Boiling in Vertical Rectangular Channel

2012 ◽  
Author(s):  
Zhi-wei Tan ◽  
Liang-ming Pan
Keyword(s):  
Bubble Size ◽  
Vapor Bubble ◽  
Large Scale ◽  
Flow Boiling ◽  
Rectangular Channel ◽  
Size Variation ◽  
Transfer Model ◽  
Bubble Deformation ◽  
Initial Diameter ◽  
System Pressure

In this study, the behavior of condensing single vapor bubble in subcooled boiling flow within two different vertical rectangular channels has been numerically investigated by using the VOF (Volume of Fluid) multiphase flow model. The mass and energy transfer model of bubble condensing process induced from the interfacial heat transfer was proposed to describe the interfacial transportation between the two phases. The results of VOF simulations showed good agreements with previous experimental data in the bubble size variation and lifetime. The bubble lifetime was almost proportional to bubble initial size and prolonged by system pressure. With the increase of subcooling, the bubble lifetime reduces significantly, and the effect of mass flux could be negligible. When bubble size increased, the bubble shape tends to be changed in a large-scale channel. The VOF simulation results of deformation have good agreement with those of Kamei’ experiment and the results of MPS (Moving Particle Semi-implicit) simulation in the large-scale channel. Furthermore, the initial bubble size, subcooling of liquid and system pressure play an important role to influence the bubble deformation behaviors significantly. The bubble could deform sharper with the increase of subcooling and initial diameter, or could breakup when the subcooling and the initial diameter reached a certain value at the last bubble stage. Whereas the trend of bubble deformation would be weaken with the increase of system pressure.

Low-Velocity Subcooled Nucleate Flow Boiling at Various Orientations

1995 ◽  
Vol 117 (2) ◽  
pp. 380-386 ◽  
Author(s):  
K. M. Kirk ◽  
H. Merte ◽  
R. Keller
Keyword(s):  
Thin Film ◽  
Heat Transfer ◽  
Liquid Velocity ◽  
Flow Boiling ◽  
Copper Substrate ◽  
Nucleate Boiling ◽  
Bulk Liquid ◽  
Heater Surface ◽  
Low Velocity ◽  
Buoyant Force

Subcooled forced convection nucleate boiling experiments with R-113 were conducted at low velocities using both thin film semitransparent gold-on-quartz and gold-coated copper substrate flat heaters at various orientations. The experiments demonstrate that if buoyancy is significant relative to bulk liquid momentum, then a decrease in the buoyant force normal to and away from the heater surface enhances the heat transfer, with the effect being greatest at low values of heat flux. Furthermore, the effect of the bulk liquid velocity is shown to be dependent on the surface orientation.

Bubble behavior of high subcooling flow boiling at different system pressure in vertical narrow channel

2011 ◽  
Vol 31 (16) ◽  
pp. 3512-3520 ◽  
Author(s):  
De-wen Yuan ◽  
Liang-ming Pan ◽  
Deqi Chen ◽  
Hui Zhang ◽  
Jing-hua Wei ◽  
...  
Keyword(s):  
Flow Boiling ◽  
Narrow Channel ◽  
Bubble Behavior ◽  
System Pressure
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