Analysis on special two-phase flow instabilities at full power natural circulation reactor condition

Kerntechnik ◽  
2004 ◽  
Vol 69 (4) ◽  
pp. 149-153
Author(s):  
Y. J. Zhang ◽  
X. T. Yang ◽  
S. Y. Jiang
Keyword(s):  
Two Phase Flow ◽  
Natural Circulation ◽  
Flow Instabilities ◽  
Phase Flow ◽  
Two Phase ◽  
Full Power

COMPARISON OF THE EFFECTS OF DIFFERENT TYPES OF TUBE INSERTS ON TWO-PHASE FLOW INSTABILITIES

2013 ◽  
Vol 20 (2) ◽  
pp. 179-194 ◽  
Author(s):  
Gokhan Omeroglu ◽  
Omer Gomakh ◽  
Sendogan Karagoz ◽  
Suleyman Karsli
Keyword(s):  
Two Phase Flow ◽  
Flow Instabilities ◽  
Phase Flow ◽  
Two Phase ◽  
Different Types

TWO-PHASE FLOW INSTABILITIES ANALYSES IN BOILING WATER REACTOR

2016 ◽  
Author(s):  
Antonella Lombardi Costa ◽  
WILMER ARUQUIPA COLOMA ◽  
Antonella Lombardi Costa ◽  
Claubia Pereira ◽  
Maria Veloso ◽  
...  
Keyword(s):  
Two Phase Flow ◽  
Boiling Water ◽  
Flow Instabilities ◽  
Boiling Water Reactor ◽  
Phase Flow ◽  
Two Phase ◽  
Water Reactor

Effect of heat transfer augmentation on two-phase flow instabilities in a vertical boiling channel

1983 ◽  
Vol 17 (3) ◽  
pp. 161-169 ◽  
Author(s):  
A. Mentes ◽  
O. T. Yildirim ◽  
H. Gürgenci ◽  
S. Kakaç ◽  
T. N. Veziro¯glu
Keyword(s):  
Heat Transfer ◽  
Two Phase Flow ◽  
Flow Instabilities ◽  
Phase Flow ◽  
Two Phase ◽  
Heat Transfer Augmentation

A Natural Circulation Model of the Closed Loop, Two-Phase Thermosyphon for Electronics Cooling

2001 ◽  
Author(s):  
S. I. Haider ◽  
Yogendra K. Joshi ◽  
Wataru Nakayama
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Closed Loop ◽  
Two Phase Flow ◽  
Natural Circulation ◽  
Saturation Temperature ◽  
Electronics Cooling ◽  
Phase Flow ◽  
Two Phase

Abstract The study presents a model for the two-phase flow and heat transfer in the closed loop, two-phase thermosyphon (CLTPT) involving co-current natural circulation. Most available models deal with two-phase thermosyphons with counter-current circulation within a closed, vertical, wickless heat pipe. The present research focuses on CLTPTs for electronics cooling that face more complex two-phase flow patterns than the vertical heat pipes, due to closed loop geometry and smaller tube size. The present model is based on mass, momentum, and energy balances in the evaporator, rising tube, condenser, and the falling tube. The homogeneous two-phase flow model is used to evaluate the friction pressure drop of the two-phase flow imposed by the available gravitational head through the loop. The saturation temperature dictates both the chip temperature and the condenser heat rejection capacity. Thermodynamic constraints are applied to model the saturation temperature, which also depends upon the local heat transfer coefficient and the two-phase flow patterns inside the condenser. The boiling characteristics of the enhanced structure are used to predict the chip temperature. The model is compared with experimental data for dielectric working fluid PF-5060 and is in general agreement with the observed trends. The degradation of condensation heat transfer coefficient due to diminished vapor convective effects, and the presence of subcooled liquid in the condenser are expected to cause higher thermal resistance at low heat fluxes. The local condensation heat transfer coefficient is a major area of uncertainty.

Two-phase flow instabilities in horizontal straight tube evaporator

2011 ◽  
Vol 31 (2-3) ◽  
pp. 181-187 ◽  
Author(s):  
Nan Liang ◽  
Shao Shuangquan ◽  
Changqing Tian ◽  
Y.Y. Yan
Keyword(s):  
Two Phase Flow ◽  
Flow Instabilities ◽  
Straight Tube ◽  
Phase Flow ◽  
Two Phase

Flow Boiling Heat Transfer and Two-Phase Flow Instability of Nanofluids in a Minichannel

2015 ◽  
Vol 137 (5) ◽  
Author(s):  
Leyuan Yu ◽  
Aritra Sur ◽  
Dong Liu
Keyword(s):  
Heat Transfer ◽  
Boiling Heat Transfer ◽  
Two Phase Flow ◽  
Flow Instability ◽  
Flow Boiling ◽  
Nucleate Boiling ◽  
Flow Instabilities ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Boiling Heat Transfer

Single-phase convective heat transfer of nanofluids has been studied extensively, and different degrees of enhancement were observed over the base fluids, whereas there is still debate on the improvement in overall thermal performance when both heat transfer and hydrodynamic characteristics are considered. Meanwhile, very few studies have been devoted to investigating two-phase heat transfer of nanofluids, and it remains inconclusive whether the same pessimistic outlook should be expected. In this work, an experimental study of forced convective flow boiling and two-phase flow was conducted for Al2O3–water nanofluids through a minichannel. General flow boiling heat transfer characteristics were measured, and the effects of nanofluids on the onset of nucleate boiling (ONB) were studied. Two-phase flow instabilities were also explored with an emphasis on the transition boundaries of onset of flow instabilities (OFI). It was found that the presence of nanoparticles delays ONB and suppresses OFI, and the extent is correlated to the nanoparticle volume concentration. These effects were attributed to the changes in available nucleation sites and surface wettability as well as thinning of thermal boundary layers in nanofluid flow. Additionally, it was observed that the pressure-drop type flow instability prevails in two-phase flow of nanofluids, but with reduced amplitude in pressure, temperature, and mass flux oscillations.

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