Two dimensional analysis of transient flow and heat transfer in a natural circulation loop

1984 ◽  
Vol 18 (2) ◽  
pp. 89-98 ◽  
Author(s):  
A. Mertol ◽  
R. Greif ◽  
Y. Zvirin
Keyword(s):  
Heat Transfer ◽  
Dimensional Analysis ◽  
Transient Flow ◽  
Natural Circulation ◽  
Circulation Loop ◽  
Two Dimensional ◽  
Flow And Heat Transfer ◽  
Natural Circulation Loop

Two Dimensional Simulation of Heat Transfer and Fluid Flow in a Rectangular Natural Circulation Loop Containing PCM Suspensions

2004 ◽  
Author(s):  
C. J. Ho ◽  
S. Y. Chiu ◽  
J. F. Lin
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Liquid Phase ◽  
Phase Change ◽  
Natural Circulation ◽  
Circulation Loop ◽  
Freezing Process ◽  
Two Dimensional ◽  
Natural Circulation Loop ◽  
Solid Liquid

A two-dimensional numerical simulation, via a finite difference method, of fluid flow and heat transfer in a rectangular natural circulation loop is presented to explore efficacy of using solid-liquid phase change material (PCM) suspensions as a heat transfer medium. A continuum mixture flow model is used for the buoyancy-driven circulation flow of the PCM suspensions together with an approximate enthalpy model to describe the solid-liquid phase change (melting/freezing) process of the PCM particles in the loop. Parametric simulations have been conducted for the pertinent physical parameters of a loop with fixed geometrical configuration in the following ranges: the modified Rayleigh number Ra* = 109 ∼ 1013, the modified Stefan number Ste* = 0.05 ∼ 0.5, the particle volumetric fraction cv = 0 ∼ 20%, and the modified subcooling factor Sb* = 0∼2.0. The melting/freezing processes of the PCM particles at the heated/cooled sections of the loop are closely interrelated in their inlet conditions of the suspension. Closer examination of numerical results reveals that there could be a flow regime in the parametric domain where heat transfer performance of the suspension circulation loop is significantly enhanced, due to contribution of the latent heat transport associated with melting/freezing of PCM particles.

Thermal Performance of Water-Based Suspensions of Phase Change Nanocapsules in a Natural Circulation Loop

2013 ◽  
Author(s):  
C. J. Ho ◽  
Chi-Ming Lai
Keyword(s):  
Heat Transfer ◽  
Phase Change ◽  
Natural Circulation ◽  
Pure Water ◽  
Circulation Loop ◽  
Core Material ◽  
Working Fluid ◽  
Outer Diameter ◽  
Natural Circulation Loop ◽  
Water Based

Experiments were conducted to investigate the heat transfer characteristics of water-based suspensions of phase change nanocapsules in a natural circulation loop with mini-channel heat sinks and heat sources. A total of 23 and 34 rectangular mini-channels, each with width 0.8 mm, depth 1.2 mm, length 50 mm and hydraulic diameter 0.96 mm, were evenly placed on the copper blocks as the heat source and heat sink, respectively. The adiabatic sections of the circulation loop were constructed using PMMA tubes with an outer diameter of 6 mm and an inner diameter of 4 mm, which were fabricated and assembled to construct a rectangular loop with a height of 630 mm and a width of 220 mm. Using a core material of n-eicosane and a shell of urea-formaldehyde resin, the phase change material nanocapsules of mean particle size 150 nm were fabricated successfully and then dispersed in pure water as the working fluid to form the water-based suspensions with mass fractions of the nanocapsules in the range 0.1–1 wt.%. The results clearly indicate that water-based suspensions of phase change nanocapsules can markedly enhance the heat transfer performance of the natural circulation loop considered.

ICONE19-43859 STUDY ON THE STEADY STATE AND TRANSIENT BEHAVIOUR OF NATURAL CIRCULATION LOOP WITH VARIOUS HEAT TRANSFER MEDIA

2011 ◽  
Vol 2011.19 (0) ◽  
pp. _ICONE1943-_ICONE1943 ◽  
Author(s):  
B. K. Jaiswal ◽  
A.K. Srivastava ◽  
A. Borgohain ◽  
Dr. N. K. Maheshwari ◽  
Dr. P. K. Vijayan
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Natural Circulation ◽  
Circulation Loop ◽  
Transient Behaviour ◽  
Natural Circulation Loop

A223 Heat Transfer and Flow Characteristics during Reflooding Process in Natural Circulation Loop

2014 ◽  
Vol 2014 (0) ◽  
pp. _A223-1_-_A223-2_
Author(s):  
Takuya Kawai ◽  
Ikki Yumoto ◽  
Takeyuki Ami ◽  
Hisashi Umekawa ◽  
Mamoru Ozawa
Keyword(s):  
Heat Transfer ◽  
Natural Circulation ◽  
Flow Characteristics ◽  
Circulation Loop ◽  
Natural Circulation Loop
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