scholarly journals Heat Transfer Enhancement in Subchannel Geometry of Pressurized Water Reactor Using Water-Based Yttrium Oxide Nanofluid

2021 ◽  
Vol 39 (3) ◽  
pp. 979-986
Author(s):  
Zeina Ali Abdul Redha ◽  
Farhan Lafta Rashid
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Convective Heat Transfer ◽  
Yttrium Oxide ◽  
Volume Fraction ◽  
Coolant Fluid ◽  
Pressurized Water Reactor ◽  
Pressurized Water ◽  
Water Reactor ◽  
Water Based

Simulation of Computational Fluid Dynamic is applied to present the thermal performance of water-based Yttrium oxide nanofluid in subchannel of pressurized water reactor (PWR) system. Thermal hydraulic aspect such as pressure drop and heat transfer are estimated in typical conditions of pressurized water with flow rates ranged (20×103≤Re≤80×103) using fresh water (0 %vol.) and different volume fraction of water-Yttrium oxide nanofluid (2 and 4% vol.) as coolant fluid. Results were obtained and compared with correlations of single-phase pressure drop and convective heat transfer for the case of fully developed turbulent flow. The addition of Yttrium oxide nanoparticles to the coolant fluid in pressurized water reactor led to increase in convective heat transfer coefficient and pressure drop. Increasing the nanoparticle volume fraction of (2 and 4% vol.) causing an increase in the average Nu by 3.46% and 7.61%, respectively. The CFD model established in ANSYS software was validated by comparing the pressure drop of CFD results with Blasius correlation and Nu with Ma¨ıga et al. correlation and gave a good agreement.

Evaluation of Nanofluids as Potential Novel Coolant for Aircraft Applications: The Case of De-ionized Water-Based Alumina Nanofluids

2014 ◽  
Vol 136 (5) ◽  
Author(s):  
Javier A. Narvaez ◽  
Aaron R. Veydt ◽  
Robert J. Wilkens
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Convective Heat Transfer ◽  
Air Force ◽  
Convective Heat ◽  
Military Aircraft ◽  
Particle Settling ◽  
Water Based ◽  
Transfer Problems

There is a critical need for improved coolants for military aircraft applications. The objective of this research is to evaluate nanofluids as potential replacement for the coolant currently used by the Air Force. Alumina/DI water nanofluids were evaluated. It was observed that at the same volumetric flow there was no significant improvement in convective heat transfer. Problems associated with the nanofluids were observed: increase of pressure drop with concentration, particle settling, and especially evidence of vaporization promoted by the nanoparticles. Results raised doubts about the applicability of using nanofluids as alternative coolants for avionic applications.

Estimation of Pressure Loads During Ex-Vessel Steam Explosion

2008 ◽  
Author(s):  
Matjazˇ Leskovar
Keyword(s):  
Heat Transfer ◽  
Steam Explosion ◽  
Phase 1 ◽  
Interaction Process ◽  
Radioactive Material ◽  
Primary System ◽  
Pressurized Water Reactor ◽  
Reactor Accident ◽  
Pressurized Water ◽  
Water Reactor

An ex-vessel steam explosion may occur when, during a severe reactor accident, the reactor vessel fails and the molten core pours into the water in the reactor cavity. A steam explosion is a fuel coolant interaction process where the heat transfer from the melt to water is so intense and rapid that the timescale for heat transfer is shorter than the timescale for pressure relief. This can lead to the formation of shock waves and production of missiles that may endanger surrounding structures. A strong enough steam explosion in a nuclear power plant could jeopardize the containment integrity and so lead to a direct release of radioactive material to the environment. In the paper, different scenarios of ex-vessel steam explosions in a typical pressurized water reactor cavity are analyzed with the code MC3D, which is being developed for the simulation of fuel-coolant interactions. A comprehensive parametric study was performed varying the location of the melt release (central and side melt pours), the cavity water sub-cooling, the primary system overpressure at vessel failure and the triggering time for explosion calculations. The main purpose of the study was to determine the most challenging ex-vessel steam explosion cases in a typical pressurized water reactor and to estimate the expected pressure loadings on the cavity walls. Special attention was given to melt droplets freezing, which may significantly influence the outcome of the fuel-coolant interaction process. The performed analysis shows that for some ex-vessel steam explosion scenarios much higher pressure loads are predicted than obtained in the OECD program SERENA Phase 1.

Heat Transfer in Pressurized Water Reactor Components Most Often Subject to Thermal Shock

1980 ◽  
Vol 47 (1) ◽  
pp. 125-152 ◽  
Author(s):  
F. Parras ◽  
M. Bosser ◽  
D. Milan ◽  
G. Berthollon
Keyword(s):  
Heat Transfer ◽  
Thermal Shock ◽  
Pressurized Water Reactor ◽  
Pressurized Water ◽  
Water Reactor

Convective Heat Transfer for Water-Based Alumina Nanofluids in a Single 1.02-mm Tube

2009 ◽  
Vol 131 (11) ◽  
Author(s):  
W. Y. Lai ◽  
S. Vinod ◽  
P. E. Phelan ◽  
Ravi Prasher
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Convective Heat Transfer ◽  
Effective Thermal Conductivity ◽  
Convective Heat ◽  
Volume Fraction ◽  
Pure Water ◽  
Submicron Particles ◽  
Strong Temperature Dependence ◽  
Water Based

Nanofluids are colloidal solutions, which contain a small volume fraction of suspended submicron particles or fibers in heat transfer liquids such as water or glycol mixtures. Compared with the base fluid, numerous experiments have generally indicated an increase in effective thermal conductivity and a strong temperature dependence of the static effective thermal conductivity. However, in practical applications, a heat conduction mechanism may not be sufficient for cooling high heat dissipation devices such as microelectronics or powerful optical equipment. Thus, thermal performance under convective heat transfer conditions becomes of primary interest. We report here the heat transfer coefficient h in both developing and fully developed regions by using water-based alumina nanofluids. Our experimental test section consists of a single 1.02-mm diameter stainless steel tube, which is electrically heated to provide a constant wall heat flux. Both pressure drop and temperature differences are measured, but mostly here we report our h measurements under laminar flow conditions. An extensive characterization of the nanofluid samples, including pH, electrical conductivity, particle sizing, and zeta potential, is also documented. The measured h values for nanofluids are generally higher than those for pure water. In the developing region, this can be at least partially explained by Pr number effects.

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