Visualization of Quench Front Propagation on Heated Rod Through Single Jet Impingement

2020 ◽  
Vol 142 (9) ◽  
Author(s):  
Vivek Gupta ◽  
Pradyumna Ghosh
Keyword(s):  
High Speed ◽  
Cooling System ◽  
Nuclear Reactors ◽  
Jet Impingement ◽  
Front Propagation ◽  
Front Velocity ◽  
High Speed Camera ◽  
Single Jet ◽  
Front Shape ◽  
Core Cooling

Abstract Quench front characteristics and flow physics have been observed for single jet impingement using de-ionized (DI) water and various oxide-based nanofluids. Quench front velocity, shape, intensities of sputtering, and postquench front phenomenon have been observed through the high-speed camera. Quench front velocity is higher in the case of nanofluids than DI water due to the presence of nanoparticles in nanofluids. However, quench front shape also differs in the case of nanofluids due to the rupture of the boundary layer, which depends on agglomeration characteristics and the nanomicroporous layer formed on the solid surface of the heater. A better understanding of quench behavior, for a very low concentration of nanofluids, will make it a viable technology for emergency core cooling system (ECCS) for upcoming nuclear reactors in India.

Exploring the Use of Alumina Nanofluid as Emergency Coolant for Nuclear Fuel Bundle

2018 ◽  
Vol 11 (2) ◽  
Author(s):  
A. S. Chinchole ◽  
Arnab Dasgupta ◽  
P. P. Kulkarni ◽  
D. K. Chandraker ◽  
A. K. Nayak
Keyword(s):  
Heat Transfer ◽  
Nuclear Fuel ◽  
Nuclear Reactor ◽  
Cooling System ◽  
Nuclear Reactors ◽  
Electrical Heating ◽  
High Dose ◽  
Potential Candidate ◽  
Alumina Nanofluid ◽  
Core Cooling

Abstract Nanofluids are suspensions of nanosized particles in any base fluid that show significant enhancement of their heat transfer properties at modest nanoparticle concentrations. Due to enhanced thermal properties at low nanoparticle concentration, it is a potential candidate for utilization in nuclear heat transfer applications. In the last decade, there have been few studies which indicate possible advantages of using nanofluids as a coolant in nuclear reactors during normal as well as accidental conditions. In continuation with these studies, the utilization of nanofluids as a viable candidate for emergency core cooling in nuclear reactors is explored in this paper by carrying out experiments in a scaled facility. The experiments carried out mainly focus on quenching behavior of a simulated nuclear fuel rod bundle by using 1% Alumina nanofluid as a coolant in emergency core cooling system (ECCS). In addition, its performance is compared with water. In the experiments, nuclear decay heat (from 1.5% to 2.6% reactor full power) is simulated through electrical heating. The present experiments show that, from heat transfer point of view, alumina nanofluids have a definite advantage over water as coolant for ECCS. Additionally, to assess the suitability of using nanofluids in reactors, their stability was investigated in radiation field. Our tests showed good stability even after very high dose of radiation, indicating the feasibility of their possible use in nuclear reactor heat transfer systems.

Risk mitigation strategy by Passive IN-core Cooling system for advanced nuclear reactors

2018 ◽  
Vol 111 ◽  
pp. 554-567 ◽  
Author(s):  
Seok Bin Seo ◽  
In Guk Kim ◽  
Kyung Mo Kim ◽  
Yeong Shin Jeong ◽  
In Cheol Bang
Keyword(s):  
Cooling System ◽  
Nuclear Reactors ◽  
Risk Mitigation ◽  
Mitigation Strategy ◽  
Core Cooling

scholarly journals Influence of Initial Temperature and Convective Heat Loss on the Self-Propagating Reaction in Al/Ni Multilayer Foils

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7815
Author(s):  
Mostafa Baloochi ◽  
Deepshikha Shekhawat ◽  
Sascha Sebastian Riegler ◽  
Sebastian Matthes ◽  
Marcus Glaser ◽  
...  
Keyword(s):  
Numerical Model ◽  
Heat Loss ◽  
Reaction Front ◽  
High Speed ◽  
Initial Temperature ◽  
Front Velocity ◽  
The Self ◽  
High Speed Camera ◽  
Multilayer Foils ◽  
Convective Heat Loss

A two-dimensional numerical model for self-propagating reactions in Al/Ni multilayer foils was developed. It was used to study thermal properties, convective heat loss, and the effect of initial temperature on the self-propagating reaction in Al/Ni multilayer foils. For model adjustments by experimental results, these Al/Ni multilayer foils were fabricated by the magnetron sputtering technique with a 1:1 atomic ratio. Heat of reaction of the fabricated foils was determined employing Differential Scanning Calorimetry (DSC). Self-propagating reaction was initiated by an electrical spark on the surface of the foils. The movement of the reaction front was recorded with a high-speed camera. Activation energy is fitted with these velocity data from the high-speed camera to adjust the numerical model. Calculated reaction front temperature of the self-propagating reaction was compared with the temperature obtained by time-resolved pyrometer measurements. X-ray diffraction results confirmed that all reactants reacted and formed a B2 NiAl phase. Finally, it is predicted that (1) increasing thermal conductivity of the final product increases the reaction front velocity; (2) effect of heat convection losses on reaction characteristics is insignificant, e.g., the foils can maintain their characteristics in water; and (3) with increasing initial temperature of the foils, the reaction front velocity and the reaction temperature increased.

Characteristics of Nanofluids Made from Solgel Synthesized-Al2O3 Nanoparticles Using Citric Acid and PEG as Organic Agent and Bauxite as Raw Material

2018 ◽  
Vol 929 ◽  
pp. 1-9 ◽  
Author(s):  
Dani Gustaman Syarif ◽  
Djoko Hadi Prajitno ◽  
Efrizon Umar
Keyword(s):  
Citric Acid ◽  
Metal Forming ◽  
Cooling System ◽  
Nuclear Reactors ◽  
Reactor Core ◽  
Heating System ◽  
Solar Heating ◽  
Raw Material ◽  
Peg 4000 ◽  
Core Cooling

Nanofluids have great attention in the world due to big potential to replace conventional fluids that have been used in some systems such as automotive, nuclear reactors, solar heating, building heating, and industry. Utilization of indigenous raw material in production of nanoparticles is a key to reach real application of the nanofluids. The aim of this study is to know the effect of combination of organic agent in solgel synthesis on characteristic of Al2O3nanoparticles and nanofluids made of them. In this study, Al2O3nanoparticles have been synthesized from local bauxite using solgel method with citric acid and PEG 4000 as chelating and capping agent. Nanofluids with pH 10 were prepared from the nanoparticles. Raw material of Al (OH)3was extracted from the bauxite. Powder of Al (OH)3was diluted in water, and citric acid and PEG 4000 was added into the solution to form a sol. The sol was heated to form a xerogel, and then calcined at 900°C for 3 hours to get the Al2O3nanoparticles. From the synthesis we got gamma-Al2O3nanoparticles with crystallite size of 4.0-4.6 nm. From the characterization data of the nanofluids it was known that the nanofluids with concentration of Al2O3nanoparticles of 0.025 vol % to 0.1 vol% possessed relatively high zeta potential of-39.2 mV to-40 mV, and good critical heat flux (CHF) enhancement of 13% to 74%. The nanofluids had large potential to be applied as coolant for External Reactor Core Cooling System (ERVCS), ECCS (Emergency Core Cooling System), electronics, automotive, metal forming and solar heating system.

Heat Transfer Characteristics of Downward Facing Hot Horizontal Surfaces Using Mist Jet Impingement

2017 ◽  
Author(s):  
Ashutosh Kumar Yadav ◽  
Parantak Sharma ◽  
Avadhesh Kumar Sharma ◽  
Mayank Modak ◽  
Vishal Nirgude ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Surface Heat Flux ◽  
Cooling System ◽  
Water Pressure ◽  
Jet Impingement ◽  
Surface Heat ◽  
Heat Transfer Characteristics ◽  
Impingement Cooling ◽  
Transfer Characteristics

Impinging jet cooling technique has been widely used extensively in various industrial processes, namely, cooling and drying of films and papers, processing of metals and glasses, cooling of gas turbine blades and most recently cooling of various components of electronic devices. Due to high heat removal rate the jet impingement cooling of the hot surfaces is being used in nuclear industries. During the loss of coolant accidents (LOCA) in nuclear power plant, an emergency core cooling system (ECCS) cool the cluster of clad tubes using consisting of fuel rods. Controlled cooling, as an important procedure of thermal-mechanical control processing technology, is helpful to improve the microstructure and mechanical properties of steel. In industries for heat transfer efficiency and homogeneous cooling performance which usually requires a jet impingement with improved heat transfer capacity and controllability. It provides better cooling in comparison to air. Rapid quenching by water jet, sometimes, may lead to formation of cracks and poor ductility to the quenched surface. Spray and mist jet impingement offers an alternative method to uncontrolled rapid cooling, particularly in steel and electronics industries. Mist jet impingement cooling of downward facing hot surface has not been extensively studied in the literature. The present experimental study analyzes the heat transfer characteristics a 0.15mm thick hot horizontal stainless steel (SS-304) foil using Internal mixing full cone (spray angle 20 deg) mist nozzle from the bottom side. Experiments have been performed for the varied range of water pressure (0.7–4.0 bar) and air pressure (0.4–5.8 bar). The effect of water and air inlet pressures, on the surface heat flux has been examined in this study. The maximum surface heat flux is achieved at stagnation point and is not affected by the change in nozzle to plate distance, Air and Water flow rates.

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