Experimental Study on Natural Circulation and Air-Injection Enhanced Circulation With Different Fluids

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
W. Ambrosini ◽  
N. Forgione ◽  
F. Oriolo ◽  
E. Semeraro ◽  
M. Tarantino
Keyword(s):  
Heavy Metal ◽  
Experimental Study ◽  
Experimental Investigation ◽  
Scaling Laws ◽  
Natural Circulation ◽  
Gas Injection ◽  
Air Injection ◽  
Working Fluid ◽  
Additional Information ◽  
Core Cooling

This paper reports on an experimental investigation on natural circulation and air-injection enhanced circulation performed adopting different fluids. This work is aimed at providing information on the basic mechanisms proposed in the design of future reactors relying on such circulation mechanisms for core cooling. Though the final objective of the research is the study of heavy metal cooling, the work is here limited to nonmetallic fluids. The working fluid adopted in past analyses was water. Further experimental campaigns were recently performed using the Novec™ HFE-7100 fluid, providing additional information on basic phenomena and the related scaling laws. The new fluid has a greater density and a greater thermal expansion coefficient with respect to water. Air was adopted for gas injection. Both natural circulation and gas-injection enhanced circulation are addressed in this work, drawing quantitative conclusions about the observed parametric trends. A systematic comparison is performed with the results obtained in previous experimental activities using water.

Experimental Study on Natural Circulation and Air-Injection Enhanced Circulation With Different Fluids

2008 ◽  
Author(s):  
W. Ambrosini ◽  
N. Forgione ◽  
F. Oriolo ◽  
E. Semeraro ◽  
M. Tarantino
Keyword(s):  
Heavy Metal ◽  
Experimental Study ◽  
Experimental Investigation ◽  
Scaling Laws ◽  
Natural Circulation ◽  
Gas Injection ◽  
Air Injection ◽  
Working Fluid ◽  
Additional Information ◽  
Core Cooling

The paper reports about an experimental investigation on natural circulation and air-injection enhanced circulation performed adopting different fluids. The work is aimed at providing information on the basic mechanisms proposed in the design of future reactors relying on such circulation mechanisms for core cooling. Though the final objective of the research is the study of heavy metal cooling, the work is here limited to non-metallic fluids. The working fluid adopted in past analyses was water. Further experimental campaigns were recently performed using the Novec™ HFE-7100 fluid, providing additional information on basic phenomena and the related scaling laws. The new fluid has a greater density and a greater thermal expansion coefficient with respect to water. Air was adopted for gas injection. Both natural circulation and gas-injection enhanced circulation are addressed in this work, drawing quantitative conclusions about the observed parametric trends. A systematic comparison is performed with the results obtained in previous experimental activities using water.

Numerical Analysis of Natural Circulation Phenomena of Supercritical Fluids

2013 ◽  
Author(s):  
Jeffrey Samuel ◽  
Glenn Harvel ◽  
Igor Pioro
Keyword(s):  
Scaling Laws ◽  
Nuclear Reactor ◽  
Nuclear Reactors ◽  
Natural Circulation ◽  
Operating Conditions ◽  
Passive Safety System ◽  
Test Loop ◽  
R 134A ◽  
Carbon Dioxide Co2 ◽  
Core Cooling

The feasibility of operating with natural circulation as the normal mode of core cooling has been successfully demonstrated for a few small sized nuclear reactors. Natural circulation is being considered for cooling the core of a nuclear reactor under normal operating conditions in several advanced reactor concepts being developed today. Although studies have been conducted in natural circulation for many decades, using natural circulation as the primary cooling mechanism for nuclear reactors or as a passive safety system requires a comprehensive understanding of local and integral system phenomena, validated benchmark data, accurate predictive tools, and reliability analysis methods. As full-scale experiments of supercritical water are expensive, scaling laws can be applied to develop test matrices using modelling fluids to reproduce similar conditions in a scaled-down experimental thermalhydraulic loop. The main aim of this work is to understand the natural circulation phenomena by analyzing water and modelling fluids such as Carbon dioxide (CO2) and Freon 134a (R-134a). The use of the modelling fluids at subcritical, pseudocritical and supercritical pressures is discussed along with fluid-to-fluid scaling techniques. The results from a one-dimensional numerical model developed using MATLAB to calculate the steady-state mass flow rate and heat transport characteristics of an experimental natural circulation test loop are presented and analyzed.

scholarly journals Experimental Investigation on Novel Parabolic Trough Collector

2021 ◽  
Author(s):  
G. Lingaiah ◽  
K. Sridhar
Keyword(s):  
Experimental Study ◽  
Experimental Investigation ◽  
Working Fluid ◽  
Manual Tracking ◽  
Solar Thermal Energy ◽  
Parabolic Trough ◽  
Tracking Method ◽  
Automated Tracking ◽  
Domestic Use ◽  
Day By Day

With the increase in demand of the cleaner energy, the use of renewable sources of energy is increasing day by day and solar energy is the answer to it. Several methods are used to harness solar thermal energy among them Concentrating Parabolic Collectors (CPC) are widely used. In this paper, A novel CPC is made, and an experimental study is carried out to find out its efficiency in manual and automated single axis tracking mode using water as working fluid. It was observed that the automated tracking method outperforms the manual tracking method with efficiency reaching up to 48% as compared to 42% in the later. Methods to improve efficiency of the CPC are not used in this study. CPC was found suitable for domestic use.  

Experimental Study of Methane Fuel Oxycombustion in an SI Engine

2012 ◽  
Author(s):  
Andrew Van Blarigan ◽  
Darko Kozarac ◽  
Reinhard Seiser ◽  
Robert Cattolica ◽  
Jyh-Yuan Chen ◽  
...  
Keyword(s):  
Experimental Study ◽  
Experimental Investigation ◽  
Compression Ratio ◽  
Thermal Efficiency ◽  
Combustion Efficiency ◽  
Working Fluid ◽  
Si Engine ◽  
Lower Efficiency ◽  
Working Fluids ◽  
Spark Timing

An experimental investigation of the thermal efficiency, combustion efficiency, and CoV IMEP, of methane fuel oxycombustion in an SI engine has been carried out. Compression ratio, spark-timing, and oxygen concentration were all varied. A variable compression ratio SI engine was operated on both wet and dry EGR working fluids, with results illustrating that the efficiency of the engine operating with a large amount of EGR was significantly reduced relative to methane-in-air operation over all oxygen concentrations and compression ratios. The maximum thermal efficiency of wet EGR, dry EGR, and air was found to be 23.6%, 24.2%, and 31.4%, respectively, corresponding to oxygen volume fractions of 29.3%, 32.7% and 21%. Combustion efficiency was above 98% for wet EGR and approximately 96% for dry EGR. CoV IMEP was low for both cases. The much lower efficiency of both EGR cases relative to air is primarily a result of the reduced specific-heat ratio of the EGR working fluids relative to air working fluid.

Experimental study of thermohydraulic characteristics and irreversibility analysis of novel axial corrugated tube with spring tape inserts

2020 ◽  
Vol 92 (3) ◽  
pp. 30901
Author(s):  
Suvanjan Bhattacharyya ◽  
Debraj Sarkar ◽  
Ulavathi Shettar Mahabaleshwar ◽  
Manoj K. Soni ◽  
M. Mohanraj
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Thermal Performance ◽  
Working Fluid ◽  
The Novel ◽  
Heat Exchanger Tube ◽  
Heat Transfer Augmentation ◽  
Corrugated Tube ◽  
The Impact ◽  
Exchanger Tube

The current study experimentally investigates the heat transfer augmentation on the novel axial corrugated heat exchanger tube in which the spring tape is introduced. Air (Pr = 0.707) is used as a working fluid. In order to augment the thermohydraulic performance, a corrugated tube with inserts is offered. The experimental study is further extended by varying the important parameters like spring ratio (y = 1.5, 2.0, 2.5) and Reynolds number (Re = 10 000–52 000). The angular pitch between the two neighboring corrugations and the angle of the corrugation is kept constant through the experiments at β = 1200 and α = 600 respectively, while two different corrugations heights (h) are analyzed. While increasing the corrugation height and decreasing the spring ratio, the impact of the swirling effect improves the thermal performance of the system. The maximum thermal performance is obtained when the corrugation height is h = 0.2 and spring ratio y = 1.5. Eventually, correlations for predicting friction factor (f) and Nusselt number (Nu) are developed.

EFFECT OF WORKING FLUID ON 3-PORT CPL PERFORMANCE: AN EXPERIMENTAL INVESTIGATION

2014 ◽  
Vol 5 (1-4) ◽  
pp. 491-497
Author(s):  
Abhijit A. Adoni ◽  
Amrit Ambirajan ◽  
Jasvanth V. S. ◽  
D. Kumar ◽  
Pradip Dutta
Keyword(s):  
Experimental Investigation ◽  
Working Fluid

EXPERIMENTAL STUDY ON STABILITY OF STARTUP IN NATURAL CIRCULATION BWRS WITH AND WITHOUT NUCLEAR COUPLING

2006 ◽  
Vol 18 (4) ◽  
pp. 335-358 ◽  
Author(s):  
M. Ishii ◽  
Selim Kuran ◽  
X. Sun ◽  
Ling Cheng ◽  
Yiban Xu ◽  
...  
Keyword(s):  
Experimental Study ◽  
Natural Circulation
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