Experimental Investigations and Analytical Improvements for HTR Pebble Bed Cores

2012 ◽  
Author(s):  
H.-J. Allelein ◽  
B. Schloegl ◽  
J. Baggemann ◽  
S. Juehe ◽  
S. Kasselmann
Keyword(s):  
Fluid Mechanics ◽  
Gas Flow ◽  
Experimental Investigations ◽  
Reactor Safety ◽  
Pebble Bed ◽  
Cfd Validation ◽  
Main Research ◽  
Cfd Models ◽  
Experimental Facilities ◽  
Air Ingress

One of the main research topics of the Chair for Reactor Safety and Technology at RWTH Aachen University and the Institute for Nuclear Waste Management and Reactor Safety (IEK-6) deals with accident scenarios of gas-cooled High-Temperature Reactors, especially the air ingress scenario. Two experimental facilities have just started operation providing experimental data for the validation and improvement of fluid mechanics codes being developed and applied at IEK-6. The INDEX (INDuction EXperiment) facility is able to heat up single spheres inductively up to 1200°C while exposed to defined gas atmospheres and gas flow conditions. This experimental setup is well suited to study pebble / gas flow interactions as well as graphite corrosion phenomena in detail. The NACOK II (NAturzug im COre mit Korrosion) facility is an integral experiment for fluid mechanics and graphite corrosion processes under natural convection effects. It will examine spherical fuel element samples as well as prismatic blocks. In addition the instrumentation is suitable for CFD validation calculations, for example because PIV (particle image velocity) is applied. The data obtained are used to validate and improve computational fluid dynamics (CFD) models for pebble bed reactors or reactor dynamics code like MGT-3D, which are able to simulate air ingress scenarios. The CFD model shall be able to simulate the fluid mechanics as well as the corrosion processes of after a total pressure release. In this paper we report on the status of the experimental facilities as well as on advances in modelling the fluid mechanics of HTR pebble cores.

Post-Test CFD Analysis of Non-Uniformly Heated 19-Pin Fuel Bundle Cooled by HLM

2018 ◽  
Author(s):  
R. Marinari ◽  
I. Di Piazza ◽  
M. Angelucci ◽  
D. Martelli
Keyword(s):  
Mixed Convection ◽  
Large Scale ◽  
Fluid Dynamic ◽  
Cfd Validation ◽  
Cfd Models ◽  
Fuel Bundle ◽  
Post Test ◽  
Fuel Pin ◽  
Experimental Facilities ◽  
Gen Iv

In the context of the studies on GEN. IV/ADS nuclear systems, the correct evaluations of the temperature distribution in the fuel pin bundle is of central interest. In particular, the use of lead or lead-bismuth eutectic (LBE) as coolant for the new generation fast reactors is one of the most promising choices. Due to the high density and high conductivity of lead or LBE, a detailed analysis of the thermo-fluid dynamic behavior of the heavy liquid metal (HLM) inside the sub-channels of a fuel rod bundle is necessary in order to support the Front-End Engineering Design (FEED) of GEN. IV/ADS prototypes and demonstrators. In this frame, the synergy between numerical analysis by CFD and data coming from large experimental facilities seems to be crucial to assess the feasibility of the components. At ENEA-Brasimone R.C., large experimental facilities exist to study HLM free, forced and mixed convection in loops and pools: e.g. NACIE-UP is a large scale LBE loop for mixed convection experiments. The MYRRHA-19 like Fuel Pin Bundle Simulator installed in the NACIE-UP facility allows to make non-uniform and dissymmetric tests with only a few pins heated. This technical feature of the FPS is very interesting for CFD validation and this kind of data tests in HLM fuel bundles are not so common in the literature. In the present paper, a post-test validation is made by a detailed CFD model of the test section. Experimental data, statistically treated by the error propagation theory, are briefly presented and a preliminary comparison with CFD results using different models/turbulent Prandtl numbers are shown. Three monitored section at different levels are compared both for wall and bulk temperatures. This post-test comparison with this experimental configuration is unique and represents a further step towards the validation of the CFD models and methods in fuel bundle geometries cooled by HLM.

CFD Investigation of helium gas flow in sphere packed (Pebble bed) in a rectangular canister using OpenFOAM

2021 ◽  
Vol 172 ◽  
pp. 112858
Author(s):  
Pratyush Kumar ◽  
Abhishek Thakur ◽  
Sandip K. Saha ◽  
Atul Sharma ◽  
Deepak Sharma ◽  
...  
Keyword(s):  
Gas Flow ◽  
Pebble Bed ◽  
Helium Gas

Experimental Inverstigations On the Pressure Fluctuations in the Sealing Gap of Dry Gas Seals with Embedded Pressure Sensors

2021 ◽  
Author(s):  
Jingjing Luo ◽  
Dieter Brillert
Keyword(s):  
High Speed ◽  
Gas Flow ◽  
Static Pressure ◽  
Pressure Sensors ◽  
Operating Conditions ◽  
Test Facility ◽  
Experimental Investigations ◽  
Mechanical Seals ◽  
Process Gas ◽  
Sealing Gap

Abstract Dry gas lubricated non-contacting mechanical seals (DGS), most commonly found in centrifugal compressors, prevent the process gas flow into the atmosphere. Especially when high speed is combined with high pressure, DGS is the preferred choice over other sealing alternatives. In order to investigate the flow field in the sealing gap and to facilitate the numerical prediction of the seal performance, a dedicated test facility is developed to carry out the measurement of key parameters in the gas film. Gas in the sealing film varies according to the seal inlet pressure, and the thickness of gas film depends on this fluctuated pressure. In this paper, the test facility, measurement methods and the first results of static pressure measurements in the sealing gap of the DGS obtained in the described test facility are presented. An industry DGS with three-dimensional grooves on the surface of the rotating ring, where experimental investigations take place, is used. The static pressure in the gas film is measured, up to 20 bar and 8,100 rpm, by several high frequency ultraminiature pressure transducers embedded into the stationary ring. The experimental results are discussed and compared with the numerical model programmed in MATLAB, the characteristic and magnitude of which have a good agreement with the numerical simulations. It suggests the feasibility of measuring pressure profiles of the standard industry DGS under pressurized dynamic operating conditions without altering the key components of the seal and thereby affecting the seal performance.

scholarly journals B205 Engineering study of gas flow in breeder pebble bed for fusion blanket

2012 ◽  
Vol 2012.17 (0) ◽  
pp. 265-266
Author(s):  
Yohji SEKI ◽  
Akira YOSHIKAWA ◽  
Hisashi TANIGAWA ◽  
Takanori HIROSE ◽  
Koichiro EZATO ◽  
...  
Keyword(s):  
Gas Flow ◽  
Pebble Bed ◽  
Engineering Study

scholarly journals Experimental investigations of CO2 seepage behaviorin naturally fractured coal under hydro-thermal-mechanical conditions

2021 ◽  
Vol 25 (6 Part B) ◽  
pp. 4651-4658
Author(s):  
Teng Teng ◽  
Xiaoyan Zhu ◽  
Yu-Ming Wang ◽  
Chao-Yang Ren
Keyword(s):  
Gas Flow ◽  
Confining Pressure ◽  
Gas Pressure ◽  
Experimental Investigations ◽  
Permeability Evolution ◽  
Coal Permeability ◽  
Naturally Fractured ◽  
Series Of Experiments ◽  
Fractured Coal ◽  
Increasing Temperature

Gas-flow in coal or rock is hypersensitive to the changes of temperature, confin?ing pressure and gas pressure. This paper implemented a series of experiments to observe the seepage behavior, especially the permeability evolution of CO2 in naturally fractured coal sample under coupled hydro-thermal-mechanical conditions. The experimental results show that coal permeability increases exponentially with the increasing gas pressure, and tends to be linear when the confining pressure is high. Coal permeability decreases exponentially with the increasing confining pressure. Coal permeability decreases with the increasing temperature generally, but it may bounce up when the temperature rises to high. The results provide reference for the projects of coal gas extraction and carbon dioxide geological sequestration.

Results of the Study Rotor Wheels Supersonic Microturbines with a Large Angle of Rotation of the Flow

2015 ◽  
Vol 752-753 ◽  
pp. 884-889 ◽  
Author(s):  
Andrey Yu. Fershalov ◽  
Mikhail Yu. Fershalov ◽  
Yuriy Ya. Fershalov ◽  
Timofey V. Sazonov
Keyword(s):  
Mach Number ◽  
Gas Flow ◽  
Large Angle ◽  
Experimental Investigations ◽  
Flow Rates ◽  
Ratio Speed ◽  
Supersonic Gas Flow ◽  
Angle Of Rotation

The article presents the results of experimental investigations of rotor wheels supersonic microturbines with a large angle of rotation of the flow. The characteristics of the studied rotor wheels. The analysis of the results of the study ratio speed of rotor wheels, depending on the Mach number. Recommendations for the design working wheels microturbines operating at high supersonic gas flow rates.

Numerical Prediction of Erosion of Mild Steel Surfaces by Boiler Fly Ash Particles

Volume 1 ◽  
2004 ◽  
Author(s):  
John G. Mbabazi ◽  
Thomas J. Sheer
Keyword(s):  
Fly Ash ◽  
Mild Steel ◽  
Flue Gas ◽  
Gas Flow ◽  
Erosive Wear ◽  
Test Facility ◽  
Experimental Investigations ◽  
Power Station ◽  
Erosion Rates ◽  
Steel Surfaces

Fly ash particles entrained in the flue gas from boiler furnaces in coal-fired power stations can cause serious erosive wear on steel surfaces along the downstream flow path. This paper describes research into fly ash impingement erosion on such surfaces, with particular reference to the heat transfer plates in rotary regenerative air heaters. The effect of the ash particle impact velocity and impact angle on the erosive wear of mild steel surfaces was determined through experimental investigations, using three different power station ash types. The experimental data were used to calibrate a fundamentally-derived model for the prediction of erosion rates. This erosion model was incorporated into a particle-tracking CFD flow simulation of the ash-laden flue gas flow through the complex channels between corrugated air heater plates. The predicted erosion rates were compared with measured erosion rates obtained using a large accelerated-erosion test facility located at a power station. Good agreement was obtained, the predictions generally being within 20 percent of the measured values.

Biodegradation of Styrene Vapor in a Biofilter

2013 ◽  
Vol 275-277 ◽  
pp. 2329-2332 ◽  
Author(s):  
Xian Sheng Huang ◽  
Hao Wu
Keyword(s):  
Gas Flow ◽  
Experimental Investigations ◽  
Flow Rates ◽  
Operational Conditions ◽  
New Class ◽  
Filter Materials ◽  
Air Stream ◽  
Volatile Organic ◽  
Maximum Elimination Capacity ◽  
Styrene Removal

Volatile organic compounds (VOCs) are a new class of air pollutants posing threat to the environment. Newer technologies are being developed for their control among which biofiltration seem to be most attractive. Biofiltration of styrene vapor from air stream was discussed in this study. Experimental investigations were conducted on a laboratory scale biofilter, containing mixture of compost and polystyrene inert particles as the filter materials. Mixed consortium of activated sludge was used as an inoculum. The continuous performance of biofilter for styrene removal was monitored for different concentrations and flow rates. The removal efficiencies decreased at higher concentrations and higher gas flow rates. A maximum elimination capacity of 85g/(m3•h) was achieved. The response of biofilter to upset loading operation showed that the biofilm in the biofilters was quite stable and quickly adapted to adverse operational conditions.

Experimental Investigations of Laminar, Transitional to Turbulent Gas Flow in a Micro-Channel

2010 ◽  
Author(s):  
Chungpyo Hong ◽  
Toru Yamada ◽  
Yutaka Asako ◽  
Mohammad Faghri ◽  
Koichi Suzuki ◽  
...  
Keyword(s):  
Mach Number ◽  
Flow Regime ◽  
Gas Flow ◽  
Flow Characteristics ◽  
Channel Length ◽  
Transitional Flow ◽  
Experimental Investigations ◽  
Compressibility Effect ◽  
Micro Channels ◽  
Wide Range

This paper presents experimental results on flow characteristics of laminar, transitional to turbulent gas flows through micro-channels. The experiments were performed for three micro-channels. The micro-channels were etched into silicon wafers, capped with glass, and their hydraulic diameter are 69.48, 99.36 and 147.76 μm. The pressure was measured at seven locations along the channel length to determine local values of Mach number and friction factor for a wide range of flow regime from laminar to turbulent flow. Flow characteristics in transitional flow regime to turbulence were obtained. The result shows that f·Re is a function of Mach number and higher than incompressible value due to the compressibility effect. The values of f·Re were compared with f·Re correlations in available literature.

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