Determination of Turbulent Exchange Coefficients in a Rod Bundle

1974 ◽  
Vol 96 (2) ◽  
pp. 172-177 ◽  
Author(s):  
M. Roidt ◽  
M. J. Pechersky ◽  
R. A. Markley ◽  
B. J. Vegter
Keyword(s):  
Flow Model ◽  
Computer Code ◽  
Eddy Diffusion ◽  
Tracer Gas ◽  
Turbulent Eddy ◽  
Pipe Flows ◽  
Rod Bundle ◽  
Lumped Parameter ◽  
Eddy Diffusion Coefficient

A tracer gas is injected into a single subchannel of a large air flow model of a reactor rod bundle. Axial variations in the tracer flux are determined by sampling at two downstream positions in both the injection subchannel and those adjacent to it. This information, with measured subchannel area changes, is used to calculate crossflows and the turbulent eddy diffusion coefficient. The latter number agrees with the results of other investigators in regular pipe flows. Also determined are distributional factors which would be required for modeling the transport equations, for this particular scalar distribution, with a typical lumped parameter computer code.

DISPERSION MODELS FOR EMISSIONS FROM AGRICULTURAL SOURCES G.-J. MEJER and K.-H. KRAUSE Institut fiir landtechnische Grundlagenforschung der Bundesforschungsanstalt fiir Landwirtschaft Summary The aim of dispersion models is the prediction of atmospheric dilution of pollutants in order to prevent or avoid nuisance. Established dispersion models, designed for the large scale of industrial air pol­ lution have to be modified to the small scale of agricultural pol­ lutions. An experimental setup is described to measure atmospheric dilution of tracer gas under agricultural conditions. The experimental results deliver the data base to identify the parameters of the models. For undisturbed airflow modified Gaussian models are applicable. For the consideration of obstacles more sophisticated models are necessary. 1. INTRODUCTION The aim of dispersion models is to develop reliable methods for calcu­ lating the atmospheric dilution of airborne pollutants under practical conditions. One application in agriculture is the determination of that distance, at which i.g. odouriferous pollutants of an animal farm are diluted in the atmosphere to a concentration below a certain threshold, in order to allow the farmer a profitable production and likewise to prevent odour nuisance from the neighbourhood. Another application is the prediction of the effectiveness of changes in the emission source configuration, in order to reduce the odour nuisance in the existent vicinity. That could help to avoid expensive misinvestments. In air pollution control it is useful! to subdivide this large problem into three main divisions /1/, fig. 1:

1986 ◽  
pp. 113-113
Keyword(s):  
Large Scale ◽  
Small Scale ◽  
Air Pollution Control ◽  
Dispersion Models ◽  
Tracer Gas ◽  
Gaussian Models ◽  
Airborne Pollutants ◽  
Animal Farm ◽  
Reliable Methods

Determination of Entrained Fraction in Vertical Annular Gas/Liquid Flow

1999 ◽  
Vol 122 (1) ◽  
pp. 146-150 ◽  
Author(s):  
Barry J. Azzopardi ◽  
Sohail H. Zaidi
Keyword(s):  
Flow Rate ◽  
Liquid Flow ◽  
Annular Flow ◽  
Flow Model ◽  
Liquid Flow Rate ◽  
Measured Concentration ◽  
Diameter Pipe ◽  
A New Technique ◽  
Gas Liquid Flow

A new technique for the measurement of drop concentration in annular gas/liquid flow is presented. This is based on scattering of light by the drops. From the measured concentration, entrained liquid flow rate and thence the entrained fraction can be determined. The technique has been employed to obtain new data for vertical upward annular flow in a 0.038 m diameter pipe. The results have been compared with data from different pipe diameters and with the predictions of an annular flow model. [S0098-2202(00)02201-X]

Observations of O2(¹Δg) in the atmosphere and allowable values of the eddy diffusion coefficient

1970 ◽  
Vol 75 (31) ◽  
pp. 6398-6401 ◽  
Author(s):  
L. R. Megill ◽  
J. C. Haslett ◽  
H. I. Schiff ◽  
G. W. Adams
Keyword(s):  
Diffusion Coefficient ◽  
Eddy Diffusion ◽  
Eddy Diffusion Coefficient

A three-dimensional coupled well-reservoir flow model for determination of horizontal well characteristics

2020 ◽  
Vol 585 ◽  
pp. 124805 ◽  
Author(s):  
Saeed Hayati-Jafarbeigi ◽  
Mehdi Mosharaf-Dehkordi ◽  
Masoud Ziaei-Rad ◽  
Morteza Dejam
Keyword(s):  
Horizontal Well ◽  
Flow Model ◽  
Three Dimensional ◽  
Reservoir Flow
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