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U.S. Department of Energy
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Surface discharge of cooling water. Effects of distortion in model investigations

Technical Report ·
OSTI ID:6180774

The investigation deals with the scaling effects that arise when the spread of cooling water is studied in a physical model with different horizontal and vertical length scale ratios. The investigation is limited to surface discharges under stationary conditions. Froude and Reynolds modelling practice is presumed. Different physical processes of importance are studied and the effects of distortion are evaluated. The analyses show that two-dimensional jet diffusion, buoyancy spread, and convective heat transport can, under certain conditions, be accurately reproduced in a distorted model. A three-dimensional nonbuoyant jet will, however, have a center-line excess temperature that is too great. For correct modelling of ambient diffusion special calibration is necessary. Analytical solutions to the spread of a buoyant surface jet indicate that the center-line excess temperature will be too great. Calculations using the Prych numerical model give similar results for discharges with high outlet densimetric Froude numbers but show also that a good agreement between model and prototype is achieved for discharges with a low densimetric Froude number. Analyses of laboratory experiments confirm these theoretical results. For a distortion of eight, the areas within isotherms can be as much as 4-6 times too great. If the receiving body of water is shallow, then a better agreement between the model and the prototype can be achieved. Model-prototype comparisons show that a good agreement between the model and the prototype often demands the model to be calibrated for ambient diffusion.

Research Organization:
Chalmers Tekniska Hoegskola, Goeteborg (Sweden). Dept. of Hydraulics
OSTI ID:
6180774
Report Number(s):
PB-287098
Country of Publication:
United States
Language:
English