Spacer Effect Model for Subchannel Analysis -Turbulence Intensity Enhancement due to Spacer-
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Mean velocity and velocity fluctuation in a test channel that consisted of five subchannels with and without ferrule-type spacer were measured using air as a working fluid, to clear turbulence intensity enhancement due to spacer. Measurements were performed at Reynolds number of 0.5-1.2×10<SUP>5</SUP>, which simulated vapor flow velocity of annular-dispersed flow in BWR condition. It was confirmed that magnitudes of velocity fluctuations in radial direction were proportional to Reynolds number and square root of friction factor downstream from a spacer. New spacer effect model to describe turbulence intensity enhancement due to the spacers was developed. In the model, dependence of the velocity fluctuation on ferrule thickness was correlated by blockage ratio. It was found that the present spacer model is applicable to prediction of turbulence intensity enhancement due to spacer.
- Journal of Nuclear Science and Technology
Journal of Nuclear Science and Technology 35(6), 399-405, 1998-06-25
Atomic Energy Society of Japan