Abstract

The study is performed to analyze the effects of heat up rate on thermal stratification phenomenon in pressurizer surge line. The horizontal section of pressurizer surge line is considered for this study since significant thermal stratification is usually observed in horizontal sections of the pressurizer surge line. The tendency of thermal stratification reduces with increasing flow rates based on which four cases of heat up rates with increasing flow velocities are analyzed. The selected flow velocities of 0.01, 0.05, 0.1 and 0.2 m/sec for the study are calculated from the operating range of dimensionless Froude number 0.02-0.2 of pressurized water reactor type nuclear power plants. The horizontal pipe model inner diameter is 305 mm with thickness of 33.5 mm and length of four diameters. The Richardson number for the four cases is greater than unity and thermal stratification is likely to occur. The transient analysis is performed using commercially available software ANSYS CFX. The transient temperature distribution along the horizontal pipe wall with different heat up rates is represented in this study. Thermal stratification reduces with increase in heat up rate or flow velocity.

Keywords:

Pressurizer surge line, reactor heat up rate, RNG K-Eturbulence model, thermel stratification,

References

Competing interests

The authors have no competing interests.

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The authors have no competing interests.