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Annals of the Assembly for International Heat Transfer Conference 13

ISBN 1-56700-225-0 / CD 1-56700-226-9

Volumes per year:

various

Year 2006

DOI: 10.1615/IHTC13.p7

HEAT TRANSFER TO WATER THROUGH THE CRITICAL POINT

J. Licht
University of Wisconsin-Madison, Wisconsin, USA

P. Allex
University of Wisconsin-Madison, Wisconsin, USA

M. Anderson
University of Wisconsin-Madison, Wisconsin, USA

ABSTRACT

In order to improve the efficiency of current light water reactors (LWR's), the Generation IV initiative has included the supercritical water reactor (SCW) as one of the next steps in future nuclear reactors. Associated with this reactor concept are several areas of fundamental research that require further study. Existing models and correlations, such as the Dittus-Boelter heat transfer correlation, cannot capture heat transfer degradation observed in previous experiments. The University of Wisconsin has built a SCW heat transfer facility to further study heat transfer at supercritical conditions. The SCW heat transfer facility is capable of operating at mass velocities of 200 to 4000 kg/m²s, heat fluxes up to 1.5 MW/m², and temperatures of up to 550 °C at 25MPa. The test section is equipped with a 1.07 cm diameter heater rod in a circular or square flow channel. The square flow annulus test section utilizes two sapphire windows to provide optical access specifically designed for Laser Doppler Velocimetry (LDV), Particle Image Velocimetry (PIV), and Raman scattering measurements. This paper focuses on the progress of heat transfer measurements in the circular annulus test section along with the Raman scattering technique being developed for single point density measurements. The first series of heat transfer experiments have been performed at bulk water temperatures of 300 and 370 °C with constant mass flux and variable heat flux. An additional experiment was performed with a bulk temperature of 370 °C with a constant heat flux and variable mass flux. The Dittus-Boelter correlation and inverse Froude number criterion are compared with experimental results. In parallel to the heat transfer measurements, the application of an optical method called Raman scattering is being developed to obtain density measurements within the flow.