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Title: Direct Contact Heat Exchange Interfacial Phenomena for Liquid Metal Reactors: Part II - Void Fraction

Conference ·
OSTI ID:21072829
; ; ; ;  [1]; ; ;  [2]
  1. University of Wisconsin-Madison, 1500 Engineering Drive, Madison, WI 53706 (United States)
  2. Argonne National Laboratory, 9700 S. Cass Avenue Argonne, IL 60439 (United States)

One concept being considered for steam generation in innovative nuclear reactor applications, involves water coming into direct contact with a circulating molten metal. The vigorous agitation of the two fluids, the direct liquid-liquid contact and the consequent large interfacial area can give rise to large heat transfer coefficients and rapid steam generation. For an optimum design of such direct contact heat exchange and vaporization systems, detailed knowledge is necessary of the various flow regimes, interfacial transport phenomena, heat transfer and operational stability. In order to investigate the interfacial transport phenomena, heat transfer and operational stability of direct liquid-liquid contact, a series of experiments are being performed in a 1-d test facility at Argonne National Laboratory and a 2-d experimental facility at UW-Madison. Each of the experimental facilities primarily consist of a liquid-metal melt chamber, heated test section (10 cm diameter tube for 1-d facility and 10 cm 50 cm rectangle for 2-d facility), water injection system and steam suppression tank. This paper is part II which, primarily addresses results and analysis of a set of preliminary experiments and void fraction measurements conducted in the 2-d facility at UW-Madison, part I deals with the heat transfer in the 1-d test facility at Argonne National Laboratory. A real-time high energy X-ray imaging system was developed and utilized to visualize the multiphase flow and measure line-average local void fractions, time-dependent void fraction distribution as well as estimates of the vapor bubble sizes and velocities. These measurements allowed us to determine the volumetric heat transfer coefficient and gain insight into the local heat transfer mechanisms. In this study, the images were captured at frame rates of 100 fps with spatial resolution of about 7 mm with a full-field view of a 15 cm square and five different positions along the test section height. The full-field average void fraction increases rapidly to about 15% in these preliminary tests, with the apparent boiling length of less than 20 cm. The volumetric heat transfer coefficient between the liquid metal and water are compared to the CRIEPI data, the only prior data for direct contact heat exchange for these liquid metal/water systems. (authors)

Research Organization:
The ASME Foundation, Inc., Three Park Avenue, New York, NY 10016-5990 (United States)
OSTI ID:
21072829
Resource Relation:
Conference: ICONE-10: 10. international conference on nuclear engineering, Arlington - Virginia (United States), 14-18 Apr 2002; Other Information: Country of input: France
Country of Publication:
United States
Language:
English