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ISSN Online: 2377-424X

ISBN Print: 1-56032-797-9

International Heat Transfer Conference 11
August, 23-28, 1998, Kyongju, Korea

EXPERIMENTAL STUDY ON FLOW RATE MEASUREMENT OF HELIUM-AIR EXCHANGE FLOW

Get access (open in a dialog) DOI: 10.1615/IHTC11.1680
pages 279-285

摘要

This paper describes an experimental study of buoyancy-driven exchange flow of helium and air through small openings. Such exchange flows may occur following rupture accident of standpipe in high temperature engineering test reactor (HTTR). A test vessel with three types of the small opening on top of test cylinder is used for experiments. An estimation method of mass increment is developed and applied to measure the exchange flow rate. In the first part of the study, flow measurements are made with single opening and partitioned opening to compare exchange flow rates, for opening ratios H1/D1 in the range 0.05 to 10, where H1 and D1 are height and diameter of the opening, respectively. At lower opening ratios (H1/D1<0.75), difference in the exchange flow rates between the single opening system and the partitioned opening system is small. The Froude numbers fluctuate at H1/D1 of 0.75 in the partitioned opening system. At higher opening ratios (H1/D1>0.75), exchange flow rates of the partitioned opening system are higher than those of the single opening system. Three flow regimes of the partitioned opening system are divided based on the above experimental results: (1) unseparated flow regime (H1/D1<0.75), (2) transition flow regime (H1/D1=0.75), (3) separated flow regime (H1/D1>0.75). In the second part of the study, effect of the variation of diameters of the partitioned openings on the exchange flow rate is investigated in separated flow regime (H1/D1>0.75). The diameters of the opening are 0.01, 0.02 and 0.04 m, and the opening ratios are 2 and 10. The exchange flow rate increases with increasing the opening diameter. The third part of the study is an experiment of the exchange flow with two-opening system and it is designed to investigate effect of fluids interaction of the partitioned opening system. As a result of comparison of the exchange flow rates between the two types of opening system, it is demonstrated that exchange flow rate of the two-opening system is higher than that of the partitioned opening system because of absence of the fluids interaction.