ABSTRACT
Studies have been performed on the exchange flow of two fluids with different densities through vertical short tubes. Epstein[5] studied the exchange flow of water and brine through various vertical tubes, experimentally and theoretically. Mercer et al. [6] studied an exchange flow through inclined tubes with water and brine experimentally. The latter experiments were carried out in the range of 3.5 <L/D < 18 and 0 deg < θ < 90 deg, and indicated that the lengthtodiameter ratio L/D, and the inclination angle θ of the tube are the important parameters for the exchange flow rate. Most of these studies were performed on the exchange flow using a relatively small difference in the densities of the two fluids (up to 10 per cent). However, in the case of a HTGR standpipe rupture, the density of the outside gas is at least three times larger than that of the gas inside the pressure vessel. Few studies have been performed so far using such a large density difference. Kang et al. [7] studied experimentally the exchange flow through a round tube with a partition plate. Although one may assume that the partitioned plate, a kind of obstacle in the tube, would reduce the exchange flow rate, Kang found that the exchange flow rate was increased by the partition plate because of separa tion of the upward and downward flows.
