On positional effect of flexible tubes in a square array subjected to freon two-phase flow

摘要

Recently published papers suggest that there is a great difference between the critical flow-velocity of a flexible tube in triangular tube-arrays and that of all flexible tubes i nthe same arrays when the fluid is Freon two-phase flow. In this paper, the effect of the position and the number of flexible tubes in a square tube-array as opposed to a triangular array are examined with a small test model in Freon two-phase flow loop. The test results show that there is a slight difference in the instability boundary among test cases including a single flexible tube and the fully flexible array. However, this differnece can be decreased when the measured flow velocity around the flexible tube is introduced. As a result, the critical flow velcoity caused by Freon two-phase is only slightly affected by the tube flexibility in the square array.