Experimental study on flow-induced vibration and heat transfer characteristics of heat exchanger with helically coiled tube bundles

An experimental study was carried out to investigate flow-induced vibration, heat transfer and pressure drop of helically coiled tube bundles of an intermediate heat exchanger (IHX) for the HTTR, using a full-size partial model and air as a testing fluid. The test model has 54 helically coiled tubes separated into three layer bundles, surrounding the center pipe. The vibration behavior in the fluid was investigated focussing on vortex-induced and fluidelastic vibrations which are main ones to cause failure of tubes. The vibration of the tube bundles was mainly at the center pipe, and their vibration amplitude was less than 0.1 mm. As the results, it was clarified that individual vibrations of the tube bundles were not significant under the operation conditions of the IHX. The Nusselt number of the tube outside, due to forced convection, was obtained as a function of Re0.56, and the drag coefficient was proportional to Re-0.14. Furthermore, effect of radiative plates on heat transfer was clarified. (author)