Experimental study on thermal mixing related to eddy structure in T-junction

This paper deals with the experimental investigation of thermal striping phenomena in a T-junction piping system as the typical part where influential temperature fluctuation in structural integrity may be induced by the thermal mixing. In this study, a simplified T-junction piping system consisting of a rectangular duct for main stream and a circular pipe for branch stream was used as the test section in the water experiment. Time series of instantaneous two-dimensional velocity fields were obtained by PIV (Particle Image Velocimetry) in the mixing area. And fluid temperature fluctuations at several positions at 2mm inside from the wall were also measured by thermo-couples. Focusing on the frequency characteristics, formation of eddy structure in the mixing area and mutual relation between the temperature fluctuation generation and the flow structure were discussed. (author)