Heat transfer and pressure loss for decaying swirl flow in a pipe

Abstract

Transient heat transfer of decaying swirl flow in a circular pipe was investigated by the technique using a high-speed infrared thermograph. The flow was swirled by a twisted tape upstream of the test section, and the heat transfer of the decaying swirl flow was measured using a test pipe composed by a heated thin foil. The Reynolds number was ranged between 1000 and 12000. It was confirmed that when the flow was swirled, heat transfer was enhanced at the same pump power in the Reynolds number range examined here. In particular, the enhancement was confirmed in the transition regime between laminar and turbulent (Re = 1600～3400), being about 40%.