Velocity Measurement of Viscoelastic Flow through a T-Shaped Junction with a Laser Doppler Velocimeter

Abstract

The velocity was measured at a T shaped channel by means of a laser doppler velocimeter. Fluids used for the investigation were water as a Newtonian fluid and polymer (PAA and HEC) solutions as a viscoelastic fluid.
A circulating secondary flow at the upstream side of a T-shaped corner was ascertained as a flowing upstream for the viscoelastic polymer flow. The velocity distribution of the viscoelastic flow was similar to that of the Newtonian flow at the low flow rate, but as increasing the flow rate and developing the circulating secondary flow, the characteristics of viscoelastic flow appeared at the juncnon. At the higher flow rate the velocity distribution reached a fixed shape, and a periodic oscillation of the local flow rate was observed near the junction.