Measurement of Flow Velocity and Turbulence in a Helically Curved Pipe

The experimental study on the flow through helically curved pipes of a circular cross-section is carried out to measure the average velocity distributions, the stability characteristics of the flow, the state of turbulence in the transition and fully developed regions, and the Reynolds stress using a X-type hot-wire anemometer for the range of the Reynolds number from 440 to 20 850. Three types of helical pipes with different pitches are used, that is, the non-dimensional pitch are taken to be 0.009, 0.203 and 0.503, while the non-dimensional curvatures are about the same value of 0.1 for three pipes. It is found that the torsion strongly affects the average axial velocity and unsteady characteristics of the flow.