311Laminar boundary layer flow on the tipendwall

The boundary layer is measured at flow measurement planel (X/Cx = —1.6). The mainstream velocity is 2.7m/s with a low turbulence intensity of 0.2%. As mentioned by Wang (1997) and shown by following results, the flow is laminar even with the trip wire placed upstream.

As plotted in fig. 3.1, the boundary layer flow on the tip-endwall is clearly laminar: the velocity profile shown in the upper figure is less steeper close to the wall and the velocity distribution in terms of the wall coordinates obviously follows the velocity profile of the sublayer (lower figure). The boundary layer displacement thickness at the point of measurement is 0.55cm with a shape factor of 2.32. The mainstream Reynolds number based on the blade chord and exit velocity is 7.0 x 104.

0 0

Post a comment