EFFECT OF SECONDARY FLOW ON HEAT TRANSFER OVER A GUIDE VANE SUCTION SIDE

摘要

An accurate design of a guide vane has become a major issue in gas turbine engineering since secondary flow in vane cascade has a significant effect on the end wall and airfoil suction surfaces. Heat transfer and average flow measurements were performed in a linear guide vane cascade consisting of five gas turbine vanes. All measurements were taken on the suction surface of the middle (third) airfoil. The height-to-pitch ratio H/S was varied from 1.0 to 0.17, the inlet boundary layer thickness δ_(in) was either 2 mm or 10 mm. The vortex structures influence the average flow parameters, the laminar-to-turbulence transition, and the local heat transfer. This is especially pronounced in the area close to the end wall area. The inlet flow temperature non-uniformity has no influence on the heat transfer, however local flow temperature 'spikes' were registered at x-bar = 0.6 due to the flow enthalpy migration in the span-wise direction. A few useful correlations are suggested as a result of the experimental data processing.