Abstract
The present paper is a progress report on the development of a linear cascade of turbine blades- for the experimental study of aerodynamic effects associated with film cooling. Primary interest is in the mixing of the coolant ejected from the blade with the mainstream. The cascade dimensions are large to provide Tnqyiirmm spatial resolution. The row contains four blades with 5.530 in (14.046 cm) axial chord and 6.912 in (17.557 cm) span. Nominal flow total turning angle is 130.6 degrees. Exit Mach number range is 0.8-1.35 and Reynolds numbers range from 1 to 2 millions (based on passage throat dimension and inlet total conditions). A coolant supply system is developed to simulate coolant/mainstream density ratios up to 2, using mixtures of air and sulfur hexafluoride (SF6). A full-perimeter bleed slot upstream of the blades is used to remove the approach boundary layers from all four walls. Adjustable tailboards are used, with perforations and suction to minimize wave reflections. The tailboards are remotely adjustable to set the exit flow angle as appropriate for the imposed pressure ratio. A three-prong wake probe will be used to determine the distributions of five flow properties in the exit region. The probe actuator design offers continuous streamwise and transverse positioning during run while retaining full optical access through endwall windows. The shock system terminating the supersonic exit flow is positioned downstream of the probe to avoid problems caused by dynamic loads. A blow-down air supply system provides run times up to four minutes at maximum flow rate.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call