EFFECT OF MACH NUMBER ON THE FLOW AND APPLICATION OF COMPRESSIBILITY CORRECTIONS IN A TWO-DIMENSIONAL SUBSONIC-TRANSONIC COMPRESSOR CASCADE HAVING VARIED POROUS-WALL SUCTION AT THE BLADE TIPS

摘要

A cascade of 65-(l2)l0 compressor blades was tested at one geo-metric setting over a range of inlet Mach number from 0.12 to 0.89. Two groups of data are presented and compared:the first from the cas¬cade operating conventionally with no boundary-layer control, and the second with the boundary layer controlled by a combination of upstream slot suction and porous-wall suction at the blade tips. A criterion for two-dimensionality was used to specify the degree of boundary-layer control by suction to be applied. The data are presented and an anal¬ysis is made to show the effect of Mach number on turning angle, blade wake, pressure distribution about the blade profile, and static-pressure rise. The influence of boundary-layer control on these param¬eters as well as on the secondary losses is illustrated. A system of correlating the measured static-pressure rise through the cascade with the theoretical isentropic values is presented which gives good agree¬ment with the data. The pressure distribution about the blade profile for an inlet Mach number of 0.21 is corrected with the Prandtl-Glauert, Karman-Tsien, and vector-mean velocity - contraction coefficient com¬pressibility correction factors to inlet Mach numbers of 0.6 and 0.7. The resulting curves are compared with the experimental pressure dis¬tributions for inlet Mach numbers of 0.6 and 0.7 so that the validity of applying the three corrections can be evaluated.