Low-speed cascade investigation of compressor blades having loaded leading edges

James C. Emery
naca-tn-4178
Jan 1958


Six-percent-thick NACA 63-series compressor-blade sections having a loaded-leading-edge A-sub-4 k-sub-6 mean line have been investigated systematically in a two-dimensional porous-wall cascade over a range of Reynolds number from 160,000 to 385,000. Blades cambered to have isolated-airfoil lift coefficients of 0.6, 1.2, 1.8, and 2.4 were tested over the usable angle-of-attack range at inlet-air angles of 30 degrees, 45 degrees, and 60 degrees and solidities of 1.0 and 1.5. A comparison with data of NACA Technical Note 3916 shows that the angle-of-attack operating range is 2 degrees to 6 degrees less than the range for the uniformly loaded section; howewer, the wake losses near design angle of attack are slightly lower than those for the uniformly loaded section. Except for highly cambered blades at high inlet angles, the NACA 63-(C-sub-l-sub-o A-sub-4 K-sub-6)06 compressor blade sections are capable of more efficient operation for moderate-speed subsonic compressors at design angle of attack than are the NACA 65-(c-sub-l-sub-o A-sub-10)10 or the NACA 65-(C-sub-l-sub-o A-sub-2 I-sub-8-sub-b)10 compressor-blade sections, where C-sub-l-sub-o in the designation is the design lift coefficient of the isolated airfoil. In contrast with the other sections, the loaded-leading-edge sections are capable of operating at the lower Reynolds numbers.

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