(The agency's name changed from NACA - Nat. Advisory Cttee for Aeronautics - in 1958.) There are NASA Web sites for both the Langley tunnel (test section 7.5 ft high, 3 ft wide, 12 atm. max.) and the Ames tunnel (test section 12 ft., dia., 6 atm. max.). The Ames tunnel has been refurbished recently and now has a heat exchanger in the settling chamber, like the Langley tunnel. There is also a NASA Web site describing the wind tunnels and gas turbine test equipment at Glenn (formerly Lewis) Research Center.
Links to component descriptions: fans and blowers, diffusers, screens and honeycombs, contractions, corners.