Compressible Flow Wind Tunnel

The Lockheed Martin Compressible Flow Wind Tunnel (CFWT) is a blowdown transonic wind tunnel designed as a versatile research facility for economical test operations. The facility has been in operation since 1970 and has conducted a wide variety of test programs for numerous customers. The test section is 20 inches wide by 28 inches high by 72 inches long and can be configured for a variety of test requirements. For two-dimensional testing, solid sidewalls are used with variable porosity top and bottom walls. A solid reflection plane floor with tunnel boundary layer bleed is used in conjunction with variable porosity side and top walls for semi-span testing. A sting support system is used with all four variable porosity walls for complete model testing. The variable porosity walls have inclined holes and the open area can be varied from near zero to 11-percent to minimize wall interference. Additional test section walls are available for special test applications.

The Mach number range with a sonic nozzle is 0.2 to 1.1, and nozzle blocks are available for M=1.5 and M=2.0. With the sonic nozzle, Reynolds numbers from normal wind tunnel values to flight values are available by varying stagnation pressure from 20 to 175 psia, e.g., at M=0.8, the range of Reynolds number per foot is approximately 5 million to 50 million.

The air storage for the facility is in four tanks totaling 18,000 cubic feet. Storage is accomplished to 300 psi using the Low Speed Wind Tunnel multi-stage compressor, and pressure recovery is approximately 20 pounds per second. The system is designed for operation at 525 psi storage, and boost from 300 to 525 psi is accomplished using a diesel-driven compressor having an output of about 2.5 pounds per second. A passive heat mass is installed in the tanks to minimize temperature drops during a run.

On site computers control start-up sequence, Mach number stabilization, Mach control, data acquisition and reduction. Immediately after the run is completed, fully reduced data is available in tabular and plotted formats.