An Experimental Investigation of the Flow in an Interstage Connecting Duct for Use on a High Power Gasdynamic Laser. II. Mass Spectrometer and Pressure Measurements.

摘要

A model of a duct used to optically connect to high-power gasdynamic lasers was tested employing the USAF Academy trisonic wind tunnel. The wind tunnel was used as the cold flow simulation of the laser operating at a Mach number of 4.38 and test section static pressures of 0.5 to 0.8 psia and a mock-up of one half of the laser duct was attached to the wind tunnel test section. Mass spectrometer analysis of the flow composition at two locations resulted in the determination of the power mass flow rate out of the duct necessary to keep it free of wind tunnel gas. Helium, nitrogen and argon were tested as purge gases. The similarity parameter used to relate the wind tunnel tests to the actual laser conditions was found to be dependent upon the type of purge gas. Shear-layer stability is thought to account for this discrepancy. Pressure measurements revealed no sharp disturbances during purging.