Investigation of Performance Parameters of a Mass Spectrometer Sampling Probe in Rarefied Flows

摘要

The basic design parameters of a mass spectrometer sampling probe to be used in the investigation of highly expanded rocket motor exhaust plumes were investigated. The primary design considerations were determined to be large internal pumping capacity, skimmer interaction with the flow field, and test chamber performance. The scattering phenomena encountered in the operation of such a device were investigated. The position at which background pressure is measured was found to have significant effect on the value of the scattering parameter proposed by Fenn and Anderson. The scattering phenomena were investigated at several source skimmer separation distances and at various source conditions along the expansion centerline. Velocity distribution measurements in the rarefied flow regime were made. The speed ratio was unaffected until the transition regime was reached. (Author)