Combustion Species Sampling
Abstract
A combustion chamber for propellant studies was developed and molecular beam gas sampling systems were analyzed in this program. A unique laboratory combustor design provides sampling from any part of the chamber by axial movement of a gas extraction port while the engine operates at pressures up to 500 psia. Variable chamber volume is also possible during operation. Sealing of moving pistons is accomplished by metal piston rings and elastomeric o-rings. Hot firings of the combustor with chlorine pentafluoride and hydrazine were made to demonstrate the operation of all components. The most severe test was of sixty seconds duration at chamber pressure of 455 psia with adiabatic flame temperature in excess of 4000 deg K. In another part of the program, an existing gas sampling probe was examined to determine its effectiveness in transferring combustion species to a mass spectrometer. A capillary quenching channel in the sampling probe cools combustion gases from 4000 deg K to 1200 deg K but allows all dissociated species (in the case of hydrazine/chlorine pentafluoride) to recombine. At the exit of this channel, an unconfined free jet forms a typical underexpanded exhaust plume and the combustion sample undergoes several successive cycles of expansion cooling, shock reheating and dilution by background gases. Skimmer locations and chamber pressures were examined for suitable molecular beam formation.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1968
- Accession Number
- AD0841178
Entities
People
- Jack Kahrs