Momentum Flux Measurements from Under Expanded Orifices: Applications for Micropropulsion Systems
Abstract
The popularity of micropropulsion system development has led to renewed interest in the determination of propulsive properties of orifice flows since micronozzle expansions ma suffer high viscous losses at low pressure operation. The mass flow and relative thrust through an underexpanded orifice is measured as a function of orifice stagnation pressure from 0.1 to 3.5 Torr. Nitrogen, argon, and helium propellant gases are passed through a 1.0 mm diameter orifice with a wall thickness of 0.015 mm. Near-free molecule, transitional and continuum flow regimes are studied. The relative thrust is determined by measuring the displacement of a novel thrust stand designed primarily for low operating pressure propulsion systems. It is shown that the thrust stand deflection is a function of the facility background pressure, and corrections are made to determine the deflection for a zero background pressure for a nitrogen propellant.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 11, 2001
- Accession Number
- ADA410837
Entities
People
- Amanda A. Green
- Andrew D. Ketsdever
- E. P. Muntz
Organizations
- Air Force Research Laboratory