Particle Sampling with Supersonic Probes. Similitude and Particle Breakup
Final rept. 21 Jun-10 Sep 1982
ARNOLD ENGINEERING DEVELOPMENT CENTER ARNOLD AFB TN
Pagination or Media Count:
The problems encountered in sampling the exhaust flow from a solid propellant rocket motor being tested at simulated altitude are examined. Characteristics of the flow field, shock detachment, and particle trajectories are discussed for a cylindrical, supersonic particle probe. The form of the scaling law for probe collection efficiency is suggested for both Stokesian and non-Stokesian particles from the normalized equation of particle motion and simple expressions for the particle drag coefficient. Conditions for the onset of particle breakup in normal shock waves were investigated. A normalized particle drag behind the shock was determined in terms of gas stagnation conditions and particle diameter for a range of gas Mach numbers between 1 and 5 by including appropriately defined particle Knudsen and Reynolds numbers in analytical expressions for the drag coefficient. Numerical computations of the particle drat, normalized with gas stagnation pressure and particle area, indicate a peak at a gas Mach number of about 2.2. The magnitude of the peak was found to decrease with increasing particle diameter and reservoir gas density.
- Test Facilities, Equipment and Methods
- Combustion and Ignition
- Solid Rocket Propellants