JET SPREADING CHARACTERISTICS AT PRESSURE ALTITUDES OF 180,000 TO 260, 000 FEET
ARNOLD ENGINEERING DEVELOPMENT CENTER ARNOLD AFB TN
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An investigation was conducted to determine the effects of certain parameters on the spreading characteristics of a jet discharging from conical underexpanded nozzles into a quiescent atmosphere. Tests were conducted in low pressure chambers using both nitrogen and carbon dioxide as the nozzle fluid. Flow visualization enabling the expanding jet to be photographed was accomplished by a glow discharge technique. Boundaries are presented for 7.5, 25.3, and 45.7 area ratio nozzles having 15-deg half-angle conical divergence. The experimental boundaries are presented and compared with contours calculated by the method-of-characteristics. Jet boundaries obtained using nitrogen as the nozzle fluid compare favorably with the theoretical boundaries. The boundaries obtained with carbon dioxide nozzle flow were expanded much more than predicted by the method-of-characteristics because of condensation in the jet.
- Fluid Mechanics