Foa 



thickness of the primary jet, and the secondary -flow entrainment during the de- 

 flection phase. 



4. Jet dissipation during the deflection phase has an adverse effect on per- 

 formance under all conditions (in the limit, if the two streams were to mix in- 

 stantly at merger, the performance of the bladeless propeller would be reduced 

 to that of the conventional ejector). 



5. The effect of mixing after the deflection phase can be favorable or un- 

 favorable, depending on the spin angle and the temperature ratio. 



6. An increase of coning angle can have a markedly beneficial effect on 

 performance. 



7. Marine applications of two-phase bladeless propellers appear to be very 

 promising. 



Further study is needed in several areas, including: 



(a) a means of inhibiting jet dissipation during the deflection phase; 



(b) the operation of bladeless propellers with large spin angles and/or 

 large area ratios; 



(c) the operation of bladeless propellers with large density ratios; 



(d) the operation of bladeless propellers at high forward speeds; 



(e) utilization of two -phase interactions, with a condensable or nonconden- 

 sable primary gas; 



(f) the determination of criteria for rotor and shroud contouring, the de- 

 sign of internal ducting, and the selection of primary orifice shapes; 



(g) utilization of rotating stall through a stationary cascade for the genera- 

 tion of cryptosteady interactions; and 



(h) optimization of thrust generators in which cryptosteady pressure ex- 

 change is compounded with other energy transfer mechanisms for the purpose 

 of augmentation. 



REFERENCES 



1. Johnson, J.K., Jr., Shumpert, P.K., and Sutton, J.F., "Steady-Flow Ejector 

 Research Program," Lockheed-Georgia Company ER-5332 (AD-263180), 

 Sept. 1961 



2. Lockwood, R.M., "Energy Transfer from an Intermittent Jet to an Ambient 

 Fluid," Hiller Aircraft Co., Summary Report ARD-238, 30 June 1959 



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