Gas-Turbine Powerplants For Two-Phase Hydropropulsion 



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Fig. Z4 - Water-jet powerplants 



two kinds of advantages: (a) higher effect of the volume ratio \i at same 



mass ratio e [as shown, the propulsive performances (cr, 



a/Aq, etc.) 



are increasing functions of k^ ; therefore an improvement of the performances 

 could be expected when hot instead of cold gas is usedj, and (b) an improve- 

 ment of the overall efficiency could also be expected when the gas was ex- 

 tracted from the turbine after partial expansion, because of the net work con- 

 tribution given to the mechanical balance. 



Therefore it seemed reasonable to analyze: (a) a conventional turbine 

 with several possible points of gas extraction, and (b) a bypass turbine (or 

 turbocompressor) to yield either cold compressed air or hot compressed gas 

 (this being produced by secondary or auxiliary gas burner). The analysis of a 

 cold-air ejector was introduced for sake of comparison, since this scheme 

 corresponds to the Marjet propulsor, which has already been mentioned (Refs. 

 [8,15,16J). 



