Gas-Turbine Powerplants For Two-Phase Hydropropulsion 



It is obviously impossible in such an analysis to take into account the ef- 

 fect of the external drag on the net thrust and on the efficiencies, and only quali- 

 tative considerations can be made about the additional drag induced by the pro- 

 pulsor and its appendages. Typical behavior of a is showed in Figs. 14 and 13 

 for a few values of /3p, while in Fig. 14 a is plotted against A A„. All these 

 functions have been calculated for exhaust gas and for ip = 0.9, as already men- 

 tioned. In Figs. 13 and 15, tho values of a^ for an underexpanded nozzle are 

 reported for /5p = (hydrojector). 



1.2 



o,e 



2.0 



00 



0.B 



12 



1.6 



2,6 



Fig. 14 - Variation of ct as a function of A^/A^ 

 for: (a) hydrojector (t3p=o) and water jet; 

 (b) pumpjector ( p = 2) ( ip = 0.9, a. p.) 



By means of the condition \-^ = the previous equations get solved for the 

 pure water jet. A plot of diagrams have been reported on Figs. 14, 16, 17, and 

 18 for the following data: = 0.9, ^ = 0.3, z„ = 1 m, zj = -3 m. In Fig. 19, 



1129 



