510 



HYDKAULICS AND ITS APPLICATIONS 



hydraulic resistances in each chamber will be less than in the single 

 chamber of the larger wheel. 



Since, however, these losses are duplicated in each successive chamber, 

 and since in addition there is a loss of head due to the resistance of the 

 connecting passages, it is not to be expected that the efficiency of the 

 compound will be so high as that of the single chamber turbine. 



Experiments carried out by the author on a small inward radial flow 



To Regulator 



FIG. 242. General Arrangement of Twin Mixed-Flow Turbine with Horizontal Shaft. 



and axial discharge turbine fitted with four similar runners in series, and 

 which could also be worked as a single turbine, showed that for this machine 

 at all events this conclusion is correct. Fig. 241 shows the efficiency curves 

 obtained from the two turbines ; A when working with a single runner ; 

 B with four runners in series, under approximately the same head. 

 Here the outer diameter of the runner = 3'35 inches. 

 inner (mean) = 1*675 



raaial at inlet. 



Head = (approx.) 85 feet. 



